urls: OSC-8 URLs can now optionally be underlined outside of url-mode

This patch adds a new configuration option,
‘osc8-underline=url-mode|always’.

When set to ‘url-mode’, OSC-8 URLs are only
highlighted (i.e. underlined) in url-mode, just like auto-detected
URLs.

When set to ‘always’, they are always underlined, regardless of mode,
and regardless of their other attributes.

This is implemented by tagging collected URLs with a boolean,
instructing urls_render() and urls_reset() whether they should update
the cells’ ‘url’ attribute or not.

The OSC-8 collecter sets this based on the value of ‘osc8-underline’.

Finally, when closing an OSC-8 URL, the cells are immediately tagged
with the ‘url’ attribute if ‘osc8-underline’ is set to ‘always’.

config.c

@@ -791,6 +791,19 @@ parse_section_main(const char *key, const char *value, struct config *conf,
         return false;
     }
 
+    else if (strcmp(key, "osc8-underline") == 0) {
+        if (strcmp(value, "url-mode") == 0)
+            conf->osc8_underline = OSC8_UNDERLINE_URL_MODE;
+        else if (strcmp(value, "always") == 0)
+            conf->osc8_underline = OSC8_UNDERLINE_URL_MODE;
+        else {
+            LOG_AND_NOTIFY_ERR(
+                "%s:%u: [default]: %s: invalid 'osc8-underline'; "
+                "must be one of 'url-mode', or 'always'", path, lineno, value);
+            return false;
+        }
+    }
+
     else {
         LOG_AND_NOTIFY_ERR("%s:%u: [default]: %s: invalid key", path, lineno, key);
         return false;
@@ -2243,6 +2256,8 @@ config_load(struct config *conf, const char *conf_path,
             .argv = NULL,
         },
 
+        .osc8_underline = OSC8_UNDERLINE_ALWAYS,
+
         .tweak = {
             .fcft_filter = FCFT_SCALING_FILTER_LANCZOS3,
             .allow_overflowing_double_width_glyphs = true,

config.h

@@ -205,6 +205,11 @@ struct config {
     struct config_spawn_template notify;
     struct config_spawn_template url_launch;
 
+    enum {
+        OSC8_UNDERLINE_URL_MODE,
+        OSC8_UNDERLINE_ALWAYS,
+    } osc8_underline;
+
     struct {
         enum fcft_scaling_filter fcft_filter;
         bool allow_overflowing_double_width_glyphs;

doc/foot.ini.5.scd

@@ -241,13 +241,25 @@ in this order:
 	Clipboard target to automatically copy selected text to. One of
 	*none*, *primary*, *clipboard* or *both*. Default: _primary_.
 
-
 *workers*
 	Number of threads to use for rendering. Set to 0 to disable
 	multithreading. Default: the number of available logical CPUs
 	(including SMT). Note that this is not always the best value. In
 	some cases, the number of physical _cores_ is better.
 
+*osc8-underline*
+	When to underline OSC-8 URLs. Possible values are *url-mode* and
+	*always*.
+	
+	When set to *url-mode*, OSC-8 URLs are only highlighted in URL
+	mode, just like auto-detected URLs.
+	
+	When set to *always*, OSC-8 URLs are always highlighted,
+	regardless of their other attributes (bold, italic etc). Note that
+	this does _not_ make them clickable.
+	
+	Default: _url-mode_
+
 
 # SECTION: scrollback
 

foot.ini

@@ -29,6 +29,7 @@
 # jump-label-letters=sadfjklewcmpgh
 # selection-target=primary
 # workers=<number of logical CPUs>
+# osc8-underline=url-mode
 
 [scrollback]
 # lines=1000

terminal.c

@@ -3049,13 +3049,25 @@ term_osc8_close(struct terminal *term)
     do {
         int end_col = r == end.row ? end.col : term->cols - 1;
 
+        struct row *row = term->grid->rows[r];
+
+        switch (term->conf->osc8_underline) {
+        case OSC8_UNDERLINE_ALWAYS:
+            for (int c = start_col; c <= end_col; c++)
+                row->cells[c].attrs.url = true;
+            break;
+
+        case OSC8_UNDERLINE_URL_MODE:
+            break;
+        }
+
         struct row_uri_range range = {
             .start = start_col,
             .end = end_col,
             .id = term->vt.osc8.id,
             .uri = xstrdup(term->vt.osc8.uri),
         };
-        grid_row_add_uri_range(term->grid->rows[r], range);
+        grid_row_add_uri_range(row, range);
         start_col = 0;
     } while (r++ != end.row);
 

terminal.h

@@ -256,6 +256,7 @@ struct url {
     struct coord start;
     struct coord end;
     enum url_action action;
+    bool url_mode_dont_change_url_attr; /* Entering/exiting URL mode doesn’t touch the cells’ attr.url */
 };
 typedef tll(struct url) url_list_t;
 

url-mode.c

@@ -374,6 +374,18 @@ UNIGNORE_WARNINGS
 static void
 osc8_uris(const struct terminal *term, enum url_action action, url_list_t *urls)
 {
+    bool dont_touch_url_attr = false;
+
+    switch (term->conf->osc8_underline) {
+    case OSC8_UNDERLINE_URL_MODE:
+        dont_touch_url_attr = false;
+        break;
+
+    case OSC8_UNDERLINE_ALWAYS:
+        dont_touch_url_attr = true;
+        break;
+    }
+
     for (int r = 0; r < term->rows; r++) {
         const struct row *row = grid_row_in_view(term->grid, r);
 
@@ -396,7 +408,8 @@ osc8_uris(const struct terminal *term, enum url_action action, url_list_t *urls)
                    .url = xstrdup(it->item.uri),
                    .start = start,
                    .end = end,
-                   .action = action}));
+                   .action = action,
+                   .url_mode_dont_change_url_attr = dont_touch_url_attr}));
        }
     }
 }
@@ -542,6 +555,9 @@ urls_assign_key_combos(const struct config *conf, url_list_t *urls)
 static void
 tag_cells_for_url(struct terminal *term, const struct url *url, bool value)
 {
+    if (url->url_mode_dont_change_url_attr)
+        return;
+
     const struct coord *start = &url->start;
     const struct coord *end = &url->end;