A shader to draw a single seven segment number over a kitty window

kitty/fast_data_types.pyi

@@ -263,6 +263,7 @@ SCROLL_LINE: int
 SCROLL_PAGE: int
 STRIKETHROUGH: int
 TINT_PROGRAM: int
+SEVEN_SEGMENT_PROGRAM: int
 FC_MONO: int = 100
 FC_DUAL: int
 FC_WEIGHT_REGULAR: int
@@ -1239,5 +1240,6 @@ def get_os_window_size(os_window_id: int) -> Optional[OSWindowSize]:
 def get_all_processes() -> Tuple[int, ...]:
     pass
 
+
 def num_users() -> int:
     pass

kitty/seven_segment_fragment.glsl

@@ -0,0 +1,39 @@
+#version GLSL_VERSION
+uniform vec4 area_bounds;
+uniform vec4 digit_color;
+uniform int digit;
+layout(origin_upper_left) in vec4 gl_FragCoord;
+
+const float PI = 3.1415926535897932384626433832795;
+const int s_map[] = int[10](182, 150, 78, 47, 104, 85, 16, 212, 15, 142);
+
+mat2 rotate2D(in float a) {
+    return mat2(cos(a), sin(a), -sin(a), cos(a));
+}
+
+float draw_number(int num, vec2 p) {
+    // return 1 if this position should be colored and 0 if not
+    int s = s_map[max(0, min(num, 9))];
+    float scale = 0.3;
+    float n = fract(sin(dot(ceil(p * rotate2D(PI / 4.) / sqrt(2.) / scale + 0.5 + float(s)), vec2(3., 5.))) * 50.);
+
+    p.y = abs(p.y);
+    p.y -= scale;
+    p = abs(p);
+    p = vec2(max(p.x, p.y), min(p.x, p.y));
+    p.x -= scale;
+    p.x = abs(p.x);
+    float d = max(p.x + p.y - scale * 0.667, p.x);
+    return step(d, scale * 0.267) * step(n, 0.5);
+}
+
+out vec4 color;
+
+void main() {
+    float left = area_bounds[0], top = area_bounds[1];
+    vec2 resolution = vec2(area_bounds[2], area_bounds[3]);
+    vec2 shifted_frag_pos = vec2(gl_FragCoord.x - left, gl_FragCoord.y - top);
+    vec2 pos = (shifted_frag_pos * 2 - resolution) / min(resolution.x, resolution.y);
+    pos.y *= -1;
+    color = digit_color * draw_number(digit, pos);
+}

kitty/shaders.c

@@ -9,7 +9,7 @@
 #include "gl.h"
 #include <stddef.h>
 
-enum { CELL_PROGRAM, CELL_BG_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FG_PROGRAM, BORDERS_PROGRAM, GRAPHICS_PROGRAM, GRAPHICS_PREMULT_PROGRAM, GRAPHICS_ALPHA_MASK_PROGRAM, BLIT_PROGRAM, BGIMAGE_PROGRAM, TINT_PROGRAM, NUM_PROGRAMS };
+enum { CELL_PROGRAM, CELL_BG_PROGRAM, CELL_SPECIAL_PROGRAM, CELL_FG_PROGRAM, BORDERS_PROGRAM, GRAPHICS_PROGRAM, GRAPHICS_PREMULT_PROGRAM, GRAPHICS_ALPHA_MASK_PROGRAM, BLIT_PROGRAM, BGIMAGE_PROGRAM, TINT_PROGRAM, SEVEN_SEGMENT_PROGRAM, NUM_PROGRAMS };
 enum { SPRITE_MAP_UNIT, GRAPHICS_UNIT, BLIT_UNIT, BGIMAGE_UNIT };
 
