Implement dynamic control of transparent background colors via escape code

Still have to implement it via remote control

docs/changelog.rst

@@ -77,6 +77,8 @@ Detailed list of changes
 0.36.3 [future]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+- The option ``second_transparent_bg`` has been removed and replaced by :opt:`transparent_background_colors` which allows setting up to seven additional colors that will be transparent, with individual opacities per color (:iss:`7646`)
+
 - Fix a regression in the previous release that broke use of the ``cd`` command in session files (:iss:`7829`)
 
 - macOS: Fix shortcuts that become entries in the global menubar being reported as removed shortcuts in the debug output
@@ -132,7 +134,7 @@ Detailed list of changes
 
 - launch command: A new :option:`launch --bias` option to adjust the size of newly created windows declaratively (:iss:`7634`)
 
-- A new option :opt:`second_transparent_bg` to make a second background color semi-transparent via :opt:`background_opacity`. Useful for things like cursor line highlight in editors (:iss:`7646`)
+- A new option :opt:`transparent_background_colors` to make a second background color semi-transparent via :opt:`background_opacity`. Useful for things like cursor line highlight in editors (:iss:`7646`)
 
 - A new :doc:`notify </kittens/notify>` kitten to show desktop notifications
   from the command line with support for icons, buttons and more.

docs/color-stack.rst

@@ -69,8 +69,11 @@ selection_foreground              The foreground color of selections
 cursor                            The color of the text cursor                    Foreground color
 cursor_text                       The color of text under the cursor              Background color
 visual_bell                       The color of a visual bell                      Automatic color selection based on current screen colors
-second_transparent_background     A color that might be rendered semi-transparent No second color is made transparent
-                                  in addition to the default background color
+transparent_background_color1..8  A background color that is rendered             Unset
+                                  with the specified opacity in cells that have
+                                  the specified background color. An opacity
+                                  value less than zero means, use the
+                                  :opt:`background_opacity` value.
 ================================= =============================================== ===============================
 
 In this table the third column shows what effect setting the color to *dynamic*
@@ -160,8 +163,19 @@ RGB colors are encoded in one of three forms:
 
 ``rgbi:<red>/<green>/<blue>``
     red, green, and blue are floating-point values between 0.0 and 1.0, inclusive. The input format for these values is an optional
-    sign, a string of numbers possibly containing a decimal point, and an optional exponent field containing an E or e followed by  a  possibly
-    signed integer string.
+    sign, a string of numbers possibly containing a decimal point, and an optional exponent field containing an E or e followed by a possibly
+    signed integer string. Values outside the ``0 - 1`` range must be clipped to be within the range.
+
+If a color should have an alpha component, it must be suffixed to the color
+specification in the form :code:`@number between zero and one`. For example::
+
+    red@0.5 rgb:ff0000@0.1 #ff0000@0.3
+
+The syntax for the floating point alpha component is the same as used for the
+components of ``rgbi`` defined above. When not specified, the default alpha
+value is ``1.0``. Values outside the range ``0 - 1`` must be clipped
+to be within the range, negative values may have special context dependent
+meaning.
 
 In addition, the following color names are accepted (case-insensitively) corresponding to the
 specified RGB values.

kitty/cell_fragment.glsl

@@ -187,7 +187,7 @@ void main() {
 #ifdef TRANSPARENT
     final_color = vec4_premul(background, bg_alpha);
 #else
-    final_color = vec4(background, draw_bg);
+    final_color = vec4(background, draw_bg * bg_alpha);
 #endif
 #endif
 

kitty/cell_vertex.glsl

@@ -4,13 +4,16 @@
 
 // Inputs {{{
 layout(std140) uniform CellRenderData {
-    float xstart, ystart, dx, dy, sprite_dx, sprite_dy, background_opacity, use_cell_bg_for_selection_fg, use_cell_fg_for_selection_fg, use_cell_for_selection_bg;
+    float xstart, ystart, dx, dy, sprite_dx, sprite_dy, use_cell_bg_for_selection_fg, use_cell_fg_for_selection_fg, use_cell_for_selection_bg;
 
-    uint default_fg, default_bg, highlight_fg, highlight_bg, cursor_fg, cursor_bg, url_color, url_style, inverted, second_transparent_bg;
+    uint default_fg, highlight_fg, highlight_bg, cursor_fg, cursor_bg, url_color, url_style, inverted;
 
     uint xnum, ynum, cursor_fg_sprite_idx;
     float cursor_x, cursor_y, cursor_w, cursor_opacity;
 
+    // must have unique entries with 0 being default_bg and unset being UINT32_MAX
+    uint bg_colors0, bg_colors1, bg_colors2, bg_colors3, bg_colors4, bg_colors5, bg_colors6, bg_colors7;
+    float bg_opacities0, bg_opacities1, bg_opacities2, bg_opacities3, bg_opacities4, bg_opacities5, bg_opacities6, bg_opacities7;
     uint color_table[NUM_COLORS + MARK_MASK + MARK_MASK + 2];
 };
 #if (PHASE == PHASE_BACKGROUND)
@@ -145,12 +148,30 @@ CellData set_vertex_position() {
     return CellData(has_cursor, has_cursor * is_block_cursor, pos);
 }
 
