Add a convenient entry point to test and work on the image serialization code

imaging is now panic safe. Also format nested panics a bit better.

README.asciidoc

@@ -1,5 +1,7 @@
 = kitty - the fast, feature-rich, cross-platform, GPU based terminal
 
+If you live in the terminal, *kitty* is made for **you**!
+
 See https://sw.kovidgoyal.net/kitty/[the kitty website].
 
 image:https://github.com/kovidgoyal/kitty/workflows/CI/badge.svg["Build status", link="https://github.com/kovidgoyal/kitty/actions?query=workflow%3ACI"]

bypy/sources.json

@@ -30,10 +30,10 @@
     },
 
     {
-        "name": "openssl 3.5.2",
+        "name": "openssl 3.5.4",
         "unix": {
             "file_extension": "tar.gz",
-            "hash": "sha256:c53a47e5e441c930c3928cf7bf6fb00e5d129b630e0aa873b08258656e7345ec",
+            "hash": "sha256:967311f84955316969bdb1d8d4b983718ef42338639c621ec4c34fddef355e99",
             "urls": ["https://www.openssl.org/source/{filename}"]
         }
     },

docs/changelog.rst

@@ -134,6 +134,29 @@ consumption to do the same tasks.
 Detailed list of changes
 -------------------------------------
 
+0.43.2 [future]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Allow kitty to read a specified set of environment variables from your
+  login shell at startup using the :opt:`env` directive in kitty.conf
+  (:iss:`9042`)
+
+- Fix a regression in 0.43.0 that caused a black flicker when closing a tab in
+  the presence of a background image (:iss:`9060`)
+
+- Splits layout: Fix a bug that could cause a corrupted layout in some
+  circumstances (:iss:`9059`)
+
+- Fix a regression in the previous release that broke ``goto_session -1``
+
+- Fix rendering broken on ancient GPU drivers that do not support rendering to 16 bit textures (:iss:`9068`)
+
+- Fix tab bar sometimes showing incorrect tabs when it is filtered to show only
+  tabs from the current session (:iss:`9079`)
+
+- macOS: Workaround for bug in macOS Tahoe that caused OS Windows that are
+  fullscreen to crash kitty when returning from sleep on some machines (:iss:`8983`)
+
 0.43.1 [2025-10-01]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

docs/faq.rst

@@ -480,6 +480,16 @@ related to localization, such as :envvar:`LANG`, ``LC_*`` and loading of
 configuration files such as ``XDG_*``, :envvar:`KITTY_CONFIG_DIRECTORY` and,
 most importantly, ``PATH`` to locate binaries.
 
+The simplest way to fix this is to have kitty load the environment variables
+from your shell configuration at startup using the :opt:`env` directive,
+adding the following to :file:`kitty.conf`::
+
+    env read_from_shell=PATH LANG LC_* XDG_* EDITOR VISUAL
+
+This works for POSIX compliant shells and the fish shell. Note that it
+does add significantly to kitty startup time, so use only if really necessary.
+This feature was added in version ``0.43.2``.
+
 To see the environment variables that kitty sees, you can add the following
 mapping to :file:`kitty.conf`::
 

docs/index.rst

@@ -1,7 +1,9 @@
 kitty
 ==========================================================
 
-*The fast, feature-rich, GPU based terminal emulator*
+*If you live in the terminal, kitty is made for YOU!*
+
+The fast, feature-rich, GPU based terminal emulator.
 
 .. toctree::
     :hidden:
@@ -20,7 +22,7 @@ kitty
 
 .. tab:: Fast
 
-   * Uses GPU and SIMD vector CPU instructions for :doc:`best in class <performance>`
+   * Uses GPU and SIMD vector CPU instructions for :doc:`best in class performance <performance>`
    * Uses threaded rendering for :iss:`absolutely minimal latency <2701#issuecomment-636497270>`
    * Performance tradeoffs can be :ref:`tuned <conf-kitty-performance>`
 

docs/kittens/custom.rst

@@ -122,9 +122,9 @@ the table below:
 .. table:: Types of input to kittens
     :align: left
 
-    =========================== =======================================================================================================
+    =========================== ========================================================================================
     Keyword                     Type of :file:`STDIN` input
-    =========================== =======================================================================================================
+    =========================== ========================================================================================
     ``text``                    Plain text of active window
     ``ansi``                    Formatted text of active window
     ``screen``                  Plain text of active window with line wrap markers
@@ -141,7 +141,7 @@ the table below:
     ``output-screen-ansi``      Formatted text of the output from the last run command with wrap markers
 
     ``selection``               The text currently selected with the mouse
-    =========================== =======================================================================================================
+    =========================== ========================================================================================
 
 In addition to ``output``, that gets the output of the last run command,
 ``last_visited_output`` gives the output of the command last jumped to
@@ -298,107 +298,6 @@ So if you run kitty from another kitty instance, the output will be visible
 in the first kitty instance.
 
 
-Adding options to kittens
-----------------------------
-
-If you would like to use kitty's config framework to make your kittens
-configurable, you will need some boilerplate. Put the following files in the
-directory of your kitten.
-
-:file:`kitten_options_definition.py`
-
-.. code-block:: python
-
-    from kitty.conf.types import Action, Definition
-
-    definition = Definition(
-        '!kitten_options_utils',
-        Action(
-            'map', 'parse_map',
-            {'key_definitions': 'kitty.conf.utils.KittensKeyMap'},
-            ['kitty.types.ParsedShortcut', 'kitty.conf.utils.KeyAction']
-        ),
-    )
-
-    agr = definition.add_group
-    egr = definition.end_group
-    opt = definition.add_option
-    map = definition.add_map
-
-    # main options {{{
-    agr('main', 'Main')
-
-    opt('some_option', '33',
-        option_type='some_option_parser',
-        long_text='''
-    Help text for this option
-    '''
-        )
-    egr()  # }}}
-
-    # shortcuts {{{
-    agr('shortcuts', 'Keyboard shortcuts')
-
-    map('Quit', 'quit q quit')
-    egr()  # }}}
-
-
-:file:`kitten_options_utils.py`
-
-.. code-block:: python
-
-    from kitty.conf.utils import KittensKeyDefinition, key_func, parse_kittens_key
-
-    func_with_args, args_funcs = key_func()
-    FuncArgsType = Tuple[str, Sequence[Any]]
-
-    def some_option_parser(val: str) -> int:
-        return int(val) + 3000
-
-    def parse_map(val: str) -> Iterable[KittensKeyDefinition]:
-        x = parse_kittens_key(val, args_funcs)
-        if x is not None:
-            yield x
-
-Then run::
-
-    kitty +runpy 'from kitty.conf.generate import main; main()' /path/to/kitten_options_definition.py
-
-You can parse and read the options in your kitten using the following code:
-
-.. code-block:: python
-
-    from .kitten_options_types import Options, defaults
-    from kitty.conf.utils import load_config as _load_config, parse_config_base
-    from typing import Optional, Iterable, Dict, Any
-
-    def load_config(*paths: str, overrides: Optional[Iterable[str]] = None) -> Options:
-        from .kitten_options_parse import  (
-            create_result_dict, merge_result_dicts, parse_conf_item
-        )
-
-        def parse_config(lines: Iterable[str]) -> Dict[str, Any]:
-            ans: Dict[str, Any] = create_result_dict()
-            parse_config_base(
-                lines,
-                parse_conf_item,
-                ans,
-            )
-            return ans
-
-        overrides = tuple(overrides) if overrides is not None else ()
-        opts_dict, found_paths = _load_config(defaults, parse_config, merge_result_dicts, *paths, overrides=overrides)
-        opts = Options(opts_dict)
-        opts.config_paths = found_paths
-        opts.all_config_paths = paths
-        opts.config_overrides = overrides
-        return opts
-
-See `the code <https://github.com/kovidgoyal/kitty/tree/master/kittens/diff>`__
-for the builtin :doc:`diff kitten </kittens/diff>` for examples of creating more
-options and keyboard shortcuts.
-
-
 Developing builtin kittens for inclusion with kitty
 ----------------------------------------------------------
 

docs/mapping.rst

@@ -230,6 +230,15 @@ copying to clipboard. In the editor, you can map it to copy to the clipboard,
 thereby allowing use of a common shortcut both inside and outside the editor
 for copying to clipboard.
 
+.. note::
+
+   When using multi-key mappings, of the form :kbd:`k1>k2` or similar, the
+   condition applies to the first key and you can have only one condition per
+   key, the last in kitty.conf wins. In particular, this means you cannot have
+   multiple conditions applying to multi-key mappings with the same first key
+   and you cannot have mappings with and without conditions applying to multi-keys
+   with the same first key.
+
 Sending arbitrary text or keys to the program running in kitty
 --------------------------------------------------------------------------------
 

docs/remote-control.rst

@@ -262,6 +262,12 @@ as shown below:
         return True
 
 
+.. note::
+
+    The payloads for the different remote control commands are documented in the
+    :doc:`remote control protocol specification <rc_protocol>`.
+
+
 .. _rc_mapping:
 
 Mapping key presses to remote control commands

embeds.go

@@ -8,6 +8,9 @@ import (
 
 var _ = fmt.Print
 
+//go:embed logo/kitty.png
+var KittyLogoAsPNGData []byte
+
 //go:embed kitty_tests/GraphemeBreakTest.json
 var grapheme_break_test_data []byte
 

gen/go_code.py

@@ -661,7 +661,7 @@ var QueryNames = []string{{ {query_names} }}
 var CommentedOutDefaultConfig = "{serialize_as_go_string(commented_out_default_config())}"
 var KittyConfigDefaults = struct {{
 Term, Shell_integration, Select_by_word_characters, Url_excluded_characters, Shell string
-Wheel_scroll_multiplier int
+Wheel_scroll_multiplier float64
 Url_prefixes []string
 }}{{
 Term: "{Options.term}", Shell_integration: "{' '.join(Options.shell_integration)}", Url_prefixes: []string{{ {url_prefixes} }},

glfw/cocoa_platform.h

@@ -138,6 +138,7 @@ typedef struct _GLFWwindowNS
     int             fbWidth, fbHeight;
     float           xscale, yscale;
     int             blur_radius;
+    bool live_resize_in_progress;
 
     // The total sum of the distances the cursor has been warped
     // since the last cursor motion event was processed

glfw/cocoa_window.m

@@ -537,6 +537,7 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
     if (self != nil) {
         window = initWindow;
         _lastScreenStates = [self captureScreenStates];
+        window->ns.live_resize_in_progress = false;
     }
     return self;
 }
@@ -566,7 +567,12 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
     (void)notification;
     NSArray<NSDictionary *> *currentScreenStates = [self captureScreenStates];
     const bool is_screen_change = ![_lastScreenStates isEqualToArray:currentScreenStates];
-    debug_rendering("windowDidResize() called, is_screen_change: %d\n", is_screen_change);
+    NSWindowStyleMask sm = [window->ns.object styleMask];
+    const bool is_fullscreen = (sm & NSWindowStyleMaskFullScreen) != 0;
+    NSRect frame = [window->ns.object frame];
+    debug_rendering(
+            "windowDidResize() called, is_screen_change: %d is_fullscreen: %d live_resize_in_progress: %d frame: %.1fx%.1f@(%.1f, %.1f)\n",
+            is_screen_change, is_fullscreen, window->ns.live_resize_in_progress, frame.size.width, frame.size.height, frame.origin.x, frame.origin.y);
     if (is_screen_change) {
         // This resize likely happened because a screen was added, removed, or changed resolution.
         [_lastScreenStates release];
@@ -608,7 +614,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
     // Because of a bug in macOS Tahoe we cannot redraw the window in response
     // to a resize event that was caused by a screen change as the OpenGL
     // context is not ready yet. See: https://github.com/kovidgoyal/kitty/issues/8983
-    if (window->ns.resizeCallback && !is_screen_change) window->ns.resizeCallback((GLFWwindow*)window);
+    if (window->ns.resizeCallback && !is_screen_change && !is_fullscreen && window->ns.live_resize_in_progress)
+        window->ns.resizeCallback((GLFWwindow*)window);
 }
 
 - (void)windowDidMove:(NSNotification *)notification
@@ -824,12 +831,14 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 - (void) viewWillStartLiveResize
 {
     if (!window) return;
+    window->ns.live_resize_in_progress = true;
     _glfwInputLiveResize(window, true);
 }
 
 - (void)viewDidEndLiveResize
 {
     if (!window) return;
+    window->ns.live_resize_in_progress = false;
     _glfwInputLiveResize(window, false);
 }
 

go.mod

@@ -13,7 +13,7 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/kovidgoyal/dbus v0.0.0-20250519011319-e811c41c0bc1
 	github.com/kovidgoyal/exiffix v0.0.0-20250919160812-dbef770c2032
-	github.com/kovidgoyal/imaging v1.6.4
+	github.com/kovidgoyal/imaging v1.6.5
 	github.com/seancfoley/ipaddress-go v1.7.1
 	github.com/shirou/gopsutil/v3 v3.24.5
 	github.com/zeebo/xxh3 v1.0.2

go.sum

@@ -28,8 +28,8 @@ github.com/kovidgoyal/dbus v0.0.0-20250519011319-e811c41c0bc1 h1:rMY/hWfcVzBm6BL
 github.com/kovidgoyal/dbus v0.0.0-20250519011319-e811c41c0bc1/go.mod h1:RbNG3Q1g6GUy1/WzWVx+S24m7VKyvl57vV+cr2hpt50=
 github.com/kovidgoyal/exiffix v0.0.0-20250919160812-dbef770c2032 h1:TEV9lpo2a6fP1byiDsoJe2fXpvrj2itae41xMM+bEAg=
 github.com/kovidgoyal/exiffix v0.0.0-20250919160812-dbef770c2032/go.mod h1:VU38Nlbvb0lbyS5YkopCZMS5HuJ5QLVJBxRWyzq79q4=
-github.com/kovidgoyal/imaging v1.6.4 h1:K0idhRPXnRrJBKnBYcTfI1HTWSNDeAn7hYDvf9I0dCk=
-github.com/kovidgoyal/imaging v1.6.4/go.mod h1:bEIgsaZmXlvFfkv/CUxr9rJook6AQkJnpB5EPosRfRY=
+github.com/kovidgoyal/imaging v1.6.5 h1:Id9DKlz/ydl5Vxt9QG5IjGSiIcHcszSKXxDubdO49PQ=
+github.com/kovidgoyal/imaging v1.6.5/go.mod h1:mBprO214rATK/6OaPAUXmHbSMelPSFEmoBAt/IJdmno=
 github.com/lufia/plan9stats v0.0.0-20230326075908-cb1d2100619a h1:N9zuLhTvBSRt0gWSiJswwQ2HqDmtX/ZCDJURnKUt1Ik=
 github.com/lufia/plan9stats v0.0.0-20230326075908-cb1d2100619a/go.mod h1:JKx41uQRwqlTZabZc+kILPrO/3jlKnQ2Z8b7YiVw5cE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=

