harfbuzz/src/hb-ft.cc

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/*
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* Copyright © 2009 Red Hat, Inc.
* Copyright © 2009 Keith Stribley
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*
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* This is part of HarfBuzz, a text shaping library.
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*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Red Hat Author(s): Behdad Esfahbod
*/
#include "hb-private.hh"
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#include "hb-ft.h"
#include "hb-font-private.hh"
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#include FT_TRUETYPE_TABLES_H
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HB_BEGIN_DECLS
/* TODO:
*
* In general, this file does a fine job of what it's supposed to do.
* There are, however, things that need more work:
*
* - We don't handle any load_flags. That definitely has API implications. :(
* I believe hb_ft_font_create() should take load_flags input.
*
* - We don't handle / allow for emboldening / obliqueing.
*
* - In the future, we should add constructors to create fonts in font space.
*
* - I believe transforms are not correctly implemented. FreeType does not
* provide any API to get to the transform/delta set on the face. :(
*
* - Always use FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH?
*/
static hb_bool_t
hb_ft_get_glyph (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t unicode,
hb_codepoint_t variation_selector,
hb_codepoint_t *glyph,
void *user_data HB_UNUSED)
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{
FT_Face ft_face = (FT_Face) font_data;
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#ifdef HAVE_FT_FACE_GETCHARVARIANTINDEX
if (unlikely (variation_selector)) {
*glyph = FT_Face_GetCharVariantIndex (ft_face, unicode, variation_selector);
if (*glyph)
return TRUE;
}
#endif
*glyph = FT_Get_Char_Index (ft_face, unicode);
return *glyph != 0;
}
static hb_bool_t
hb_ft_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t glyph,
hb_position_t *x_advance,
hb_position_t *y_advance,
void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
int load_flags = FT_LOAD_DEFAULT;
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if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
return FALSE;
*x_advance = ft_face->glyph->metrics.horiAdvance;
return TRUE;
}
static hb_bool_t
hb_ft_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t glyph,
hb_position_t *x_advance,
hb_position_t *y_advance,
void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
int load_flags = FT_LOAD_DEFAULT;
if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
return FALSE;
*y_advance = -ft_face->glyph->metrics.vertAdvance;
return TRUE;
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}
static hb_bool_t
hb_ft_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t glyph,
hb_position_t *x_origin,
hb_position_t *y_origin,
void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
int load_flags = FT_LOAD_DEFAULT;
if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
return FALSE;
*y_origin = ft_face->glyph->metrics.vertAdvance;
return TRUE;
}
static hb_bool_t
hb_ft_get_h_kerning (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t left_glyph,
hb_codepoint_t right_glyph,
hb_position_t *x_kern,
hb_position_t *y_kern,
void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
FT_Vector kerning;
if (FT_Get_Kerning (ft_face, left_glyph, right_glyph, FT_KERNING_DEFAULT, &kerning))
return FALSE;
*x_kern = kerning.x;
*y_kern = kerning.y;
return TRUE;
}
static hb_bool_t
hb_ft_get_v_kerning (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t top_glyph,
hb_codepoint_t bottom_glyph,
hb_position_t *x_kern,
hb_position_t *y_kern,
void *user_data HB_UNUSED)
{
/* FreeType API doesn't support vertical kerning */
return FALSE;
}
static hb_bool_t
hb_ft_get_glyph_extents (hb_font_t *font HB_UNUSED,
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void *font_data,
hb_codepoint_t glyph,
hb_bool_t *vertical,
hb_glyph_extents_t *extents,
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void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
int load_flags = FT_LOAD_DEFAULT;
/* TODO: load_flags, embolden, etc, shape/transform */
if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
return FALSE;
/* XXX: A few negations should be in order here, not sure. */
extents->x_bearing = ft_face->glyph->metrics.horiBearingX;
extents->y_bearing = ft_face->glyph->metrics.horiBearingY;
extents->width = ft_face->glyph->metrics.width;
extents->height = ft_face->glyph->metrics.height;
return TRUE;
}
static hb_bool_t
hb_ft_get_contour_point (hb_font_t *font HB_UNUSED,
void *font_data,
hb_codepoint_t glyph,
unsigned int point_index,
hb_bool_t *vertical,
hb_position_t *x,
hb_position_t *y,
void *user_data HB_UNUSED)
{
FT_Face ft_face = (FT_Face) font_data;
int load_flags = FT_LOAD_DEFAULT;
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if (unlikely (FT_Load_Glyph (ft_face, glyph, load_flags)))