 // Sprites {{{
@@ -172,6 +172,10 @@ typedef struct {
     GLint tint_color_location, edges_location;
 } TintProgramLayout;
 static TintProgramLayout tint_program_layout = {0};
+typedef struct {
+    GLint edges_location, area_bounds_location, digit_color_location, digit_location;
+} SevenSegmentProgramLayout;
+static SevenSegmentProgramLayout seven_segment_program_layout = {0};
 
 static void
 init_cell_program(void) {
@@ -197,6 +201,10 @@ init_cell_program(void) {
     bgimage_program_layout.premult_location = get_uniform_location(BGIMAGE_PROGRAM, "premult");
     tint_program_layout.tint_color_location = get_uniform_location(TINT_PROGRAM, "tint_color");
     tint_program_layout.edges_location = get_uniform_location(TINT_PROGRAM, "edges");
+    seven_segment_program_layout.edges_location = get_uniform_location(SEVEN_SEGMENT_PROGRAM, "edges");
+    seven_segment_program_layout.area_bounds_location = get_uniform_location(SEVEN_SEGMENT_PROGRAM, "area_bounds");
+    seven_segment_program_layout.digit_color_location = get_uniform_location(SEVEN_SEGMENT_PROGRAM, "digit_color");
+    seven_segment_program_layout.digit_location = get_uniform_location(SEVEN_SEGMENT_PROGRAM, "digit");
 }
 
 #define CELL_BUFFERS enum { cell_data_buffer, selection_buffer, uniform_buffer };
@@ -458,6 +466,26 @@ draw_tint(bool premult, Screen *screen, GLfloat xstart, GLfloat ystart, GLfloat
     glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 }
 
+static void
+draw_window_number(OSWindow *os_window, Screen *screen, GLfloat xstart, GLfloat ystart, GLfloat width, GLfloat height) {
+    glEnable(GL_BLEND);
+    glBlendFuncSeparate(GL_ONE, GL_ONE_MINUS_SRC_ALPHA, GL_ZERO, GL_ONE);  // BLEND_PREMULT
+    bind_program(SEVEN_SEGMENT_PROGRAM);
+    GLfloat left = os_window->viewport_width * (xstart + 1.f) / 2.f;
+    GLfloat right = left + os_window->viewport_width * width / 2.f;
+    GLfloat top = os_window->viewport_height * (1.f - ystart) / 2.f;
+    GLfloat bottom = os_window->viewport_height * (1.f + height - ystart) / 2.f;
+    glUniform4f(seven_segment_program_layout.edges_location, xstart, ystart - height, xstart + width, ystart);
+    glUniform4f(seven_segment_program_layout.area_bounds_location, left, top, right - left, bottom - top);
+    color_type digit_color = colorprofile_to_color(screen->color_profile, screen->color_profile->overridden.highlight_bg, screen->color_profile->configured.highlight_bg);
+#define C(shift) ((((GLfloat)((digit_color >> shift) & 0xFF)) / 255.0f))
+    glUniform4f(seven_segment_program_layout.digit_color_location, C(16), C(8), C(0), 1.);
+#undef C
+    glUniform1i(seven_segment_program_layout.digit_location, 8);
+    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+    glDisable(GL_BLEND);
+}
+
 static void
 draw_visual_bell_flash(GLfloat intensity, GLfloat xstart, GLfloat ystart, GLfloat w, GLfloat h, Screen *screen) {
     glEnable(GL_BLEND);
@@ -706,6 +734,8 @@ draw_cells(ssize_t vao_idx, ssize_t gvao_idx, GLfloat xstart, GLfloat ystart, GL
         GLfloat intensity = get_visual_bell_intensity(screen);
         if (intensity > 0.0f) draw_visual_bell_flash(intensity, xstart, ystart, w, h, screen);
     }
+
+    if (false) draw_window_number(os_window, screen, xstart, ystart, w, h);
 }
 // }}}
 