kittens/choose_files/graphics.go

@@ -0,0 +1,322 @@
+package choose_files
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync/atomic"
+
+	"github.com/kovidgoyal/kitty/tools/tui"
+	"github.com/kovidgoyal/kitty/tools/tui/graphics"
+	"github.com/kovidgoyal/kitty/tools/tui/loop"
+	"github.com/kovidgoyal/kitty/tools/utils"
+	"github.com/kovidgoyal/kitty/tools/utils/images"
+)
+
+var _ = fmt.Print
+
+type placement struct {
+	gc             *graphics.GraphicsCommand
+	x, y, x_offset int
+}
+
+func (p placement) equal(o placement) bool {
+	return p.x == o.x && p.x_offset == o.x_offset && p.y == o.y
+}
+
+type GraphicsHandler struct {
+	running_in_tmux                     bool
+	image_id_counter, detection_file_id uint32
+	files_to_delete                     []string
+	files_supported                     atomic.Bool
+	last_rendered_image                 struct {
+		p                         *ImagePreview
+		width, height             int
+		image_width, image_height int
+	}
+	image_transmitted                             uint32
+	current_placement, last_transmitted_placement placement
+}
+
+func (self *GraphicsHandler) Cleanup() {
+	for _, f := range self.files_to_delete {
+		_ = os.Remove(f)
+	}
+}
+
+func (self *GraphicsHandler) new_graphics_command() *graphics.GraphicsCommand {
+	gc := graphics.GraphicsCommand{}
+	if self.running_in_tmux {
+		gc.WrapPrefix = "\033Ptmux;"
+		gc.WrapSuffix = "\033\\"
+		gc.EncodeSerializedDataFunc = func(x string) string { return strings.ReplaceAll(x, "\033", "\033\033") }
+	}
+	return &gc
+}
+
+func (self *GraphicsHandler) Initialize(lp *loop.Loop) error {
+	tmux := tui.TmuxSocketAddress()
+	if tmux != "" && tui.TmuxAllowPassthrough() == nil {
+		self.running_in_tmux = true
+	}
+	if !self.running_in_tmux {
+		g := func(t graphics.GRT_t, payload string) uint32 {
+			self.image_id_counter++
+			g1 := self.new_graphics_command()
+			g1.SetTransmission(t).SetAction(graphics.GRT_action_query).SetImageId(self.image_id_counter).SetDataWidth(1).SetDataHeight(1).SetFormat(
+				graphics.GRT_format_rgb).SetDataSize(uint64(len(payload)))
+			_ = g1.WriteWithPayloadToLoop(lp, utils.UnsafeStringToBytes(payload))
+			return self.image_id_counter
+		}
+		tf, err := images.CreateTempInRAM()
+		if err == nil {
+			if _, err = tf.Write([]byte{1, 2, 3}); err == nil {
+				self.detection_file_id = g(graphics.GRT_transmission_tempfile, tf.Name())
+				self.files_to_delete = append(self.files_to_delete, tf.Name())
+			}
+			tf.Close()
+		}
+
+	}
+	self.image_id_counter++
+	return nil
+}
+
+func (self *GraphicsHandler) free_image_from_terminal(lp *loop.Loop) {
+	if self.image_transmitted > 0 {
+		self.new_graphics_command().SetAction(graphics.GRT_action_delete).SetDelete(graphics.GRT_free_by_id).SetImageId(self.image_transmitted).WriteWithPayloadToLoop(lp, nil)
+		self.image_transmitted = 0
+	}
+}
+
+func (self *GraphicsHandler) Finalize(lp *loop.Loop) {
+	self.free_image_from_terminal(lp)
+}
+
+func (self *GraphicsHandler) ClearPlacements(lp *loop.Loop) {
+	self.current_placement.gc = nil
+}
+
+func (self *GraphicsHandler) ApplyPlacements(lp *loop.Loop) {
+	if self.current_placement.gc == nil {
+		g := self.new_graphics_command()
+		g.SetAction(graphics.GRT_action_delete).SetDelete(graphics.GRT_delete_by_id).SetImageId(self.image_transmitted)
+		_ = g.WriteWithPayloadToLoop(lp, nil)
+		self.last_transmitted_placement.gc = nil
+	} else {
+		if self.last_transmitted_placement.gc == nil || !self.current_placement.equal(self.last_transmitted_placement) {
+			lp.MoveCursorTo(self.current_placement.x, self.current_placement.y)
+			_ = self.current_placement.gc.WriteWithPayloadToLoop(lp, nil)
+			self.last_transmitted_placement = self.current_placement
+		}
+	}
+}
+
+func (self *GraphicsHandler) HandleGraphicsCommand(gc *graphics.GraphicsCommand) error {
+	switch gc.ImageId() {
+	case self.detection_file_id:
+		if gc.ResponseMessage() == "OK" {
+			self.files_supported.Store(true)
+		}
+	}
+
+	return nil
+}
+
+func (self *GraphicsHandler) cache_resized_image(cdir, cache_key string, img *images.ImageData) (m *images.SerializableImageMetadata, cached_data map[string]string, err error) {
+	s, frames := img.Serialize()
+	sd, err := json.Marshal(s)
+	if err != nil {
+		return nil, nil, err
+	}
+	path := filepath.Join(cdir, fmt.Sprintf("rsz-%s-metadata.json", cache_key))
+	if err = os.WriteFile(path, sd, 0o600); err != nil {
+		return nil, nil, fmt.Errorf("failed to write resized frame metadata to cache: %w", err)
+	}
+	cached_data = make(map[string]string, len(frames)+1)
+	cached_data[IMAGE_METADATA_KEY] = path
+	for i, f := range frames {
+		path := filepath.Join(cdir, fmt.Sprintf("rsz-%s-%d", cache_key, i))
+		key := IMAGE_DATA_PREFIX + strconv.Itoa(i)
+		if err = os.WriteFile(path, f, 0o600); err != nil {
+			return nil, nil, fmt.Errorf("failed to write resized frame %d data to cache: %w", i, err)
+		}
+		cached_data[key] = path
+	}
+	m = &s
+	return
+}
+
+func (self *GraphicsHandler) cached_resized_image(cdir, cache_key string) (m *images.SerializableImageMetadata, cached_data map[string]string) {
+	path := filepath.Join(cdir, fmt.Sprintf("rsz-%s-metadata.json", cache_key))
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return
+	}
+	var s images.SerializableImageMetadata
+	if err = json.Unmarshal(b, &s); err != nil {
+		return
+	}
+	m = &s
+	cached_data = make(map[string]string, len(s.Frames)+1)
+	cached_data[IMAGE_METADATA_KEY] = path
+	for i := range len(s.Frames) {
+		path := filepath.Join(cdir, fmt.Sprintf("rsz-%s-%d", cache_key, i))
+		key := IMAGE_DATA_PREFIX + strconv.Itoa(i)
+		cached_data[key] = path
+	}
+	return
+}
+
+func transmit_by_escape_code(lp *loop.Loop, frame []byte, gc *graphics.GraphicsCommand) {
+	atomic := lp.IsAtomicUpdateActive()
+	lp.EndAtomicUpdate()
+	gc.SetTransmission(graphics.GRT_transmission_direct)
+	_ = gc.WriteWithPayloadToLoop(lp, frame)
+	if atomic {
+		lp.StartAtomicUpdate()
+	}
+}
+
+func transmit_by_file(lp *loop.Loop, frame_path []byte, gc *graphics.GraphicsCommand) {
+	gc.SetTransmission(graphics.GRT_transmission_file)
+	_ = gc.WriteWithPayloadToLoop(lp, frame_path)
+}
+
+func (self *GraphicsHandler) transmit(lp *loop.Loop, img *images.ImageData, m *images.SerializableImageMetadata, cached_data map[string]string) {
+	if m == nil {
+		s := img.SerializeOnlyMetadata()
+		m = &s
+	}
+	self.image_transmitted = self.image_id_counter
+	self.last_transmitted_placement.gc = nil
+	self.last_rendered_image.image_width = m.Width
+	self.last_rendered_image.image_height = m.Height
+	is_animated := len(m.Frames) > 0
+	frame_control_cmd := self.new_graphics_command()
+	frame_control_cmd.SetAction(graphics.GRT_action_animate).SetImageId(self.image_transmitted)
+	for frame_num, frame := range m.Frames {
+		gc := self.new_graphics_command()
+		gc.SetImageId(self.image_transmitted)
+		gc.SetDataWidth(uint64(frame.Width)).SetDataHeight(uint64(frame.Height))
+		gc.SetFormat(utils.IfElse(frame.Is_opaque, graphics.GRT_format_rgb, graphics.GRT_format_rgba))
+		switch frame_num {
+		case 0:
+			gc.SetAction(graphics.GRT_action_transmit)
+			gc.SetCursorMovement(graphics.GRT_cursor_static)
+		default:
+			gc.SetAction(graphics.GRT_action_frame)
+			gc.SetGap(int32(frame.Delay_ms))
+			if frame.Compose_onto > 0 {
+				gc.SetOverlaidFrame(uint64(frame.Compose_onto))
+			}
+			gc.SetLeftEdge(uint64(frame.Left)).SetTopEdge(uint64(frame.Top))
+		}
+		if cached_data == nil {
+			transmit_by_escape_code(lp, img.Frames[frame_num].Data(), gc)
+		} else {
+			path := cached_data[IMAGE_DATA_PREFIX+strconv.Itoa(frame_num)]
+			transmit_by_file(lp, utils.UnsafeStringToBytes(path), gc)
+		}
+		if is_animated {
+			switch frame_num {
+			case 0:
+				// set gap for the first frame and number of loops for the animation
+				c := frame_control_cmd
+				c.SetTargetFrame(uint64(frame.Number))
+				c.SetGap(int32(frame.Delay_ms))
+				c.SetNumberOfLoops(1)
+				_ = c.WriteWithPayloadToLoop(lp, nil)
+			case 1:
+				c := frame_control_cmd
+				c.SetAnimationControl(2) // set animation to loading mode
+				_ = c.WriteWithPayloadToLoop(lp, nil)
+			}
+		}
+	}
+	if is_animated {
+		c := frame_control_cmd
+		c.SetAnimationControl(3) // set animation to normal mode
+		_ = c.WriteWithPayloadToLoop(lp, nil)
+	}
+
+}
+
+func (self *GraphicsHandler) place_image(x, y, px_width, y_offset int, sz ScreenSize) {
+	gc := self.new_graphics_command()
+	gc.SetAction(graphics.GRT_action_display).SetImageId(self.image_transmitted).SetPlacementId(1).SetCursorMovement(graphics.GRT_cursor_static)
+	if extra := px_width - self.last_rendered_image.image_width; extra > 1 {
+		extra /= 2
+		x += extra / sz.cell_width
+		self.current_placement.x_offset = extra % sz.cell_width
+		gc.SetXOffset(uint64(self.current_placement.x_offset))
+	}
+	gc.SetYOffset(uint64(y_offset))
+	self.current_placement.x, self.current_placement.y = x, y
+	self.current_placement.gc = gc
+}
+
+func (self *GraphicsHandler) RenderImagePreview(h *Handler, p *ImagePreview, x, y, width, height int) {
+	sz := h.screen_size
+	px_width, px_height := width*sz.cell_width, height*sz.cell_height
+	y_offset := sz.cell_height / 2
+	px_height -= y_offset
+	var err error
+	defer func() {
+		self.last_rendered_image.p = p
+		self.last_rendered_image.width, self.last_rendered_image.height = width, height
+		if err != nil {
+			NewErrorPreview(fmt.Errorf("Failed to render image: %w", err)).Render(h, x, y, width, height)
+		} else if self.image_transmitted > 0 {
+			self.place_image(x, y, px_width, y_offset, sz)
+		}
+	}()
+	if self.last_rendered_image.p == p && self.last_rendered_image.width == width && self.last_rendered_image.height == height {
+		return
+	}
+	files_supported := self.files_supported.Load()
+
+	if p.img_metadata.Width <= px_width && p.img_metadata.Height <= px_height {
+		if files_supported {
+			self.transmit(h.lp, nil, p.img_metadata, p.cached_data)
+		} else {
+			if err = p.ensure_source_image(); err != nil {
+				return
+			}
+			self.transmit(h.lp, p.source_img, p.img_metadata, nil)
+		}
+		return
+	}
+	cache_key := fmt.Sprintf("%d-%d-%p", width, height, p)
+	img_metadata, cached_data := self.cached_resized_image(p.disk_cache.ResultsDir(), cache_key)
+	var img *images.ImageData
+	if len(cached_data) == 0 {
+		if err = p.ensure_source_image(); err != nil {
+			return
+		}
+		img = p.source_img
+		final_width, final_height := images.FitImage(img.Width, img.Height, px_width, px_height)
+		if final_width != img.Width || final_height != img.Height {
+			x_frac, y_frac := float64(final_width)/float64(img.Width), float64(final_height)/float64(img.Height)
+			img = img.Resize(x_frac, y_frac)
+		}
+		if img_metadata, cached_data, err = self.cache_resized_image(p.disk_cache.ResultsDir(), cache_key, img); err != nil {
+			err = fmt.Errorf("failed to cache resized image: %w", err)
+			return
+		}
+	}
+	if files_supported {
+		self.transmit(h.lp, img, img_metadata, cached_data)
+	} else {
+		if img == nil {
+			if img, err = load_image(cached_data); err != nil {
+				err = fmt.Errorf("failed to load resized image from cache: %w", err)
+				return
+			}
+		}
+		self.transmit(h.lp, img, nil, nil)
+	}
+}

