harfbuzz/src/hb-ot-shape.cc

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/*
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* Copyright © 2009,2010 Red Hat, Inc.
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* Copyright © 2010,2011 Google, Inc.
*
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* This is part of HarfBuzz, a text shaping library.
*
* 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
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* Google Author(s): Behdad Esfahbod
*/
#define HB_SHAPER ot
#define hb_ot_shaper_face_data_t hb_ot_layout_t
#define hb_ot_shaper_shape_plan_data_t hb_ot_shape_plan_t
#include "hb-shaper-impl-private.hh"
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#include "hb-ot-shape-private.hh"
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#include "hb-ot-shape-normalize-private.hh"
#include "hb-ot-layout-private.hh"
#include "hb-set-private.hh"
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hb_tag_t common_features[] = {
HB_TAG('c','c','m','p'),
HB_TAG('l','i','g','a'),
HB_TAG('l','o','c','l'),
HB_TAG('m','a','r','k'),
HB_TAG('m','k','m','k'),
HB_TAG('r','l','i','g'),
};
hb_tag_t horizontal_features[] = {
HB_TAG('c','a','l','t'),
HB_TAG('c','l','i','g'),
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HB_TAG('c','u','r','s'),
HB_TAG('k','e','r','n'),
};
/* Note:
* Technically speaking, vrt2 and vert are mutually exclusive.
* According to the spec, valt and vpal are also mutually exclusive.
* But we apply them all for now.
*/
hb_tag_t vertical_features[] = {
HB_TAG('v','a','l','t'),
HB_TAG('v','e','r','t'),
HB_TAG('v','k','r','n'),
HB_TAG('v','p','a','l'),
HB_TAG('v','r','t','2'),
};
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struct hb_ot_shape_planner_t
{
hb_ot_map_builder_t map;
const hb_ot_complex_shaper_t *shaper;
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hb_ot_shape_planner_t (void) : map () {}
~hb_ot_shape_planner_t (void) { map.finish (); }
inline void compile (hb_face_t *face,
const hb_segment_properties_t *props,
hb_ot_shape_plan_t &plan)
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{
plan.shaper = shaper;
map.compile (face, props, plan.map);
}
private:
NO_COPY (hb_ot_shape_planner_t);
};
static void
hb_ot_shape_collect_features (hb_ot_shape_planner_t *planner,
const hb_segment_properties_t *props,
const hb_feature_t *user_features,
unsigned int num_user_features)
{
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switch (props->direction) {
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case HB_DIRECTION_LTR:
planner->map.add_bool_feature (HB_TAG ('l','t','r','a'));
planner->map.add_bool_feature (HB_TAG ('l','t','r','m'));
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break;
case HB_DIRECTION_RTL:
planner->map.add_bool_feature (HB_TAG ('r','t','l','a'));
planner->map.add_bool_feature (HB_TAG ('r','t','l','m'), false);
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break;
case HB_DIRECTION_TTB:
case HB_DIRECTION_BTT:
case HB_DIRECTION_INVALID:
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default:
break;
}
#define ADD_FEATURES(array) \
HB_STMT_START { \
for (unsigned int i = 0; i < ARRAY_LENGTH (array); i++) \
planner->map.add_bool_feature (array[i]); \
} HB_STMT_END
if (planner->shaper->collect_features)
planner->shaper->collect_features (planner->shaper, &planner->map, props);
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ADD_FEATURES (common_features);
if (HB_DIRECTION_IS_HORIZONTAL (props->direction))
ADD_FEATURES (horizontal_features);
else
ADD_FEATURES (vertical_features);
if (planner->shaper->override_features)
planner->shaper->override_features (planner->shaper, &planner->map, props);
#undef ADD_FEATURES
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for (unsigned int i = 0; i < num_user_features; i++) {
const hb_feature_t *feature = &user_features[i];
planner->map.add_feature (feature->tag, feature->value, (feature->start == 0 && feature->end == (unsigned int) -1));
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}
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}
/*
* shaper face data
*/
hb_ot_shaper_face_data_t *
_hb_ot_shaper_face_data_create (hb_face_t *face)
{
return _hb_ot_layout_create (face);
}
void
_hb_ot_shaper_face_data_destroy (hb_ot_shaper_face_data_t *data)
{
_hb_ot_layout_destroy (data);
}
/*
* shaper font data
*/
struct hb_ot_shaper_font_data_t {};
hb_ot_shaper_font_data_t *
_hb_ot_shaper_font_data_create (hb_font_t *font)
{
return (hb_ot_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
}
void
_hb_ot_shaper_font_data_destroy (hb_ot_shaper_font_data_t *data)
{
}
/*
* shaper shape_plan data
*/
hb_ot_shaper_shape_plan_data_t *
_hb_ot_shaper_shape_plan_data_create (hb_shape_plan_t *shape_plan,
const hb_feature_t *user_features,
unsigned int num_user_features)
{
hb_ot_shape_plan_t *data = (hb_ot_shape_plan_t *) calloc (1, sizeof (hb_ot_shape_plan_t));
if (unlikely (!data))
return NULL;
hb_ot_shape_planner_t planner;
