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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;
+ 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