render: implement 'underline'

main.c

@@ -10,6 +10,7 @@
 #include <poll.h>
 #include <errno.h>
 
+#include <cairo-ft.h>
 #include <wayland-client.h>
 #include <wayland-cursor.h>
 #include <xdg-shell.h>
@@ -349,23 +350,48 @@ main(int argc, char *const *argv)
     thrd_t keyboard_repeater_id;
     thrd_create(&keyboard_repeater_id, &keyboard_repeater, &term);
 
-    term.fonts[0] = font_from_name(conf.font);
-    if (term.fonts[0] == NULL)
+    term.fonts[0].font = font_from_name(conf.font);
+    if (term.fonts[0].font == NULL)
         goto out;
 
     {
         char fname[1024];
         snprintf(fname, sizeof(fname), "%s:style=bold", conf.font);
-        term.fonts[1] = font_from_name(fname);
+        term.fonts[1].font = font_from_name(fname);
 
         snprintf(fname, sizeof(fname), "%s:style=italic", conf.font);
-        term.fonts[2] = font_from_name(fname);
+        term.fonts[2].font = font_from_name(fname);
 
         snprintf(fname, sizeof(fname), "%s:style=bold italic", conf.font);
-        term.fonts[3] = font_from_name(fname);
+        term.fonts[3].font = font_from_name(fname);
     }
 
-    cairo_scaled_font_extents(term.fonts[0],  &term.fextents);
+    /* Underline position and size */
+    for (size_t i = 0; i < sizeof(term.fonts) / sizeof(term.fonts[0]); i++) {
+        struct font *f = &term.fonts[i];
+
+        if (f->font == NULL)
+            continue;
+
+        FT_Face ft_face = cairo_ft_scaled_font_lock_face(f->font);
+
+        double x_scale = ft_face->size->metrics.x_scale / 65526.;
+        f->underline.position = ft_face->underline_position * x_scale / 64.;
+        f->underline.thickness = ft_face->underline_thickness * x_scale / 64.;
+
+        if (f->underline.position == 0.) {
+            double descent = ft_face->size->metrics.descender / 64;
+            f->underline.position =  descent / 2.;
+            f->underline.thickness =  fabs(round(descent / 5.));
+        }
+
+        LOG_DBG("underline: pos=%f, thick=%f",
+                f->underline.position, f->underline.thickness);
+
+        cairo_ft_scaled_font_unlock_face(f->font);
+    }
+
+    cairo_scaled_font_extents(term.fonts[0].font,  &term.fextents);
     term.cell_width = (int)ceil(term.fextents.max_x_advance);
     term.cell_height = (int)ceil(term.fextents.height);
 
@@ -699,8 +725,8 @@ out:
     free(term.alt.rows);
 
     for (size_t i = 0; i < sizeof(term.fonts) / sizeof(term.fonts[0]); i++) {
-        if (term.fonts[i] != NULL)
-            cairo_scaled_font_destroy(term.fonts[i]);
+        if (term.fonts[i].font != NULL)
+            cairo_scaled_font_destroy(term.fonts[i].font);
     }
 
     if (term.ptmx != -1)

render.c

@@ -15,11 +15,11 @@
 #define min(x, y) ((x) < (y) ? (x) : (y))
 #define max(x, y) ((x) > (y) ? (x) : (y))
 
-cairo_scaled_font_t *
+const struct font *
 attrs_to_font(struct terminal *term, const struct attributes *attrs)
 {
     int idx = attrs->italic << 1 | attrs->bold;
-    return term->fonts[idx];
+    return &term->fonts[idx];
 }
 
 struct glyph_sequence {
@@ -28,11 +28,7 @@ struct glyph_sequence {
     int count;
 
     struct attributes attrs;
-#if 0
-    struct rgb foreground;
-#else
     uint32_t foreground;
-#endif
 };
 
 static struct glyph_sequence gseq;
@@ -41,18 +37,18 @@ static void
 gseq_flush(struct terminal *term, struct buffer *buf)
 {
     struct rgb fg = {
-        ((gseq.foreground >> 16) & 0xff) / 255.0,
-        ((gseq.foreground >>  8) & 0xff) / 255.0,
-        ((gseq.foreground >>  0) & 0xff) / 255.0,
+        ((gseq.foreground >> 16) & 0xff) / 255.,
+        ((gseq.foreground >>  8) & 0xff) / 255.,
+        ((gseq.foreground >>  0) & 0xff) / 255.,
     };
 
     if (gseq.attrs.dim) {
-        fg.r /= 2.0;
-        fg.g /= 2.0;
-        fg.b /= 2.0;
+        fg.r /= 2.;
+        fg.g /= 2.;
+        fg.b /= 2.;
     }
 