assert (HB_DIRECTION_IS_VALID (shape_plan->props.direction));
planner.shaper = hb_ot_shape_complex_categorize (&shape_plan->props);
hb_ot_shape_collect_features (&planner, &shape_plan->props, user_features, num_user_features);
planner.compile (shape_plan->face, &shape_plan->props, *data);
return data;
}
void
_hb_ot_shaper_shape_plan_data_destroy (hb_ot_shaper_shape_plan_data_t *data)
{
data->map.finish ();
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free (data);
}
/*
* shaper
*/
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struct hb_ot_shape_context_t
{
/* Input to hb_ot_shape_internal() */
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hb_ot_shape_plan_t *plan;
hb_font_t *font;
hb_face_t *face;
hb_buffer_t *buffer;
const hb_feature_t *user_features;
unsigned int num_user_features;
/* Transient stuff */
hb_direction_t target_direction;
hb_bool_t applied_position_complex;
};
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static void
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hb_ot_shape_setup_masks (hb_ot_shape_context_t *c)
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{
hb_mask_t global_mask = c->plan->map.get_global_mask ();
c->buffer->reset_masks (global_mask);
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if (c->plan->shaper->setup_masks)
c->plan->shaper->setup_masks (c->plan->shaper, &c->plan->map, c->buffer, c->font);
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for (unsigned int i = 0; i < c->num_user_features; i++)
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{
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const hb_feature_t *feature = &c->user_features[i];
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if (!(feature->start == 0 && feature->end == (unsigned int)-1)) {
unsigned int shift;
hb_mask_t mask = c->plan->map.get_mask (feature->tag, &shift);
c->buffer->set_masks (feature->value << shift, mask, feature->start, feature->end);
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}
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}
}
/* Main shaper */
/* Prepare */
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static void
hb_set_unicode_props (hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
_hb_glyph_info_set_unicode_props (&buffer->info[i], buffer->unicode);
}
static void
hb_form_clusters (hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
for (unsigned int i = 1; i < count; i++)
if (FLAG (_hb_glyph_info_get_general_category (&buffer->info[i])) &
(FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) |
FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
buffer->merge_clusters (i - 1, i + 1);
}
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static void
hb_ensure_native_direction (hb_buffer_t *buffer)
{
hb_direction_t direction = buffer->props.direction;
/* TODO vertical:
* The only BTT vertical script is Ogham, but it's not clear to me whether OpenType
* Ogham fonts are supposed to be implemented BTT or not. Need to research that
* first. */
if ((HB_DIRECTION_IS_HORIZONTAL (direction) && direction != hb_script_get_horizontal_direction (buffer->props.script)) ||
(HB_DIRECTION_IS_VERTICAL (direction) && direction != HB_DIRECTION_TTB))
{
hb_buffer_reverse_clusters (buffer);
buffer->props.direction = HB_DIRECTION_REVERSE (buffer->props.direction);
}
}
/* Substitute */
static void
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hb_mirror_chars (hb_ot_shape_context_t *c)
{
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hb_unicode_funcs_t *unicode = c->buffer->unicode;
if (HB_DIRECTION_IS_FORWARD (c->target_direction))
return;
hb_mask_t rtlm_mask = c->plan->map.get_1_mask (HB_TAG ('r','t','l','m'));
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unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++) {
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hb_codepoint_t codepoint = unicode->mirroring (c->buffer->info[i].codepoint);
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if (likely (codepoint == c->buffer->info[i].codepoint))
c->buffer->info[i].mask |= rtlm_mask; /* XXX this should be moved to before setting user-feature masks */
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else
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c->buffer->info[i].codepoint = codepoint;
}
}
static void
hb_map_glyphs (hb_font_t *font,
hb_buffer_t *buffer)
{
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hb_codepoint_t glyph;
if (unlikely (!buffer->len))
return;
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buffer->clear_output ();
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unsigned int count = buffer->len - 1;
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for (buffer->idx = 0; buffer->idx < count;) {
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if (unlikely (buffer->unicode->is_variation_selector (buffer->cur(+1).codepoint))) {
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font->get_glyph (buffer->cur().codepoint, buffer->cur(+1).codepoint, &glyph);
