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[ft] Implement loading (color) bitmap fonts 

Fixes https://github.com/harfbuzz/harfbuzz/issues/489

Something about the vertical metrics is still off, not matching
hb-ot.  I cannot figure out what.
This commit is contained in:
Behdad Esfahbod 2022-07-15 12:55:31 -06:00
parent 3ac110560d
commit 901236f721
1 changed files with 56 additions and 36 deletions
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92
src/hb-ft.cc
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@ -136,18 +136,36 @@ _hb_ft_font_destroy (void *data)
/* hb_font changed, update FT_Face. */ /* hb_font changed, update FT_Face. */
static void _hb_ft_hb_font_changed (hb_font_t *font, FT_Face ft_face) static void _hb_ft_hb_font_changed (hb_font_t *font, FT_Face ft_face)
{ {
float x_mult = 1.f, y_mult = 1.f;
FT_Set_Char_Size (ft_face, if (FT_Set_Char_Size (ft_face,
abs (font->x_scale), abs (font->y_scale), abs (font->x_scale), abs (font->y_scale),
0, 0); 0, 0
#if 0 #if 0
font->x_ppem * 72 * 64 / font->x_scale, font->x_ppem * 72 * 64 / font->x_scale,
font->y_ppem * 72 * 64 / font->y_scale); font->y_ppem * 72 * 64 / font->y_scale
#endif #endif
if (font->x_scale < 0 || font->y_scale < 0) ) && ft_face->num_fixed_sizes)
{ {
FT_Matrix matrix = { font->x_scale < 0 ? -(1<<16) : +(1<<16), 0, /* Bitmap font, eg. bitmap color emoji. */
0, font->y_scale < 0 ? -(1<<16) : +(1<<16)}; /* TODO Pick largest size? */
int x_scale = ft_face->available_sizes[0].x_ppem;
int y_scale = ft_face->available_sizes[0].y_ppem;
FT_Set_Char_Size (ft_face,
x_scale, y_scale,
0, 0);
x_mult = (float) font->x_scale / x_scale;
y_mult = (float) font->y_scale / y_scale;
}
else
{ /* Shrug */ }
if (font->x_scale < 0) x_mult = -x_mult;
if (font->y_scale < 0) y_mult = -y_mult;
if (x_mult != 1.f || y_mult != 1.f)
{
FT_Matrix matrix = { (int) roundf (x_mult * (1<<16)), 0,
0, (int) roundf (y_mult * (1<<16))};
FT_Set_Transform (ft_face, &matrix, nullptr); FT_Set_Transform (ft_face, &matrix, nullptr);
} }
@ -404,7 +422,9 @@ hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
hb_lock_t lock (ft_font->lock); hb_lock_t lock (ft_font->lock);
FT_Face ft_face = ft_font->ft_face; FT_Face ft_face = ft_font->ft_face;
int load_flags = ft_font->load_flags; int load_flags = ft_font->load_flags;
int mult = font->x_scale < 0 ? -1 : +1; FT_Matrix matrix;
FT_Get_Transform (ft_face, &matrix, nullptr);
float mult = matrix.xx / 65536.f;
for (unsigned int i = 0; i < count; i++) for (unsigned int i = 0; i < count; i++)
{ {
@ -420,7 +440,7 @@ hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
ft_font->advance_cache.set (glyph, v); ft_font->advance_cache.set (glyph, v);
} }
*first_advance = (v * mult + (1<<9)) >> 10; *first_advance = (int) (v * mult + (1<<9)) >> 10;
first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride); first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride); first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
} }
@ -436,12 +456,14 @@ hb_ft_get_glyph_v_advance (hb_font_t *font,
const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data; const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
hb_lock_t lock (ft_font->lock); hb_lock_t lock (ft_font->lock);
FT_Fixed v; FT_Fixed v;
FT_Matrix matrix;
FT_Get_Transform (ft_font->ft_face, &matrix, nullptr);
float y_mult = matrix.yy / 65536.f;
if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v))) if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v)))
return 0; return 0;
if (font->y_scale < 0) v = (int) (y_mult * v);
v = -v;
/* Note: FreeType's vertical metrics grows downward while other FreeType coordinates /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
* have a Y growing upward. Hence the extra negation. */ * have a Y growing upward. Hence the extra negation. */
@ -462,6 +484,10 @@ hb_ft_get_glyph_v_origin (hb_font_t *font,
