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Get font ascender and descender metrics from OS/2 table.

This commit is contained in:
Simon Cozens 2015-10-26 16:23:22 +09:00 committed by Behdad Esfahbod
parent 097c998a0c
commit 6f2e6de1fa
5 changed files with 274 additions and 8 deletions
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39
src/hb-font-private.hh
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@ -42,6 +42,8 @@
*/
#define HB_FONT_FUNCS_IMPLEMENT_CALLBACKS \
HB_FONT_FUNC_IMPLEMENT (font_h_extents) \
HB_FONT_FUNC_IMPLEMENT (font_v_extents) \
HB_FONT_FUNC_IMPLEMENT (glyph) \
HB_FONT_FUNC_IMPLEMENT (glyph_h_advance) \
HB_FONT_FUNC_IMPLEMENT (glyph_v_advance) \
@ -160,6 +162,21 @@ struct hb_font_t {
HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_FONT_FUNC_IMPLEMENT
inline hb_bool_t get_font_h_extents (hb_font_extents_t *extents)
{
memset (extents, 0, sizeof (*extents));
return klass->get.f.font_h_extents (this, user_data,
extents,
klass->user_data.font_h_extents);
}
inline hb_bool_t get_font_v_extents (hb_font_extents_t *extents)
{
memset (extents, 0, sizeof (*extents));
return klass->get.f.font_v_extents (this, user_data,
extents,
klass->user_data.font_v_extents);
}
inline bool has_glyph (hb_codepoint_t unicode)
{
hb_codepoint_t glyph;
@ -265,6 +282,26 @@ struct hb_font_t {
/* A bit higher-level, and with fallback */
inline void get_extents_for_direction (hb_direction_t direction,
hb_font_extents_t *extents)
{
if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
if (!get_font_h_extents (extents))
{
extents->ascender = y_scale * .8;
extents->descender = y_scale - extents->ascender;
extents->line_gap = 0;
}
} else {
if (!get_font_v_extents (extents))
{
extents->ascender = x_scale / 2;
extents->descender = x_scale - extents->ascender;
extents->line_gap = 0;
}
}
}
inline void get_glyph_advance_for_direction (hb_codepoint_t glyph,
hb_direction_t direction,
hb_position_t *x, hb_position_t *y)
@ -284,7 +321,7 @@ struct hb_font_t {
{
*x = get_glyph_h_advance (glyph) / 2;
/* TODO use font_metrics.ascent */
/* TODO use font_extents.ascender */
*y = y_scale;
}

102
src/hb-font.cc
View File

@ -44,6 +44,54 @@
* hb_font_funcs_t
*/
static hb_bool_t
hb_font_get_font_h_extents_nil (hb_font_t *font,
void *font_data HB_UNUSED,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
memset (metrics, 0, sizeof (*metrics));
return false;
}
static hb_bool_t
hb_font_get_font_h_extents_parent (hb_font_t *font,
void *font_data HB_UNUSED,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
hb_bool_t ret = font->parent->get_font_h_extents (metrics);
if (ret) {
metrics->ascender = font->parent_scale_y_distance (metrics->ascender);
metrics->descender = font->parent_scale_y_distance (metrics->descender);
metrics->line_gap = font->parent_scale_y_distance (metrics->line_gap);
}
return ret;
}
static hb_bool_t
hb_font_get_font_v_extents_nil (hb_font_t *font,
void *font_data HB_UNUSED,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
memset (metrics, 0, sizeof (*metrics));
return false;
}
static hb_bool_t
hb_font_get_font_v_extents_parent (hb_font_t *font,
void *font_data HB_UNUSED,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
hb_bool_t ret = font->parent->get_font_v_extents (metrics);
if (ret) {
metrics->ascender = font->parent_scale_x_distance (metrics->ascender);
metrics->descender = font->parent_scale_x_distance (metrics->descender);
metrics->line_gap = font->parent_scale_x_distance (metrics->line_gap);
}
return ret;
}
static hb_bool_t
hb_font_get_glyph_nil (hb_font_t *font HB_UNUSED,
void *font_data HB_UNUSED,
@ -280,7 +328,6 @@ hb_font_get_glyph_from_name_parent (hb_font_t *font,
return font->parent->get_glyph_from_name (name, len, glyph);
}
static const hb_font_funcs_t _hb_font_funcs_nil = {
HB_OBJECT_HEADER_STATIC,
@ -521,6 +568,42 @@ hb_font_t::has_func (unsigned int i)
/* Public getters */
/**
* hb_font_get_h_extents:
* @font: a font.
* @extents: (out):
*
*
*
* Return value:
*
* Since: 1.1.2
**/
hb_bool_t
hb_font_get_h_extents (hb_font_t *font,
hb_font_extents_t *extents)
{
return font->get_font_h_extents (extents);
}
/**
* hb_font_get_v_extents:
* @font: a font.
* @extents: (out):
*
*
*
* Return value:
*
* Since: 1.1.2
**/
hb_bool_t
hb_font_get_v_extents (hb_font_t *font,
hb_font_extents_t *extents)
{
return font->get_font_v_extents (extents);
}
/**
* hb_font_get_glyph:
* @font: a font.
@ -745,6 +828,23 @@ hb_font_get_glyph_from_name (hb_font_t *font,
/* A bit higher-level, and with fallback */
/**
* hb_font_get_extents_for_direction:
* @font: a font.
* @direction:
* @extents:
*
*
*
* Since: 1.1.2
**/
void
hb_font_get_extents_for_direction (hb_font_t *font,
hb_direction_t direction,
hb_font_extents_t *extents)
{
return font->get_extents_for_direction (direction, extents);
}
/**
* hb_font_get_glyph_advance_for_direction:
* @font: a font.