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buffer->replace_glyphs (2, 1, &glyph);
} else {
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font->get_glyph (buffer->cur().codepoint, 0, &glyph);
buffer->replace_glyph (glyph);
}
}
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if (likely (buffer->idx < buffer->len)) {
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font->get_glyph (buffer->cur().codepoint, 0, &glyph);
buffer->replace_glyph (glyph);
}
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buffer->swap_buffers ();
}
static void
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hb_substitute_default (hb_ot_shape_context_t *c)
{
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hb_mirror_chars (c);
hb_map_glyphs (c->font, c->buffer);
}
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static void
hb_synthesize_glyph_classes (hb_ot_shape_context_t *c)
{
unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++)
c->buffer->info[i].glyph_props() = FLAG (_hb_glyph_info_get_general_category (&c->buffer->info[i])) &
(FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) |
FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)) ?
HB_OT_LAYOUT_GLYPH_CLASS_MARK :
HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH;
}
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static void
hb_ot_substitute_complex (hb_ot_shape_context_t *c)
{
hb_ot_layout_substitute_start (c->face, c->buffer);
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if (!hb_ot_layout_has_glyph_classes (c->face))
hb_synthesize_glyph_classes (c);
if (hb_ot_layout_has_substitution (c->face))
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c->plan->map.substitute (c->face, c->buffer);
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hb_ot_layout_substitute_finish (c->face, c->buffer);
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return;
}
/* Position */
static void
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hb_position_default (hb_ot_shape_context_t *c)
{
hb_ot_layout_position_start (c->font, c->buffer);
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unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++) {
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c->font->get_glyph_advance_for_direction (c->buffer->info[i].codepoint,
c->buffer->props.direction,
&c->buffer->pos[i].x_advance,
&c->buffer->pos[i].y_advance);
c->font->subtract_glyph_origin_for_direction (c->buffer->info[i].codepoint,
c->buffer->props.direction,
&c->buffer->pos[i].x_offset,
&c->buffer->pos[i].y_offset);
}
}
static void
hb_zero_mark_advances (hb_ot_shape_context_t *c)
{
unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++)
if (c->buffer->info[i].glyph_props() & HB_OT_LAYOUT_GLYPH_CLASS_MARK)
{
c->buffer->pos[i].x_advance = 0;
c->buffer->pos[i].y_advance = 0;
}
}
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static void
hb_ot_position_complex (hb_ot_shape_context_t *c)
{
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if (hb_ot_layout_has_positioning (c->face))
{
/* Change glyph origin to what GPOS expects, apply GPOS, change it back. */
unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++) {
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c->font->add_glyph_origin_for_direction (c->buffer->info[i].codepoint,
HB_DIRECTION_LTR,
&c->buffer->pos[i].x_offset,
&c->buffer->pos[i].y_offset);
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}
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c->plan->map.position (c->font, c->buffer);
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for (unsigned int i = 0; i < count; i++) {
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c->font->subtract_glyph_origin_for_direction (c->buffer->info[i].codepoint,
HB_DIRECTION_LTR,
&c->buffer->pos[i].x_offset,
&c->buffer->pos[i].y_offset);
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}
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c->applied_position_complex = true;
} else
hb_zero_mark_advances (c);
hb_ot_layout_position_finish (c->font, c->buffer, c->plan->shaper->zero_width_attached_marks);
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return;
}
static void
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hb_position_complex_fallback (hb_ot_shape_context_t *c HB_UNUSED)
{
/* TODO Mark pos */
}
static void
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hb_truetype_kern (hb_ot_shape_context_t *c)
{
/* TODO Check for kern=0 */
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unsigned int count = c->buffer->len;
for (unsigned int i = 1; i < count; i++) {
hb_position_t x_kern, y_kern, kern1, kern2;
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c->font->get_glyph_kerning_for_direction (c->buffer->info[i - 1].codepoint, c->buffer->info[i].codepoint,
c->buffer->props.direction,
&x_kern, &y_kern);
kern1 = x_kern >> 1;
kern2 = x_kern - kern1;
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c->buffer->pos[i - 1].x_advance += kern1;
