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Diffstat (limited to 'gfx/harfbuzz/src/hb-shape.cc')
| -rw-r--r-- | gfx/harfbuzz/src/hb-shape.cc | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-shape.cc b/gfx/harfbuzz/src/hb-shape.cc new file mode 100644 index 0000000000..d9598fc704 --- /dev/null +++ b/gfx/harfbuzz/src/hb-shape.cc @@ -0,0 +1,445 @@ +/* + * 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; + 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 |