+float background_opacity_for(uint bg, uint colorval, float opacity_if_matched) {  // opacity_if_matched if bg == colorval else 1
+    float not_matched = step(1.f, abs(float(colorval - bg)));  // not_matched = 0 if bg == colorval else 1
+    return not_matched + opacity_if_matched * (1.f - not_matched);
+}
+
+float calc_background_opacity(uint bg) {
+    return (
+        background_opacity_for(bg, bg_colors0, bg_opacities0) *
+        background_opacity_for(bg, bg_colors1, bg_opacities1) *
+        background_opacity_for(bg, bg_colors2, bg_opacities2) *
+        background_opacity_for(bg, bg_colors3, bg_opacities3) *
+        background_opacity_for(bg, bg_colors4, bg_opacities4) *
+        background_opacity_for(bg, bg_colors5, bg_opacities5) *
+        background_opacity_for(bg, bg_colors6, bg_opacities6) *
+        background_opacity_for(bg, bg_colors7, bg_opacities7)
+    );
+}
+
 void main() {
 
     CellData cell_data = set_vertex_position();
 
     // set cell color indices {{{
-    uvec2 default_colors = uvec2(default_fg, default_bg);
+    uvec2 default_colors = uvec2(default_fg, bg_colors0);
     uint text_attrs = sprite_coords[3];
     uint is_reversed = ((text_attrs >> REVERSE_SHIFT) & ONE);
     uint is_inverted = is_reversed + inverted;
@@ -194,42 +215,34 @@ void main() {
     // }}}
 
     // Background {{{
-    float bg_is_not_transparent = step(1, float(abs(
-        (bg_as_uint - default_colors[1]) * (bg_as_uint - second_transparent_bg)
-    )));  // bg_is_not_transparent = 0 if bg_as_uint in (default_colors[1], second_transparent_bg) else 1
+#if PHASE == PHASE_BOTH && !defined(TRANSPARENT)  // fast case single pass opaque background
+    bg_alpha = 1;
     draw_bg = 1;
-
+#else
+    bg_alpha = calc_background_opacity(bg_as_uint);
 #if (PHASE == PHASE_BACKGROUND)
     // draw_bg_bitfield has bit 0 set to draw default bg cells and bit 1 set to draw non-default bg cells
-    uint draw_bg_mask = uint(2 * bg_is_not_transparent + (1 - bg_is_not_transparent));
-    draw_bg = step(1, float(draw_bg_bitfield & draw_bg_mask));
+    float cell_has_non_default_bg = step(1.f, abs(float(bg_as_uint - bg_colors0))); // 0 if has default bg else 1
+    uint draw_bg_mask = uint(2.f * cell_has_non_default_bg + (1.f - cell_has_non_default_bg)); // 1 if has default bg else 2
+    draw_bg = step(0.5, float(draw_bg_bitfield & draw_bg_mask));
+#else
+    draw_bg = 1;
 #endif
 
-    bg_alpha = 1.f;
-#ifdef TRANSPARENT
-    // Set bg_alpha to background_opacity on cells that have the default background color
-    // Which means they must not have a block cursor or a selection or reverse video
-    // On other cells it should be 1. For the SPECIAL program it should be 1 on cells with
-    // selections/block cursor and 0 everywhere else.
     float is_special_cell = cell_data.has_block_cursor + float(is_selected & ONE);
-#if (PHASE != PHASE_SPECIAL)
-    is_special_cell += bg_is_not_transparent + float(is_reversed);
-#endif
+#if PHASE == PHASE_SPECIAL
+    // Only special cells must be drawn and they must have bg_alpha 1
     bg_alpha = step(0.5, is_special_cell); // bg_alpha = 1 if is_special_cell else 0
-#if (PHASE != PHASE_SPECIAL)
-    bg_alpha = bg_alpha + (1.0f - bg_alpha) * background_opacity;  // bg_alpha = 1 if bg_alpha else background_opacity
-    bg_alpha *= draw_bg;  // if not draw_bg: bg_alpha = 0
-#endif
+#else
+    is_special_cell += float(is_reversed);  // bg_alpha should be 1 for reverse video cells as well
+    is_special_cell = step(0.5, is_special_cell);  // is_special_cell = 1 if is_special_cell else 0
+    bg_alpha = bg_alpha * (1. - float(is_special_cell)) + is_special_cell;  // bg_alpha = 1 if is_special_cell else bg_alpha
 #endif
+    bg_alpha *= draw_bg;
+#endif  // ends fast case #if else
 
