config: add cursor.blink-rate option

The default is 500ms, which corresponds to the old, hardcoded default.

Closes #1707

CHANGELOG.md

@@ -54,6 +54,13 @@
 
 ## Unreleased
 ### Added
+
+* `cursor.blink-rate` option, allowing you to configure the rate the
+  cursor blinks with (when `cursor.blink=yes`) ([#1707][1707]);
+
+[1707]: https://codeberg.org/dnkl/foot/issues/1707
+
+
 ### Changed
 
 * All `XTGETTCAP` capabilities are now in the `tigetstr()` format:

config.c

@@ -1395,7 +1395,10 @@ parse_section_cursor(struct context *ctx)
     }
 
     else if (streq(key, "blink"))
-        return value_to_bool(ctx, &conf->cursor.blink);
+        return value_to_bool(ctx, &conf->cursor.blink.enabled);
+
+    else if (streq(key, "blink-rate"))
+        return value_to_uint32(ctx, 10, &conf->cursor.blink.rate_ms);
 
     else if (streq(key, "color")) {
         if (!value_to_two_colors(
@@ -3102,7 +3105,10 @@ config_load(struct config *conf, const char *conf_path,
         .cursor = {
             .style = CURSOR_BLOCK,
             .unfocused_style = CURSOR_UNFOCUSED_HOLLOW,
-            .blink = false,
+            .blink = {
+                .enabled = false,
+                .rate_ms = 500,
+            },
             .color = {
                 .text = 0,
                 .cursor = 0,

config.h

@@ -262,7 +262,10 @@ struct config {
     struct {
         enum cursor_style style;
         enum cursor_unfocused_style unfocused_style;
-        bool blink;
+        struct {
+            bool enabled;
+            uint32_t rate_ms;
+        } blink;
         struct {
             uint32_t text;
             uint32_t cursor;

csi.c

@@ -1665,7 +1665,7 @@ csi_dispatch(struct terminal *term, uint8_t final)
             switch (param) {
             case 0: /* blinking block, but we use it to reset to configured default */
                 term->cursor_style = term->conf->cursor.style;
-                term->cursor_blink.deccsusr = term->conf->cursor.blink;
+                term->cursor_blink.deccsusr = term->conf->cursor.blink.enabled;
                 term_cursor_blink_update(term);
                 break;
 

doc/foot.ini.5.scd

@@ -511,7 +511,12 @@ applications can change these at runtime.
 
 *blink*
 	Boolean. Enables blinking cursor. Note that this can be overridden
-	by applications. Default: _no_.
+	by applications. Related option: *blink-rate*. Default: _no_.
+
+*blink-rate*
+	The rate at which the cursor blink, when cursor blinking has been
+	enabled. Expressed in milliseconds between each blink. Default:
+	_500_.
 
 *color*
 	Two space separated RRGGBB values (i.e. plain old 6-digit hex

terminal.c

@@ -1229,7 +1229,7 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
         .cursor_style = conf->cursor.style,
         .cursor_blink = {
             .decset = false,
-            .deccsusr = conf->cursor.blink,
+            .deccsusr = conf->cursor.blink.enabled,
             .state = CURSOR_BLINK_ON,
             .fd = -1,
         },
@@ -2046,7 +2046,7 @@ term_reset(struct terminal *term, bool hard)
     term->alt.saved_cursor = (struct cursor){.point = {0, 0}};
     term->cursor_style = term->conf->cursor.style;
     term->cursor_blink.decset = false;
-    term->cursor_blink.deccsusr = term->conf->cursor.blink;
+    term->cursor_blink.deccsusr = term->conf->cursor.blink.enabled;
     term_cursor_blink_update(term);
     term->cursor_color.text = term->conf->cursor.color.text;
     term->cursor_color.cursor = term->conf->cursor.color.cursor;
@@ -2746,9 +2746,13 @@ cursor_blink_rearm_timer(struct terminal *term)
         term->cursor_blink.fd = fd;
     }
 
-    static const struct itimerspec timer = {
+    const int rate_ms = term->conf->cursor.blink.rate_ms;
-        .it_value = {.tv_sec = 0, .tv_nsec = 500000000},
+    const long secs = rate_ms / 1000;
-        .it_interval = {.tv_sec = 0, .tv_nsec = 500000000},
+    const long nsecs = (rate_ms % 1000) * 1000000;
+
+    const struct itimerspec timer = {
+        .it_value = {.tv_sec = secs, .tv_nsec = nsecs},
+        .it_interval = {.tv_sec = secs, .tv_nsec = nsecs},
     };
 
     if (timerfd_settime(term->cursor_blink.fd, 0, &timer, NULL) < 0) {

tests/test-config.c

@@ -641,7 +641,8 @@ test_section_cursor(void)
         (const char *[]){"unchanged", "hollow", "none"},
         (int []){CURSOR_UNFOCUSED_UNCHANGED, CURSOR_UNFOCUSED_HOLLOW, CURSOR_UNFOCUSED_NONE},
         (int *)&conf.cursor.unfocused_style);
-    test_boolean(&ctx, &parse_section_cursor, "blink", &conf.cursor.blink);
+    test_boolean(&ctx, &parse_section_cursor, "blink", &conf.cursor.blink.enabled);
+    test_uint32(&ctx, &parse_section_cursor, "blink-rate", &conf.cursor.blink.rate_ms);
     test_pt_or_px(&ctx, &parse_section_cursor, "beam-thickness",
                   &conf.cursor.beam_thickness);
     test_pt_or_px(&ctx, &parse_section_cursor, "underline-thickness",