HarfBuzz text shaping engine
http://harfbuzz.github.io/
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223 lines
6.9 KiB
223 lines
6.9 KiB
/* |
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* Copyright © 2011 Google, Inc. |
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* |
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* This is part of HarfBuzz, a text shaping library. |
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* |
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* Permission is hereby granted, without written agreement and without |
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* license or royalty fees, to use, copy, modify, and distribute this |
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* software and its documentation for any purpose, provided that the |
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* above copyright notice and the following two paragraphs appear in |
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* all copies of this software. |
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* |
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR |
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES |
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN |
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, |
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND |
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO |
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
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* |
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* Google Author(s): Behdad Esfahbod |
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*/ |
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#ifndef VIEW_CAIRO_HH |
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#define VIEW_CAIRO_HH |
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#include "view-options.hh" |
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#include "output-options.hh" |
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#include "helper-cairo.hh" |
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struct view_cairo_t : view_options_t, output_options_t<> |
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{ |
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~view_cairo_t () |
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{ |
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cairo_debug_reset_static_data (); |
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} |
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void add_options (option_parser_t *parser) |
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{ |
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parser->set_summary ("View text with given font."); |
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view_options_t::add_options (parser); |
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output_options_t::add_options (parser, helper_cairo_supported_formats); |
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} |
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void init (hb_buffer_t *buffer, const font_options_t *font_opts) |
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{ |
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lines = g_array_new (false, false, sizeof (helper_cairo_line_t)); |
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subpixel_bits = font_opts->subpixel_bits; |
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} |
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void new_line () {} |
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void consume_text (hb_buffer_t *buffer, |
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const char *text, |
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unsigned int text_len, |
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hb_bool_t utf8_clusters) {} |
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void error (const char *message) |
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{ g_printerr ("%s: %s\n", g_get_prgname (), message); } |
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void consume_glyphs (hb_buffer_t *buffer, |
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const char *text, |
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unsigned int text_len, |
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hb_bool_t utf8_clusters) |
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{ |
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direction = hb_buffer_get_direction (buffer); |
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helper_cairo_line_t l (text, text_len, buffer, utf8_clusters, subpixel_bits); |
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g_array_append_val (lines, l); |
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} |
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void finish (hb_buffer_t *buffer, const font_options_t *font_opts) |
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{ |
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render (font_opts); |
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for (unsigned int i = 0; i < lines->len; i++) { |
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helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i); |
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line.finish (); |
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} |
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#if GLIB_CHECK_VERSION (2, 22, 0) |
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g_array_unref (lines); |
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#else |
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g_array_free (lines, TRUE); |
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#endif |
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} |
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protected: |
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void render (const font_options_t *font_opts); |
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hb_direction_t direction = HB_DIRECTION_INVALID; // Remove this, make segment_properties accessible |
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GArray *lines = nullptr; |
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unsigned subpixel_bits = 0; |
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}; |
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inline void |
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view_cairo_t::render (const font_options_t *font_opts) |
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{ |
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bool vertical = HB_DIRECTION_IS_VERTICAL (direction); |
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int vert = vertical ? 1 : 0; |
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int horiz = vertical ? 0 : 1; |
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int x_sign = font_opts->font_size_x < 0 ? -1 : +1; |
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int y_sign = font_opts->font_size_y < 0 ? -1 : +1; |
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hb_font_t *font = font_opts->font; |
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if (!have_font_extents) |
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{ |
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hb_font_extents_t hb_extents; |
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hb_font_get_extents_for_direction (font, direction, &hb_extents); |
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font_extents.ascent = scalbn ((double) hb_extents.ascender, - (int) subpixel_bits); |
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font_extents.descent = -scalbn ((double) hb_extents.descender, - (int) subpixel_bits); |
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font_extents.line_gap = scalbn ((double) hb_extents.line_gap, - (int) subpixel_bits); |
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have_font_extents = true; |