     // Selection and cursor
     bg = choose_color(float(is_selected & ONE), choose_color(use_cell_for_selection_bg, color_to_vec(fg_as_uint), color_to_vec(highlight_bg)), bg);
     background = choose_color(cell_data.has_block_cursor, mix(bg, color_to_vec(cursor_bg), cursor_opacity), bg);
-#if !defined(TRANSPARENT) && (PHASE == PHASE_SPECIAL)
-    float is_special_cell = cell_data.has_block_cursor + float(is_selected & ONE);
-    bg_alpha = step(0.5, is_special_cell);
-#endif
-
     // }}}
-
 }

kitty/colors.c

@@ -80,9 +80,18 @@ set_configured_colors(ColorProfile *self, PyObject *opts) {
     n(default_fg, foreground); n(default_bg, background);
     n(cursor_color, cursor); n(cursor_text_color, cursor_text_color);
     n(highlight_fg, selection_foreground); n(highlight_bg, selection_background);
-    n(visual_bell_color, visual_bell_color); n(second_transparent_bg, second_transparent_bg);
+    n(visual_bell_color, visual_bell_color);
 #undef n
-    return true;
+    memset(self->configured_transparent_colors, 0, sizeof(self->configured_transparent_colors));
+    RAII_PyObject(src, PyObject_GetAttrString(opts, "transparent_background_colors"));
+    if (!src) { PyErr_SetString(PyExc_TypeError, "No transparent_background_colors on opts object"); return false; }
+    for (Py_ssize_t i = 0; i < MIN(PyTuple_GET_SIZE(src), (Py_ssize_t)arraysz(self->configured_transparent_colors)); i++) {
+        PyObject *e = PyTuple_GET_ITEM(src, i);
+        self->configured_transparent_colors[i].color = ((Color*)(PyTuple_GET_ITEM(e, 0)))->color.val & 0xffffff;
+        self->configured_transparent_colors[i].opacity = (float)PyFloat_AsDouble(PyTuple_GET_ITEM(e, 1));
+        self->configured_transparent_colors[i].is_set = true;
+    }
+    return PyErr_Occurred() ? false : true;
 }
 
 static bool
@@ -162,6 +171,8 @@ copy_color_profile(ColorProfile *dest, ColorProfile *src) {
     memcpy(dest->orig_color_table, src->orig_color_table, sizeof(dest->color_table));
     memcpy(&dest->configured, &src->configured, sizeof(dest->configured));
     memcpy(&dest->overridden, &src->overridden, sizeof(dest->overridden));
+    memcpy(dest->overriden_transparent_colors, src->overriden_transparent_colors, sizeof(dest->overriden_transparent_colors));
+    memcpy(dest->configured_transparent_colors, src->configured_transparent_colors, sizeof(dest->configured_transparent_colors));
     dest->dirty = true;
 }
 
@@ -226,12 +237,30 @@ patch_color_profiles(PyObject *module UNUSED, PyObject *args) {
         S(foreground, default_fg); S(background, default_bg); S(cursor, cursor_color);
         S(selection_foreground, highlight_fg); S(selection_background, highlight_bg);
         S(cursor_text_color, cursor_text_color); S(visual_bell_color, visual_bell_color);
-        S(second_transparent_bg, second_transparent_bg);
 #undef SI
 #undef S
+    // TODO: Patch transparent_colors
     Py_RETURN_NONE;
 }
 
+bool
+colorprofile_to_transparent_color(const ColorProfile *self, unsigned index, color_type *color, float *opacity) {
+    *color = UINT32_MAX; *opacity = 1.0;
+    if (index < arraysz(self->configured_transparent_colors)) {
+        if (self->overriden_transparent_colors[index].is_set) {
+            *color = self->overriden_transparent_colors[index].color; *opacity = self->overriden_transparent_colors[index].opacity;
+            if (*opacity < 0) *opacity = OPT(background_opacity);
+            return true;
+        }
+        if (self->configured_transparent_colors[index].is_set) {
+            *color = self->configured_transparent_colors[index].color; *opacity = self->configured_transparent_colors[index].opacity;
+            if (*opacity < 0) *opacity = OPT(background_opacity);
+            return true;
+        }
+    }
+    return false;
+}
+
 DynamicColor
 colorprofile_to_color(const ColorProfile *self, DynamicColor entry, DynamicColor defval) {
     switch(entry.type) {
@@ -295,9 +324,10 @@ as_dict(ColorProfile *self, PyObject *args UNUSED) {
     }}
     D(default_fg, foreground); D(default_bg, background);
     D(cursor_color, cursor); D(cursor_text_color, cursor_text); D(highlight_fg, selection_foreground);
-    D(highlight_bg, selection_background); D(visual_bell_color, visual_bell_color); D(second_transparent_bg, second_transparent_bg);
+    D(highlight_bg, selection_background); D(visual_bell_color, visual_bell_color);
 
 #undef D
+    // TODO: Add transparent_colors
     return ans;
 }
 
@@ -373,6 +403,8 @@ copy_color_table_to_buffer(ColorProfile *self, color_type *buf, int offset, size
 
 static void
 push_onto_color_stack_at(ColorProfile *self, unsigned int i) {
+    self->color_stack[i].dynamic_colors = self->overridden;
+    memcpy(self->color_stack[i].transparent_colors, self->overriden_transparent_colors, sizeof(self->overriden_transparent_colors));
     self->color_stack[i].dynamic_colors = self->overridden;
     memcpy(self->color_stack[i].color_table, self->color_table, sizeof(self->color_stack->color_table));
 }
@@ -381,6 +413,7 @@ static void
 copy_from_color_stack_at(ColorProfile *self, unsigned int i) {
     self->overridden = self->color_stack[i].dynamic_colors;
     memcpy(self->color_table, self->color_stack[i].color_table, sizeof(self->color_table));
+    memcpy(self->overriden_transparent_colors, self->color_stack[i].transparent_colors, sizeof(self->overriden_transparent_colors));
 }
 
