Apply st-ligatures-boxdraw-20200430-0.8.3

1 files changed, 140 insertions, 0 deletions

diff --git a/hb.c b/hb.c
new file mode 100644
index 0000000..467bcac
--- /dev/null
+++ b/hb.c
@@ -0,0 +1,140 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <X11/Xft/Xft.h>
+#include <hb.h>
+#include <hb-ft.h>
+
+#include "st.h"
+
+void hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length);
+hb_font_t *hbfindfont(XftFont *match);
+
+typedef struct {
+        XftFont *match;
+        hb_font_t *font;
+} HbFontMatch;
+
+static int hbfontslen = 0;
+static HbFontMatch *hbfontcache = NULL;
+
+void
+hbunloadfonts()
+{
+        for (int i = 0; i < hbfontslen; i++) {
+                hb_font_destroy(hbfontcache[i].font);
+                XftUnlockFace(hbfontcache[i].match);
+        }
+
+        if (hbfontcache != NULL) {
+                free(hbfontcache);
+                hbfontcache = NULL;
+        }
+        hbfontslen = 0;
+}
+
+hb_font_t *
+hbfindfont(XftFont *match)
+{
+        for (int i = 0; i < hbfontslen; i++) {
+                if (hbfontcache[i].match == match)
+                        return hbfontcache[i].font;
+        }
+
+        /* Font not found in cache, caching it now. */
+        hbfontcache = realloc(hbfontcache, sizeof(HbFontMatch) * (hbfontslen + 1));
+        FT_Face face = XftLockFace(match);
+        hb_font_t *font = hb_ft_font_create(face, NULL);
+        if (font == NULL)
+                die("Failed to load Harfbuzz font.");
+
+        hbfontcache[hbfontslen].match = match;
+        hbfontcache[hbfontslen].font = font;
+        hbfontslen += 1;
+
+        return font;
+}
+
+void
+hbtransform(XftGlyphFontSpec *specs, const Glyph *glyphs, size_t len, int x, int y)
+{
+        int start = 0, length = 1, gstart = 0;
+        hb_codepoint_t *codepoints = calloc(len, sizeof(hb_codepoint_t));
+
+        for (int idx = 1, specidx = 1; idx < len; idx++) {
+                if (glyphs[idx].mode & ATTR_WDUMMY) {
+                        length += 1;
+                        continue;
+                }
+
+                if (specs[specidx].font != specs[start].font || ATTRCMP(glyphs[gstart], glyphs[idx]) || selected(x + idx, y) != selected(x + gstart, y)) {
+                        hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+                        /* Reset the sequence. */
+                        length = 1;
+                        start = specidx;
+                        gstart = idx;
+                } else {
+                        length += 1;
+                }
+
+                specidx++;
+        }
+
+        /* EOL. */
+        hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+        /* Apply the transformation to glyph specs. */
+        for (int i = 0, specidx = 0; i < len; i++) {
+                if (glyphs[i].mode & ATTR_WDUMMY)
+                        continue;
+                if (glyphs[i].mode & ATTR_BOXDRAW) {
+                        specidx++;
+                        continue;
+                }
+
+                if (codepoints[i] != specs[specidx].glyph)
+                        ((Glyph *)glyphs)[i].mode |= ATTR_LIGA;
+
+                specs[specidx++].glyph = codepoints[i];
+        }
+
+        free(codepoints);
+}
+
+void
+hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length)
+{
+        hb_font_t *font = hbfindfont(xfont);
+        if (font == NULL)
+                return;
+
+        Rune rune;
+        ushort mode = USHRT_MAX;
+        hb_buffer_t *buffer = hb_buffer_create();
+        hb_buffer_set_direction(buffer, HB_DIRECTION_LTR);
+
+        /* Fill buffer with codepoints. */
+        for (int i = start; i < (start+length); i++) {
+                rune = string[i].u;
+                mode = string[i].mode;
+                if (mode & ATTR_WDUMMY)
+                        rune = 0x0020;
+                hb_buffer_add_codepoints(buffer, &rune, 1, 0, 1);
+        }
+
+        /* Shape the segment. */
+        hb_shape(font, buffer, NULL, 0);
+
+        /* Get new glyph info. */
+        hb_glyph_info_t *info = hb_buffer_get_glyph_infos(buffer, NULL);
+
+        /* Write new codepoints. */
+        for (int i = 0; i < length; i++) {
+                hb_codepoint_t gid = info[i].codepoint;
+                codepoints[start+i] = gid;
+        }
+
+        /* Cleanup. */
+        hb_buffer_destroy(buffer);
+}