kittens/choose_files/image_preview.go

@@ -0,0 +1,247 @@
+package choose_files
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+	"sync/atomic"
+
+	"github.com/kovidgoyal/kitty/tools/disk_cache"
+	"github.com/kovidgoyal/kitty/tools/icons"
+	"github.com/kovidgoyal/kitty/tools/utils"
+	"github.com/kovidgoyal/kitty/tools/utils/humanize"
+	"github.com/kovidgoyal/kitty/tools/utils/images"
+)
+
+const IMAGE_METADATA_KEY = "image-metadata.json"
+const IMAGE_DATA_PREFIX = "image-data-"
+
+var dc_size atomic.Int64
+var _ = fmt.Print
+
+var preview_cache = sync.OnceValues(func() (*disk_cache.DiskCache, error) {
+	cdir := utils.CacheDir()
+	cdir = filepath.Join(cdir, "choose-files")
+	return disk_cache.NewDiskCache(cdir, dc_size.Load())
+})
+
+type ShowData struct {
+	abspath             string
+	metadata            fs.FileInfo
+	x, y, width, height int
+	cached_data         map[string]string
+	img_metadata        *images.SerializableImageMetadata
+}
+
+type PreviewRenderer interface {
+	Render(string) (map[string][]byte, *images.ImageData, error)
+	ShowMetadata(h *Handler, s ShowData) int
+}
+
+type render_data struct {
+	cached_data  map[string]string
+	img          *images.ImageData
+	img_metadata *images.SerializableImageMetadata
+	err          error
+}
+
+type ImagePreview struct {
+	abspath               string
+	metadata              fs.FileInfo
+	disk_cache            *disk_cache.DiskCache
+	cached_data           map[string]string
+	render_err            Preview
+	render_channel        chan render_data
+	source_img            *images.ImageData
+	img_metadata          *images.SerializableImageMetadata
+	renderer              PreviewRenderer
+	file_metadata_preview Preview
+	WakeupMainThread      func() bool
+}
+
+func (p *ImagePreview) IsValidForColorScheme(bool) bool { return true }
+
+func (p *ImagePreview) Unload() {
+	p.source_img = nil
+}
+
+func load_image(cached_data map[string]string) (img *images.ImageData, err error) {
+	fp := cached_data[IMAGE_METADATA_KEY]
+	if fp == "" {
+		return nil, fmt.Errorf("missing cached image metadata")
+	}
+	b, err := os.ReadFile(fp)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read cached image metadata: %w", err)
+	}
+	var m images.SerializableImageMetadata
+	if err = json.Unmarshal(b, &m); err != nil {
+		return nil, fmt.Errorf("failed to decode cached image metadata: %w", err)
+	}
+	frames := make([][]byte, len(m.Frames))
+	for i := range m.Frames {
+		path := cached_data[IMAGE_DATA_PREFIX+strconv.Itoa(i)]
+		if path == "" {
+			return nil, fmt.Errorf("missing cached data for frame: %d", i)
+		}
+		d, e := os.ReadFile(path)
+		if e != nil {
+			return nil, fmt.Errorf("failed to read cached image frame %d data: %w", i, e)
+		}
+		m.Frames[i].Size = len(d)
+		frames[i] = d
+	}
+	return images.ImageFromSerialized(m, frames)
+}
+
+func (p *ImagePreview) ensure_source_image() (err error) {
+	if p.source_img != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			p.render_err = NewErrorPreview(err)
+		}
+	}()
+	p.source_img, err = load_image(p.cached_data)
+	return
+}
+
+func (p *ImagePreview) render_image(h *Handler, x, y, width, height int) {
+	defer func() {
+		if r := recover(); r != nil {
+			text, _ := utils.Format_stacktrace_on_panic(r)
+			h.err_chan <- fmt.Errorf("%s", text)
+			p.WakeupMainThread()
+		}
+	}()
+
+	offset := p.renderer.ShowMetadata(h, ShowData{
+		abspath: p.abspath, metadata: p.metadata, x: x, y: y, width: width, height: height, cached_data: p.cached_data,
+		img_metadata: p.img_metadata,
+	})
+	h.graphics_handler.RenderImagePreview(h, p, x, y+offset, width, height-offset)
+}
+
+func (p *ImagePreview) Render(h *Handler, x, y, width, height int) {
+	if p.render_channel == nil {
+		if p.render_err == nil {
+			p.render_image(h, x, y, width, height)
+		} else {
+			p.render_err.Render(h, x, y, width, height)
+		}
+		return
+	}
+	select {
+	case hd := <-p.render_channel:
+		p.render_channel = nil
+		p.cached_data = hd.cached_data
+		p.source_img = hd.img
+		p.img_metadata = hd.img_metadata
+		if hd.err != nil {
+			p.render_err = NewErrorPreview(fmt.Errorf("Failed to render the preview with error: %w", hd.err))
+		}
+		p.Render(h, x, y, width, height)
+		return
+	default:
+	}
+	if p.file_metadata_preview == nil {
+		p.file_metadata_preview = NewFileMetadataPreview(p.abspath, p.metadata)
+		m := p.file_metadata_preview.(*MessagePreview)
+		m.trailers = append(m.trailers, "", "Rendering image preview, please wait…")
+	}
+	p.file_metadata_preview.Render(h, x, y, width, height)
+}
+
+func (p *ImagePreview) start_rendering() {
+	defer func() {
+		if r := recover(); r != nil {
+			text, _ := utils.Format_stacktrace_on_panic(r)
+			p.render_channel <- render_data{err: fmt.Errorf("%s", text)}
+		}
+		close(p.render_channel)
+		p.WakeupMainThread()
+	}()
+	key, ans, err := p.disk_cache.GetPath(p.abspath)
+	if err != nil {
+		p.render_channel <- render_data{err: err}
+		return
+	}
+	if len(ans) > 0 {
+		if d := ans[IMAGE_METADATA_KEY]; d != "" {
+			if b, err := os.ReadFile(d); err == nil {
+				var m images.SerializableImageMetadata
+				if err = json.Unmarshal(b, &m); err == nil {
+					p.render_channel <- render_data{cached_data: ans, img_metadata: &m}
+					return
+				}
+			}
+		}
+	}
+	rdata, img, err := p.renderer.Render(p.abspath)
+	if err != nil {
+		p.render_channel <- render_data{err: err}
+	} else {
+		ans, err = p.disk_cache.AddPath(p.abspath, key, rdata)
+		if err == nil {
+			m := img.SerializeOnlyMetadata()
+			p.render_channel <- render_data{cached_data: ans, img_metadata: &m, img: img}
+		} else {
+			p.render_channel <- render_data{err: err}
+		}
+	}
+}
+
+type ImagePreviewRenderer uint
+
+func (p ImagePreviewRenderer) Render(abspath string) (ans map[string][]byte, img *images.ImageData, err error) {
+	if img, err = images.OpenImageFromPath(abspath); err != nil {
+		return nil, nil, err
+	}
+	m, data := img.Serialize()
+	ans = make(map[string][]byte, len(data)+1)
+	metadata, err := json.Marshal(m)
+	if err != nil {
+		return nil, nil, err
+	}
+	ans[IMAGE_METADATA_KEY] = metadata
+	for i, d := range data {
+		key := IMAGE_DATA_PREFIX + strconv.Itoa(i)
+		ans[key] = d
+	}
+	return
+}
+
+func (p ImagePreviewRenderer) ShowMetadata(h *Handler, s ShowData) int {
+	text := ""
+	offset := 0
+	if s.img_metadata != nil {
+		text = fmt.Sprintf("%s: %dx%d %s", s.img_metadata.Format_uppercase, s.img_metadata.Width, s.img_metadata.Height, humanize.Bytes(uint64(s.metadata.Size())))
+		icon := icons.IconForPath("/a.gif")
+		text = icon + "  " + text
+		offset += h.render_wrapped_text_in_region(text, s.x, s.y, s.width, s.height, true)
+	}
+	offset += h.render_wrapped_text_in_region(humanize.Time(s.metadata.ModTime()), s.x, s.y+offset, s.width, s.height-offset, true)
+	return offset
+}
+
+func NewImagePreview(
+	abspath string, metadata fs.FileInfo, opts Settings, WakeupMainThread func() bool, r PreviewRenderer,
+) (Preview, error) {
+	dc_size.Store(opts.DiskCacheSize())
+	ans := &ImagePreview{
+		abspath: abspath, metadata: metadata, render_channel: make(chan render_data, 1),
+		WakeupMainThread: WakeupMainThread, renderer: r,
+	}
+	if dc, err := preview_cache(); err != nil {
+		return nil, err
+	} else {
+		ans.disk_cache = dc
+	}
+	go ans.start_rendering()
+	return ans, nil
+}

kittens/choose_files/main.go

@@ -16,6 +16,7 @@ import (
 	"github.com/kovidgoyal/kitty/tools/ignorefiles"
 	"github.com/kovidgoyal/kitty/tools/tty"
 	"github.com/kovidgoyal/kitty/tools/tui"
+	"github.com/kovidgoyal/kitty/tools/tui/graphics"
 	"github.com/kovidgoyal/kitty/tools/tui/loop"
 	"github.com/kovidgoyal/kitty/tools/tui/readline"
 	"github.com/kovidgoyal/kitty/tools/utils"
@@ -123,6 +124,7 @@ type State struct {
 	display_title                       bool
 	pygments_style, dark_pygments_style string
 	syntax_aliases                      map[string]string
+	max_disk_cache_size                 int64
 
 	selections    []string
 	current_idx   CollectionIndex
@@ -131,6 +133,7 @@ type State struct {
 	redraw_needed bool
 }
 
+func (s State) DiskCacheSize() int64                  { return s.max_disk_cache_size }
 func (s State) HighlightStyles() (string, string)     { return s.pygments_style, s.dark_pygments_style }
 func (s State) SyntaxAliases() map[string]string      { return s.syntax_aliases }
 func (s State) DisplayTitle() bool                    { return s.display_title }
@@ -204,16 +207,29 @@ type ScreenSize struct {
 }
 
 type Handler struct {
-	state            State
-	screen_size      ScreenSize
-	result_manager   *ResultManager
-	lp               *loop.Loop
-	rl               *readline.Readline
-	err_chan         chan error
-	shortcut_tracker config.ShortcutTracker
-	msg_printer      *message.Printer
-	spinner          *tui.Spinner
-	preview_manager  *PreviewManager
+	state                 State
+	screen_size           ScreenSize
+	result_manager        *ResultManager
+	lp                    *loop.Loop
+	rl                    *readline.Readline
+	err_chan              chan error
+	shortcut_tracker      config.ShortcutTracker
+	msg_printer           *message.Printer
+	spinner               *tui.Spinner
+	preview_manager       *PreviewManager
+	last_rendered_preview Preview
+	graphics_handler      GraphicsHandler
+}
+
+func (self *Handler) on_escape_code(etype loop.EscapeCodeType, payload []byte) error {
+	switch etype {
+	case loop.APC:
+		gc := graphics.GraphicsCommandFromAPC(payload)
+		if gc != nil {
+			return self.graphics_handler.HandleGraphicsCommand(gc)
+		}
+	}
+	return nil
 }
 
 func (h *Handler) draw_screen() (err error) {
@@ -222,15 +238,8 @@ func (h *Handler) draw_screen() (err error) {
 	defer func() {
 		h.state.mouse_state.UpdateHoveredIds()
 		h.state.mouse_state.ApplyHoverStyles(h.lp)
-		h.lp.EndAtomicUpdate()
-	}()
-	h.lp.ClearScreen()
-	h.state.mouse_state.ClearCellRegions()
-	switch h.state.screen {
-	case NORMAL:
-		matches, is_complete := h.get_results()
-		h.lp.SetWindowTitle(h.state.WindowTitle())
-		defer func() { // so that the cursor ends up in the right place
+		h.graphics_handler.ApplyPlacements(h.lp)
+		if h.state.screen == NORMAL { // so that the cursor ends up in the right place
 			h.lp.MoveCursorTo(1, 1)
 			if h.state.DisplayTitle() {
 				h.lp.Println(h.state.WindowTitle())
@@ -238,7 +247,16 @@ func (h *Handler) draw_screen() (err error) {
 			} else {
 				h.draw_search_bar(0)
 			}
-		}()
+		}
+		h.lp.EndAtomicUpdate()
+	}()
+	h.lp.ClearScreenButNotGraphics()
+	h.graphics_handler.ClearPlacements(h.lp)
+	h.state.mouse_state.ClearCellRegions()
+	switch h.state.screen {
+	case NORMAL:
+		matches, is_complete := h.get_results()
+		h.lp.SetWindowTitle(h.state.WindowTitle())
 		y := SEARCH_BAR_HEIGHT + utils.IfElse(h.state.DisplayTitle(), 1, 0)
 		footer_height, err := h.draw_footer()
 		if err != nil {
@@ -292,6 +310,7 @@ func (h *Handler) OnInitialize() (ans string, err error) {
 			}
 		}
 	}
+	err = h.graphics_handler.Initialize(h.lp)
 	h.result_manager.set_root_dir()
 	h.draw_screen()
 	return
@@ -718,6 +737,7 @@ func (h *Handler) set_state_from_config(conf *Config, opts *Options) (err error)
 	h.state.pygments_style = conf.Pygments_style
 	h.state.dark_pygments_style = conf.Dark_pygments_style
 	h.state.syntax_aliases = conf.Syntax_aliases
+	h.state.max_disk_cache_size = int64(conf.Cache_size * (1024 * 1024 * 1024))
 	return
 }
 
@@ -775,6 +795,7 @@ func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
 	lp.MouseTrackingMode(loop.FULL_MOUSE_TRACKING)
 	lp.ColorSchemeChangeNotifications()
 	handler := Handler{lp: lp, err_chan: make(chan error, 8), msg_printer: message.NewPrinter(utils.LanguageTag()), spinner: tui.NewSpinner("dots")}
+	defer handler.graphics_handler.Cleanup()
 	handler.rl = readline.New(lp, readline.RlInit{
 		Prompt: "> ", ContinuationPrompt: ". ", Completer: FilePromptCompleter(handler.state.CurrentDir),
 	})
@@ -810,6 +831,10 @@ func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
 		lp.RequestCurrentColorScheme()
 		return handler.OnInitialize()
 	}
+	lp.OnFinalize = func() string {
+		handler.graphics_handler.Finalize(lp)
+		return ""
+	}
 	lp.OnResize = func(old, new_size loop.ScreenSize) (err error) {
 		handler.init_sizes(new_size)
 		return handler.draw_screen()
@@ -826,6 +851,7 @@ func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
 	lp.OnKeyEvent = handler.OnKeyEvent
 	lp.OnText = handler.OnText
 	lp.OnMouseEvent = handler.OnMouseEvent
+	lp.OnEscapeCode = handler.on_escape_code
 	lp.OnWakeup = func() (err error) {
 		select {
 		case err = <-handler.err_chan:

kittens/choose_files/main.py

@@ -61,6 +61,11 @@ builtin styles <https://pygments.org/styles/>` for a list of schemes.
 This sets the colors used for dark color schemes, use :opt:`pygments_style` to change the
 colors for light color schemes.''')
 
+opt('cache_size', '0.5', option_type='positive_float', long_text='''
+The maximum size of the disk cache, in gigabytes, used for previews. Zero or negative values
+mean no limit.
+''')
+
 opt('syntax_aliases', 'pyj:py pyi:py recipe:py', ctype='strdict_ _:', option_type='syntax_aliases',
     long_text='''
 File extension aliases for syntax highlight. For example, to syntax highlight

kittens/choose_files/preview.go

@@ -25,6 +25,7 @@ var _ = fmt.Print
 type Preview interface {
 	Render(h *Handler, x, y, width, height int)
 	IsValidForColorScheme(light bool) bool
+	Unload()
 }
 
 type PreviewManager struct {
@@ -80,6 +81,7 @@ type MessagePreview struct {
 
 func (p MessagePreview) IsValidForColorScheme(bool) bool { return true }
 
+func (p MessagePreview) Unload() {}
 func (p MessagePreview) Render(h *Handler, x, y, width, height int) {
 	offset := 0
 	if p.title != "" {
@@ -189,6 +191,8 @@ type TextFilePreview struct {
 
 func (p TextFilePreview) IsValidForColorScheme(light bool) bool { return p.light == light }
 
+func (p *TextFilePreview) Unload() {}
+
 func (p *TextFilePreview) Render(h *Handler, x, y, width, height int) {
 	if p.highlighted_chan != nil {
 		select {
@@ -255,13 +259,19 @@ func (pm *PreviewManager) highlight_file_async(path string, output chan highligh
 	s := style_resolver{light: use_light_colors, syntax_aliases: pm.settings.SyntaxAliases()}
 	s.light_style, s.dark_style = pm.settings.HighlightStyles()
 	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				text, _ := utils.Format_stacktrace_on_panic(r)
+				debugprintln(fmt.Sprintf("Failed to highlight: %s with panic: %s", path, text))
+			}
+			close(output)
+			pm.WakeupMainThread()
+		}()
 		highlighted, err := pm.highlighter.HighlightFile(path, &s)
 		if err != nil {
 			debugprintln(fmt.Sprintf("Failed to highlight: %s with error: %s", path, err))
 		}
 		output <- highlighed_data{text: highlighted, err: err, light: s.light}
-		close(output)
-		pm.WakeupMainThread()
 	}()
 }
 
@@ -297,6 +307,14 @@ func (pm *PreviewManager) preview_for(abspath string, ftype fs.FileMode) (ans Pr
 		pm.highlight_file_async(abspath, ch)
 		return NewTextFilePreview(abspath, s, ch, pm.highlighter.Sanitize)
 	}
+	if strings.HasPrefix(mt, "image/") {
+		var r ImagePreviewRenderer
+		if ans, err := NewImagePreview(abspath, s, pm.settings, pm.WakeupMainThread, r); err == nil {
+			return ans
+		} else {
+			return NewErrorPreview(err)
+		}
+	}
 	return NewFileMetadataPreview(abspath, s)
 }
 
@@ -308,9 +326,14 @@ func (h *Handler) draw_preview_content(x, y, width, height int) {
 		return
 	}
 	abspath := filepath.Join(h.state.CurrentDir(), r.text)
+	if h.last_rendered_preview != nil {
+		h.last_rendered_preview.Unload()
+		h.last_rendered_preview = nil
+	}
 	if p := h.preview_manager.preview_for(abspath, r.ftype); p == nil {
 		h.render_wrapped_text_in_region("No preview available", x, y, width, height, false)
 	} else {
+		h.last_rendered_preview = p
 		p.Render(h, x, y, width, height)
 	}
 }

kittens/choose_files/results.go

@@ -235,8 +235,8 @@ func (h *Handler) draw_list_of_results(matches *SortedResults, y, height int) (n
 		}
 		if num_matches > height {
 			col_width = BASE_COL_WIDTH
-			num_cols = available_width / col_width
-			for num_cols > 0 && height*(num_cols-1) >= num_matches {
+			num_cols = max(1, available_width/col_width)
+			for num_cols > 1 && height*(num_cols-1) >= num_matches {
 				num_cols--
 			}
 			col_width = available_width / num_cols

kittens/choose_files/scan.go

@@ -634,6 +634,7 @@ type Settings interface {
 	GlobalIgnores() ignorefiles.IgnoreFile
 	HighlightStyles() (string, string)
 	SyntaxAliases() map[string]string
+	DiskCacheSize() int64
 }
 
 type ResultManager struct {

kittens/diff/highlight.go

@@ -32,7 +32,7 @@ var highlighter = sync.OnceValue(func() highlight.Highlighter {
 func highlight_all(paths []string, light bool) {
 	ctx := images.Context{}
 	srd := prefer_light_colors(light)
-	ctx.Parallel(0, len(paths), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, len(paths), func(nums <-chan int) {
 		for i := range nums {
 			path := paths[i]
 			raw, err := highlighter().HighlightFile(path, &srd)
@@ -45,5 +45,7 @@ func highlight_all(paths []string, light bool) {
 				dark_highlighted_lines_cache.Set(path, text_to_lines(raw))
 			}
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 }

kittens/diff/mouse.go

@@ -4,6 +4,7 @@ package diff
 
 import (
 	"fmt"
+	"math"
 	"strconv"
 	"strings"
 	"sync"
@@ -20,7 +21,7 @@ import (
 var _ = fmt.Print
 
 type KittyOpts struct {
-	Wheel_scroll_multiplier int
+	Wheel_scroll_multiplier float64
 	Copy_on_select          bool
 }
 