 bool
@@ -477,7 +510,6 @@ CGETSET(cursor_text_color, true)
 CGETSET(highlight_fg, true)
 CGETSET(highlight_bg, true)
 CGETSET(visual_bell_color, true)
-CGETSET(second_transparent_bg, true)
 #undef CGETSET
 
 static PyGetSetDef cp_getsetters[] = {
@@ -488,7 +520,6 @@ static PyGetSetDef cp_getsetters[] = {
     GETSET(highlight_fg)
     GETSET(highlight_bg)
     GETSET(visual_bell_color)
-    GETSET(second_transparent_bg)
     {NULL}  /* Sentinel */
 };
 
@@ -508,6 +539,36 @@ reload_from_opts(ColorProfile *self, PyObject *args UNUSED) {
     Py_RETURN_NONE;
 }
 
+static PyObject*
+get_transparent_background_color(ColorProfile *self, PyObject *index) {
+    if (!PyLong_Check(index)) { PyErr_SetString(PyExc_TypeError, "index must be an int"); return NULL; }
+    unsigned long idx = PyLong_AsUnsignedLong(index);
+    if (PyErr_Occurred()) return NULL;
+    if (idx >= arraysz(self->configured_transparent_colors)) Py_RETURN_NONE;
+    TransparentDynamicColor *c = self->overriden_transparent_colors[idx].is_set ? self->overriden_transparent_colors + idx : self->configured_transparent_colors + idx;
+    if (!c->is_set) Py_RETURN_NONE;
+    float opacity = c->opacity >= 0 ? c->opacity : OPT(background_opacity);
+    return (PyObject*)alloc_color((c->color >> 16) & 0xff, (c->color >> 8) & 0xff, c->color & 0xff, (unsigned)(255.f * opacity));
+}
+
+static PyObject*
+set_transparent_background_color(ColorProfile *self, PyObject *const *args, Py_ssize_t nargs) {
+    if (nargs < 1) { PyErr_SetString(PyExc_TypeError, "must specify index"); return NULL; }
+    if (!PyLong_Check(args[0])) { PyErr_SetString(PyExc_TypeError, "index must be an int"); return NULL; }
+    unsigned long idx = PyLong_AsUnsignedLong(args[0]);
+    if (PyErr_Occurred()) return NULL;
+    if (idx >= arraysz(self->configured_transparent_colors)) Py_RETURN_NONE;
+    if (nargs < 2) { self->overriden_transparent_colors[idx].is_set = false; Py_RETURN_NONE; }
+    if (!PyObject_TypeCheck(args[1], &Color_Type)) { PyErr_SetString(PyExc_TypeError, "color must be Color object"); return NULL; }
+    Color *c = (Color*)args[1];
+    float opacity = (float)(c->color.alpha) / 255.f;
+    if (nargs > 2 && PyFloat_Check(args[2])) opacity = (float)PyFloat_AsDouble(args[2]);
+    self->overriden_transparent_colors[idx].is_set = true;
+    self->overriden_transparent_colors[idx].color = c->color.rgb;
+    self->overriden_transparent_colors[idx].opacity = MAX(-1.f, MIN(opacity, 1.f));
+    Py_RETURN_NONE;
+}
+
 static PyMethodDef cp_methods[] = {
     METHOD(reset_color_table, METH_NOARGS)
     METHOD(as_dict, METH_NOARGS)
@@ -515,7 +576,9 @@ static PyMethodDef cp_methods[] = {
     METHOD(as_color, METH_O)
     METHOD(reset_color, METH_O)
     METHOD(set_color, METH_VARARGS)
+    METHODB(get_transparent_background_color, METH_O),
     METHODB(reload_from_opts, METH_VARARGS),
+    {"set_transparent_background_color", (PyCFunction)(void(*)(void))set_transparent_background_color, METH_FASTCALL, ""},
     {NULL}  /* Sentinel */
 };
 
@@ -552,7 +615,7 @@ new_color(PyTypeObject *type UNUSED, PyObject *args, PyObject *kwds) {
 }
 
 static PyObject*
-color_as_int(Color *self) {
+Color_as_int(Color *self) {
     return PyLong_FromUnsignedLong(self->color.val);
 }
 
@@ -566,7 +629,7 @@ color_truediv(Color *self, PyObject *divisor) {
 }
 
 static PyNumberMethods color_number_methods = {
-    .nb_int = (unaryfunc)color_as_int,
+    .nb_int = (unaryfunc)Color_as_int,
     .nb_true_divide = (binaryfunc)color_truediv,
 };
 

kitty/data-types.h

@@ -323,15 +323,21 @@ typedef union DynamicColor {
 } DynamicColor;
 
 typedef struct {
-    DynamicColor default_fg, default_bg, cursor_color, cursor_text_color, highlight_fg, highlight_bg, visual_bell_color, second_transparent_bg;
+    DynamicColor default_fg, default_bg, cursor_color, cursor_text_color, highlight_fg, highlight_bg, visual_bell_color;
 } DynamicColors;
 
