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Fix rendering of the new infinite length ligatures on CoreText

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Apparently on CoreText, harfbuzz gives incorrect values for glyph
positions. So we use it only for selection and grouping of glyphs.
Actual positioning is done using CoreText. This means sophisticated
positioning using GPOS tables is probably broken, but that isn't really
useable in a character grid anyway.

Also remove the hack where glyph_centering was done for calt ligatures
as it seems to not be needed with modern FiraCode and CoreText
rendering. Fixes #3372
This commit is contained in:
Kovid Goyal 2021-03-11 20:11:40 +05:30
parent a94b94cab0
commit 1f4fdb174a
No known key found for this signature in database
GPG Key ID: 06BC317B515ACE7C
2 changed files with 12 additions and 10 deletions
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17
kitty/core_text.m
View File

@ -390,6 +390,7 @@ static size_t render_buf_sz = 0;
static CGGlyph glyphs[128];
static CGRect boxes[128];
static CGPoint positions[128];
static CGSize advances[128];
static void
finalize(void) {
@ -459,15 +460,15 @@ render_simple_text_impl(PyObject *s, const char *text, unsigned int baseline) {
CTFontRef font = self->ct_font;
size_t num_chars = strnlen(text, 32);
unichar chars[num_chars];
CGSize advances[num_chars];
CGSize local_advances[num_chars];
for (size_t i = 0; i < num_chars; i++) chars[i] = text[i];
CTFontGetGlyphsForCharacters(font, chars, glyphs, num_chars);
CTFontGetAdvancesForGlyphs(font, kCTFontOrientationDefault, glyphs, advances, num_chars);
CTFontGetAdvancesForGlyphs(font, kCTFontOrientationDefault, glyphs, local_advances, num_chars);
CGRect bounding_box = CTFontGetBoundingRectsForGlyphs(font, kCTFontOrientationDefault, glyphs, boxes, num_chars);
CGFloat x = 0, y = 0;
for (size_t i = 0; i < num_chars; i++) {
positions[i] = CGPointMake(x, y);
x += advances[i].width; y += advances[i].height;
x += local_advances[i].width; y += local_advances[i].height;
}
StringCanvas ans = { .width = (size_t)ceil(x), .height = (size_t)(2 * bounding_box.size.height) };
ensure_render_space(ans.width, ans.height);
@ -482,11 +483,13 @@ static inline bool
do_render(CTFontRef ct_font, bool bold, bool italic, hb_glyph_info_t *info, hb_glyph_position_t *hb_positions, unsigned int num_glyphs, pixel *canvas, unsigned int cell_width, unsigned int cell_height, unsigned int num_cells, unsigned int baseline, bool *was_colored, bool allow_resize, FONTS_DATA_HANDLE fg, bool center_glyph) {
unsigned int canvas_width = cell_width * num_cells;
CGRect br = CTFontGetBoundingRectsForGlyphs(ct_font, kCTFontOrientationHorizontal, glyphs, boxes, num_glyphs);
const bool debug_rendering = false;
if (allow_resize) {
// Resize glyphs that would bleed into neighboring cells, by scaling the font size
float right = 0;
for (unsigned i=0; i < num_glyphs; i++) right = MAX(right, boxes[i].origin.x + boxes[i].size.width);
if (!bold && !italic && right > canvas_width + 1) {
if (debug_rendering) printf("resizing glyphs, right: %f canvas_width: %u\n", right, canvas_width);
CGFloat sz = CTFontGetSize(ct_font);
sz *= canvas_width / right;
CTFontRef new_font = CTFontCreateCopyWithAttributes(ct_font, sz, NULL, NULL);
@ -495,9 +498,12 @@ do_render(CTFontRef ct_font, bool bold, bool italic, hb_glyph_info_t *info, hb_g
return ret;
}
}
CGFloat x = 0, y = 0;
CTFontGetAdvancesForGlyphs(ct_font, kCTFontOrientationDefault, glyphs, advances, num_glyphs);
for (unsigned i=0; i < num_glyphs; i++) {
positions[i].x = MAX(0, -boxes[i].origin.x) + hb_positions[i].x_offset / 64.f;
positions[i].y = hb_positions[i].y_offset / 64.f;
positions[i].x = x; positions[i].y = y;
if (debug_rendering) printf("x=%f origin=%f width=%f advance=%f\n", x, boxes[i].origin.x, boxes[i].size.width, advances[i].width);
x += advances[i].width; y += advances[i].height;
}
if (*was_colored) {
render_color_glyph(ct_font, (uint8_t*)canvas, info[0].codepoint, cell_width * num_cells, cell_height, baseline);
@ -508,6 +514,7 @@ do_render(CTFontRef ct_font, bool bold, bool italic, hb_glyph_info_t *info, hb_g
render_alpha_mask(render_buf, canvas, &src, &dest, canvas_width, canvas_width);
}
if (num_cells && (center_glyph || (num_cells == 2 && *was_colored))) {
if (debug_rendering) printf("centering glyphs: center_glyph: %d\n", center_glyph);
// center glyphs (two cell emoji, PUA glyphs, ligatures, etc)
CGFloat delta = (((CGFloat)canvas_width - br.size.width) / 2.f);
// FiraCode ligatures result in negative origins

5
kitty/fonts.c
View File

@ -1102,11 +1102,6 @@ render_groups(FontGroup *fg, Font *font, bool center_glyph) {
// there exist stupid fonts like Powerline that have no space glyph,
// so special case it: https://github.com/kovidgoyal/kitty/issues/1225
unsigned int num_glyphs = group->is_space_ligature ? 1 : group->num_glyphs;
#ifdef __APPLE__
// FiraCode ligatures need to be centered on macOS
// see https://github.com/kovidgoyal/kitty/issues/2591
if (is_group_calt_ligature(group)) center_glyph = true;
#endif
render_group(fg, group->num_cells, num_glyphs, G(first_cpu_cell) + group->first_cell_idx, G(first_gpu_cell) + group->first_cell_idx, G(info) + group->first_glyph_idx, G(positions) + group->first_glyph_idx, font, primary, &ed, center_glyph);
idx++;
}