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+/*
+ * Copyright © 2022 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.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HELPER_CAIRO_USER_HH
+#define HELPER_CAIRO_USER_HH
+
+#include "font-options.hh"
+
+#include <cairo.h>
+#include <hb.h>
+
+#include "hb-blob.hh"
+
+static void
+move_to (hb_draw_funcs_t *dfuncs,
+ cairo_t *cr,
+ hb_draw_state_t *st,
+ float to_x, float to_y,
+ void *)
+{
+ cairo_move_to (cr,
+ (double) to_x, (double) to_y);
+}
+
+static void
+line_to (hb_draw_funcs_t *dfuncs,
+ cairo_t *cr,
+ hb_draw_state_t *st,
+ float to_x, float to_y,
+ void *)
+{
+ cairo_line_to (cr,
+ (double) to_x, (double) to_y);
+}
+
+static void
+cubic_to (hb_draw_funcs_t *dfuncs,
+ cairo_t *cr,
+ hb_draw_state_t *st,
+ float control1_x, float control1_y,
+ float control2_x, float control2_y,
+ float to_x, float to_y,
+ void *)
+{
+ cairo_curve_to (cr,
+ (double) control1_x, (double) control1_y,
+ (double) control2_x, (double) control2_y,
+ (double) to_x, (double) to_y);
+}
+
+static void
+close_path (hb_draw_funcs_t *dfuncs,
+ cairo_t *cr,
+ hb_draw_state_t *st,
+ void *)
+{
+ cairo_close_path (cr);
+}
+
+
+static hb_draw_funcs_t *
+get_cairo_draw_funcs ()
+{
+ static hb_draw_funcs_t *funcs;
+
+ if (!funcs)
+ {
+ funcs = hb_draw_funcs_create ();
+ hb_draw_funcs_set_move_to_func (funcs, (hb_draw_move_to_func_t) move_to, nullptr, nullptr);
+ hb_draw_funcs_set_line_to_func (funcs, (hb_draw_line_to_func_t) line_to, nullptr, nullptr);
+ hb_draw_funcs_set_cubic_to_func (funcs, (hb_draw_cubic_to_func_t) cubic_to, nullptr, nullptr);
+ hb_draw_funcs_set_close_path_func (funcs, (hb_draw_close_path_func_t) close_path, nullptr, nullptr);
+ }
+
+ return funcs;
+}
+
+static const cairo_user_data_key_t _hb_font_cairo_user_data_key = {0};
+
+static cairo_status_t
+render_glyph (cairo_scaled_font_t *scaled_font,
+ unsigned long glyph,
+ cairo_t *cr,
+ cairo_text_extents_t *extents)
+{
+ hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
+ &_hb_font_cairo_user_data_key));
+
+ hb_position_t x_scale, y_scale;
+ hb_font_get_scale (font, &x_scale, &y_scale);
+ cairo_scale (cr, +1./x_scale, -1./y_scale);
+
+ hb_font_get_glyph_shape (font, glyph, get_cairo_draw_funcs (), cr);
+ cairo_fill (cr);
+
+ return CAIRO_STATUS_SUCCESS;
+}
+
+#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
+
+#ifdef CAIRO_HAS_PNG_FUNCTIONS
+static inline cairo_status_t
+_hb_bytes_read_func (hb_bytes_t *src,
+ char *data,
+ unsigned length)
+{
+ if (unlikely (src->length < length))
+ return CAIRO_STATUS_READ_ERROR;
+
+ memcpy (data, src->arrayZ, length);
+ *src += length;
+
+ return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+render_color_glyph_png (cairo_scaled_font_t *scaled_font,
+ unsigned long glyph,
+ cairo_t *cr,
+ cairo_text_extents_t *extents)
+{
+ hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
+ &_hb_font_cairo_user_data_key));
+
+ hb_blob_t *blob = hb_ot_color_glyph_reference_png (font, glyph);
+ if (blob == hb_blob_get_empty ())
+ return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
+
+ hb_position_t x_scale, y_scale;
+ hb_font_get_scale (font, &x_scale, &y_scale);
+ cairo_scale (cr, +1./x_scale, -1./y_scale);
+
+ /* Draw PNG. */
+ hb_bytes_t bytes = blob->as_bytes ();
+ cairo_surface_t *surface = cairo_image_surface_create_from_png_stream ((cairo_read_func_t) _hb_bytes_read_func,
+ std::addressof (bytes));
+ hb_blob_destroy (blob);
+
+ if (unlikely (cairo_surface_status (surface)) != CAIRO_STATUS_SUCCESS)
+ {
+ cairo_surface_destroy (surface);
+ return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
+ }
+
+ int width = cairo_image_surface_get_width (surface);
+ int height = cairo_image_surface_get_width (surface);
+
+ hb_glyph_extents_t hb_extents;
+ if (unlikely (!hb_font_get_glyph_extents (font, glyph, &hb_extents)))
+ {
+ cairo_surface_destroy (surface);
+ return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
+ }
+