@@ -867,7 +897,7 @@ static PyMethodDef module_methods[] = {
 bool
 init_shaders(PyObject *module) {
 #define C(x) if (PyModule_AddIntConstant(module, #x, x) != 0) { PyErr_NoMemory(); return false; }
-    C(CELL_PROGRAM); C(CELL_BG_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FG_PROGRAM); C(BORDERS_PROGRAM); C(GRAPHICS_PROGRAM); C(GRAPHICS_PREMULT_PROGRAM); C(GRAPHICS_ALPHA_MASK_PROGRAM); C(BLIT_PROGRAM); C(BGIMAGE_PROGRAM); C(TINT_PROGRAM);
+    C(CELL_PROGRAM); C(CELL_BG_PROGRAM); C(CELL_SPECIAL_PROGRAM); C(CELL_FG_PROGRAM); C(BORDERS_PROGRAM); C(GRAPHICS_PROGRAM); C(GRAPHICS_PREMULT_PROGRAM); C(GRAPHICS_ALPHA_MASK_PROGRAM); C(BLIT_PROGRAM); C(BGIMAGE_PROGRAM); C(TINT_PROGRAM); C(SEVEN_SEGMENT_PROGRAM);
     C(GLSL_VERSION);
     C(GL_VERSION);
     C(GL_VENDOR);

kitty/utils.py

@@ -64,13 +64,14 @@ def platform_window_id(os_window_id: int) -> Optional[int]:
             return x11_window_id(os_window_id)
 
 
-def load_shaders(name: str) -> Tuple[str, str]:
+def load_shaders(name: str, vertex_name: str = '', fragment_name: str = '') -> Tuple[str, str]:
     from .fast_data_types import GLSL_VERSION
 
-    def load(which: str) -> str:
-        return read_kitty_resource(f'{name}_{which}.glsl').decode('utf-8').replace('GLSL_VERSION', str(GLSL_VERSION), 1)
+    def load(which: str, lname: str = '') -> str:
+        lname = lname or name
+        return read_kitty_resource(f'{lname}_{which}.glsl').decode('utf-8').replace('GLSL_VERSION', str(GLSL_VERSION), 1)
 
-    return load('vertex'), load('fragment')
+    return load('vertex', vertex_name), load('fragment', fragment_name)
 
 
 def safe_print(*a: Any, **k: Any) -> None:

kitty/window.py

@@ -26,13 +26,13 @@ from .fast_data_types import (
     CURSOR_UNDERLINE, DCS, DECORATION, DIM, GLFW_MOD_CONTROL,
     GRAPHICS_ALPHA_MASK_PROGRAM, GRAPHICS_PREMULT_PROGRAM, GRAPHICS_PROGRAM,
     MARK, MARK_MASK, NO_CURSOR_SHAPE, OSC, REVERSE, SCROLL_FULL, SCROLL_LINE,
-    SCROLL_PAGE, STRIKETHROUGH, TINT_PROGRAM, KeyEvent, Screen, add_timer,
-    add_window, cell_size_for_window, click_mouse_url, compile_program,
-    encode_key_for_tty, get_boss, get_clipboard_string, get_options,
-    init_cell_program, mouse_selection, move_cursor_to_mouse_if_in_prompt,
-    pt_to_px, set_clipboard_string, set_titlebar_color, set_window_padding,
-    set_window_render_data, update_window_title, update_window_visibility,
-    viewport_for_window
+    SCROLL_PAGE, SEVEN_SEGMENT_PROGRAM, STRIKETHROUGH, TINT_PROGRAM, KeyEvent,
+    Screen, add_timer, add_window, cell_size_for_window, click_mouse_url,
+    compile_program, encode_key_for_tty, get_boss, get_clipboard_string,
+    get_options, init_cell_program, mouse_selection,
+    move_cursor_to_mouse_if_in_prompt, pt_to_px, set_clipboard_string,
+    set_titlebar_color, set_window_padding, set_window_render_data,
+    update_window_title, update_window_visibility, viewport_for_window
 )
 from .keys import keyboard_mode_name, mod_mask
 from .notify import NotificationCommand, handle_notification_cmd
@@ -255,6 +255,8 @@ class LoadShaderPrograms:
         compile_program(BGIMAGE_PROGRAM, v, f)
         v, f = load_shaders('tint')
         compile_program(TINT_PROGRAM, v, f)
+        v, f = load_shaders('seven_segment', vertex_name='tint')
+        compile_program(SEVEN_SEGMENT_PROGRAM, v, f)
         init_cell_program()