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font: initial support for double-width *and* color emoji glyphs

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Fonts are now loaded with FT_LOAD_COLOR and we recognize and support
the FT_PIXEL_MODE_BGRA pixel mode.

This is mapped to a CAIRO_FORMAT_ARGB32 surface, that is blitted
as-is (instead of used as a mask like we do for gray and mono glyphs).

Furthermore, since many emojis are double-width, we add initial
support for double-width glyphs.

These are assumed to always be utf8. When PRINT:ing an utf8 character,
we check its width, and add empty "spacer" cells after the cell with
the multi-column glyph.

When rendering, we render the columns in each row backwards. This
ensures the spacer cells get cleared *before* we render the glyph (so
that we don't end up erasing part of the glyph).

Finally, emoji fonts are usually bitmap fonts with *large*
glyphs. These aren't automatically scaled down. I.e. even if we
request a glyph of 13 pixels, we might end up getting a 100px glyph.

To handle this, fontconfig must be configured to scale bitmap
fonts. When it is, we can look at the 'scalable' and 'pixelsizefixup'
properties, and use these to scale the rendered glyph.
This commit is contained in:
Daniel Eklöf 2019-07-31 18:03:35 +02:00
parent 748a1f229c
commit 858a0d9906
No known key found for this signature in database
GPG key ID: 5BBD4992C116573F
5 changed files with 110 additions and 60 deletions
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85
font.c
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@ -106,6 +106,14 @@ from_name(const char *base_name, const font_list_t *fallbacks, const char *attri
return false;
}
FcBool scalable;
if (FcPatternGetBool(final_pattern, FC_SCALABLE, 0, &scalable) != FcResultMatch)
scalable = FcTrue;
double pixel_fixup;
if (FcPatternGetDouble(final_pattern, "pixelsizefixupfactor", 0, &pixel_fixup) != FcResultMatch)
pixel_fixup = 1.;
LOG_DBG("loading: %s", face_file);
mtx_lock(&ft_lock);
@ -199,9 +207,10 @@ from_name(const char *base_name, const font_list_t *fallbacks, const char *attri
mtx_init(&font->lock, mtx_plain);
font->face = ft_face;
font->load_flags = load_flags;
font->load_flags = load_flags | FT_LOAD_COLOR;
font->render_flags = render_flags;
font->is_fallback = is_fallback;
font->pixel_size_fixup = scalable ? pixel_fixup : 1.;
if (fallbacks != NULL) {
tll_foreach(*fallbacks, it) {
@ -222,7 +231,6 @@ from_name(const char *base_name, const font_list_t *fallbacks, const char *attri
if (is_fallback)
return true;
//font_populate_glyph_cache(font);
font->cache = calloc(cache_size, sizeof(font->cache[0]));
return true;
}
@ -272,15 +280,16 @@ glyph_for_wchar(struct font *font, wchar_t wc, struct glyph *glyph)
FT_UInt idx = FT_Get_Char_Index(font->face, wc);
if (idx == 0) {
/* LOG_DBG("no glyph found for %02x %02x %02x %02x", */
/* (unsigned char)utf8[0], (unsigned char)utf8[1], */
/* (unsigned char)utf8[2], (unsigned char)utf8[3]); */
LOG_DBG("no glyph found for %02x %02x %02x %02x",
(unsigned char)utf8[0], (unsigned char)utf8[1],
(unsigned char)utf8[2], (unsigned char)utf8[3]);