+typedef struct TransparentDynamicColor {
+    color_type color; float opacity; bool is_set;
+} TransparentDynamicColor;
+
+
 typedef struct {
     PyObject_HEAD
 
     bool dirty;
     uint32_t color_table[256], orig_color_table[256];
-    struct { DynamicColors dynamic_colors; uint32_t color_table[256]; } *color_stack;
+    TransparentDynamicColor configured_transparent_colors[8], overriden_transparent_colors[8];
+    struct { DynamicColors dynamic_colors; uint32_t color_table[256]; TransparentDynamicColor transparent_colors[8]; } *color_stack;
     unsigned int color_stack_idx, color_stack_sz;
     DynamicColors configured, overridden;
     color_type mark_foregrounds[MARK_MASK+1], mark_backgrounds[MARK_MASK+1];
@@ -403,6 +409,7 @@ bool schedule_write_to_child_python(unsigned long id, const char *prefix, PyObje
 bool set_iutf8(int, bool);
 
 DynamicColor colorprofile_to_color(const ColorProfile *self, DynamicColor entry, DynamicColor defval);
+bool colorprofile_to_transparent_color(const ColorProfile *self, unsigned index, color_type *color, float *opacity);
 color_type
 colorprofile_to_color_with_fallback(ColorProfile *self, DynamicColor entry, DynamicColor defval, DynamicColor fallback, DynamicColor falback_defval);
 void copy_color_table_to_buffer(ColorProfile *self, color_type *address, int offset, size_t stride);

kitty/fast_data_types.pyi

@@ -809,11 +809,6 @@ class ColorProfile:
     @visual_bell_color.setter
     def visual_bell_color(self, val: Union[None|int|Color]) -> None: ...
 
-    @property
-    def second_transparent_bg(self) -> Optional[Color]: ...
-    @second_transparent_bg.setter
-    def second_transparent_bg(self, val: Union[None|int|Color]) -> None: ...
-
     def __init__(self, opts: Optional[Options] = None): ...
 
     def as_dict(self) -> Dict[str, Optional[int]]:
@@ -833,6 +828,9 @@ class ColorProfile:
 
     def reload_from_opts(self, opts: Optional[Options] = None) -> None: ...
 
+    def get_transparent_background_color(self, index: int) -> Color | None: ...
+    def set_transparent_background_color(self, index: int, color: Color | None = None, opacity: float | None = None) -> None: ...
+
 
 def patch_color_profiles(
     spec: Dict[str, Optional[int]], profiles: Tuple[ColorProfile, ...], change_configured: bool

kitty/options/definition.py

@@ -1481,7 +1481,7 @@ theme with a background color in your editor, it will not be rendered as
 transparent. Instead you should change the default background color in your
 kitty config and not use a background color in the editor color scheme. Or use
 the escape codes to set the terminals default colors in a shell script to
-launch your editor. See also :opt:`second_transparent_bg`.
+launch your editor. See also :opt:`transparent_background_colors`.
 Be aware that using a value less than 1.0 is a (possibly
 significant) performance hit. When using a low value for this setting, it is
 desirable that you set the :opt:`background` color to a color the matches the
@@ -1527,14 +1527,22 @@ opt('background_image_linear', 'no',
     long_text='When background image is scaled, whether linear interpolation should be used.'
     )
 
-opt('second_transparent_bg', 'none', option_type='to_color_or_none', long_text='''
-When the background color matches this color, :opt:`background_opacity` is applied to it
-to render it as semi-transparent, just as for colors matching the main :opt:`background` color.
+opt('transparent_background_colors', '', option_type='transparent_background_colors', long_text='''
+A space separated list of upto 7 colors, with opacity. When the background color of a cell matches one of these colors,
+it is rendered semi-transparent using the specified opacity.
+
 Useful in more complex UIs like editors where you could want more than a single background color
-to be rendered as transparent, for instance, for a cursor highlight line background.
+to be rendered as transparent, for instance, for a cursor highlight line background or a highlighted block.
 Terminal applications can set this color using :ref:`The kitty color control <color_control>`
 escape code.
-''')
+
+The syntax for specifiying colors is: :code:`color@opacity`, where the :code:`@opacity`
+part is optional. When unspecified, the value of :opt:`background_opacity` is used. For example::
+
+    transparent_background_colors red@0.5 #00ff00@0.3
+
+'''
+)
 
 opt('dynamic_background_opacity', 'no',
     option_type='to_bool', ctype='bool',

kitty/options/parse.py

@@ -19,8 +19,9 @@ from kitty.options.utils import (
     shell_integration, store_multiple, symbol_map, tab_activity_symbol, tab_bar_edge,
     tab_bar_margin_height, tab_bar_min_tabs, tab_fade, tab_font_style, tab_separator,
     tab_title_template, titlebar_color, to_cursor_shape, to_cursor_unfocused_shape, to_font_size,
-    to_layout_names, to_modifiers, url_prefixes, url_style, visual_bell_duration,
-    visual_window_select_characters, window_border_width, window_logo_scale, window_size
+    to_layout_names, to_modifiers, transparent_background_colors, url_prefixes, url_style,
+    visual_bell_duration, visual_window_select_characters, window_border_width, window_logo_scale,
+    window_size
 )
 