@@ -29,7 +30,7 @@ func read_relevant_kitty_opts() KittyOpts {
 	handle_line := func(key, val string) error {
 		switch key {
 		case "wheel_scroll_multiplier":
-			v, err := strconv.Atoi(val)
+			v, err := strconv.ParseFloat(val, 64)
 			if err == nil {
 				ans.Wheel_scroll_multiplier = v
 			}
@@ -47,7 +48,10 @@ var RelevantKittyOpts = sync.OnceValue(func() KittyOpts {
 })
 
 func (self *Handler) handle_wheel_event(up bool) {
-	amt := RelevantKittyOpts().Wheel_scroll_multiplier
+	amt := int(math.Round(RelevantKittyOpts().Wheel_scroll_multiplier))
+	if amt == 0 {
+		amt = 1
+	}
 	if up {
 		amt *= -1
 	}

kittens/diff/patch.go

@@ -358,14 +358,16 @@ func diff(jobs []diff_job, context_count int) (ans map[string]*Patch, err error)
 		patch        *Patch
 	}
 	results := make(chan result, len(jobs))
-	ctx.Parallel(0, len(jobs), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, len(jobs), func(nums <-chan int) {
 		for i := range nums {
 			job := jobs[i]
 			r := result{file1: job.file1, file2: job.file2}
 			r.patch, r.err = do_diff(job.file1, job.file2, context_count)
 			results <- r
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 	close(results)
 	for r := range results {
 		if r.err != nil {

kittens/diff/search.go

@@ -106,7 +106,7 @@ func (self *Search) search(logical_lines *LogicalLines) {
 	self.matches = make(map[ScrollPos][]Span)
 	ctx := images.Context{}
 	mutex := sync.Mutex{}
-	ctx.Parallel(0, logical_lines.Len(), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, logical_lines.Len(), func(nums <-chan int) {
 		for i := range nums {
 			line := logical_lines.At(i)
 			if line.line_type == EMPTY_LINE || line.line_type == IMAGE_LINE {
@@ -121,7 +121,9 @@ func (self *Search) search(logical_lines *LogicalLines) {
 				}
 			})
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 	for _, spans := range self.matches {
 		slices.SortFunc(spans, func(a, b Span) int { return a.start - b.start })
 	}

kittens/icat/process_images.go

@@ -299,8 +299,12 @@ func process_arg(arg input_arg) {
 		}
 		err = render_image_with_go(&imgd, &f)
 		if err != nil {
-			report_error(arg.value, "Could not render image to RGB", err)
-			return
+			merr := render_image_with_magick(&imgd, &f)
+			if merr != nil {
+				report_error(arg.value, "Could not render image to RGB", err)
+				return
+			}
+			err = nil
 		}
 	} else {
 		err = render_image_with_magick(&imgd, &f)

kitty/cell_vertex.glsl

@@ -76,14 +76,18 @@ vec3 color_to_vec(uint c) {
     return vec3(gamma_lut[r], gamma_lut[g], gamma_lut[b]);
 }
 
-#define one_if_equal_zero_otherwise(a, b) (1.0f - zero_or_one(abs(float(a) - float(b))))
+float one_if_equal_zero_otherwise(float a, float b) { return (1.0f - zero_or_one(abs(float(a) - float(b)))); }
+// Wee need an integer variant to accommodate GPU driver bugs, see
+// https://github.com/kovidgoyal/kitty/issues/9072
+uint one_if_equal_zero_otherwise(int a, int b) { return (1u - uint(zero_or_one(abs(float(a) - float(b))))); }
+uint one_if_equal_zero_otherwise(uint a, uint b) { return (1u - uint(zero_or_one(abs(float(a) - float(b))))); }
 
 
 uint resolve_color(uint c, uint defval) {
     // Convert a cell color to an actual color based on the color table
     int t = int(c & BYTE_MASK);
-    uint is_one = uint(one_if_equal_zero_otherwise(t, 1));
-    uint is_two = uint(one_if_equal_zero_otherwise(t, 2));
+    uint is_one = one_if_equal_zero_otherwise(t, 1);
+    uint is_two = one_if_equal_zero_otherwise(t, 2);
     uint is_neither_one_nor_two = 1u - is_one - is_two;
     return is_one * color_table[(c >> 8) & BYTE_MASK] + is_two * (c >> 8) + is_neither_one_nor_two * defval;
 }
@@ -94,7 +98,7 @@ vec3 to_color(uint c, uint defval) {
 
 vec3 resolve_dynamic_color(uint c, vec3 special_val, vec3 defval) {
     float type = float((c >> 24) & BYTE_MASK);
-#define q(which, val) one_if_equal_zero_otherwise(type, which) * val
+#define q(which, val) one_if_equal_zero_otherwise(type, float(which)) * val
     return (
         q(COLOR_IS_RGB, color_to_vec(c)) + q(COLOR_IS_INDEX, color_to_vec(color_table[c & BYTE_MASK])) +
         q(COLOR_IS_SPECIAL, special_val) + q(COLOR_NOT_SET, defval)
@@ -185,7 +189,7 @@ uvec2 get_decorations_indices(uint in_url /* [0, 1] */, uint text_attrs) {
     return uvec2(strike_idx, has_underline * (decorations_idx + underline_style));
 }
 
-float is_cursor(uint x, uint y) {
+uint is_cursor(uint x, uint y) {
     uint clamped_x = clamp(x, cursor_x1, cursor_x2);
     uint clamped_y = clamp(y, cursor_y1, cursor_y2);
     return one_if_equal_zero_otherwise(x, clamped_x) * one_if_equal_zero_otherwise(y, clamped_y);
@@ -217,7 +221,7 @@ CellData set_vertex_position(vec3 cell_fg, vec3 cell_bg) {
     colored_sprite = float((sprite_idx[0] & SPRITE_COLORED_MASK) >> SPRITE_COLORED_SHIFT);
 #endif
     // Cursor shape and colors
-    float has_main_cursor = is_cursor(column, row);
+    float has_main_cursor = float(is_cursor(column, row));
     float multicursor_shape = float((is_selected >> 2) & 3u);
     float multicursor_uses_main_cursor_shape = float((is_selected >> 4) & BIT_MASK);
     multicursor_shape = if_one_then(multicursor_uses_main_cursor_shape, cursor_shape, multicursor_shape);

kitty/conf/generate.py

@@ -491,7 +491,7 @@ def go_type_data(parser_func: ParserFuncType, ctype: str, is_multiple: bool = Fa
     if p == 'positive_int':
         return 'uint64', 'strconv.ParseUint(val, 10, 64)'
     if p == 'positive_float':
-        return 'float64', 'config.PositiveFloat(val, 10, 64)'
+        return 'float64', 'config.PositiveFloat(val)'
     if p == 'unit_float':
         return 'float64', 'config.UnitFloat(val)'
     if p == 'python_string':

kitty/disk-cache.h

@@ -28,5 +28,9 @@ static inline void* disk_cache_malloc_allocator(void *x, size_t sz) {
 static inline bool
 read_from_disk_cache_simple(PyObject *self_, const void *key, size_t key_sz, void **data, size_t *data_sz, bool store_in_ram) {
     *data = read_from_disk_cache(self_, key, key_sz, disk_cache_malloc_allocator, data_sz, store_in_ram);
-    return PyErr_Occurred() == NULL;
+    if (PyErr_Occurred()) {
+        PyErr_Clear();
+        return false;
+    }
+    return *data != NULL;
 }

kitty/gl.c

@@ -84,7 +84,7 @@ gl_init(void) {
     }
 }
 
-static const char*
+const char*
 check_framebuffer_status(void) {
     GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
     switch (status) {
@@ -100,12 +100,6 @@ check_framebuffer_status(void) {
     }
 }
 
-void
-check_framebuffer_status_or_die(void) {
-    const char *err = check_framebuffer_status();
-    if (err != NULL) fatal("Framebuffer not complete with error: %s", err);
-}
-
 void
 free_texture(GLuint *tex_id) {
     glDeleteTextures(1, tex_id);

kitty/gl.h

@@ -63,7 +63,7 @@ void unbind_program(void);
 GLuint compile_shaders(GLenum shader_type, GLsizei count, const GLchar * const * string);
 void save_viewport_using_top_left_origin(GLsizei x, GLsizei y, GLsizei width, GLsizei height, GLsizei full_framebuffer_height);
 void save_viewport_using_bottom_left_origin(GLsizei x, GLsizei y, GLsizei width, GLsizei height);
-void check_framebuffer_status_or_die(void);
+const char* check_framebuffer_status(void);
 void restore_viewport(void);
 void bind_framebuffer_for_output(unsigned fbid);
 void set_framebuffer_to_use_for_output(unsigned fbid);

kitty/layout/splits.py

@@ -511,24 +511,21 @@ class Splits(Layout):
 
     def do_layout(self, all_windows: WindowList) -> None:
         groups = tuple(all_windows.iter_all_layoutable_groups())
-        window_count = len(groups)
         root = self.pairs_root
-        all_present_window_ids = frozenset(w.id for w in groups)
-        already_placed_window_ids = frozenset(root.all_window_ids())
-        windows_to_remove = already_placed_window_ids - all_present_window_ids
-        if windows_to_remove:
-            self.remove_windows(*windows_to_remove)
-        id_window_map = {w.id: w for w in groups}
-        id_idx_map = {w.id: i for i, w in enumerate(groups)}
-        windows_to_add = all_present_window_ids - already_placed_window_ids
-        if windows_to_add:
-            for wid in sorted(windows_to_add, key=id_idx_map.__getitem__):
-                root.balanced_add(wid)
+        all_present_group_ids = {g.id for g in groups}
+        already_placed_group_ids = frozenset(root.all_window_ids())
+        if groups_to_remove := already_placed_group_ids - all_present_group_ids:
+            self.remove_windows(*groups_to_remove)
+        if groups_to_add := all_present_group_ids - already_placed_group_ids:
+            id_idx_map = {g.id: i for i, g in enumerate(groups)}
+            for gid in sorted(groups_to_add, key=id_idx_map.__getitem__):
+                root.balanced_add(gid)
 
-        if window_count == 1:
+        if len(groups) == 1:
             self.layout_single_window_group(groups[0])
         else:
-            root.layout_pair(lgd.central.left, lgd.central.top, lgd.central.width, lgd.central.height, id_window_map, self)
+            id_group_map = {g.id: g for g in groups}
+            root.layout_pair(lgd.central.left, lgd.central.top, lgd.central.width, lgd.central.height, id_group_map, self)
 
     def add_non_overlay_window(
         self,
@@ -563,7 +560,9 @@ class Splits(Layout):
                     parent_pair.bias = bias if parent_pair.one == target_group.id else (1 - bias)
                 return
         all_windows.add_window(window)
-        p = self.pairs_root.balanced_add(window.id)
+        g = all_windows.group_for_window(window)
+        assert g is not None
+        p = self.pairs_root.balanced_add(g.id)
         if bias is not None:
             p.bias = bias
 

kitty/main.py

@@ -67,6 +67,7 @@ from .utils import (
     get_custom_window_icon,
     log_error,
     parse_os_window_state,
+    read_shell_environment,
     safe_mtime,
     startup_notification_handler,
 )
@@ -478,6 +479,17 @@ def setup_environment(opts: Options, cli_opts: CLIOptions) -> None:
         from_config_file = True
     if cli_opts.listen_on:
         cli_opts.listen_on = expand_listen_on(cli_opts.listen_on, from_config_file)
+    if vars := opts.env.pop('read_from_shell', ''):
+        import fnmatch
+        import re
+        senv = read_shell_environment(opts)
+        patterns = tuple(re.compile(fnmatch.translate(x.strip())) for x in vars.split() if x.strip())
+        if patterns:
+            for k, v in senv.items():
+                for pat in patterns:
+                    if pat.match(k) is not None:
+                        opts.env[k] = v
+                        break
     env = opts.env.copy()
     ensure_kitty_in_path()
     ensure_kitten_in_path()

kitty/options/definition.py

@@ -3254,7 +3254,9 @@ Changing this option by reloading the config is not supported.
 '''
     )
 
-opt('+env', '',
+opt(
+    '+env',
+    '',
     option_type='env',
     add_to_default=False,
     long_text='''
@@ -3268,8 +3270,17 @@ recursively, for example::
     env VAR2=${HOME}/${VAR1}/b
 
 The value of :code:`VAR2` will be :code:`<path to home directory>/a/b`.
-'''
-    )
+
+Use the special
+value :code:`read_from_shell` to have kitty read the specified variables from
+your :opt:`login shell <shell>` configuration.
+Useful if your shell startup files setup a bunch of environment variables that you want available to kitty and
+in kitty session files. Each variable name is treated as a glob pattern to match. For example:
+:code:`env read_from_shell=PATH LANG LC_* XDG_* EDITOR VISUAL`. Note that these variables are only
+read after the configuration is fully processed, thus they are not available for recursive expansion and
+they will override any variables set by other :opt:`env` directives.
+''',
+)
 
 opt('+filter_notification', '', option_type='filter_notification', add_to_default=False, long_text='''
 Specify rules to filter out notifications sent by applications running in kitty.

kitty/rc/base.py

@@ -82,8 +82,7 @@ CmdGenerator = Iterator[CmdReturnType]
 PayloadType = Optional[Union[CmdReturnType, CmdGenerator]]
 PayloadGetType = PayloadGetter
 ArgsType = list[str]
-ImageCompletion = CompletionSpec.from_string('type:file group:"Images"')._replace(
-    extensions=('png', 'jpg', 'jpeg', 'webp', 'gif', 'bmp', 'tiff'))
+ImageCompletion = CompletionSpec.from_string('type:file group:"Images" ext:png,jpg,jpeg,webp,gif,bmp,tiff')
 SUPPORTED_IMAGE_FORMATS = tuple(x.upper() for x in ImageCompletion.extensions if x != 'jpg')
 
 

kitty/session.py

@@ -3,6 +3,7 @@
 
 import json
 import os
+import re
 import shlex
 import sys
 from collections.abc import Callable, Generator, Iterator, Mapping
@@ -64,7 +65,7 @@ class Tab:
         self.pending_resize_spec: ResizeSpec | None = None
         self.pending_focus_matching_window: str = ''
         self.name = name.strip()
-        self.active_window_idx = 0
+        self.active_window_idx = -1
         self.enabled_layouts = opts.enabled_layouts
         self.layout = (self.enabled_layouts or ['tall'])[0]
         self.layout_state: dict[str, Any] | None = None
@@ -518,7 +519,6 @@ def parse_goto_session_cmdline(args: list[str]) -> tuple[GotoSessionOptions, lis
     return ans, leftover_args
 
 
-
 def goto_session_options() -> str:
     return '''
 --sort-by
@@ -528,7 +528,23 @@ When interactively choosing sessions from a list, how to sort the list.
 '''
 