-    cairo_set_scaled_font(buf->cairo, attrs_to_font(term, &gseq.attrs));
+    cairo_set_scaled_font(buf->cairo, attrs_to_font(term, &gseq.attrs)->font);
     cairo_set_source_rgb(buf->cairo, fg.r, fg.g, fg.b);
     cairo_show_glyphs(buf->cairo, gseq.glyphs, gseq.count);
 
@@ -109,22 +105,44 @@ render_cell(struct terminal *term, struct buffer *buf, const struct cell *cell,
         _background = swap;
     }
 
-    struct rgb background = {
-        ((_background >> 16) & 0xff) / 255.0,
-        ((_background >>  8) & 0xff) / 255.0,
-        ((_background >>  0) & 0xff) / 255.0,
+    struct rgb foreground = {
+        ((_foreground >> 16) & 0xff) / 255.,
+        ((_foreground >>  8) & 0xff) / 255.,
+        ((_foreground >>  0) & 0xff) / 255.,
     };
 
+    struct rgb background = {
+        ((_background >> 16) & 0xff) / 255.,
+        ((_background >>  8) & 0xff) / 255.,
+        ((_background >>  0) & 0xff) / 255.,
+    };
+
+    if (cell->attrs.dim) {
+        foreground.r /= 2.;
+        foreground.g /= 2.;
+        foreground.b /= 2.;
+    }
+
     /* Background */
     cairo_set_source_rgb(buf->cairo, background.r, background.g, background.b);
     cairo_rectangle(buf->cairo, x, y, width, height);
     cairo_fill(buf->cairo);
 
-    if (cell->c[0] == '\0' || cell->c[0] == ' ')
+    if (cell->c[0] == '\0' || cell->attrs.conceal)
         return;
 
-    if (cell->attrs.conceal)
-        return;
+    /* Underline */
+    if (cell->attrs.underline) {
+        const struct font *font = attrs_to_font(term, &cell->attrs);
+        double width = font->underline.thickness;
+        double y_under = y + term->cell_height + font->underline.position + width / 2.;
+
+        cairo_set_source_rgb(buf->cairo, foreground.r, foreground.g, foreground.b);
+        cairo_set_line_width(buf->cairo, width);
+        cairo_move_to(buf->cairo, x, y_under);
+        cairo_line_to(buf->cairo, x + term->cell_width, y_under);
+        cairo_stroke(buf->cairo);
+    }
 
     /*
      * cairo_show_glyphs() apparently works *much* faster when
@@ -151,7 +169,7 @@ render_cell(struct terminal *term, struct buffer *buf, const struct cell *cell,
         = sizeof(gseq.glyphs) / sizeof(gseq.glyphs[0]) - gseq.count;
 
     cairo_status_t status = cairo_scaled_font_text_to_glyphs(
-        attrs_to_font(term, &cell->attrs), x, y + term->fextents.ascent,
+        attrs_to_font(term, &cell->attrs)->font, x, y + term->fextents.ascent,
         cell->c, strnlen(cell->c, 4), &gseq.g, &new_glyphs,
         NULL, NULL, NULL);
 
@@ -256,9 +274,9 @@ grid_render(struct terminal *term)
 #else
             uint32_t _bg = !term->reverse ? term->background : term->foreground;
             struct rgb bg = {
-                ((_bg >> 16) & 0xff) / 255.0,
-                ((_bg >>  8) & 0xff) / 255.0,
-                ((_bg >>  0) & 0xff) / 255.0,
+                ((_bg >> 16) & 0xff) / 255.,
+                ((_bg >>  8) & 0xff) / 255.,
+                ((_bg >>  0) & 0xff) / 255.,
             };
 #endif
             cairo_set_source_rgb(buf->cairo, bg.r, bg.g, bg.b);

render.h

@@ -2,7 +2,7 @@
 
 #include "terminal.h"
 
-cairo_scaled_font_t *attrs_to_font(
+const struct font *attrs_to_font(
     struct terminal *term, const struct attributes *attrs);
 
 void grid_render(struct terminal *term);

terminal.h

@@ -202,6 +202,14 @@ struct primary {
     uint32_t serial;
 };
 
+struct font {
+    cairo_scaled_font_t *font;
+    struct {
+        double position;
+        double thickness;
+    } underline;
+};
+
 struct terminal {
     pid_t slave;
     int ptmx;
@@ -258,7 +266,7 @@ struct terminal {
     struct grid alt;
     struct grid *grid;
 
-    cairo_scaled_font_t *fonts[4];
+    struct font fonts[4];
     cairo_font_extents_t fextents;
 
     struct wayland wl;