/* Try fallback fonts */
tll_foreach(font->fallbacks, it) {
struct font fallback;
if (from_name(it->item, NULL, "", &fallback, true)) {
if (glyph_for_wchar(&fallback, wc, glyph)) {
LOG_DBG("used fallback %s (fixup = %f)", it->item, fallback.pixel_size_fixup);
font_destroy(&fallback);
return true;
}
@ -306,11 +315,15 @@ glyph_for_wchar(struct font *font, wchar_t wc, struct glyph *glyph)
assert(font->face->glyph->format == FT_GLYPH_FORMAT_BITMAP);
FT_Bitmap *bitmap = &font->face->glyph->bitmap;
assert(bitmap->pixel_mode == FT_PIXEL_MODE_GRAY ||
bitmap->pixel_mode == FT_PIXEL_MODE_MONO);
assert(bitmap->pixel_mode == FT_PIXEL_MODE_MONO ||
bitmap->pixel_mode == FT_PIXEL_MODE_GRAY ||
bitmap->pixel_mode == FT_PIXEL_MODE_BGRA);
cairo_format_t cr_format = bitmap->pixel_mode == FT_PIXEL_MODE_GRAY
? CAIRO_FORMAT_A8 : CAIRO_FORMAT_A1;
/* Map FT pixel format to cairo surface format */
cairo_format_t cr_format =
bitmap->pixel_mode == FT_PIXEL_MODE_MONO ? CAIRO_FORMAT_A1 :
bitmap->pixel_mode == FT_PIXEL_MODE_GRAY ? CAIRO_FORMAT_A8 :
bitmap->pixel_mode == FT_PIXEL_MODE_BGRA ? CAIRO_FORMAT_ARGB32 : CAIRO_FORMAT_INVALID;
int stride = cairo_format_stride_for_width(cr_format, bitmap->width);
assert(stride >= bitmap->pitch);
@ -318,6 +331,7 @@ glyph_for_wchar(struct font *font, wchar_t wc, struct glyph *glyph)
uint8_t *data = malloc(bitmap->rows * stride);
assert(bitmap->pitch >= 0);
/* Convert FT bitmap to cairo surface (well, the backing image) */
switch (bitmap->pixel_mode) {
case FT_PIXEL_MODE_MONO:
for (size_t r = 0; r < bitmap->rows; r++) {
@ -339,6 +353,11 @@ glyph_for_wchar(struct font *font, wchar_t wc, struct glyph *glyph)
}
break;
case FT_PIXEL_MODE_BGRA:
assert(stride == bitmap->pitch);
memcpy(data, bitmap->buffer, bitmap->rows * bitmap->pitch);
break;
default:
LOG_ERR("unimplemented FreeType bitmap pixel mode: %d",
bitmap->pixel_mode);
@ -357,10 +376,11 @@ glyph_for_wchar(struct font *font, wchar_t wc, struct glyph *glyph)
*glyph = (struct glyph){
.wc = wc,
.data = data,
.width = wcwidth(wc),
.surf = surf,
.left = font->face->glyph->bitmap_left,
.top = font->face->glyph->bitmap_top,
.pixel_size_fixup = font->pixel_size_fixup,
};
return true;
@ -428,30 +448,25 @@ font_destroy(struct font *font)
mtx_unlock(&ft_lock);
}
if (font->cache != NULL) {
for (size_t i = 0; i < cache_size; i++) {
if (font->cache[i] == NULL)
continue;
tll_foreach(*font->cache[i], it) {
cairo_surface_destroy(it->item.surf);
free(it->item.data);
}
tll_free(*font->cache[i]);
free(font->cache[i]);
}
free(font->cache);
}
#if 0
for (size_t i = 0; i < 256; i++) {
if (font->cache[i].surf != NULL)
cairo_surface_destroy(font->cache[i].surf);
if (font->cache[i].data != NULL)
free(font->cache[i].data);
}
#endif
mtx_destroy(&font->lock);
if (font->cache == NULL)
return;
for (size_t i = 0; i < cache_size; i++) {
if (font->cache[i] == NULL)
continue;
tll_foreach(*font->cache[i], it) {
cairo_surface_flush(it->item.surf);
void *image = cairo_image_surface_get_data(it->item.surf);
cairo_surface_destroy(it->item.surf);
free(image);
}
tll_free(*font->cache[i]);
free(font->cache[i]);
}
free(font->cache);
}