 
+def goto_previous_session(boss: BossType, idx: int) -> None:
+    if boss.active_session:
+        nidx = max(0, len(goto_session_history) - 1 + idx)
+        if nidx < len(goto_session_history):
+            switch_to_session(boss, goto_session_history[nidx])
+            return
+    else:
+        if goto_session_history:
+            switch_to_session(boss, goto_session_history[-1])
+            return
+    boss.ring_bell_if_allowed()
+
+
 def goto_session(boss: BossType, cmdline: Sequence[str]) -> None:
+    if len(cmdline) == 1 and re.match(r'-\d+', cmdline[0]) is not None:
+        # special case for backwards compat goto_session -1
+        return goto_previous_session(boss, int(cmdline[0]))
     try:
         opts, cmdline = parse_goto_session_cmdline(list(cmdline))
     except Exception as e:
@@ -539,28 +555,13 @@ def goto_session(boss: BossType, cmdline: Sequence[str]) -> None:
         choose_session(boss, opts)
         return
     path = cmdline[0]
-    if len(cmdline) == 1:
+    if len(cmdline) == 1:  # goto_session -- -1
         try:
             idx = int(path)
         except Exception:
             idx = 0
         if idx < 0:
-            if boss.active_session:
-                nidx = max(0, len(goto_session_history) - 1 + idx)
-                if nidx < len(goto_session_history):
-                    switch_to_session(boss, goto_session_history[nidx])
-                    return
-            else:
-                if goto_session_history:
-                    switch_to_session(boss, goto_session_history[-1])
-                    return
-            boss.ring_bell_if_allowed()
-            return
-    else:
-        for x in cmdline:
-            if not x.startswith('-'):
-                path = x
-                break
+            return goto_previous_session(boss, idx)
     path, session_name = resolve_session_path_and_name(path)
     if not session_name:
         boss.show_error(_('Invalid session'), _('{} is not a valid path for a session').format(path))

kitty/shaders.c

@@ -656,9 +656,29 @@ setup_texture_as_render_target(unsigned width, unsigned height, GLuint *texture_
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     // We use GL_RGBA16 to avoid incorrect colors due to quantization loss when
     // blending, see https://github.com/kovidgoyal/kitty/issues/8953
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    static struct { bool ok; int fmt; } status = { false, GL_RGBA16};
+    glTexImage2D(GL_TEXTURE_2D, 0, status.fmt, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     bind_framebuffer_for_output(*framebuffer_id);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, *texture_id, 0);
+    if (!status.ok) {
+        if (check_framebuffer_status() == NULL) {
+            status.ok = true;
+        } else {
+            if (status.fmt == GL_RGBA16) {
+                // Driver does not support 16 bit FBO so let it choose the
+                // format. It will probably end up choosing 8 bit but
+                // inaccurate colors are better than completely broken rendering.
+                // See https://github.com/kovidgoyal/kitty/issues/9068
+                status.fmt = GL_RGBA;
+                free_framebuffer(framebuffer_id);
+                free_texture(texture_id);
+                setup_texture_as_render_target(width, height, texture_id, framebuffer_id);
+                log_error("WARNING: Your GPU driver does not support 16bit textures as framebuffer targets, some colors may be slightly inaccurate.");
+            } else {
+                fatal("Your GPU driver does not support indirect rendering to a GL_RGBA texture via a framebuffer");
+            }
+        }
+    }
 }
 
 static void
@@ -1241,14 +1261,13 @@ draw_cursor_trail(CursorTrail *trail, Window *active_window) {
 
 // OSWindow {{{
 static void
-draw_bg_image(OSWindow *os_window) {
+draw_bg_image(OSWindow *os_window, Tab *tab) {
     if (!has_bgimage(os_window)) return;
     BackgroundImageRenderSettings s = {
         .os_window.width = os_window->viewport_width, .os_window.height = os_window->viewport_height,
         .instance_id = os_window->bgimage->id, .layout=OPT(background_image_layout),
         .linear=OPT(background_image_linear), .bgcolor=OPT(background), .opacity=effective_os_window_alpha(os_window),
     };
-    bind_program(BGIMAGE_PROGRAM);
     GLfloat iwidth = os_window->bgimage->width, iheight = os_window->bgimage->height;
     GLfloat vwidth = s.os_window.width, vheight = s.os_window.height;
     if (CENTER_SCALED == OPT(background_image_layout)) {
@@ -1278,6 +1297,9 @@ draw_bg_image(OSWindow *os_window) {
             bottom += hfrac;
         } break;
     }
+    bind_program(BGIMAGE_PROGRAM);
+    // altough we dont use this VO we need to ensure *some* VAO is bound at this point.
+    bind_vertex_array(tab->border_rects.vao_idx);
     glUniform4f(bgimage_program_layout.uniforms.sizes, vwidth, vheight, iwidth, iheight);
     glUniform1f(bgimage_program_layout.uniforms.tiled, tiled);
     glUniform4f(bgimage_program_layout.uniforms.positions, left, top, right, bottom);
@@ -1339,7 +1361,7 @@ blank_os_window(OSWindow *osw) {
 }
 
 static void
-start_os_window_rendering(OSWindow *os_window) {
+start_os_window_rendering(OSWindow *os_window, Tab *tab) {
     if (os_window->live_resize.in_progress) {
         blank_os_window(os_window);
         save_viewport_using_bottom_left_origin(0, 0, os_window->viewport_width, os_window->viewport_height);
@@ -1357,7 +1379,7 @@ start_os_window_rendering(OSWindow *os_window) {
         set_framebuffer_to_use_for_output(os_window->indirect_output.framebuffer_id);
         bind_framebuffer_for_output(0);
         clear_current_framebuffer();
-        draw_bg_image(os_window);
+        draw_bg_image(os_window, tab);
     }
 }
 
@@ -1382,7 +1404,7 @@ stop_os_window_rendering(OSWindow *os_window, Tab *tab, Window *active_window) {
 
 void
 setup_os_window_for_rendering(OSWindow *os_window, Tab *tab, Window *active_window, bool start) {
-    if (start) start_os_window_rendering(os_window);
+    if (start) start_os_window_rendering(os_window, tab);
     else stop_os_window_rendering(os_window, tab, active_window);
 }
 // }}}

kitty/tabs.py

@@ -251,10 +251,14 @@ class Tab:  # {{{
     def _startup(self, session_tab: SessionTab) -> None:
         target_tab = self
         boss = get_boss()
-        for window in session_tab.windows:
+        active_window_id = 0
+        did_focus_matching_spec = False
+        first_window_id = 0
+        for i, window in enumerate(session_tab.windows):
             spec = window.launch_spec
+            launched_window: Window | None = None
             if isinstance(spec, SpecialWindowInstance):
-                self.new_special_window(spec)
+                launched_window = self.new_special_window(spec)
             else:
                 from .launch import launch
                 spec.opts.add_to_session = self.created_in_session_name
@@ -263,6 +267,12 @@ class Tab:  # {{{
                     startup_command_via_shell_integration=window.run_command_at_shell_startup)
                 if launched_window is not None:
                     launched_window.serialized_id = window.serialized_id
+            if launched_window is not None:
+                if not first_window_id:
+                    first_window_id = launched_window.id
+                if session_tab.active_window_idx == i:
+                    active_window_id = launched_window.id
+                    did_focus_matching_spec = False
             if window.resize_spec is not None:
                 self.resize_window(*window.resize_spec)
             if window.focus_matching_window_spec:
@@ -275,6 +285,8 @@ class Tab:  # {{{
                 ):
                     tab = w.tabref()
                     if tab:
+                        did_focus_matching_spec = True
+                        active_window_id = 0
                         target_tab = tab or self
                         tm = tab.tab_manager_ref()
                         if tm and boss.active_tab is not target_tab:
@@ -283,8 +295,10 @@ class Tab:  # {{{
                             target_tab.set_active_window(w)
                         boss.focus_os_window(w.os_window_id)
 
-        with suppress(IndexError):
-            self.windows.set_active_window_group_for(self.windows.all_windows[session_tab.active_window_idx])
+        if not did_focus_matching_spec and not active_window_id:
+            active_window_id = first_window_id
+        if active_window_id and not did_focus_matching_spec:
+            self.windows.set_active_window_group_for(active_window_id)
         if session_tab.layout_state:
             self.current_layout.unserialize(session_tab.layout_state, self.windows)
 
@@ -1374,12 +1388,21 @@ class TabManager:  # {{{
             while self.active_tab_history and self.active_tab_history[-1] == tab.id:
                 self.active_tab_history.pop()
 
+        def previous_active_tab() -> Tab | None:
+            while self.active_tab_history:
+                tab_id = self.active_tab_history.pop()
+                if tab_id != removed_tab.id:
+                    if (ans := self.tab_for_id(tab_id)) is not None:
+                        return ans
+            return self.tabs[0] if self.tabs else None
+
         if active_tab_before_removal is removed_tab:
-            if len(self.tabs) == 0:
-                self._active_tab_idx = 0
-            elif len(self.tabs) == 1:
-                remove_from_end_of_active_history(self.tabs[0])
-                self._set_active_tab(0, store_in_history=False)
+            if len(tabs) == 0 or (len(tabs) == 1 and removed_tab is tabs[0]):
+                tab = previous_active_tab()
+                if tab is None:
+                    self._active_tab_idx = 0
+                else:
+                    self._set_active_tab(self.tabs.index(tab), store_in_history=False)
             else:
                 next_active_tab: Tab | None = None
                 match get_options().tab_switch_strategy:
@@ -1387,6 +1410,8 @@ class TabManager:  # {{{
                         while self.active_tab_history and next_active_tab is None:
                             tab_id = self.active_tab_history.pop()
                             next_active_tab = self.tab_for_id(tab_id)
+                            if next_active_tab not in tabs:
+                                next_active_tab = None
                     case 'left':
                         next_active_tab = tabs[(tabs.index(active_tab_before_removal) - 1 + len(tabs)) % len(tabs)]
                         remove_from_end_of_active_history(next_active_tab)

kitty/utils.py

@@ -11,11 +11,13 @@ from collections.abc import Callable, Generator, Iterable, Iterator, Mapping, Se
 from contextlib import contextmanager, suppress
 from functools import lru_cache
 from re import Match, Pattern
+from types import MappingProxyType
 from typing import (
     TYPE_CHECKING,
     Any,
     BinaryIO,
     NamedTuple,
+    NoReturn,
     Optional,
     cast,
 )
@@ -540,7 +542,8 @@ def get_editor_from_env(env: Mapping[str, str]) -> str | None:
 
 
 def get_editor_from_env_vars(opts: Options | None = None) -> list[str]:
-    editor = get_editor_from_env(os.environ)
+    from .child import default_env
+    editor = get_editor_from_env(default_env())
     if not editor:
         shell_env = read_shell_environment(opts)
         editor = get_editor_from_env(shell_env)
@@ -578,6 +581,15 @@ def get_editor(opts: Options | None = None, path_to_edit: str = '', line_number:
     return ans
 
 
+def edit_file(path: str = '') -> NoReturn:
+    ' This exists for: map whatever launch kitty +runpy "from kitty.utils import *; edit_file()" to edit kitty config '
+    from .config import prepare_config_file_for_editing
+    editor = get_editor()
+    path = path or prepare_config_file_for_editing()
+    editor.append(path)
+    os.execlp(editor[0], *editor)
+
+
 def is_path_in_temp_dir(path: str) -> bool:
     if not path:
         return False
@@ -743,62 +755,72 @@ def which(name: str, only_system: bool = False) -> str | None:
     return None
 
 
-def read_shell_environment(opts: Options | None = None) -> dict[str, str]:
-    ans: dict[str, str] | None = getattr(read_shell_environment, 'ans', None)
-    if ans is None:
-        from .child import openpty
-        ans = {}
-        setattr(read_shell_environment, 'ans', ans)
-        import subprocess
-        shell = resolved_shell(opts)
-        master, slave = openpty()
-        os.set_blocking(master, False)
-        if '-l' not in shell and '--login' not in shell:
-            shell += ['-l']
-        if '-i' not in shell and '--interactive' not in shell:
-            shell += ['-i']
-        try:
-            p = subprocess.Popen(
-                shell + ['-c', 'env'], stdout=slave, stdin=slave, stderr=slave, start_new_session=True, close_fds=True,
-                preexec_fn=clear_handled_signals)
-        except FileNotFoundError:
-            log_error('Could not find shell to read environment')
-            return ans
-        with os.fdopen(master, 'rb') as stdout, os.fdopen(slave, 'wb'):
-            raw = b''
-            from time import monotonic
-            start_time = monotonic()
-            while monotonic() - start_time < 1.5:
+@lru_cache(4)
+def read_resolved_shell_environment(shell: tuple[str, ...]) -> MappingProxyType[str, str]:
+    import subprocess
+    cmdline = list(shell)
+    if '-l' not in cmdline and '--login' not in cmdline:
+        cmdline += ['-l']
+    if '-i' not in cmdline and '--interactive' not in cmdline:
+        cmdline += ['-i']
+    q = os.path.basename(cmdline[0]).lower()
+    has_builtin = q in ('bash', 'zsh')
+    cmd = 'builtin command env -0' if has_builtin else 'command env -0'
+    ans: MappingProxyType[str, str] = MappingProxyType({})
+
+    from .child import openpty
+    master, slave = openpty()
+    os.set_blocking(master, False)
+    try:
+        p = subprocess.Popen(
+            cmdline + ['-c', cmd], stdout=slave, stdin=slave, stderr=slave, start_new_session=True, close_fds=True,
+            preexec_fn=clear_handled_signals)
+    except FileNotFoundError:
+        log_error(f'Could not find shell {cmdline[0]} to read environment')
+        return ans
+    with os.fdopen(master, 'rb') as stdout, os.fdopen(slave, 'wb'):
+        raw = b''
+        from time import monotonic
+        start_time = monotonic()
+        ret: int | None = None
+        while monotonic() - start_time < 1.5:
+            try:
+                ret = p.wait(0.01)
+            except subprocess.TimeoutExpired:
+                ret = None
+            with suppress(Exception):
+                raw += stdout.read()
+            if ret is not None:
+                break
+        if ret is None:
+            log_error(f'Timed out waiting for shell {cmdline} to quit while reading shell environment')
+            p.kill()
+        elif ret == 0:
+            while True:
                 try:
-                    ret: int | None = p.wait(0.01)
-                except subprocess.TimeoutExpired:
-                    ret = None
-                with suppress(Exception):
-                    raw += stdout.read()
-                if ret is not None:
+                    x = stdout.read()
+                except Exception:
                     break
-            if cast(Optional[int], p.returncode) is None:
-                log_error('Timed out waiting for shell to quit while reading shell environment')
-                p.kill()
-            elif p.returncode == 0:
-                while True:
-                    try:
-                        x = stdout.read()
-                    except Exception:
-                        break
-                    if not x:
-                        break
-                    raw += x
-                draw = raw.decode('utf-8', 'replace')
-                for line in draw.splitlines():
-                    k, v = line.partition('=')[::2]
-                    if k and v:
-                        ans[k] = v
-            else:
-                log_error('Failed to run shell to read its environment')
+                if not x:
+                    break
+                raw += x
+            draw = raw.decode('utf-8', 'replace')
+            env = {}
+            for line in draw.split('\0'):
+                k, sep, v = line.partition('=')
+                if k and v and sep:
+                    env[k] = v
+            ans = MappingProxyType(env)
+        else:
+            log_error(f'Failed to run shell {cmdline} to read its environment')
     return ans
 
 
+def read_shell_environment(opts: Options | None = None) -> MappingProxyType[str, str]:
+    shell = resolved_shell(opts)
+    return read_resolved_shell_environment(tuple(shell))
+
+
 def parse_uri_list(text: str) -> Generator[str, None, None]:
     ' Get paths from file:// URLs '
     from urllib.parse import unquote, urlparse

kitty/window.py

@@ -718,12 +718,12 @@ class Window:
         self.title_stack: Deque[str] = deque(maxlen=10)
         self.user_vars: dict[str, str] = {}
         self.id: int = add_window(tab.os_window_id, tab.id, self.title)
+        if not self.id:
+            raise Exception(f'No tab with id: {tab.id} in OS Window: {tab.os_window_id} was found, or the window counter wrapped')
         self.clipboard_request_manager = ClipboardRequestManager(self.id)
         self.margin = EdgeWidths()
         self.padding = EdgeWidths()
         self.kitten_result: dict[str, Any] | None = None
-        if not self.id:
-            raise Exception(f'No tab with id: {tab.id} in OS Window: {tab.os_window_id} was found, or the window counter wrapped')
         self.tab_id = tab.id
         self.os_window_id = tab.os_window_id
         self.tabref: Callable[[], TabType | None] = weakref.ref(tab)

kitty/window_list.py

@@ -33,6 +33,9 @@ class WindowGroup:
         self.windows: list[WindowType] = []
         self.id = next(group_id_counter)
 
+    def __repr__(self) -> str:
+        return f'WindowGroup(id={self.id}, windows={", ".join(str(w.id) for w in self.windows)})'
+
     def __len__(self) -> int:
         return len(self.windows)
 

tools/disk_cache/api.go

@@ -17,6 +17,7 @@ type Entry struct {
 
 type Metadata struct {
 	TotalSize     int64
+	PathMap       map[string]string
 	SortedEntries []*Entry
 }
 
@@ -24,35 +25,55 @@ type DiskCache struct {
 	Path    string
 	MaxSize int64
 
-	lock_file        *os.File
-	lock_mutex       sync.Mutex
-	entries          Metadata
-	entry_map        map[string]*Entry
-	entries_mod_time time.Time
-	get_dir          string
+	lock_file               *os.File
+	lock_mutex              sync.Mutex
+	entries                 Metadata
+	entry_map               map[string]*Entry
+	entries_last_read_state *file_state
+	entries_dirty           bool
+	get_dir                 string
+	read_count              int
 }
 
 func NewDiskCache(path string, max_size int64) (dc *DiskCache, err error) {
 	return new_disk_cache(path, max_size)
 }
 
