conf: allow the user to configure a fixed cursor color

The default is to reverse the foreground/background colors in the cell
with the cursor.

But, if the user configures a specific set of cursor colors, those
will always be used, regardless of other cell attributes (dim, reverse
etc).

The cursor color is specified as two color values, 'text' and
'cursor'.

The block cursor uses the 'cursor' color as background, and the 'text'
color for the glyph.

All other cursor styles uses the 'cursor' color for the cursor, but
uses the cell's foreground color for the glyph (meaning,
dim/reverse/etc applies).

config.c

@@ -106,6 +106,30 @@ get_config_path(void)
     return NULL;
 }
 
+static bool
+str_to_color(const char *s, uint32_t *color, const char *path, int lineno)
+{
+    if (s == NULL)
+        return false;
+
+    errno = 0;
+    char *end = NULL;
+    unsigned long res = strtoul(s, &end, 16);
+
+    if (errno != 0) {
+        LOG_ERRNO("%s:%d: invalid color: %s", path, lineno, s);
+        return false;
+    }
+
+    if (*end != '\0') {
+        LOG_ERR("%s:%d: invalid color: %s", path, lineno, s);
+        return false;
+    }
+
+    *color = res & 0xffffff;
+    return true;
+}
+
 static bool
 parse_section_main(const char *key, const char *value, struct config *conf,
                    const char *path, unsigned lineno)
@@ -163,21 +187,11 @@ parse_section_colors(const char *key, const char *value, struct config *conf,
         return false;
     }
 
-    errno = 0;
-    char *end = NULL;
-    unsigned long res = strtoul(value, &end, 16);
-
-    if (errno != 0) {
-        LOG_ERRNO("%s:%d: invalid color: %s", path, lineno, value);
+    uint32_t color_value;
+    if (!str_to_color(value, &color_value, path, lineno))
         return false;
-    }
 
-    if (*end != '\0') {
-        LOG_ERR("%s:%d: invalid color: %s", path, lineno, value);
-        return false;
-    }
-
-    *color = res & 0xffffff;
+    *color = color_value;
     return true;
 }
 
@@ -199,6 +213,26 @@ parse_section_cursor(const char *key, const char *value, struct config *conf,
         }
     }
 
+    else if (strcmp(key, "color") == 0) {
+        char *value_copy = strdup(value);
+        const char *text = strtok(value_copy, " ");
+        const char *cursor = strtok(NULL, " ");
+
+        uint32_t text_color, cursor_color;
+        if (text == NULL || cursor == NULL ||
+            !str_to_color(text, &text_color, path, lineno) ||
+            !str_to_color(cursor, &cursor_color, path, lineno))
+        {
+            LOG_ERR("%s:%d: invalid cursor colors: %s", path, lineno, value);
+            free(value_copy);
+            return false;
+        }
+
+        conf->cursor.color.text = 1 << 31 | text_color;
+        conf->cursor.color.cursor = 1 << 31 | cursor_color;
+        free(value_copy);
+    }
+
     else {
         LOG_ERR("%s:%d: invalid key: %s", path, lineno, key);
         return false;
@@ -388,6 +422,10 @@ config_load(struct config *conf)
 
         .cursor = {
             .style = CURSOR_BLOCK,
+            .color = {
+                .text = 0,
+                .cursor = 0,
+            },
         },
     };
 

config.h

@@ -19,6 +19,10 @@ struct config {
 
     struct {
         enum cursor_style style;
+        struct {
+            uint32_t text;
+            uint32_t cursor;
+        } color;
     } cursor;
 };
 

main.c

@@ -373,6 +373,14 @@ main(int argc, char *const *argv)
         },
         .default_cursor_style = conf.cursor.style,
         .cursor_style = conf.cursor.style,
+        .default_cursor_color = {
+            .text = conf.cursor.color.text,
+            .cursor = conf.cursor.color.cursor,
+        },
+        .cursor_color = {
+            .text = conf.cursor.color.text,
+            .cursor = conf.cursor.color.cursor,
+        },
         .selection = {
             .start = {-1, -1},
             .end = {-1, -1},

render.c

@@ -194,6 +194,13 @@ render_cell(struct terminal *term, struct buffer *buf, const struct cell *cell,
     if (cell->attrs.dim)
         color_dim(&fg);
 
+    if (block_cursor && term->cursor_color.text >> 31) {
+        /* User configured cursor color overrides all attributes */
+        assert(term->cursor_color.cursor >> 31);
+        fg = color_hex_to_rgb(term->cursor_color.text);
+        bg = color_hex_to_rgb(term->cursor_color.cursor);
+    }
+
     /* Background */
     cairo_set_source_rgb(buf->cairo, bg.r, bg.g, bg.b);
     cairo_rectangle(buf->cairo, x, y, width, height);
@@ -201,11 +208,12 @@ render_cell(struct terminal *term, struct buffer *buf, const struct cell *cell,
 
     /* Non-block cursors */
     if (has_cursor) {
+        struct rgb cursor_color = color_hex_to_rgb(term->cursor_color.cursor);
         if (term->cursor_style == CURSOR_BAR)
-            draw_bar(term, buf, fg, x, y);
+            draw_bar(term, buf, cursor_color, x, y);
         else if (term->cursor_style == CURSOR_UNDERLINE)
             draw_underline(
-                term, buf, attrs_to_font(term, &cell->attrs), fg, x, y);
+                term, buf, attrs_to_font(term, &cell->attrs), cursor_color, x, y);
     }
 
     if (cell->attrs.blink && !term->blink.active) {

terminal.h

@@ -296,6 +296,14 @@ struct terminal {
     enum cursor_style default_cursor_style;
     enum cursor_style cursor_style;
     bool cursor_blinking;
+    struct {
+        uint32_t text;
+        uint32_t cursor;
+    } default_cursor_color;
+    struct {
+        uint32_t text;
+        uint32_t cursor;
+    } cursor_color;
 
     uint32_t input_serial;
     struct {