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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): a
++ * `NULL`-terminated array of supported shapers constant string.
++ * The returned array is owned by HarfBuzz and should not be
++ * modified or freed.
++ *
++ * 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);
++
++ hb_shape_plan_destroy (shape_plan);
++
++ if (text_buffer)
++ {
++ if (res && buffer->successful
++ && 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
++ #ifndef HB_NO_VAR
++
++ 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_malloc2 (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
++
++
++ #endif