-func KeyForPath(path string) (key string, err error) {
-	return key_for_path(path)
+func (dc *DiskCache) ResultsDir() string {
+	return dc.get_dir
 }
 
-func (dc *DiskCache) Get(key string, items ...string) map[string]string {
+func (dc *DiskCache) Get(key string, items ...string) (map[string]string, error) {
 	dc.lock()
 	defer dc.unlock()
 	return dc.get(key, items)
 }
 
+func (dc *DiskCache) GetPath(path string, items ...string) (string, map[string]string, error) {
+	dc.lock()
+	defer dc.unlock()
+	key, err := key_for_path(path)
+	if err != nil {
+		return "", nil, err
+	}
+	ans, err := dc.get(key, items)
+	return key, ans, err
+}
+
 func (dc *DiskCache) Remove(key string) (err error) {
 	dc.lock()
 	defer dc.unlock()
 	return dc.remove(key)
 }
 
-func (dc *DiskCache) Add(key string, items map[string][]byte) (err error) {
+func (dc *DiskCache) AddPath(path, key string, items map[string][]byte) (ans map[string]string, err error) {
+	dc.lock()
+	defer dc.unlock()
+	ans, err = dc.add_path(path, key, items)
+	return
+}
+
+func (dc *DiskCache) Add(key string, items map[string][]byte) (ans map[string]string, err error) {
 	dc.lock()
 	defer dc.unlock()
 	return dc.add(key, items)

tools/disk_cache/implementation.go

@@ -5,9 +5,12 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"io/fs"
+	"maps"
 	"os"
 	"path/filepath"
 	"slices"
+	"syscall"
 	"time"
 
 	"github.com/kovidgoyal/kitty/tools/utils"
@@ -15,6 +18,48 @@ import (
 
 var _ = fmt.Print
 
+type file_state struct {
+	Size    int64
+	ModTime time.Time
+	Inode   uint64
+}
+
+func (s file_state) String() string {
+	return fmt.Sprintf("fs{Size: %d, Inode: %d, ModTime: %s}", s.Size, s.Inode, s.ModTime)
+}
+
+func (s *file_state) equal(o *file_state) bool {
+	return o != nil && s.Size == o.Size && s.ModTime.Equal(o.ModTime) && s.Inode == o.Inode
+}
+
+func get_file_state(fi fs.FileInfo) *file_state {
+	// The Sys() method returns the underlying data source (can be nil).
+	// For Unix-like systems, it's a *syscall.Stat_t.
+	stat, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		// For non-Unix systems, you might not have an inode.
+		// In that case, you can fall back to using only size and mod time.
+		return &file_state{
+			Size:    fi.Size(),
+			ModTime: fi.ModTime(),
+			Inode:   0, // Inode not available
+		}
+	}
+	return &file_state{
+		Size:    fi.Size(),
+		ModTime: fi.ModTime(),
+		Inode:   stat.Ino,
+	}
+}
+
+func get_file_state_from_path(path string) (*file_state, error) {
+	if s, err := os.Stat(path); err != nil {
+		return nil, err
+	} else {
+		return get_file_state(s), nil
+	}
+}
+
 func new_disk_cache(path string, max_size int64) (dc *DiskCache, err error) {
 	if path, err = filepath.Abs(path); err != nil {
 		return
@@ -28,12 +73,13 @@ func new_disk_cache(path string, max_size int64) (dc *DiskCache, err error) {
 	if err = ans.ensure_entries(); err != nil {
 		return
 	}
-	if pruned, err := ans.prune(); err != nil {
-		return nil, err
-	} else if pruned {
-		if err = ans.write_entries(); err != nil {
-			return nil, err
+	defer func() {
+		if we := ans.write_entries_if_dirty(); we != nil && err == nil {
+			err = we
 		}
+	}()
+	if _, err := ans.prune(); err != nil {
+		return nil, err
 	}
 	if ans.get_dir, err = os.MkdirTemp(ans.Path, "getdir-*"); err != nil {
 		return
@@ -85,19 +131,50 @@ func (dc *DiskCache) unlock() {
 
 func (dc *DiskCache) entries_path() string { return filepath.Join(dc.Path, "entries.json") }
 
-func (dc *DiskCache) write_entries() (err error) {
+func (dc *DiskCache) write_entries_if_dirty() (err error) {
+	if !dc.entries_dirty {
+		return
+	}
+	path := dc.entries_path()
+	defer func() {
+		if err == nil {
+			dc.entries_dirty = false
+			if s, serr := get_file_state_from_path(path); serr == nil {
+				dc.entries_last_read_state = s
+			}
+		}
+	}()
 	if d, err := json.Marshal(dc.entries); err != nil {
 		return err
 	} else {
-		return os.WriteFile(dc.entries_path(), d, 0o600)
+		// use a rename so that the inode number changes
+		// dont bother with full utils.AtomicWriteFile() as it is slower
+		temp := path + ".temp"
+		removed := false
+		defer func() {
+			if !removed {
+				_ = os.Remove(temp)
+				removed = true
+			}
+		}()
+		if err = os.WriteFile(temp, d, 0o600); err == nil {
+			if err = os.Rename(temp, path); err == nil {
+				removed = true
+			}
+		}
+		return err
 	}
 }
 
-func (dc *DiskCache) rebuild_entries() error {
+func (e Entry) String() string {
+	return fmt.Sprintf("Entry{Key: %s, Size: %d, LastUsed: %s}", e.Key, e.Size, e.LastUsed)
+}
+
+func (dc *DiskCache) entries_from_folders() (total_size int64, ans map[string]*Entry, sorted []*Entry, err error) {
 	if entries, err := os.ReadDir(dc.Path); err != nil {
-		return err
+		return 0, nil, nil, err
 	} else {
-		ans := make(map[string]*Entry)
+		ans = make(map[string]*Entry)
 		var total int64
 		for _, x := range entries {
 			if x.IsDir() {
@@ -105,7 +182,7 @@ func (dc *DiskCache) rebuild_entries() error {
 					key := sub_entries[0].Name()
 					path := dc.folder_for_key(key)
 					if file_entries, err := os.ReadDir(path); err == nil {
-						e := Entry{}
+						e := Entry{Key: key}
 						for _, f := range file_entries {
 							if fi, err := f.Info(); err == nil {
 								e.Size += fi.Size()
@@ -120,37 +197,58 @@ func (dc *DiskCache) rebuild_entries() error {
 				}
 			}
 		}
-		sorted := utils.Values(ans)
+		sorted = utils.Values(ans)
 		slices.SortFunc(sorted, func(a, b *Entry) int {
 			return a.LastUsed.Compare(b.LastUsed)
 		})
-		dc.entries = Metadata{TotalSize: total, SortedEntries: sorted}
-		dc.entry_map = ans
+		return total, ans, sorted, nil
 	}
-	return nil
+}
+
+func (dc *DiskCache) rebuild_entries() error {
+	total, ans, sorted, err := dc.entries_from_folders()
+	if err != nil {
+		return err
+	}
+	dc.entries = Metadata{TotalSize: total, SortedEntries: sorted, PathMap: make(map[string]string)}
+	dc.entry_map = ans
+	dc.entries_dirty = true
+	return dc.write_entries_if_dirty()
 }
 
 func (dc *DiskCache) ensure_entries() error {
-	needed := dc.entry_map == nil
+	needed := dc.entry_map == nil || dc.entries_last_read_state == nil
 	path := dc.entries_path()
+	var fstate *file_state
 	if !needed {
-		if s, err := os.Stat(path); err == nil && s.ModTime().After(dc.entries_mod_time) {
-			needed = true
+		if s, err := get_file_state_from_path(path); err == nil {
+			fstate = s
+			if !s.equal(dc.entries_last_read_state) {
+				needed = true
+			}
 		}
 	}
 	if needed {
 		if data, err := os.ReadFile(path); err != nil {
 			if os.IsNotExist(err) {
 				dc.entry_map = make(map[string]*Entry)
-				dc.entries = Metadata{SortedEntries: make([]*Entry, 0)}
+				dc.entries = Metadata{SortedEntries: make([]*Entry, 0), PathMap: make(map[string]string)}
 			} else {
 				return err
 			}
 		} else {
-			dc.entries = Metadata{SortedEntries: make([]*Entry, 0)}
+			dc.read_count += 1
+			dc.entries = Metadata{SortedEntries: make([]*Entry, 0), PathMap: make(map[string]string)}
 			if err := json.Unmarshal(data, &dc.entries); err != nil {
 				// corrupted data
 				dc.rebuild_entries()
+			} else {
+				if fstate == nil {
+					if s, err := get_file_state_from_path(path); err == nil {
+						fstate = s
+					}
+				}
+				dc.entries_last_read_state = fstate
 			}
 			dc.entry_map = make(map[string]*Entry)
 			for _, e := range dc.entries.SortedEntries {
@@ -170,43 +268,68 @@ func (dc *DiskCache) folder_for_key(key string) (ans string) {
 	return filepath.Join(dc.Path, ans)
 }
 
-func (dc *DiskCache) update_last_used(key string) {
-	if dc.ensure_entries() == nil {
-		dc.update_timestamp(key)
+func (dc *DiskCache) export_to_get_dir(key, path string) (string, error) {
+	dest := filepath.Join(dc.get_dir, key+"-"+filepath.Base(path))
+	if err := os.Link(path, dest); err != nil {
+		os.Remove(dest)
+		if err := os.Link(path, dest); err != nil {
+			return "", err
+		}
 	}
+	return dest, nil
 
 }
 
-func (dc *DiskCache) get(key string, items []string) map[string]string {
-	ans := make(map[string]string, len(items))
-	base := dc.folder_for_key(key)
-	if s, err := os.Stat(base); err != nil || !s.IsDir() {
-		return ans
+func (dc *DiskCache) get(key string, items []string) (map[string]string, error) {
+	if err := dc.ensure_entries(); err != nil {
+		return nil, err
 	}
+	base := dc.folder_for_key(key)
+	if len(items) == 0 {
+		if entries, err := os.ReadDir(base); err != nil {
+			if os.IsNotExist(err) {
+				err = nil
+			}
+			return nil, err
+		} else {
+			for _, e := range entries {
+				items = append(items, e.Name())
+			}
+		}
+	} else {
+		if s, err := os.Stat(base); err != nil || !s.IsDir() {
+			if os.IsNotExist(err) {
+				err = nil
+			}
+			return nil, err
+		}
+	}
+	ans := make(map[string]string, len(items))
 	for _, x := range items {
 		p := filepath.Join(base, x)
 		if s, err := os.Stat(p); err != nil || s.IsDir() {
 			continue
 		}
-		dest := filepath.Join(dc.get_dir, key+"-"+x)
-		if err := os.Link(p, dest); err != nil {
-			os.Remove(dest)
-			if err := os.Link(p, dest); err != nil {
-				dest = ""
-			}
-		}
+		dest, _ := dc.export_to_get_dir(key, p)
 		if dest != "" {
 			ans[x] = dest
 		}
 	}
-	dc.update_last_used(key)
-	return ans
+	if len(items) > 0 {
+		dc.update_timestamp(key)
+	}
+	return ans, dc.write_entries_if_dirty()
 }
 
 func (dc *DiskCache) remove(key string) (err error) {
 	if err = dc.ensure_entries(); err != nil {
 		return
 	}
+	defer func() {
+		if we := dc.write_entries_if_dirty(); we != nil && err == nil {
+			err = we
+		}
+	}()
 	base := dc.folder_for_key(key)
 	if err = os.RemoveAll(base); err == nil {
 		t := dc.entry_map[key]
@@ -214,7 +337,7 @@ func (dc *DiskCache) remove(key string) (err error) {
 			delete(dc.entry_map, key)
 			dc.entries.TotalSize = max(0, dc.entries.TotalSize-t.Size)
 			dc.entries.SortedEntries = utils.Filter(dc.entries.SortedEntries, func(x *Entry) bool { return x.Key != key })
-			return dc.write_entries()
+			dc.entries_dirty = true
 		}
 	}
 	return
@@ -229,8 +352,10 @@ func (dc *DiskCache) prune() (bool, error) {
 		if err := os.RemoveAll(base); err == nil {
 			t := dc.entries.SortedEntries[0]
 			delete(dc.entry_map, t.Key)
+			maps.DeleteFunc(dc.entries.PathMap, func(path, key string) bool { return key == t.Key })
 			dc.entries.TotalSize = max(0, dc.entries.TotalSize-t.Size)
 			dc.entries.SortedEntries = dc.entries.SortedEntries[1:]
+			dc.entries_dirty = true
 		} else {
 			return false, err
 		}
@@ -244,6 +369,7 @@ func (dc *DiskCache) update_timestamp(key string) {
 	idx := slices.Index(dc.entries.SortedEntries, t)
 	copy(dc.entries.SortedEntries[idx:], dc.entries.SortedEntries[idx+1:])
 	dc.entries.SortedEntries[len(dc.entries.SortedEntries)-1] = t
+	dc.entries_dirty = true
 }
 
 func (dc *DiskCache) update_accounting(key string, changed int64) (err error) {
@@ -257,25 +383,52 @@ func (dc *DiskCache) update_accounting(key string, changed int64) (err error) {
 	t.Size += changed
 	t.Size = max(0, t.Size)
 	dc.entries.TotalSize += t.Size - old_size
+	dc.entries_dirty = true
 	dc.update_timestamp(key)
 	dc.prune()
-	return dc.write_entries()
+	return dc.write_entries_if_dirty()
 }
 
 func (dc *DiskCache) keys() (ans []string, err error) {
 	if err = dc.ensure_entries(); err != nil {
 		return
 	}
-	return utils.Keys(dc.entry_map), nil
+	ans = make([]string, len(dc.entries.SortedEntries))
+	for i, e := range dc.entries.SortedEntries {
+		ans[i] = e.Key
+	}
+	return
 }
 
-func (dc *DiskCache) add(key string, items map[string][]byte) (err error) {
+func (dc *DiskCache) add_path(path, key string, items map[string][]byte) (ans map[string]string, err error) {
+	if err = dc.ensure_entries(); err != nil {
+		return
+	}
+	defer func() {
+		if we := dc.write_entries_if_dirty(); we != nil && err == nil {
+			err = we
+		}
+	}()
+
+	if existing := dc.entries.PathMap[path]; existing != "" && existing != key {
+		delete(dc.entries.PathMap, path)
+		dc.entries_dirty = true
+		if err = dc.remove(existing); err != nil {
+			return
+		}
+	}
+	dc.entries.PathMap[path] = key
+	dc.entries_dirty = true
+	return dc.add(key, items)
+}
+
+func (dc *DiskCache) add(key string, items map[string][]byte) (ans map[string]string, err error) {
 	if err = dc.ensure_entries(); err != nil {
 		return
 	}
 	base := dc.folder_for_key(key)
 	if err = os.MkdirAll(base, 0o700); err != nil {
-		return err
+		return
 	}
 	var changed int64
 	defer func() {
@@ -284,22 +437,40 @@ func (dc *DiskCache) add(key string, items map[string][]byte) (err error) {
 			err = e
 		}
 	}()
+	ans = make(map[string]string, len(items))
 	for x, data := range items {
 		p := filepath.Join(base, x)
 		var before int64
+		exists := false
 		if s, err := os.Stat(p); err == nil {
 			before = s.Size()
+			exists = true
 		}
 		if len(data) == 0 {
-			if err = os.Remove(p); err != nil {
-				return
+			if exists {
+				if err = os.Remove(p); err != nil {
+					if !os.IsNotExist(err) {
+						return
+					}
+					err = nil
+				}
+				changed -= before
 			}
-			changed -= before
 		} else {
+			// unlink the file so that writing to it does not change a
+			// previously linked copy created by get()
+			if exists {
+				_ = os.Remove(p)
+			}
 			if err = os.WriteFile(p, data, 0o700); err != nil {
 				return
 			}
 			changed += int64(len(data)) - before
+			if dest, err := dc.export_to_get_dir(key, p); err != nil {
+				return ans, err
+			} else {
+				ans[x] = dest
+			}
 		}
 	}
 	return

tools/disk_cache/implementation_test.go

@@ -3,7 +3,8 @@ package disk_cache
 import (
 	"fmt"
 	"os"
-	"slices"
+	"path/filepath"
+	"runtime/debug"
 	"strings"
 	"testing"
 