 
@@ -1193,9 +1194,6 @@ class Parser:
     def scrollback_pager_history_size(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['scrollback_pager_history_size'] = scrollback_pager_history_size(val)
 
-    def second_transparent_bg(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
-        ans['second_transparent_bg'] = to_color_or_none(val)
-
     def select_by_word_characters(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['select_by_word_characters'] = str(val)
 
@@ -1326,6 +1324,9 @@ class Parser:
     def touch_scroll_multiplier(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['touch_scroll_multiplier'] = float(val)
 
+    def transparent_background_colors(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
+        ans['transparent_background_colors'] = transparent_background_colors(val)
+
     def undercurl_style(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         val = val.lower()
         if val not in self.choices_for_undercurl_style:

kitty/options/types.py

@@ -409,7 +409,6 @@ option_names = (  # {{{
  'scrollback_lines',
  'scrollback_pager',
  'scrollback_pager_history_size',
- 'second_transparent_bg',
  'select_by_word_characters',
  'select_by_word_characters_forward',
  'selection_background',
@@ -443,6 +442,7 @@ option_names = (  # {{{
  'text_composition_strategy',
  'text_fg_override_threshold',
  'touch_scroll_multiplier',
+ 'transparent_background_colors',
  'undercurl_style',
  'underline_hyperlinks',
  'update_check_interval',
@@ -574,7 +574,6 @@ class Options:
     scrollback_lines: int = 2000
     scrollback_pager: typing.List[str] = ['less', '--chop-long-lines', '--RAW-CONTROL-CHARS', '+INPUT_LINE_NUMBER']
     scrollback_pager_history_size: int = 0
-    second_transparent_bg: typing.Optional[kitty.fast_data_types.Color] = None
     select_by_word_characters: str = '@-./_~?&=%+#'
     select_by_word_characters_forward: str = ''
     selection_background: typing.Optional[kitty.fast_data_types.Color] = Color(255, 250, 205)
@@ -607,6 +606,7 @@ class Options:
     text_composition_strategy: str = 'platform'
     text_fg_override_threshold: float = 0.0
     touch_scroll_multiplier: float = 1.0
+    transparent_background_colors: typing.Tuple[typing.Tuple[kitty.fast_data_types.Color, float], ...] = ()
     undercurl_style: choices_for_undercurl_style = 'thin-sparse'
     underline_hyperlinks: choices_for_underline_hyperlinks = 'hover'
     update_check_interval: float = 24.0
@@ -1035,7 +1035,6 @@ nullable_colors = frozenset({
     'active_border_color'
     'tab_bar_background'
     'tab_bar_margin_color'
-    'second_transparent_bg'
     'selection_foreground'
     'selection_background'
 })

kitty/options/utils.py

@@ -1554,6 +1554,23 @@ def visual_bell_duration(spec: str) -> Tuple[float, EasingFunction, EasingFuncti
     return parse_animation(spec, interval=0.)
 
 
+def transparent_background_colors(spec: str) -> Tuple[Tuple[Color, float], ...]:
+    if not spec:
+        return ()
+    ans: list[tuple[Color, float]] = []
+    seen: dict[Color, int] = {}
+    for part in spec.split():
+        col, sep, alpha = part.partition('@')
+        c = to_color(col)
+        o = unit_float(alpha) if alpha else -1
+        if (idx := seen.get(c)) is not None:
+            ans[idx] = c, o
+            continue
+        seen[c] = len(ans)
+        ans.append((c, o))
+    return tuple(ans[:7])
+
+
 def deprecated_hide_window_decorations_aliases(key: str, val: str, ans: Dict[str, Any]) -> None:
     if not hasattr(deprecated_hide_window_decorations_aliases, key):
         setattr(deprecated_hide_window_decorations_aliases, key, True)

kitty/shaders.c

@@ -293,12 +293,14 @@ pick_cursor_color(Line *line, const ColorProfile *color_profile, color_type cell
 static void
 cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, const CellRenderData *crd, CursorRenderInfo *cursor, OSWindow *os_window) {
     struct GPUCellRenderData {
-        GLfloat xstart, ystart, dx, dy, sprite_dx, sprite_dy, background_opacity, use_cell_bg_for_selection_fg, use_cell_fg_for_selection_color, use_cell_for_selection_bg;
+        GLfloat xstart, ystart, dx, dy, sprite_dx, sprite_dy, use_cell_bg_for_selection_fg, use_cell_fg_for_selection_color, use_cell_for_selection_bg;
 
-        GLuint default_fg, default_bg, highlight_fg, highlight_bg, cursor_fg, cursor_bg, url_color, url_style, inverted, second_transparent_bg;
+        GLuint default_fg, highlight_fg, highlight_bg, cursor_fg, cursor_bg, url_color, url_style, inverted;
 