return FALSE;
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if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))
return FALSE;
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if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))
return FALSE;
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*x = ft_face->glyph->outline.points[point_index].x;
*y = ft_face->glyph->outline.points[point_index].y;
*vertical = FALSE; /* We always return position in horizontal coordinates */
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return TRUE;
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}
static hb_font_funcs_t ft_ffuncs = {
HB_OBJECT_HEADER_STATIC,
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TRUE, /* immutable */
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{
hb_ft_get_glyph,
hb_ft_get_glyph_h_advance,
hb_ft_get_glyph_v_advance,
hb_ft_get_glyph_v_origin,
hb_ft_get_h_kerning,
hb_ft_get_v_kerning,
hb_ft_get_glyph_extents,
hb_ft_get_contour_point,
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}
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};
hb_font_funcs_t *
hb_ft_get_font_funcs (void)
{
return &ft_ffuncs;
}
static hb_blob_t *
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get_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
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{
FT_Face ft_face = (FT_Face) user_data;
FT_Byte *buffer;
FT_ULong length = 0;
FT_Error error;
if (unlikely (tag == HB_TAG_NONE))
return NULL;
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error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
if (error)
return NULL;
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buffer = (FT_Byte *) malloc (length);
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if (buffer == NULL)
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return NULL;
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error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
if (error)
return NULL;
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return hb_blob_create ((const char *) buffer, length,
HB_MEMORY_MODE_WRITABLE,
buffer, free);
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}
hb_face_t *
hb_ft_face_create (FT_Face ft_face,
hb_destroy_func_t destroy)
{
hb_face_t *face;
if (ft_face->stream->read == NULL) {
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hb_blob_t *blob;
blob = hb_blob_create ((const char *) ft_face->stream->base,
(unsigned int) ft_face->stream->size,
/* TODO: We assume that it's mmap()'ed, but FreeType code
* suggests that there are cases we reach here but font is
* not mmapped. For example, when mmap() fails. No idea
* how to deal with it better here. */
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HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE,
ft_face, destroy);
face = hb_face_create (blob, ft_face->face_index);
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hb_blob_destroy (blob);
} else {
face = hb_face_create_for_tables (get_table, ft_face, destroy);
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}
return face;
}
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static void
hb_ft_face_finalize (FT_Face ft_face)
{
hb_face_destroy ((hb_face_t *) ft_face->generic.data);
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}
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hb_face_t *
hb_ft_face_create_cached (FT_Face ft_face)
{
if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))
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{
if (ft_face->generic.finalizer)
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ft_face->generic.finalizer (ft_face);
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ft_face->generic.data = hb_ft_face_create (ft_face, NULL);
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ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
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}
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return hb_face_reference ((hb_face_t *) ft_face->generic.data);
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}
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hb_font_t *
hb_ft_font_create (FT_Face ft_face,
hb_destroy_func_t destroy)
{
hb_font_t *font;
hb_face_t *face;
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face = hb_ft_face_create (ft_face, destroy);
font = hb_font_create (face);
hb_face_destroy (face);
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hb_font_set_funcs (font,
hb_ft_get_font_funcs (),
ft_face, NULL);
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hb_font_set_scale (font,
((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM) >> 16,
((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM) >> 16);
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hb_font_set_ppem (font,
ft_face->size->metrics.x_ppem,
ft_face->size->metrics.y_ppem);
return font;
}
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HB_END_DECLS