@@ -23,16 +24,45 @@ func TestDiskCache(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	ensure_entries := func() {
+		for _, x := range []*DiskCache{dc, dc2} {
+			if err = x.ensure_entries(); err != nil {
+				t.Fatal(err)
+			}
+		}
 
-	m := dc.Get("missing", "one", "two")
-	if diff := cmp.Diff(m, make(map[string]string)); diff != "" {
-		t.Fatalf("Unexpected return from missing: %s", diff)
 	}
-	dc.Add("k1", map[string][]byte{"1": []byte("abcd"), "2": []byte("efgh")})
+	arc := func(counts ...int) {
+		ensure_entries()
+		if diff := cmp.Diff(counts, []int{dc.read_count, dc2.read_count}); diff != "" {
+			t.Fatalf("disk cache has unexpected read count\n%s\n%s", diff, debug.Stack())
+		}
+	}
+	add := func(dc *DiskCache, key string, data map[string]string) {
+		d := make(map[string][]byte, len(data))
+		for k, v := range data {
+			d[k] = []byte(v)
+		}
+		if _, err := dc.Add(key, d); err != nil {
+			t.Fatal(err)
+		}
+		ensure_entries()
+	}
+
+	m, err := dc.Get("missing", "one", "two")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(m) > 0 {
+		t.Fatalf("Unexpected return from missing: %s", m)
+	}
 
 	ad := func(key string, expected map[string]string) {
 		for _, x := range []*DiskCache{dc, dc2} {
-			actual := x.Get(key, utils.Keys(expected)...)
+			actual, err := x.Get(key, utils.Keys(expected)...)
+			if err != nil {
+				t.Fatal(err)
+			}
 
 			for k, path := range actual {
 				d, err := os.ReadFile(path)
@@ -44,35 +74,78 @@ func TestDiskCache(t *testing.T) {
 			if diff := cmp.Diff(expected, actual); diff != "" {
 				t.Fatalf("Data for %s not equal: %s", key, diff)
 			}
+			ensure_entries()
 		}
 	}
 	ak := func(keys ...string) {
-		for _, x := range []*DiskCache{dc, dc2} {
+		for i, x := range []*DiskCache{dc, dc2} {
 			kk, err := x.keys()
 			if err != nil {
 				t.Fatal(err)
 			}
-			slices.Sort(kk)
-			slices.Sort(keys)
 			if diff := cmp.Diff(keys, kk); diff != "" {
-				t.Fatalf("Unexpected keys: %s", diff)
+				t.Fatalf("wrong keys in %d: %s", i+1, diff)
 			}
 		}
+		ensure_entries()
 	}
+	add(dc, "k1", map[string]string{"1": "abcd", "2": "efgh"})
+	arc(0, 1)
 	ad("k1", map[string]string{"1": "abcd", "2": "efgh"})
-	dc.Add("k1", map[string][]byte{"3": []byte("ijk"), "4": []byte("lmo")})
-	dc2.Add("k2", map[string][]byte{"1": []byte("123456789")})
+	arc(1, 2) // the two gets cause two updates
+	add(dc, "k1", map[string]string{"3": "ijk", "4": "lmo"})
+	arc(1, 3) // dc.Add() causes re-read in dc2
+	ak("k1")
+	arc(1, 3)
+	add(dc2, "k2", map[string]string{"1": "123456789"})
+	arc(2, 3) // dc2.Add() causes re-read in dc
+	ak("k1", "k2")
+	arc(2, 3)
 	ad("k1", map[string]string{"1": "abcd", "2": "efgh", "3": "ijk"})
 	if dc.entries.TotalSize != 14+9 {
 		t.Fatalf("TotalSize: %d != %d", dc.entries.TotalSize, 14+9)
 	}
+	arc(3, 4) // the two gets cause two updates
+	ak("k2", "k1")
+	dc.Get("k2")
+	arc(3, 5) // dc.Get() causes dc2 to read
 	ak("k1", "k2")
-	dc.Add("k3", map[string][]byte{"1": []byte(strings.Repeat("a", int(dc.MaxSize)-10))})
-	ak("k3", "k2")
+	add(dc, "k3", map[string]string{"1": strings.Repeat("a", int(dc.MaxSize)-10)})
+	arc(3, 6) // dc.Add() causes dc2 to read
+	ak("k2", "k3")
 	// check that creating a new disk cache prunes
 	_, err = NewDiskCache(tdir, dc.MaxSize-8)
 	if err != nil {
 		t.Fatal(err)
 	}
 	ak("k3")
+	arc(4, 7) // NewDiskCache()
+
+	// test the path api
+	path := filepath.Join(tdir, "source")
+	if err = os.WriteFile(path, []byte("abcdfjrof"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	key, _, err := dc.GetPath(path)
+	if _, err = dc.AddPath(path, key, map[string][]byte{"1": []byte("1")}); err != nil {
+		t.Fatal(err)
+	}
+	_, _, entries_before, _ := dc.entries_from_folders()
+	if diff := cmp.Diff(1, len(dc.entries.PathMap)); diff != "" {
+		t.Fatalf("unexpected pathmap count: %s", diff)
+	}
+	if err = os.WriteFile(path, []byte("changed contents"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if _, err = dc.AddPath(path, key, map[string][]byte{"1": []byte("2")}); err != nil {
+		t.Fatal(err)
+	}
+	if diff := cmp.Diff(1, len(dc.entries.PathMap)); diff != "" {
+		t.Fatalf("unexpected pathmap count: %s", diff)
+	}
+	_, _, entries_after, _ := dc.entries_from_folders()
+	if len(entries_before) != len(entries_after) {
+		t.Fatalf("unexpected entries: %s", entries_after)
+	}
+	arc(4, 8) // dc.AddPath() causes dc2 to read
 }

tools/tui/download_with_progress.go

@@ -101,6 +101,7 @@ func DownloadFileWithProgress(destpath, url string, kill_if_signaled bool) (err
 	}
 
 	do_download := func() {
+		lp.RecoverFromPanicInGoRoutine()
 		dl_data.mutex.Lock()
 		dl_data.download_started = true
 		dl_data.mutex.Unlock()

tools/tui/graphics/collection.go

@@ -136,14 +136,16 @@ func (self *ImageCollection) ResizeForPageSize(width, height int) {
 
 	ctx := images.Context{}
 	keys := utils.Keys(self.images)
-	ctx.Parallel(0, len(keys), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, len(keys), func(nums <-chan int) {
 		for i := range nums {
 			img := self.images[keys[i]]
 			if img.src.loaded && img.err == nil {
 				img.ResizeForPageSize(width, height)
 			}
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 }
 
 func (self *ImageCollection) DeleteAllVisiblePlacements(lp *loop.Loop) {
@@ -294,7 +296,7 @@ func (self *ImageCollection) LoadAll() {
 	defer self.mutex.Unlock()
 	ctx := images.Context{}
 	all := utils.Values(self.images)
-	ctx.Parallel(0, len(self.images), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, len(self.images), func(nums <-chan int) {
 		for i := range nums {
 			img := all[i]
 			if !img.src.loaded {
@@ -305,7 +307,9 @@ func (self *ImageCollection) LoadAll() {
 				img.src.loaded = true
 			}
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 }
 
 func NewImageCollection(paths ...string) *ImageCollection {

tools/tui/loop/read.go

@@ -44,6 +44,12 @@ func read_ignoring_temporary_errors(f *tty.Term, buf []byte) (int, error) {
 }
 
 func read_from_tty(pipe_r *os.File, term *tty.Term, results_channel chan<- []byte, err_channel chan<- error, quit_channel <-chan byte, leftover_channel chan<- []byte) {
+	defer func() {
+		if r := recover(); r != nil {
+			text, _ := utils.Format_stacktrace_on_panic(r)
+			err_channel <- fmt.Errorf("%s", text)
+		}
+	}()
 	keep_going := true
 	pipe_fd := int(pipe_r.Fd())
 	tty_fd := term.Fd()
@@ -115,6 +121,12 @@ func read_until_primary_device_attributes_response(term *tty.Term, initial_bytes
 	}
 	received := make(chan error)
 	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				text, _ := utils.Format_stacktrace_on_panic(r)
+				received <- fmt.Errorf("%s", text)
+			}
+		}()
 		buf := make([]byte, 1024)
 		n, err := read_ignoring_temporary_errors(term, buf)
 		if n > 0 {

tools/tui/loop/write.go

@@ -168,6 +168,12 @@ func write_to_tty(
 	pipe_r *os.File, term *tty.Term,
 	job_channel <-chan write_msg, err_channel chan<- error, write_done_channel chan<- IdType,
 ) {
+	defer func() {
+		if r := recover(); r != nil {
+			text, _ := utils.Format_stacktrace_on_panic(r)
+			err_channel <- fmt.Errorf("%s", text)
+		}
+	}()
 	keep_going := true
 	defer func() {
 		pipe_r.Close()

tools/unicode_names/query.go

@@ -99,6 +99,9 @@ func find_matching_codepoints(prefix string) (ans mark_set) {
 			ans.AddItems(marks...)
 		}
 	}
+	if ans == nil {
+		ans = utils.NewSet[uint16](0)
+	}
 	return ans
 }
 
@@ -107,11 +110,13 @@ func marks_for_query(query string) (ans mark_set) {
 	prefixes := strings.Split(strings.ToLower(query), " ")
 	results := make(chan mark_set, len(prefixes))
 	ctx := images.Context{}
-	ctx.Parallel(0, len(prefixes), func(nums <-chan int) {
+	if err := ctx.SafeParallel(0, len(prefixes), func(nums <-chan int) {
 		for i := range nums {
 			results <- find_matching_codepoints(prefixes[i])
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 	close(results)
 	for x := range results {
 		if ans == nil {

tools/utils/images/convert.go

@@ -5,8 +5,10 @@ import (
 	"encoding/binary"
 	"fmt"
 	"image"
+	"image/color"
 	"io"
 	"os"
+	"slices"
 	"strings"
 
 	"github.com/kovidgoyal/kitty/tools/cli"
@@ -17,9 +19,9 @@ var _ = fmt.Print
 
 func encode_rgba(output io.Writer, img image.Image) (err error) {
 	var final_img *image.NRGBA
-	switch img.(type) {
+	switch ti := img.(type) {
 	case *image.NRGBA:
-		final_img = img.(*image.NRGBA)
+		final_img = ti
 	default:
 		b := img.Bounds()
 		final_img = image.NewNRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
@@ -68,6 +70,48 @@ func convert_image(input io.ReadSeeker, output io.Writer, format string) (err er
 	return Encode(output, img, mt)
 }
 
+func PalettedToNRGBA(paletted *image.Paletted) *image.NRGBA {
+	bounds := paletted.Bounds()
+	nrgba := image.NewNRGBA(bounds)
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			c := color.NRGBAModel.Convert(paletted.At(x, y))
+			nrgba.Set(x, y, c)
+		}
+	}
+	return nrgba
+}
+
+func develop_serialize(input_data []byte) (err error) {
+	img, err := OpenNativeImageFromReader(bytes.NewReader(input_data))
+	if err != nil {
+		return err
+	}
+	m, b := img.Serialize()
+	rimg, err := ImageFromSerialized(m, b)
+	if err != nil {
+		return err
+	}
+	for i := range img.Frames {
+		a, b := img.Frames[i], rimg.Frames[i]
+		if a.Img.Bounds() != b.Img.Bounds() {
+			return fmt.Errorf("bounds of frame %d not equal: %v != %v", i, a.Img.Bounds(), b.Img.Bounds())
+		}
+		for y := a.Img.Bounds().Min.Y; y < a.Img.Bounds().Max.Y; y++ {
+			for x := a.Img.Bounds().Min.X; x < a.Img.Bounds().Max.X; x++ {
+				or, og, ob, oa := a.Img.At(x, y).RGBA()
+				nr, ng, nb, na := b.Img.At(x, y).RGBA()
+				a, b := []uint32{or, og, ob, oa}, []uint32{nr, ng, nb, na}
+				if !slices.Equal(a, b) {
+					return fmt.Errorf("pixel at %dx%d differs: %v != %v", x, y, a, b)
+				}
+			}
+		}
+
+	}
+	return
+}
+
 func ConvertEntryPoint(root *cli.Command) {
 	root.AddSubCommand(&cli.Command{
 		Name:            "__convert_image__",
@@ -82,6 +126,11 @@ func ConvertEntryPoint(root *cli.Command) {
 			if _, err = io.Copy(buf, os.Stdin); err != nil {
 				return 1, err
 			}
+			if format == "develop-serialize" {
+				err = develop_serialize(buf.Bytes())
+				rc = utils.IfElse(err == nil, 0, 1)
+				return
+			}
 			if err = convert_image(bytes.NewReader(buf.Bytes()), os.Stdout, format); err != nil {
 				rc = 1
 			}

tools/utils/images/loading.go

@@ -10,6 +10,7 @@ import (
 	"image"
 	"image/color"
 	"image/gif"
+	"image/png"
 	"io"
 	"os"
 	"os/exec"
@@ -53,6 +54,27 @@ type ImageFrame struct {
 	Img                      image.Image
 }
 
+type SerializableImageFrame struct {
+	Width, Height, Left, Top int
+	Number                   int // 1-based number
+	Compose_onto             int // number of frame to compose onto
+	Delay_ms                 int // negative for gapless frame, zero ignored, positive is number of ms
+	Is_opaque                bool
+	Size                     int
+}
+
+func (s SerializableImageFrame) NeededSize() int {
+	return utils.IfElse(s.Is_opaque, 3, 4) * s.Width * s.Height
+}
+
+func (s *ImageFrame) Serialize() SerializableImageFrame {
+	return SerializableImageFrame{
+		Width: s.Width, Height: s.Height, Left: s.Left, Top: s.Top,
+		Number: s.Number, Compose_onto: s.Compose_onto, Delay_ms: int(s.Delay_ms),
+		Is_opaque: s.Is_opaque,
+	}
+}
+
 func (self *ImageFrame) DataAsSHM(pattern string) (ans shm.MMap, err error) {
 	bytes_per_pixel := 4
 	if self.Is_opaque {
@@ -122,12 +144,82 @@ func (self *ImageFrame) Data() (ans []byte) {
 	return
 }
 
+func ImageFrameFromSerialized(s SerializableImageFrame, data []byte) (aa *ImageFrame, err error) {
+	ans := ImageFrame{
+		Width: s.Width, Height: s.Height, Left: s.Left, Top: s.Top,
+		Number: s.Number, Compose_onto: s.Compose_onto, Delay_ms: int32(s.Delay_ms),
+		Is_opaque: s.Is_opaque,
+	}
+	bytes_per_pixel := utils.IfElse(s.Is_opaque, 3, 4)
+	if expected := bytes_per_pixel * s.Width * s.Height; len(data) != expected {
+		return nil, fmt.Errorf("serialized image data has size: %d != %d", len(data), expected)
+	}
+	if s.Is_opaque {
+		ans.Img, err = NewNRGBWithContiguousRGBPixels(data, s.Left, s.Top, s.Width, s.Height)
+	} else {
+		ans.Img, err = NewNRGBAWithContiguousRGBAPixels(data, s.Left, s.Top, s.Width, s.Height)
+	}
+	return &ans, err
+}
+
 type ImageData struct {
 	Width, Height    int
 	Format_uppercase string
 	Frames           []*ImageFrame
 }
 