62
src/hb-font.h
View File

@ -78,7 +78,15 @@ HB_EXTERN hb_bool_t
hb_font_funcs_is_immutable (hb_font_funcs_t *ffuncs);
/* glyph extents */
/* font and glyph extents */
/* Note that typically ascender is positive and descender negative in coordinate systems that grow up. */
typedef struct hb_font_extents_t
{
hb_position_t ascender; /* typographic ascender. */
hb_position_t descender; /* typographic descender. */
hb_position_t line_gap; /* suggested line spacing gap. */
} hb_font_extents_t;
/* Note that height is negative in coordinate systems that grow up. */
typedef struct hb_glyph_extents_t
@ -89,9 +97,15 @@ typedef struct hb_glyph_extents_t
hb_position_t height; /* distance from top to bottom side. */
} hb_glyph_extents_t;
/* func types */
typedef hb_bool_t (*hb_font_get_font_extents_func_t) (hb_font_t *font, void *font_data,
hb_font_extents_t *metrics,
void *user_data);
typedef hb_font_get_font_extents_func_t hb_font_get_font_h_extents_func_t;
typedef hb_font_get_font_extents_func_t hb_font_get_font_v_extents_func_t;
typedef hb_bool_t (*hb_font_get_glyph_func_t) (hb_font_t *font, void *font_data,
hb_codepoint_t unicode, hb_codepoint_t variation_selector,
hb_codepoint_t *glyph,
@ -140,6 +154,38 @@ typedef hb_bool_t (*hb_font_get_glyph_from_name_func_t) (hb_font_t *font, void *
/* func setters */
/**
* hb_font_funcs_set_font_h_extents_func:
* @ffuncs: font functions.
* @func: (closure user_data) (destroy destroy) (scope notified):
* @user_data:
* @destroy:
*
*
*
* Since: 1.1.2
**/
HB_EXTERN void
hb_font_funcs_set_font_h_extents_func (hb_font_funcs_t *ffuncs,
hb_font_get_font_h_extents_func_t func,
void *user_data, hb_destroy_func_t destroy);
/**
* hb_font_funcs_set_font_v_extents_func:
* @ffuncs: font functions.
* @func: (closure user_data) (destroy destroy) (scope notified):
* @user_data:
* @destroy:
*
*
*
* Since: 1.1.2
**/
HB_EXTERN void
hb_font_funcs_set_font_v_extents_func (hb_font_funcs_t *ffuncs,
hb_font_get_font_v_extents_func_t func,
void *user_data, hb_destroy_func_t destroy);
/**
* hb_font_funcs_set_glyph_func:
* @ffuncs: font functions.
@ -316,9 +362,15 @@ hb_font_funcs_set_glyph_from_name_func (hb_font_funcs_t *ffuncs,
hb_font_get_glyph_from_name_func_t func,
void *user_data, hb_destroy_func_t destroy);
/* func dispatch */
HB_EXTERN hb_bool_t
hb_font_get_h_extents (hb_font_t *font,
hb_font_extents_t *extents);
HB_EXTERN hb_bool_t
hb_font_get_v_extents (hb_font_t *font,
hb_font_extents_t *extents);
HB_EXTERN hb_bool_t
hb_font_get_glyph (hb_font_t *font,
hb_codepoint_t unicode, hb_codepoint_t variation_selector,
@ -369,6 +421,10 @@ hb_font_get_glyph_from_name (hb_font_t *font,
/* high-level funcs, with fallback */
HB_EXTERN void
hb_font_get_extents_for_direction (hb_font_t *font,
hb_direction_t direction,
hb_font_extents_t *extents);
HB_EXTERN void
hb_font_get_glyph_advance_for_direction (hb_font_t *font,
hb_codepoint_t glyph,