+ cairo_pattern_t *pattern = cairo_pattern_create_for_surface (surface);
+ cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);
+
+ cairo_matrix_t matrix = {(double) width, 0, 0, (double) height, 0, 0};
+ cairo_pattern_set_matrix (pattern, &matrix);
+
+ cairo_translate (cr, hb_extents.x_bearing, hb_extents.y_bearing);
+ cairo_scale (cr, hb_extents.width, hb_extents.height);
+ cairo_set_source (cr, pattern);
+
+ cairo_rectangle (cr, 0, 0, 1, 1);
+ cairo_fill (cr);
+ cairo_pattern_destroy (pattern);
+
+ cairo_surface_destroy (surface);
+ return CAIRO_STATUS_SUCCESS;
+}
+#endif
+
+static cairo_status_t
+render_color_glyph_layers (cairo_scaled_font_t *scaled_font,
+ unsigned long glyph,
+ cairo_t *cr,
+ cairo_text_extents_t *extents)
+{
+ hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
+ &_hb_font_cairo_user_data_key));
+ hb_face_t *face = hb_font_get_face (font);
+
+ unsigned count = hb_ot_color_glyph_get_layers (face, glyph, 0, nullptr, nullptr);
+ if (!count)
+ return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
+
+ hb_ot_color_layer_t layers[16];
+ unsigned offset = 0, len;
+ do {
+ len = ARRAY_LENGTH (layers);
+ hb_ot_color_glyph_get_layers (face, glyph,
+ offset,
+ &len,
+ layers);
+ for (unsigned i = 0; i < len; i++)
+ {
+ hb_color_t color;
+ unsigned clen = 1;
+ unsigned color_index = layers[i].color_index;
+ bool is_foreground = color_index == 65535;
+
+ if (!is_foreground)
+ {
+ hb_ot_color_palette_get_colors (face,
+ 0/*palette_index*/,
+ color_index/*start_offset*/,
+ &clen/*color_count*/,
+ &color);
+ if (clen < 1)
+ continue;
+ }
+
+ cairo_save (cr);
+ {
+ if (!is_foreground)
+ cairo_set_source_rgba (cr,
+ hb_color_get_red (color) / 255.,
+ hb_color_get_green (color) / 255.,
+ hb_color_get_blue (color) / 255.,
+ hb_color_get_alpha (color) / 255.);
+
+ cairo_status_t ret = render_glyph (scaled_font, layers[i].glyph, cr, extents);
+ if (ret != CAIRO_STATUS_SUCCESS)
+ return ret;
+ }
+ cairo_restore (cr);
+ }
+ }
+ while (len == ARRAY_LENGTH (layers));
+ return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+render_color_glyph (cairo_scaled_font_t *scaled_font,
+ unsigned long glyph,
+ cairo_t *cr,
+ cairo_text_extents_t *extents)
+{
+ cairo_status_t ret = CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
+
+#ifdef CAIRO_HAS_PNG_FUNCTIONS
+ ret = render_color_glyph_png (scaled_font, glyph, cr, extents);
+ if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
+ return ret;
+#endif
+
+ ret = render_color_glyph_layers (scaled_font, glyph, cr, extents);
+ if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
+ return ret;
+
+ return render_glyph (scaled_font, glyph, cr, extents);
+}
+
+#endif
+
+static inline cairo_font_face_t *
+helper_cairo_create_user_font_face (const font_options_t *font_opts)
+{
+ cairo_font_face_t *cairo_face = cairo_user_font_face_create ();
+
+ cairo_font_face_set_user_data (cairo_face,
+ &_hb_font_cairo_user_data_key,
+ hb_font_reference (font_opts->font),
+ (cairo_destroy_func_t) hb_font_destroy);
+
+ cairo_user_font_face_set_render_glyph_func (cairo_face, render_glyph);
+#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
+ hb_face_t *face = hb_font_get_face (font_opts->font);
+ if (hb_ot_color_has_png (face) || hb_ot_color_has_layers (face))
+ cairo_user_font_face_set_render_color_glyph_func (cairo_face, render_color_glyph);
+#endif
+
+ return cairo_face;
+}
+
+static inline bool
+helper_cairo_user_font_face_has_data (cairo_font_face_t *font_face)
+{
+ return cairo_font_face_get_user_data (font_face, &_hb_font_cairo_user_data_key);
+}
+
+static inline bool
+helper_cairo_user_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
+{
+ /* Ignoring SVG for now, since we cannot render it. */
+ hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
+ &_hb_font_cairo_user_data_key));
+ hb_face_t *face = hb_font_get_face (font);
+ return hb_ot_color_has_png (face) || hb_ot_color_has_layers (face);
+}
+
+#endif
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