c->buffer->pos[i].x_advance += kern2;
c->buffer->pos[i].x_offset += kern2;
kern1 = y_kern >> 1;
kern2 = y_kern - kern1;
c->buffer->pos[i - 1].y_advance += kern1;
c->buffer->pos[i].y_advance += kern2;
c->buffer->pos[i].y_offset += kern2;
}
}
static void
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hb_position_complex_fallback_visual (hb_ot_shape_context_t *c)
{
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hb_truetype_kern (c);
}
static void
hb_hide_zerowidth (hb_ot_shape_context_t *c)
{
hb_codepoint_t space;
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if (!c->font->get_glyph (' ', 0, &space))
return; /* No point! */
unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++)
if (unlikely (!is_a_ligature (c->buffer->info[i]) &&
_hb_glyph_info_is_zero_width (&c->buffer->info[i]))) {
c->buffer->info[i].codepoint = space;
c->buffer->pos[i].x_advance = 0;
c->buffer->pos[i].y_advance = 0;
}
}
/* Do it! */
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static void
hb_ot_shape_internal (hb_ot_shape_context_t *c)
{
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c->buffer->deallocate_var_all ();
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/* Save the original direction, we use it later. */
c->target_direction = c->buffer->props.direction;
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HB_BUFFER_ALLOCATE_VAR (c->buffer, unicode_props0);
HB_BUFFER_ALLOCATE_VAR (c->buffer, unicode_props1);
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c->buffer->clear_output ();
hb_set_unicode_props (c->buffer);
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hb_form_clusters (c->buffer);
hb_ensure_native_direction (c->buffer);
_hb_ot_shape_normalize (c->font, c->buffer,
c->plan->shaper->normalization_preference ?
c->plan->shaper->normalization_preference (c->plan->shaper, &c->buffer->props) :
HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT);
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hb_ot_shape_setup_masks (c);
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/* SUBSTITUTE */
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{
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hb_substitute_default (c);
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hb_ot_substitute_complex (c);
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}
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/* POSITION */
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{
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hb_position_default (c);
hb_ot_position_complex (c);
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hb_bool_t position_fallback = !c->applied_position_complex;
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if (position_fallback)
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hb_position_complex_fallback (c);
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if (HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction))
hb_buffer_reverse (c->buffer);
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if (position_fallback)
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hb_position_complex_fallback_visual (c);
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}
hb_hide_zerowidth (c);
HB_BUFFER_DEALLOCATE_VAR (c->buffer, unicode_props1);
HB_BUFFER_DEALLOCATE_VAR (c->buffer, unicode_props0);
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c->buffer->props.direction = c->target_direction;
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c->buffer->deallocate_var_all ();
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}
hb_bool_t
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_hb_ot_shape (hb_shape_plan_t *shape_plan,
hb_font_t *font,
hb_buffer_t *buffer,
const hb_feature_t *features,
unsigned int num_features)
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{
hb_ot_shape_context_t c = {HB_SHAPER_DATA_GET (shape_plan), font, font->face, buffer, features, num_features};
hb_ot_shape_internal (&c);
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return true;
}
void
hb_ot_shape_glyphs_closure (hb_font_t *font,
hb_buffer_t *buffer,
const hb_feature_t *features,
unsigned int num_features,
hb_set_t *glyphs)
{
hb_ot_shape_plan_t plan;
buffer->guess_properties ();
/* TODO cache / ensure correct backend, etc. */
hb_shape_plan_t *shape_plan = hb_shape_plan_create (font->face, &buffer->props, features, num_features, NULL);
/* TODO: normalization? have shapers do closure()? */
/* TODO: Deal with mirrored chars? */
hb_map_glyphs (font, buffer);
/* Seed it. It's user's responsibility to have cleard glyphs
* if that's what they desire. */
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
hb_set_add (glyphs, buffer->info[i].codepoint);
/* And find transitive closure. */
hb_set_t copy;
copy.init ();
do {
copy.set (glyphs);
HB_SHAPER_DATA_GET (shape_plan)->map.substitute_closure (font->face, glyphs);
} while (!copy.equal (glyphs));
hb_shape_plan_destroy (shape_plan);
}