key-binding: add binds for changing alpha

box-drawing.c

@@ -15,8 +15,6 @@
 #include "util.h"
 #include "xmalloc.h"
 
-#define clamp(x, lower, upper) (min(upper, max(x, lower)))
-
 enum thickness {
     LIGHT,
     HEAVY,

config.c

@@ -124,6 +124,10 @@ static const char *const binding_action_map[] = {
     [BIND_ACTION_FONT_SIZE_UP] = "font-increase",
     [BIND_ACTION_FONT_SIZE_DOWN] = "font-decrease",
     [BIND_ACTION_FONT_SIZE_RESET] = "font-reset",
+    [BIND_ACTION_ALPHA_UP] = "alpha-increase",
+    [BIND_ACTION_ALPHA_DOWN] = "alpha-decrease",
+    [BIND_ACTION_ALPHA_RESET] = "alpha-reset",
+    [BIND_ACTION_ALPHA_TOGGLE] = "alpha-toggle",
     [BIND_ACTION_SPAWN_TERMINAL] = "spawn-terminal",
     [BIND_ACTION_MINIMIZE] = "minimize",
     [BIND_ACTION_MAXIMIZE] = "maximize",

doc/foot.ini.5.scd

@@ -1307,6 +1307,18 @@ e.g. *search-start=none*.
 *font-reset*
 	Resets the font size to the default. Default: _Control+0 Control+KP\_0_.
 
+*alpha-increase*
+	Increases alpha by 5 percentage points. Default: _not_bound_.
+
+*alpha-decrease*
+	Decreases alpha by 5 percentage points. Default: _not_bound_.
+
+*alpha-reset*
+	Resets alpha to the default. Default: _not_bound_.
+
+*alpha-toggle*
+	Toggles alpha between 100% and the default. Default: _not_bound_.
+
 *spawn-terminal*
 	Spawns a new terminal. If the shell has been configured to emit
 	the OSC 7 escape sequence, the new terminal will start in the

foot.ini

@@ -199,6 +199,10 @@
 # font-increase=Control+plus Control+equal Control+KP_Add
 # font-decrease=Control+minus Control+KP_Subtract
 # font-reset=Control+0 Control+KP_0
+# alpha-increase=none
+# alpha-decrease=none
+# alpha-reset=none
+# alpha-toggle=none
 # spawn-terminal=Control+Shift+n
 # minimize=none
 # maximize=none

input.c

@@ -198,6 +198,25 @@ execute_binding(struct seat *seat, struct terminal *term,
         term_font_size_reset(term);
         return true;
 
+    case BIND_ACTION_ALPHA_UP:
+        term_alpha_set(term,
+                clamp(term->colors.alpha + 0.05 * UINT16_MAX, 0, UINT16_MAX));
+        return true;
+
+    case BIND_ACTION_ALPHA_DOWN:
+        term_alpha_set(term,
+                clamp(term->colors.alpha - 0.05 * UINT16_MAX, 0, UINT16_MAX));
+        return true;
+
+    case BIND_ACTION_ALPHA_RESET:
+        term_alpha_set(term, term->conf->colors.alpha);
+        return true;
+
+    case BIND_ACTION_ALPHA_TOGGLE:
+        term_alpha_set(term, term->colors.alpha == UINT16_MAX
+            ? term->conf->colors.alpha : UINT16_MAX);
+        return true;
+
     case BIND_ACTION_SPAWN_TERMINAL:
         term_spawn_new(term);
         return true;

key-binding.h

@@ -25,6 +25,10 @@ enum bind_action_normal {
     BIND_ACTION_FONT_SIZE_UP,
     BIND_ACTION_FONT_SIZE_DOWN,
     BIND_ACTION_FONT_SIZE_RESET,
+    BIND_ACTION_ALPHA_UP,
+    BIND_ACTION_ALPHA_DOWN,
+    BIND_ACTION_ALPHA_RESET,
+    BIND_ACTION_ALPHA_TOGGLE,
     BIND_ACTION_SPAWN_TERMINAL,
     BIND_ACTION_MINIMIZE,
     BIND_ACTION_MAXIMIZE,

terminal.c

@@ -2323,6 +2323,15 @@ term_font_size_reset(struct terminal *term)
     return load_fonts_from_conf(term);
 }
 
+void
+term_alpha_set(struct terminal *term, uint16_t alpha)
+{
+    term->colors.alpha = alpha;
+    term_damage_margins(term);
+    wayl_win_alpha_changed(term->window);
+    term_font_subpixel_changed(term);
+}
+
 bool
 term_fractional_scaling(const struct terminal *term)
 {

terminal.h

@@ -859,6 +859,7 @@ bool term_update_scale(struct terminal *term);
 bool term_font_size_increase(struct terminal *term);
 bool term_font_size_decrease(struct terminal *term);
 bool term_font_size_reset(struct terminal *term);
+void term_alpha_set(struct terminal *term, uint16_t alpha);
 bool term_font_dpi_changed(struct terminal *term, float old_scale);
 void term_font_subpixel_changed(struct terminal *term);
 int term_font_baseline(const struct terminal *term);

util.h

@@ -8,6 +8,7 @@
 #define ALEN(v) (sizeof(v) / sizeof((v)[0]))
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #define max(x, y) ((x) > (y) ? (x) : (y))
+#define clamp(x, lower, upper) (min(upper, max(x, lower)))
 
 static inline bool
 streq(const char *a, const char *b)