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/*
* 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"
#ifndef HB_NO_SHAPER
/**
* 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);
}
#ifdef HB_EXPERIMENTAL_API
static float
buffer_advance (hb_buffer_t *buffer)
{
float a = 0;
auto *pos = buffer->pos;
unsigned count = buffer->len;
if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
for (unsigned i = 0; i < count; i++)
a += pos[i].x_advance;
else
for (unsigned i = 0; i < count; i++)
a += pos[i].y_advance;
return a;
}
static void
reset_buffer (hb_buffer_t *buffer,
hb_array_t<const hb_glyph_info_t> text)
{
assert (buffer->ensure (text.length));
buffer->have_positions = false;
buffer->len = text.length;
hb_memcpy (buffer->info, text.arrayZ, text.length * sizeof (buffer->info[0]));
hb_buffer_set_content_type (buffer, HB_BUFFER_CONTENT_TYPE_UNICODE);
}
/**
* hb_shape_justify:
* @font: a mutable #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`
* @min_target_advance: Minimum advance width/height to aim for.
* @max_target_advance: Maximum advance width/height to aim for.
* @advance: (inout): Input/output advance width/height of the buffer.
* @var_tag: (out): Variation-axis tag used for justification.
* @var_value: (out): Variation-axis value used to reach target justification.
*
* See hb_shape_full() for basic 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.
*
* In addition, justify the shaping results such that the shaping results reach
* the target advance width/height, depending on the buffer direction.
*
* If the advance of the buffer shaped with hb_shape_full() is already known,
* put that in *advance. Otherwise set *advance to zero.
*
* This API is currently experimental and will probably change in the future.
*
* Return value: false if all shapers failed, true otherwise
*
* XSince: EXPERIMENTAL
**/
hb_bool_t
hb_shape_justify (hb_font_t *font,
hb_buffer_t *buffer,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shaper_list,
float min_target_advance,
float max_target_advance,
float *advance, /* IN/OUT */
hb_tag_t *var_tag, /* OUT */
float *var_value /* OUT */)
{
// TODO Negative font scales?
/* If default advance already matches target, nothing to do. Shape and return. */
if (min_target_advance <= *advance && *advance <= max_target_advance)
{
*var_tag = HB_TAG_NONE;
*var_value = 0.0f;
return hb_shape_full (font, buffer,
features, num_features,
shaper_list);
}
hb_face_t *face = font->face;
/* Choose variation tag to use for justification. */
hb_tag_t tag = HB_TAG_NONE;
hb_ot_var_axis_info_t axis_info;
hb_tag_t tags[] =
{
HB_TAG ('j','s','t','f'),
HB_TAG ('w','d','t','h'),
};
for (unsigned i = 0; i < ARRAY_LENGTH (tags); i++)
if (hb_ot_var_find_axis_info (face, tags[i], &axis_info))
{
tag = *var_tag = tags[i];
break;
}
/* If no suitable variation axis found, can't justify. Just shape and return. */
if (!tag)
{
*var_tag = HB_TAG_NONE;
*var_value = 0.0f;
if (hb_shape_full (font, buffer,
features, num_features,
shaper_list))
{
*advance = buffer_advance (buffer);
return true;
}
else
return false;
}
/* Copy buffer text as we need it so we can shape multiple times. */
unsigned text_len = buffer->len;
auto *text_info = (hb_glyph_info_t *) hb_malloc (text_len * sizeof (buffer->info[0]));
if (unlikely (text_len && !text_info))
return false;
hb_memcpy (text_info, buffer->info, text_len * sizeof (buffer->info[0]));
auto text = hb_array<const hb_glyph_info_t> (text_info, text_len);
/* If default advance was not provided to us, calculate it. */
if (!*advance)
{
hb_font_set_variation (font, tag, axis_info.default_value);
if (!hb_shape_full (font, buffer,
features, num_features,
shaper_list))
return false;
*advance = buffer_advance (buffer);
}
/* If default advance already matches target, nothing to do. Shape and return.
* Do this again, in case advance was just calculated.
*/
if (min_target_advance <= *advance && *advance <= max_target_advance)
{
*var_tag = HB_TAG_NONE;
*var_value = 0.0f;
return true;
}
/* Prepare for running the solver. */
double a, b, ya, yb;
if (*advance < min_target_advance)
{
/* Need to expand. */
ya = (double) *advance;
a = (double) axis_info.default_value;
b = (double) axis_info.max_value;
/* Shape buffer for maximum expansion to use as other
* starting point for the solver. */
hb_font_set_variation (font, tag, (float) b);
reset_buffer (buffer, text);
if (!hb_shape_full (font, buffer,
features, num_features,
shaper_list))
return false;
yb = (double) buffer_advance (buffer);
/* If the maximum expansion is less than max target,
* there's nothing to solve for. Just return it. */
if (yb <= (double) max_target_advance)
{
*var_value = (float) b;
*advance = (float) yb;
return true;
}
}
else
{
/* Need to shrink. */
yb = (double) *advance;
a = (double) axis_info.min_value;
b = (double) axis_info.default_value;
/* Shape buffer for maximum shrinkate to use as other
* starting point for the solver. */
hb_font_set_variation (font, tag, (float) a);
reset_buffer (buffer, text);
if (!hb_shape_full (font, buffer,
features, num_features,
shaper_list))
return false;
ya = (double) buffer_advance (buffer);
/* If the maximum shrinkate is more than min target,
* there's nothing to solve for. Just return it. */
if (ya >= (double) min_target_advance)
{
*var_value = (float) a;
*advance = (float) ya;
return true;
}
}
/* Run the solver to find a var axis value that hits
* the desired width. */
double epsilon = (b - a) / (1<<14);
bool failed = false;
auto f = [&] (double x)
{
hb_font_set_variation (font, tag, (float) x);
reset_buffer (buffer, text);
if (unlikely (!hb_shape_full (font, buffer,
features, num_features,
shaper_list)))
{
failed = true;
return (double) min_target_advance;
}
double w = (double) buffer_advance (buffer);
DEBUG_MSG (JUSTIFY, nullptr, "Trying '%c%c%c%c' axis parameter %f. Advance %g. Target: min %g max %g",
HB_UNTAG (tag), x, w,
(double) min_target_advance, (double) max_target_advance);
return w;
};
double y = 0;
double itp = solve_itp (f,
a, b,
epsilon,
(double) min_target_advance, (double) max_target_advance,
ya, yb, y);
hb_free (text_info);
if (failed)
return false;
*var_value = (float) itp;
*advance = (float) y;
return true;
}
#endif
#endif