From a0942f950df3b8826db4b1a3f149b7d0ed45adcf Mon Sep 17 00:00:00 2001
From: Yorick Peterse <git@yorickpeterse.com>
Date: Fri, 19 Aug 2022 02:54:49 +0200
Subject: [PATCH] config: add setting for underline thickness

This adds an "underline-thickness" setting to the "main" section,
similar to the existing "underline-offset" setting. This setting is used
to specify a custom height for regular (= non-cursor) underlines.

Fixes #1136
---
 CHANGELOG.md        |  6 ++++++
 config.c            |  4 ++++
 config.h            |  1 +
 doc/foot.ini.5.scd  | 12 ++++++++++++
 foot.ini            |  1 +
 render.c            |  5 ++++-
 tests/test-config.c |  1 +
 7 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5fa35a63..f0bf2624 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,6 +42,12 @@
 
 ## Unreleased
 ### Added
+
+* Support for adjusting the thickness of regular underlines ([#1136][1136]).
+
+[1136]: https://codeberg.org/dnkl/foot/issues/1136
+
+
 ### Changed
 
 * Window is now dimmed while in Unicode input mode.
diff --git a/config.c b/config.c
index fbeab3e6..0ee01373 100644
--- a/config.c
+++ b/config.c
@@ -904,6 +904,9 @@ parse_section_main(struct context *ctx)
         return true;
     }
 
+    else if (strcmp(key, "underline-thickness") == 0)
+        return value_to_pt_or_px(ctx, &conf->underline_thickness);
+
     else if (strcmp(key, "dpi-aware") == 0) {
         if (strcmp(value, "auto") == 0)
             conf->dpi_aware = DPI_AWARE_AUTO;
@@ -2833,6 +2836,7 @@ config_load(struct config *conf, const char *conf_path,
         .vertical_letter_offset = {.pt = 0, .px = 0},
         .use_custom_underline_offset = false,
         .box_drawings_uses_font_glyphs = false,
+        .underline_thickness = {.pt = 0., .px = -1},
         .dpi_aware = DPI_AWARE_AUTO, /* DPI-aware when scaling-factor == 1 */
         .bell = {
             .urgent = false,
diff --git a/config.h b/config.h
index 70e182e3..f98e4d35 100644
--- a/config.h
+++ b/config.h
@@ -150,6 +150,7 @@ struct config {
 
     bool use_custom_underline_offset;
     struct pt_or_px underline_offset;
+    struct pt_or_px underline_thickness;
 
     bool box_drawings_uses_font_glyphs;
     bool can_shape_grapheme;
diff --git a/doc/foot.ini.5.scd b/doc/foot.ini.5.scd
index 995a7e33..0bc21786 100644
--- a/doc/foot.ini.5.scd
+++ b/doc/foot.ini.5.scd
@@ -132,6 +132,18 @@ commented out will usually be installed to */etc/xdg/foot/foot.ini*.
 	
 	Default: _unset_.
 
+*underline-thickness*
+	Use a custom thickness (height) for underlines. The thickness is, by
+	default, in _points_.
+
+	To specify a thickness in _pixels_, append *px*:
+	*underline-thickness=1px*.
+
+	If left unset (the default), the thickness specified in the font is
+	used.
+
+	Default: _unset_
+
 *box-drawings-uses-font-glyphs* Boolean. When disabled, foot generates
 	box/line drawing characters itself. The are several advantages to
 	doing this instead of using font glyphs:
diff --git a/foot.ini b/foot.ini
index 4c857296..0c19951e 100644
--- a/foot.ini
+++ b/foot.ini
@@ -17,6 +17,7 @@
 # horizontal-letter-offset=0
 # vertical-letter-offset=0
 # underline-offset=<font metrics>
+# underline-thickness=<font underline thickness>
 # box-drawings-uses-font-glyphs=no
 # dpi-aware=auto
 
diff --git a/render.c b/render.c
index 82c9bd13..ef698911 100644
--- a/render.c
+++ b/render.c
@@ -372,7 +372,10 @@ draw_underline(const struct terminal *term, pixman_image_t *pix,
                const struct fcft_font *font,
                const pixman_color_t *color, int x, int y, int cols)
 {
-    const int thickness = font->underline.thickness;
+    const int thickness = term->conf->underline_thickness.px >= 0
+        ? term_pt_or_px_as_pixels(
+            term, &term->conf->underline_thickness)
+        : font->underline.thickness;
 
     /* Make sure the line isn't positioned below the cell */
     const int y_ofs = min(underline_offset(term, font),
diff --git a/tests/test-config.c b/tests/test-config.c
index 930be6bf..837c5106 100644
--- a/tests/test-config.c
+++ b/tests/test-config.c
@@ -470,6 +470,7 @@ test_section_main(void)
     test_pt_or_px(&ctx, &parse_section_main, "letter-spacing", &conf.letter_spacing);
     test_pt_or_px(&ctx, &parse_section_main, "horizontal-letter-offset", &conf.horizontal_letter_offset);
     test_pt_or_px(&ctx, &parse_section_main, "vertical-letter-offset", &conf.vertical_letter_offset);
+    test_pt_or_px(&ctx, &parse_section_main, "underline-thickness", &conf.underline_thickness);
 
     test_uint16(&ctx, &parse_section_main, "resize-delay-ms", &conf.resize_delay_ms);
     test_uint16(&ctx, &parse_section_main, "workers", &conf.render_worker_count);