         GLuint xnum, ynum, cursor_fg_sprite_idx;
         GLfloat cursor_x, cursor_y, cursor_w, cursor_opacity;
+        GLuint bg_colors0, bg_colors1, bg_colors2, bg_colors3, bg_colors4, bg_colors5, bg_colors6, bg_colors7;
+        GLfloat bg_opacities0, bg_opacities1, bg_opacities2, bg_opacities3, bg_opacities4, bg_opacities5, bg_opacities6, bg_opacities7;
     };
     // Send the uniform data
     struct GPUCellRenderData *rd = (struct GPUCellRenderData*)map_vao_buffer(vao_idx, uniform_buffer, GL_WRITE_ONLY);
@@ -307,8 +309,13 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
         copy_color_table_to_buffer(cp, (GLuint*)rd, cell_program_layouts[CELL_PROGRAM].color_table.offset / sizeof(GLuint), cell_program_layouts[CELL_PROGRAM].color_table.stride / sizeof(GLuint));
     }
 #define COLOR(name) colorprofile_to_color(cp, cp->overridden.name, cp->configured.name).rgb
-    rd->default_fg = COLOR(default_fg); rd->default_bg = COLOR(default_bg);
+    rd->default_fg = COLOR(default_fg);
     rd->highlight_fg = COLOR(highlight_fg); rd->highlight_bg = COLOR(highlight_bg);
+    rd->bg_colors0 = COLOR(default_bg);
+    rd->bg_opacities0 = os_window->is_semi_transparent ? os_window->background_opacity : 1.0f;
+#define SETBG(which) colorprofile_to_transparent_color(cp, which - 1, &rd->bg_colors##which, &rd->bg_opacities##which)
+    SETBG(1); SETBG(2); SETBG(3); SETBG(4); SETBG(5); SETBG(6); SETBG(7);
+#undef SETBG
     // selection
     if (IS_SPECIAL_COLOR(highlight_fg)) {
         if (IS_SPECIAL_COLOR(highlight_bg)) {
@@ -320,7 +327,6 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
         rd->use_cell_bg_for_selection_fg = 0.f; rd->use_cell_fg_for_selection_color = 0.f;
     }
     rd->use_cell_for_selection_bg = IS_SPECIAL_COLOR(highlight_bg) ? 1. : 0.;
-    rd->second_transparent_bg = IS_SPECIAL_COLOR(second_transparent_bg) ? rd->default_bg : COLOR(second_transparent_bg);
     // Cursor position
     enum { BLOCK_IDX = 0, BEAM_IDX = NUM_UNDERLINE_STYLES + 3, UNDERLINE_IDX = NUM_UNDERLINE_STYLES + 4, UNFOCUSED_IDX = NUM_UNDERLINE_STYLES + 5 };
     Line *line_for_cursor = NULL;
@@ -338,7 +344,7 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
             case CURSOR_HOLLOW:
                 rd->cursor_fg_sprite_idx = UNFOCUSED_IDX; break;
         };
-        color_type cell_fg = rd->default_fg, cell_bg = rd->default_bg;
+        color_type cell_fg = rd->default_fg, cell_bg = rd->bg_colors0;
         index_type cell_color_x = cursor->x;
         bool reversed = false;
         if (cursor->x < screen->columns && cursor->y < screen->lines) {
@@ -352,10 +358,10 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
             colors_for_cell(line_for_cursor, cp, &cell_color_x, &cell_fg, &cell_bg, &reversed);
         }
         if (IS_SPECIAL_COLOR(cursor_color)) {
-            if (line_for_cursor) pick_cursor_color(line_for_cursor, cp, cell_fg, cell_bg, cell_color_x, &rd->cursor_fg, &rd->cursor_bg, rd->default_fg, rd->default_bg);
-            else { rd->cursor_fg = rd->default_bg; rd->cursor_bg = rd->default_fg; }
+            if (line_for_cursor) pick_cursor_color(line_for_cursor, cp, cell_fg, cell_bg, cell_color_x, &rd->cursor_fg, &rd->cursor_bg, rd->default_fg, rd->bg_colors0);
+            else { rd->cursor_fg = rd->bg_colors0; rd->cursor_bg = rd->default_fg; }
             if (cell_bg == cell_fg) {
-                rd->cursor_fg = rd->default_bg; rd->cursor_bg = rd->default_fg;
+                rd->cursor_fg = rd->bg_colors0; rd->cursor_bg = rd->default_fg;
             } else { rd->cursor_fg = cell_bg; rd->cursor_bg = cell_fg; }
         } else {
             rd->cursor_bg = COLOR(cursor_color);
@@ -375,7 +381,6 @@ cell_update_uniform_block(ssize_t vao_idx, Screen *screen, int uniform_buffer, c
     sprite_tracker_current_layout(os_window->fonts_data, &x, &y, &z);
     rd->sprite_dx = 1.0f / (float)x; rd->sprite_dy = 1.0f / (float)y;
     rd->inverted = screen_invert_colors(screen) ? 1 : 0;
-    rd->background_opacity = os_window->is_semi_transparent ? os_window->background_opacity : 1.0f;
 
 #undef COLOR
     rd->url_color = OPT(url_color); rd->url_style = OPT(url_style);

kitty/window.py

@@ -447,17 +447,46 @@ def process_remote_print(msg: memoryview) -> str:
     return replace_c0_codes_except_nl_space_tab(base64_decode(msg)).decode('utf-8', 'replace')
 