+type SerializableImageMetadata struct {
+	Version          int
+	Width, Height    int
+	Format_uppercase string
+	Frames           []SerializableImageFrame
+}
+
+const SERIALIZE_VERSION = 1
+
+func (self *ImageFrame) SaveAsUncompressedPNG(output io.Writer) error {
+	encoder := png.Encoder{CompressionLevel: png.NoCompression}
+	return encoder.Encode(output, self.Img)
+}
+
+func (self *ImageData) SerializeOnlyMetadata() SerializableImageMetadata {
+	f := make([]SerializableImageFrame, len(self.Frames))
+	for i, s := range self.Frames {
+		f[i] = s.Serialize()
+	}
+	return SerializableImageMetadata{Version: SERIALIZE_VERSION, Width: self.Width, Height: self.Height, Format_uppercase: self.Format_uppercase, Frames: f}
+}
+
+func (self *ImageData) Serialize() (SerializableImageMetadata, [][]byte) {
+	m := self.SerializeOnlyMetadata()
+	data := make([][]byte, len(self.Frames))
+	for i, f := range self.Frames {
+		data[i] = f.Data()
+		m.Frames[i].Size = len(data[i])
+	}
+	return m, data
+}
+
+func ImageFromSerialized(m SerializableImageMetadata, data [][]byte) (*ImageData, error) {
+	if m.Version > SERIALIZE_VERSION {
+		return nil, fmt.Errorf("serialized image data has unsupported version: %d", m.Version)
+	}
+	if len(m.Frames) != len(data) {
+		return nil, fmt.Errorf("serialized image data has %d frames in metadata but have data for: %d", len(m.Frames), len(data))
+	}
+	ans := ImageData{
+		Width: m.Width, Height: m.Height, Format_uppercase: m.Format_uppercase,
+	}
+	for i, f := range m.Frames {
+		if ff, err := ImageFrameFromSerialized(f, data[i]); err != nil {
+			return nil, err
+		} else {
+			ans.Frames = append(ans.Frames, ff)
+		}
+	}
+	return &ans, nil
+}
+
 func (self *ImageFrame) Resize(x_frac, y_frac float64) *ImageFrame {
 	b := self.Img.Bounds()
 	left, top, width, height := b.Min.X, b.Min.Y, b.Dx(), b.Dy()
@@ -194,29 +286,7 @@ func MakeTempDir(template string) (ans string, err error) {
 	return os.MkdirTemp("", template)
 }
 
-func check_resize(frame *ImageFrame, filename string) error {
-	// ImageMagick sometimes generates RGBA images smaller than the specified
-	// size. See https://github.com/kovidgoyal/kitty/issues/276 for examples
-	s, err := os.Stat(filename)
-	if err != nil {
-		return err
-	}
-	sz := int(s.Size())
-	bytes_per_pixel := 4
-	if frame.Is_opaque {
-		bytes_per_pixel = 3
-	}
-	expected_size := bytes_per_pixel * frame.Width * frame.Height
-	if sz < expected_size {
-		missing := expected_size - sz
-		if missing%(bytes_per_pixel*frame.Width) != 0 {
-			return fmt.Errorf("ImageMagick failed to resize correctly. It generated %d < %d of data (w=%d h=%d bpp=%d)", sz, expected_size, frame.Width, frame.Height, bytes_per_pixel)
-		}
-		frame.Height -= missing / (bytes_per_pixel * frame.Width)
-	}
-	return nil
-}
-
+// Native {{{
 func (frame *ImageFrame) set_delay(min_gap, delay int) {
 	frame.Delay_ms = int32(max(min_gap, delay) * 10)
 	if frame.Delay_ms == 0 {
@@ -266,10 +336,36 @@ func OpenNativeImageFromReader(f io.ReadSeeker) (ans *ImageData, err error) {
 	return
 }
 
+// }}}
+
+// ImageMagick {{{
 var MagickExe = sync.OnceValue(func() string {
 	return utils.FindExe("magick")
 })
 
+func check_resize(frame *ImageFrame, filename string) error {
+	// ImageMagick sometimes generates RGBA images smaller than the specified
+	// size. See https://github.com/kovidgoyal/kitty/issues/276 for examples
+	s, err := os.Stat(filename)
+	if err != nil {
+		return err
+	}
+	sz := int(s.Size())
+	bytes_per_pixel := 4
+	if frame.Is_opaque {
+		bytes_per_pixel = 3
+	}
+	expected_size := bytes_per_pixel * frame.Width * frame.Height
+	if sz < expected_size {
+		missing := expected_size - sz
+		if missing%(bytes_per_pixel*frame.Width) != 0 {
+			return fmt.Errorf("ImageMagick failed to resize correctly. It generated %d < %d of data (w=%d h=%d bpp=%d)", sz, expected_size, frame.Width, frame.Height, bytes_per_pixel)
+		}
+		frame.Height -= missing / (bytes_per_pixel * frame.Width)
+	}
+	return nil
+}
+
 func RunMagick(path string, cmd []string) ([]byte, error) {
 	if MagickExe() != "magick" {
 		cmd = append([]string{MagickExe()}, cmd...)
@@ -610,6 +706,8 @@ func OpenImageFromPathWithMagick(path string) (ans *ImageData, err error) {
 	return ans, nil
 }
 
+// }}}
+
 func OpenImageFromPath(path string) (ans *ImageData, err error) {
 	mt := utils.GuessMimeType(path)
 	if DecodableImageTypes[mt] {
@@ -620,7 +718,7 @@ func OpenImageFromPath(path string) (ans *ImageData, err error) {
 		defer f.Close()
 		ans, err = OpenNativeImageFromReader(f)
 		if err != nil {
-			return nil, fmt.Errorf("Failed to load image at %#v with error: %w", path, err)
+			return OpenImageFromPathWithMagick(path)
 		}
 	} else {
 		return OpenImageFromPathWithMagick(path)

tools/utils/images/opaque.go

@@ -9,6 +9,35 @@ import (
 
 var _ = fmt.Print
 
+func paletted_is_opaque(p *image.Paletted) bool {
+	if len(p.Palette) > 256 {
+		return p.Opaque()
+	}
+	var is_alpha [256]bool
+	has_alpha := false
+	for i, c := range p.Palette {
+		_, _, _, a := c.RGBA()
+		if a != 0xffff {
+			is_alpha[i] = true
+			has_alpha = true
+		}
+	}
+	if !has_alpha {
+		return true
+	}
+	i0, i1 := 0, p.Rect.Dx()
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if is_alpha[c] {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
 func IsOpaque(img image.Image) bool {
 	switch i := img.(type) {
 	case *image.RGBA:
@@ -30,7 +59,7 @@ func IsOpaque(img image.Image) bool {
 	case *image.CMYK:
 		return i.Opaque()
 	case *image.Paletted:
-		return i.Opaque()
+		return paletted_is_opaque(i)
 	case *image.Uniform:
 		return i.Opaque()
 	case *image.YCbCr:

tools/utils/images/serialize_test.go

@@ -0,0 +1,31 @@
+package images
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/kovidgoyal/kitty"
+)
+
+var _ = fmt.Print
+
+func TestImageSerialize(t *testing.T) {
+	img, err := OpenNativeImageFromReader(bytes.NewReader(kitty.KittyLogoAsPNGData))
+	if err != nil {
+		t.Fatal(err)
+	}
+	m, data := img.Serialize()
+	img2, err := ImageFromSerialized(m, data)
+	if err != nil {
+		t.Fatal(err)
+	}
+	m2, data2 := img2.Serialize()
+	if diff := cmp.Diff(m, m2); diff != "" {
+		t.Fatalf("Image metadata failed to roundtrip:\n%s", diff)
+	}
+	if diff := cmp.Diff(data, data2); diff != "" {
+		t.Fatalf("Image data failed to roundtrip:\n%s", diff)
+	}
+}

tools/utils/images/to_rgb.go

@@ -25,14 +25,14 @@ func (c NRGBColor) RGBA() (r, g, b, a uint32) {
 	g |= g << 8
 	b = uint32(c.B)
 	b |= b << 8
-	a = 65280 // ( 255 << 8 )
+	a = 65535 // (255 << 8 | 255)
 	return
 }
 
 // NRGB is an in-memory image whose At method returns NRGBColor values.
 type NRGB struct {
-	// Pix holds the image's pixels, in R, G, B, A order. The pixel at
-	// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*4].
+	// Pix holds the image's pixels, in R, G, B order. The pixel at
+	// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*3].
 	Pix []uint8
 	// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
 	Stride int
@@ -45,17 +45,18 @@ func nrgbModel(c color.Color) color.Color {
 		return c
 	}
 	r, g, b, a := c.RGBA()
-	if a == 0xffff {
+	switch a {
+	case 0xffff:
+		return NRGBColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8)}
+	case 0:
+		return NRGBColor{0, 0, 0}
+	default:
+		// Since Color.RGBA returns an alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
+		r = (r * 0xffff) / a
+		g = (g * 0xffff) / a
+		b = (b * 0xffff) / a
 		return NRGBColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8)}
 	}
-	if a == 0 {
-		return NRGBColor{0, 0, 0}
-	}
-	// Since Color.RGBA returns an alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
-	r = (r * 0xffff) / a
-	g = (g * 0xffff) / a
-	b = (b * 0xffff) / a
-	return NRGBColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8)}
 }
 
 var NRGBModel color.Model = color.ModelFunc(nrgbModel)
@@ -73,14 +74,14 @@ func (p *NRGB) NRGBAt(x, y int) NRGBColor {
 		return NRGBColor{}
 	}
 	i := p.PixOffset(x, y)
-	s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
+	s := p.Pix[i : i+3 : i+3] // Small cap improves performance, see https://golang.org/issue/27857
 	return NRGBColor{s[0], s[1], s[2]}
 }
 
 // PixOffset returns the index of the first element of Pix that corresponds to
 // the pixel at (x, y).
 func (p *NRGB) PixOffset(x, y int) int {
-	return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*4
+	return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*3
 }
 
 func (p *NRGB) Set(x, y int, c color.Color) {
@@ -170,14 +171,17 @@ func newScannerRGB(img image.Image, opaque_base NRGBColor) *scanner_rgb {
 	}
 	if img, ok := img.(*image.Paletted); ok {
 		s.palette = make([]NRGBColor, max(256, len(img.Palette)))
-		d := make([]uint8, 3)
+		d := [3]uint8{0, 0, 0}
+		ds := d[:]
 		for i := 0; i < len(img.Palette); i++ {
 			r, g, b, a := img.Palette[i].RGBA()
 			switch a {
 			case 0:
 				s.palette[i] = opaque_base
+			case 0xffff:
+				s.palette[i] = NRGBColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8)}
 			default:
-				blend(d, s.opaque_base, uint8((r*0xffff/a)>>8), uint8((g*0xffff/a)>>8), uint8((b*0xffff/a)>>8), uint8(a>>8))
+				blend(ds, s.opaque_base, uint8((r*0xffff/a)>>8), uint8((g*0xffff/a)>>8), uint8((b*0xffff/a)>>8), uint8(a>>8))
 				s.palette[i] = NRGBColor{d[0], d[1], d[2]}
 			}
 		}
@@ -425,3 +429,15 @@ func NewNRGB(r image.Rectangle) *NRGB {
 		Rect:   r,
 	}
 }
+
+func NewNRGBWithContiguousRGBPixels(p []byte, left, top, width, height int) (*NRGB, error) {
+	const bpp = 3
+	if expected := bpp * width * height; expected != len(p) {
+		return nil, fmt.Errorf("the image width and height dont match the size of the specified pixel data: width=%d height=%d sz=%d != %d", width, height, len(p), expected)
+	}
+	return &NRGB{
+		Pix:    p,
+		Stride: bpp * width,
+		Rect:   image.Rectangle{image.Point{left, top}, image.Point{left + width, top + height}},
+	}, nil
+}

tools/utils/images/to_rgba.go

@@ -321,7 +321,7 @@ func (self *Context) run_paste(src Scanner, background image.Image, pos image.Po
 	default:
 		panic(fmt.Sprintf("Unsupported image type: %v", v))
 	}
-	self.Parallel(interRect.Min.Y, interRect.Max.Y, func(ys <-chan int) {
+	if err := self.SafeParallel(interRect.Min.Y, interRect.Max.Y, func(ys <-chan int) {
 		for y := range ys {
 			x1 := interRect.Min.X - pasteRect.Min.X
 			x2 := interRect.Max.X - pasteRect.Min.X
@@ -333,7 +333,9 @@ func (self *Context) run_paste(src Scanner, background image.Image, pos image.Po
 			src.scan(x1, y1, x2, y2, dst)
 			postprocess(dst)
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 
 }
 
@@ -403,3 +405,15 @@ func FitImage(width, height, pwidth, pheight int) (final_width int, final_height
 
 	return width, height
 }
+
+func NewNRGBAWithContiguousRGBAPixels(p []byte, left, top, width, height int) (*image.NRGBA, error) {
+	const bpp = 4
+	if expected := bpp * width * height; expected != len(p) {
+		return nil, fmt.Errorf("the image width and height dont match the size of the specified pixel data: width=%d height=%d sz=%d != %d", width, height, len(p), expected)
+	}
+	return &image.NRGBA{
+		Pix:    p,
+		Stride: bpp * width,
+		Rect:   image.Rectangle{image.Point{left, top}, image.Point{left + width, left + height}},
+	}, nil
+}

tools/utils/images/transforms.go

@@ -27,18 +27,20 @@ func reverse_row(bytes_per_pixel int, pix []uint8) {
 
 func (self *Context) FlipPixelsH(bytes_per_pixel, width, height int, pix []uint8) {
 	stride := bytes_per_pixel * width
-	self.Parallel(0, height, func(ys <-chan int) {
+	if err := self.SafeParallel(0, height, func(ys <-chan int) {
 		for y := range ys {
 			i := y * stride
 			reverse_row(bytes_per_pixel, pix[i:i+stride])
 		}
-	})
+	}); err != nil {
+		panic(err)
+	}
 }
 
 func (self *Context) FlipPixelsV(bytes_per_pixel, width, height int, pix []uint8) {
 	stride := bytes_per_pixel * width
 	num := height / 2
-	self.Parallel(0, num, func(ys <-chan int) {
+	if err := self.SafeParallel(0, num, func(ys <-chan int) {
 		for y := range ys {
 			upper := y
 			lower := height - 1 - y
@@ -50,6 +52,7 @@ func (self *Context) FlipPixelsV(bytes_per_pixel, width, height int, pix []uint8
 				as[i], bs[i] = bs[i], as[i]
 			}
 		}
-	})
-
+	}); err != nil {
+		panic(err)
+	}
 }

tools/utils/images/utils.go

@@ -7,6 +7,8 @@ import (
 	"runtime"
 	"sync"
 	"sync/atomic"
+
+	"github.com/kovidgoyal/kitty/tools/utils"
 )
 
 var _ = fmt.Print
@@ -31,8 +33,10 @@ func (self *Context) EffectiveNumberOfThreads() int {
 	return ans
 }
 
-// parallel processes the data in separate goroutines.
-func (self *Context) Parallel(start, stop int, fn func(<-chan int)) {
+// parallel processes the data in separate goroutines. If any of them panics,
+// returns an error. Note that if multiple goroutines panic, only one error is
+// returned.
+func (self *Context) SafeParallel(start, stop int, fn func(<-chan int)) (err error) {
 	count := stop - start
 	if count < 1 {
 		return
@@ -49,9 +53,16 @@ func (self *Context) Parallel(start, stop int, fn func(<-chan int)) {
 	for range procs {
 		wg.Add(1)
 		go func() {
-			defer wg.Done()
+			defer func() {
+				if r := recover(); r != nil {
+					text, _ := utils.Format_stacktrace_on_panic(r)
+					err = fmt.Errorf("%s", text)
+				}
+				wg.Done()
+			}()
 			fn(c)
 		}()
 	}
 	wg.Wait()
+	return
 }

tools/utils/misc.go

@@ -73,8 +73,16 @@ func Format_stacktrace_on_panic(r any) (text string, err error) {
 	n := runtime.Callers(3, pcs)
 	lines := []string{}
 	frames := runtime.CallersFrames(pcs[:n])
-	err = fmt.Errorf("Panicked: %s", r)
-	lines = append(lines, fmt.Sprintf("\r\nPanicked with error: %s\r\nStacktrace (most recent call first):\r\n", r))
+	rt := fmt.Sprint(r)
+	if strings.HasPrefix(rt, "Panicked with error:") {
+		err = fmt.Errorf("%s", rt)
+		lines = append(lines, "Panic caused by previous panic (probably in a gouroutine). Previous panic:\r\n")
+		lines = append(lines, rt)
+		lines = append(lines, "\r\n\r\nStacktrace of current panic (most recent call first):\r\n")
+	} else {
+		err = fmt.Errorf("Panicked: %s", r)
+		lines = append(lines, fmt.Sprintf("\r\nPanicked with error: %s\r\nStacktrace (most recent call first):\r\n", r))
+	}
 	found_first_frame := false
 	for frame, more := frames.Next(); more; frame, more = frames.Next() {
 		if !found_first_frame {