const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data; const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
hb_lock_t lock (ft_font->lock); hb_lock_t lock (ft_font->lock);
FT_Face ft_face = ft_font->ft_face; FT_Face ft_face = ft_font->ft_face;
FT_Matrix matrix;
FT_Get_Transform (ft_face, &matrix, nullptr);
float x_mult = matrix.xx / 65536.f;
float y_mult = matrix.yy / 65536.f;
if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags))) if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
return false; return false;
@ -471,10 +497,8 @@ hb_ft_get_glyph_v_origin (hb_font_t *font,
*x = ft_face->glyph->metrics.horiBearingX - ft_face->glyph->metrics.vertBearingX; *x = ft_face->glyph->metrics.horiBearingX - ft_face->glyph->metrics.vertBearingX;
*y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY); *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);
if (font->x_scale < 0) *x = (hb_position_t) (x_mult * *x);
*x = -*x; *y = (hb_position_t) (y_mult * *y);
if (font->y_scale < 0)
*y = -*y;
return true; return true;
} }
@ -510,24 +534,19 @@ hb_ft_get_glyph_extents (hb_font_t *font,
const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data; const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
hb_lock_t lock (ft_font->lock); hb_lock_t lock (ft_font->lock);
FT_Face ft_face = ft_font->ft_face; FT_Face ft_face = ft_font->ft_face;
FT_Matrix matrix;
FT_Get_Transform (ft_face, &matrix, nullptr);
float x_mult = matrix.xx / 65536.f;
float y_mult = matrix.yy / 65536.f;
if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags))) if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
return false; return false;
extents->x_bearing = ft_face->glyph->metrics.horiBearingX; extents->x_bearing = (hb_position_t) (x_mult * ft_face->glyph->metrics.horiBearingX);
extents->y_bearing = ft_face->glyph->metrics.horiBearingY; extents->y_bearing = (hb_position_t) (y_mult * ft_face->glyph->metrics.horiBearingY);
extents->width = ft_face->glyph->metrics.width; extents->width = (hb_position_t) (x_mult * ft_face->glyph->metrics.width);
extents->height = -ft_face->glyph->metrics.height; extents->height = (hb_position_t) (y_mult * -ft_face->glyph->metrics.height);
if (font->x_scale < 0)
{
extents->x_bearing = -extents->x_bearing;
extents->width = -extents->width;
}
if (font->y_scale < 0)
{
extents->y_bearing = -extents->y_bearing;
extents->height = -extents->height;
}
return true; return true;
} }
@ -620,16 +639,17 @@ hb_ft_get_font_h_extents (hb_font_t *font HB_UNUSED,
const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data; const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
hb_lock_t lock (ft_font->lock); hb_lock_t lock (ft_font->lock);
FT_Face ft_face = ft_font->ft_face; FT_Face ft_face = ft_font->ft_face;
FT_Matrix matrix;
FT_Get_Transform (ft_face, &matrix, nullptr);
float y_mult = matrix.yy / 65536.f;
metrics->ascender = FT_MulFix(ft_face->ascender, ft_face->size->metrics.y_scale); metrics->ascender = FT_MulFix(ft_face->ascender, ft_face->size->metrics.y_scale);
metrics->descender = FT_MulFix(ft_face->descender, ft_face->size->metrics.y_scale); metrics->descender = FT_MulFix(ft_face->descender, ft_face->size->metrics.y_scale);
metrics->line_gap = FT_MulFix( ft_face->height, ft_face->size->metrics.y_scale ) - (metrics->ascender - metrics->descender); metrics->line_gap = FT_MulFix( ft_face->height, ft_face->size->metrics.y_scale ) - (metrics->ascender - metrics->descender);
if (font->y_scale < 0) metrics->ascender = (hb_position_t) (y_mult * metrics->ascender);
{ metrics->descender = (hb_position_t) (y_mult * metrics->descender);
metrics->ascender = -metrics->ascender; metrics->line_gap = (hb_position_t) (y_mult * metrics->line_gap);
metrics->descender = -metrics->descender;
metrics->line_gap = -metrics->line_gap;
}
return true; return true;
} }