 
+def transparent_background_color_control(cp: ColorProfile, responses: dict[str, str], index: int, key: str, sep: str, val: str) -> None:
+    if sep == '=':
+        if val == '?':
+            if index > 8:
+                responses[key] = '?'
+            else:
+                c = cp.get_transparent_background_color(index - 1)
+                if c is None:
+                    responses[key] = ''
+                else:
+                    opacity = max(0, min(c.alpha / 255.0, 1))
+                    responses[key] = f'rgb:{c.red:02x}/{c.green:02x}/{c.blue:02x}@{opacity:.4f}'
+        elif index <= 8:
+            col, _, o = val.partition('@')
+            try:
+                opacity = float(o)
+            except Exception:
+                opacity = -1.0
+            c = to_color(col)
+            if c is not None:
+                cp.set_transparent_background_color(index - 1, c, opacity)
+    elif index <= 8:
+        cp.set_transparent_background_color(index - 1)
+
+
 def color_control(cp: ColorProfile, code: int, value: Union[str, bytes, memoryview] = '') -> str:
     if isinstance(value, (bytes, memoryview)):
         value = str(value, 'utf-8', 'replace')
-    responses = {}
+    responses: dict[str, str] = {}
     for rec in value.split(';'):
         key, sep, val = rec.partition('=')
+        if key.startswith('transparent_background_color'):
+            index = int(key[len('transparent_background_color'):])
+            transparent_background_color_control(cp, responses, index, key, sep, val)
+            continue
         attr = {
             'foreground': 'default_fg', 'background': 'default_bg',
             'selection_background': 'highlight_bg', 'selection_foreground': 'highlight_fg',
             'cursor': 'cursor_color', 'cursor_text': 'cursor_text_color',
-            'visual_bell': 'visual_bell_color', 'second_transparent_background': 'second_transparent_bg',
+            'visual_bell': 'visual_bell_color',
         }.get(key, '')
         colnum = -1
         with suppress(Exception):
@@ -480,6 +509,7 @@ def color_control(cp: ColorProfile, code: int, value: Union[str, bytes, memoryvi
             else:
                 if attr:
                     if val:
+                        val = val.partition('@')[0]
                         col = to_color(val)
                         if col is not None:
                             setattr(cp, attr, col)
@@ -488,6 +518,7 @@ def color_control(cp: ColorProfile, code: int, value: Union[str, bytes, memoryvi
                             setattr(cp, attr, None)
                 else:
                     if 0 <= colnum <= 255:
+                        val = val.partition('@')[0]
                         col = to_color(val)
                         if col is not None:
                             cp.set_color(colnum, color_as_int(col))

kitty_tests/__init__.py

@@ -59,6 +59,8 @@ class Callbacks:
         response = color_control(self.color_profile, code, data)
         if response:
             def p(x):
+                if '@' in x:
+                    return (to_color(x.partition('@')[0]), int(255 * float(x.partition('@')[2])))
                 ans = to_color(x)
                 if ans is None:
                     ans = x

kitty_tests/screen.py

@@ -1280,3 +1280,10 @@ class TestScreen(BaseTest):
         q({'selection_background': ''})
         self.assertIsNone(s.color_profile.highlight_bg)
         q({'selection_background': '?'}, {'selection_background': ''})
+        s.color_profile.reload_from_opts(defaults)
+        q({'transparent_background_color9': '?'}, {'transparent_background_color9': '?'})
+        q({'transparent_background_color2': '?'}, {'transparent_background_color2': ''})
+        q({'transparent_background_color2': 'red@0.5'})
+        q({'transparent_background_color2': '?'}, {'transparent_background_color2': (Color(255, 0, 0), 126)})
+        q({'transparent_background_color2': '#ffffff@-1'})
+        q({'transparent_background_color2': '?'}, {'transparent_background_color2': (Color(255, 255, 255), 255)})

tools/cmd/at/set_colors.go

@@ -15,15 +15,14 @@ import (
 var nullable_colors = map[string]bool{
 	// generated by gen-config.py do not edit
 	// NULLABLE_COLORS_START
-	"active_border_color":   true,
-	"cursor":                true,
-	"cursor_text_color":     true,
-	"second_transparent_bg": true,
-	"selection_background":  true,
-	"selection_foreground":  true,
-	"tab_bar_background":    true,
-	"tab_bar_margin_color":  true,
-	"visual_bell_color":     true,
+	"active_border_color":  true,
+	"cursor":               true,
+	"cursor_text_color":    true,
+	"selection_background": true,
+	"selection_foreground": true,
+	"tab_bar_background":   true,
+	"tab_bar_margin_color": true,
+	"visual_bell_color":    true,
 	// NULLABLE_COLORS_END
 }
 

tools/themes/collection.go

@@ -309,7 +309,6 @@ var AllColorSettingNames = map[string]bool{ // {{{
 	"mark2_foreground":        true,
 	"mark3_background":        true,
 	"mark3_foreground":        true,
-	"second_transparent_bg":   true,
 	"selection_background":    true,
 	"selection_foreground":    true,
 	"tab_bar_background":      true,