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kc3-lang/harfbuzz/src/hb-shape.cc
Behdad Esfahbod
- src/hb-shape.cc
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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