harfbuzz/src/hb-shape.cc

195 lines
5.5 KiB
C++

/*
* Copyright © 2009 Red Hat, Inc.
* Copyright © 2012 Google, Inc.
*
* 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
* Google Author(s): Behdad Esfahbod
*/
#include "hb.hh"
#include "hb-shaper.hh"
#include "hb-shape-plan.hh"
#include "hb-buffer.hh"
#include "hb-font.hh"
#include "hb-machinery.hh"
/**
* SECTION:hb-shape
* @title: hb-shape
* @short_description: Conversion of text strings into positioned glyphs
* @include: hb.h
*
* Shaping is the central operation of HarfBuzz. Shaping operates on buffers,
* which are sequences of Unicode characters that use the same font and have
* the same text direction, script, and language. After shaping the buffer
* contains the output glyphs and their positions.
**/
static inline void free_static_shaper_list ();
static const char * const nil_shaper_list[] = {nullptr};
static struct hb_shaper_list_lazy_loader_t : hb_lazy_loader_t<const char *,
hb_shaper_list_lazy_loader_t>
{
static const char ** create ()
{
const char **shaper_list = (const char **) hb_calloc (1 + HB_SHAPERS_COUNT, sizeof (const char *));
if (unlikely (!shaper_list))
return nullptr;
const hb_shaper_entry_t *shapers = _hb_shapers_get ();
unsigned int i;
for (i = 0; i < HB_SHAPERS_COUNT; i++)
shaper_list[i] = shapers[i].name;
shaper_list[i] = nullptr;
hb_atexit (free_static_shaper_list);
return shaper_list;
}
static void destroy (const char **l)
{ hb_free (l); }
static const char * const * get_null ()
{ return nil_shaper_list; }
} static_shaper_list;
static inline
void free_static_shaper_list ()
{
static_shaper_list.free_instance ();
}
/**
* hb_shape_list_shapers:
*
* Retrieves the list of shapers supported by HarfBuzz.
*
* Return value: (transfer none) (array zero-terminated=1): an array of
* constant strings
*
* Since: 0.9.2
**/
const char **
hb_shape_list_shapers ()
{
return static_shaper_list.get_unconst ();
}
/**
* hb_shape_full:
* @font: an #hb_font_t to use for shaping
* @buffer: an #hb_buffer_t to shape
* @features: (array length=num_features) (nullable): an array of user
* specified #hb_feature_t or `NULL`
* @num_features: the length of @features array
* @shaper_list: (array zero-terminated=1) (nullable): a `NULL`-terminated
* array of shapers to use or `NULL`
*
* See hb_shape() for details. If @shaper_list is not `NULL`, the specified
* shapers will be used in the given order, otherwise the default shapers list
* will be used.
*
* Return value: false if all shapers failed, true otherwise
*
* Since: 0.9.2
**/
hb_bool_t
hb_shape_full (hb_font_t *font,
hb_buffer_t *buffer,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shaper_list)
{
if (unlikely (!buffer->len))
return true;
buffer->enter ();
hb_buffer_t *text_buffer = nullptr;
if (buffer->flags & HB_BUFFER_FLAG_VERIFY)
{
text_buffer = hb_buffer_create ();
hb_buffer_append (text_buffer, buffer, 0, -1);
}
hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached2 (font->face, &buffer->props,
features, num_features,
font->coords, font->num_coords,
shaper_list);
hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);
if (buffer->max_ops <= 0)
buffer->shaping_failed = true;
hb_shape_plan_destroy (shape_plan);
if (text_buffer)
{
if (res && buffer->successful && !buffer->shaping_failed
&& text_buffer->successful
&& !buffer->verify (text_buffer,
font,
features,
num_features,
shaper_list))
res = false;
hb_buffer_destroy (text_buffer);
}
buffer->leave ();
return res;
}
/**
* hb_shape:
* @font: an #hb_font_t to use for shaping
* @buffer: an #hb_buffer_t to shape
* @features: (array length=num_features) (nullable): an array of user
* specified #hb_feature_t or `NULL`
* @num_features: the length of @features array
*
* Shapes @buffer using @font turning its Unicode characters content to
* positioned glyphs. If @features is not `NULL`, it will be used to control the
* features applied during shaping. If two @features have the same tag but
* overlapping ranges the value of the feature with the higher index takes
* precedence.
*
* Since: 0.9.2
**/
void
hb_shape (hb_font_t *font,
hb_buffer_t *buffer,
const hb_feature_t *features,
unsigned int num_features)
{
hb_shape_full (font, buffer, features, num_features, nullptr);
}