21
src/hb-ft.cc
View File

@ -366,6 +366,25 @@ hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
return *glyph != 0;
}
static hb_bool_t
hb_ft_get_font_h_extents (hb_font_t *font HB_UNUSED,
void *font_data,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
FT_Face ft_face = ft_font->ft_face;
metrics->ascender = ft_face->ascender;
metrics->descender = ft_face->descender;
metrics->line_gap = ft_face->height - (ft_face->ascender - ft_face->descender);
if (font->y_scale < 0)
{
metrics->ascender = -metrics->ascender;
metrics->descender = -metrics->descender;
metrics->line_gap = -metrics->line_gap;
}
return true;
}
static hb_font_funcs_t *static_ft_funcs = NULL;
@ -387,6 +406,8 @@ retry:
{
funcs = hb_font_funcs_create ();
hb_font_funcs_set_font_h_extents_func (funcs, hb_ft_get_font_h_extents, NULL, NULL);
//hb_font_funcs_set_font_v_extents_func (funcs, hb_ft_get_font_v_extents, NULL, NULL);
hb_font_funcs_set_glyph_func (funcs, hb_ft_get_glyph, NULL, NULL);
hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ft_get_glyph_h_advance, NULL, NULL);
hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ft_get_glyph_v_advance, NULL, NULL);

58
src/hb-ot-font.cc
View File

@ -35,6 +35,7 @@
#include "hb-ot-head-table.hh"
#include "hb-ot-hhea-table.hh"
#include "hb-ot-hmtx-table.hh"
#include "hb-ot-os2-table.hh"
struct hb_ot_face_metrics_accelerator_t
@ -42,17 +43,41 @@ struct hb_ot_face_metrics_accelerator_t
unsigned int num_metrics;
unsigned int num_advances;
unsigned int default_advance;
unsigned short ascender;
unsigned short descender;
unsigned short line_gap;
const OT::_mtx *table;
hb_blob_t *blob;
inline void init (hb_face_t *face,
hb_tag_t _hea_tag, hb_tag_t _mtx_tag)
hb_tag_t _hea_tag,
hb_tag_t _mtx_tag,
hb_tag_t os2_tag)
{
this->default_advance = face->get_upem ();
bool got_font_extents = false;
if (os2_tag)
{
hb_blob_t *os2_blob = OT::Sanitizer<OT::os2>::sanitize (face->reference_table (os2_tag));
const OT::os2 *os2 = OT::Sanitizer<OT::os2>::lock_instance (os2_blob);
this->ascender = os2->sTypoAscender;
this->descender = os2->sTypoDescender;
this->line_gap = os2->sTypoLineGap;
hb_blob_destroy (os2_blob);
got_font_extents = (this->ascender | this->descender) != 0;
}
hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
this->num_advances = _hea->numberOfLongMetrics;
if (!got_font_extents)
{
this->ascender = _hea->ascender;
this->descender = _hea->descender;
this->line_gap = _hea->lineGap;
}
hb_blob_destroy (_hea_blob);
this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
@ -252,8 +277,8 @@ _hb_ot_font_create (hb_face_t *face)
return NULL;
ot_font->cmap.init (face);
ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx);
ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx); /* TODO Can we do this lazily? */
ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_os2);
ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_TAG_NONE); /* TODO Can we do this lazily? */
ot_font->glyf.init (face);
return ot_font;
@ -320,6 +345,31 @@ hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
return ret;
}
static hb_bool_t
hb_ot_get_font_h_extents (hb_font_t *font HB_UNUSED,
void *font_data,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
metrics->ascender = font->em_scale_y (ot_font->h_metrics.ascender);
metrics->descender = font->em_scale_y (ot_font->h_metrics.descender);
metrics->line_gap = font->em_scale_y (ot_font->h_metrics.line_gap);
return true;
}
static hb_bool_t
hb_ot_get_font_v_extents (hb_font_t *font HB_UNUSED,
void *font_data,
hb_font_extents_t *metrics,
void *user_data HB_UNUSED)
{
const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
metrics->ascender = font->em_scale_x (ot_font->v_metrics.ascender);
metrics->descender = font->em_scale_x (ot_font->v_metrics.descender);
metrics->line_gap = font->em_scale_x (ot_font->v_metrics.line_gap);
return true;
}
static hb_font_funcs_t *static_ot_funcs = NULL;
@ -341,6 +391,8 @@ retry:
{
funcs = hb_font_funcs_create ();
hb_font_funcs_set_font_h_extents_func (funcs, hb_ot_get_font_h_extents, NULL, NULL);
hb_font_funcs_set_font_v_extents_func (funcs, hb_ot_get_font_v_extents, NULL, NULL);
hb_font_funcs_set_glyph_func (funcs, hb_ot_get_glyph, NULL, NULL);
hb_font_funcs_set_glyph_h_advance_func (funcs, hb_ot_get_glyph_h_advance, NULL, NULL);
hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ot_get_glyph_v_advance, NULL, NULL);