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} |
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double ascent = y_sign * font_extents.ascent; |
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double descent = y_sign * font_extents.descent; |
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double line_gap = y_sign * font_extents.line_gap + line_space; |
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double leading = ascent + descent + line_gap; |
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/* Calculate surface size. */ |
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double w = 0, h = 0; |
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(vertical ? w : h) = (int) lines->len * leading - (font_extents.line_gap + line_space); |
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(vertical ? h : w) = 0; |
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for (unsigned int i = 0; i < lines->len; i++) { |
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helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i); |
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double x_advance, y_advance; |
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line.get_advance (&x_advance, &y_advance); |
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if (vertical) |
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h = MAX (h, y_sign * y_advance); |
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else |
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w = MAX (w, x_sign * x_advance); |
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} |
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cairo_scaled_font_t *scaled_font = helper_cairo_create_scaled_font (font_opts, |
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this); |
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/* See if font needs color. */ |
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cairo_content_t content = CAIRO_CONTENT_ALPHA; |
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if (helper_cairo_scaled_font_has_color (scaled_font)) |
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content = CAIRO_CONTENT_COLOR; |
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/* Create surface. */ |
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cairo_t *cr = helper_cairo_create_context (w + margin.l + margin.r, |
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h + margin.t + margin.b, |
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this, |
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this, |
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content); |
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cairo_set_scaled_font (cr, scaled_font); |
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/* Setup coordinate system. */ |
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cairo_translate (cr, margin.l, margin.t); |
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if (vertical) |
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cairo_translate (cr, |
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w - ascent, /* We currently always stack lines right to left */ |
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y_sign < 0 ? h : 0); |
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else |
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{ |
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cairo_translate (cr, |
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x_sign < 0 ? w : 0, |
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y_sign < 0 ? descent : ascent); |
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} |
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/* Draw. */ |
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cairo_translate (cr, +vert * leading, -horiz * leading); |
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for (unsigned int i = 0; i < lines->len; i++) |
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{ |
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helper_cairo_line_t &l = g_array_index (lines, helper_cairo_line_t, i); |
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cairo_translate (cr, -vert * leading, +horiz * leading); |
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if (show_extents) |
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{ |
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cairo_save (cr); |
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cairo_set_source_rgba (cr, 1., 0., 0., .5); |
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cairo_set_line_width (cr, 10); |
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cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND); |
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for (unsigned i = 0; i < l.num_glyphs; i++) { |
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cairo_move_to (cr, l.glyphs[i].x, l.glyphs[i].y); |
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cairo_rel_line_to (cr, 0, 0); |
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} |
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cairo_stroke (cr); |
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cairo_restore (cr); |
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cairo_save (cr); |
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cairo_set_source_rgba (cr, 1., 0., 1., .5); |
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cairo_set_line_width (cr, 3); |
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for (unsigned i = 0; i < l.num_glyphs; i++) |
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{ |
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hb_glyph_extents_t hb_extents; |
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hb_font_get_glyph_extents (font, l.glyphs[i].index, &hb_extents); |
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double x1 = scalbn ((double) hb_extents.x_bearing, - (int) subpixel_bits); |
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double y1 = -scalbn ((double) hb_extents.y_bearing, - (int) subpixel_bits); |
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double width = scalbn ((double) hb_extents.width, - (int) subpixel_bits); |
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double height = -scalbn ((double) hb_extents.height, - (int) subpixel_bits); |
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cairo_rectangle (cr, l.glyphs[i].x + x1, l.glyphs[i].y + y1, width, height); |
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} |
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cairo_stroke (cr); |
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cairo_restore (cr); |
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} |
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// https://github.com/harfbuzz/harfbuzz/issues/4378 |
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#if CAIRO_VERSION >= 11705 |
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if (l.num_clusters) |
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cairo_show_text_glyphs (cr, |
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l.utf8, l.utf8_len, |
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l.glyphs, l.num_glyphs, |
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l.clusters, l.num_clusters, |
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l.cluster_flags); |
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else |
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#endif |
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cairo_show_glyphs (cr, l.glyphs, l.num_glyphs); |
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} |
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/* Clean up. */ |
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helper_cairo_destroy_context (cr); |
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cairo_scaled_font_destroy (scaled_font); |
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} |
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#endif
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