HarfBuzz text shaping engine
http://harfbuzz.github.io/
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500 lines
14 KiB
500 lines
14 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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#include "view-cairo.hh" |
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#ifdef CAIRO_HAS_SVG_SURFACE |
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# include <cairo-svg.h> |
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#endif |
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#ifdef CAIRO_HAS_PDF_SURFACE |
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# include <cairo-pdf.h> |
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#endif |
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#ifdef CAIRO_HAS_PS_SURFACE |
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# include <cairo-ps.h> |
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# if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,6,0) |
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# define HAS_EPS 1 |
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static cairo_surface_t * |
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_cairo_eps_surface_create_for_stream (cairo_write_func_t write_func, |
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void *closure, |
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double width, |
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double height) |
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{ |
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cairo_surface_t *surface; |
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surface = cairo_ps_surface_create_for_stream (write_func, closure, width, height); |
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cairo_ps_surface_set_eps (surface, TRUE); |
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return surface; |
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} |
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# else |
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# undef HAS_EPS |
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# endif |
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#endif |
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struct line_t { |
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cairo_glyph_t *glyphs; |
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unsigned int num_glyphs; |
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char *utf8; |
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unsigned int utf8_len; |
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cairo_text_cluster_t *clusters; |
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unsigned int num_clusters; |
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cairo_text_cluster_flags_t cluster_flags; |
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void finish (void) { |
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if (glyphs) |
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cairo_glyph_free (glyphs); |
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if (clusters) |
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cairo_text_cluster_free (clusters); |
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if (utf8) |
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g_free (utf8); |
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} |
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}; |
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void |
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view_cairo_t::init (const font_options_t *font_opts) |
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{ |
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lines = g_array_new (FALSE, FALSE, sizeof (line_t)); |
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scale = double (font_size) / hb_face_get_upem (hb_font_get_face (font_opts->get_font ())); |
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} |
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void |
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view_cairo_t::consume_line (hb_buffer_t *buffer, |
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const char *text, |
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unsigned int text_len) |
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{ |
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line_t l = {0}; |
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l.num_glyphs = hb_buffer_get_length (buffer); |
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hb_glyph_info_t *hb_glyph = hb_buffer_get_glyph_infos (buffer, NULL); |
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hb_glyph_position_t *hb_position = hb_buffer_get_glyph_positions (buffer, NULL); |
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l.glyphs = cairo_glyph_allocate (l.num_glyphs + 1); |
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if (text) { |
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l.utf8 = g_strndup (text, text_len); |
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l.utf8_len = text_len; |
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l.num_clusters = l.num_glyphs ? 1 : 0; |
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for (unsigned int i = 1; i < l.num_glyphs; i++) |
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if (hb_glyph[i].cluster != hb_glyph[i-1].cluster) |
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l.num_clusters++; |
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l.clusters = cairo_text_cluster_allocate (l.num_clusters); |
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} else { |
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l.utf8_len = 0; |
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l.num_clusters = 0; |
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} |
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if ((l.num_glyphs && !l.glyphs) || |
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(l.utf8_len && !l.utf8) || |
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(l.num_clusters && !l.clusters)) |
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{ |
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l.finish (); |
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return; |
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} |
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hb_position_t x = 0, y = 0; |
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int i; |
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for (i = 0; i < (int) l.num_glyphs; i++) |
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{ |
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l.glyphs[i].index = hb_glyph[i].codepoint; |
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l.glyphs[i].x = ( hb_position->x_offset + x) * scale; |
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l.glyphs[i].y = (-hb_position->y_offset + y) * scale; |
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x += hb_position->x_advance; |
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y += -hb_position->y_advance; |
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hb_position++; |
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} |
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l.glyphs[i].index = 0; |
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l.glyphs[i].x = x; |
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l.glyphs[i].y = y; |
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if (l.num_clusters) { |
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memset ((void *) l.clusters, 0, l.num_clusters * sizeof (l.clusters[0])); |
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bool backward = HB_DIRECTION_IS_BACKWARD (hb_buffer_get_direction (buffer)); |
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l.cluster_flags = backward ? CAIRO_TEXT_CLUSTER_FLAG_BACKWARD : (cairo_text_cluster_flags_t) 0; |
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unsigned int cluster = 0; |
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if (!l.num_glyphs) |
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goto done; |
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l.clusters[cluster].num_glyphs++; |
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if (backward) { |
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for (i = l.num_glyphs - 2; i >= 0; i--) { |
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if (hb_glyph[i].cluster != hb_glyph[i+1].cluster) { |
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g_assert (hb_glyph[i].cluster > hb_glyph[i+1].cluster); |
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l.clusters[cluster].num_bytes += hb_glyph[i].cluster - hb_glyph[i+1].cluster; |
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cluster++; |
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} |
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l.clusters[cluster].num_glyphs++; |
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} |
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l.clusters[cluster].num_bytes += text_len - hb_glyph[0].cluster; |
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} else { |
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for (i = 1; i < (int) l.num_glyphs; i++) { |
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if (hb_glyph[i].cluster != hb_glyph[i-1].cluster) { |
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g_assert (hb_glyph[i].cluster > hb_glyph[i-1].cluster); |
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l.clusters[cluster].num_bytes += hb_glyph[i].cluster - hb_glyph[i-1].cluster; |
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cluster++; |
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} |
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l.clusters[cluster].num_glyphs++; |
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} |
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l.clusters[cluster].num_bytes += text_len - hb_glyph[i - 1].cluster; |
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} |
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} |
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done: |
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g_array_append_val (lines, l); |
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} |
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void |
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view_cairo_t::finish (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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line_t &line = g_array_index (lines, line_t, i); |
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line.finish (); |
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} |
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g_array_unref (lines); |
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} |
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double |
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view_cairo_t::line_width (unsigned int i) |
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{ |
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line_t &line = g_array_index (lines, line_t, i); |
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return line.glyphs[line.num_glyphs].x * scale; |
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} |
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void |
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view_cairo_t::get_surface_size (cairo_scaled_font_t *scaled_font, |
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double *w, double *h) |
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{ |
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cairo_font_extents_t font_extents; |
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cairo_scaled_font_extents (scaled_font, &font_extents); |
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*h = font_extents.ascent |
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+ font_extents.descent |
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+ ((int) lines->len - 1) * font_extents.height; |
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*w = 0; |
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for (unsigned int i = 0; i < lines->len; i++) |
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*w = MAX (*w, line_width (i)); |
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*w += margin.l + margin.r; |
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*h += margin.t + margin.b; |
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} |
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cairo_scaled_font_t * |
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view_cairo_t::create_scaled_font (const font_options_t *font_opts) |
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{ |
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hb_font_t *font = hb_font_reference (font_opts->get_font ()); |
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cairo_font_face_t *cairo_face; |
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FT_Face ft_face = hb_ft_font_get_face (font); |
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if (!ft_face) |
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/* This allows us to get some boxes at least... */ |
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cairo_face = cairo_toy_font_face_create ("@cairo:sans", |
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CAIRO_FONT_SLANT_NORMAL, |
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CAIRO_FONT_WEIGHT_NORMAL); |
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else |
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cairo_face = cairo_ft_font_face_create_for_ft_face (ft_face, 0); |
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cairo_matrix_t ctm, font_matrix; |
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cairo_font_options_t *font_options; |
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cairo_matrix_init_identity (&ctm); |
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cairo_matrix_init_scale (&font_matrix, |
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font_size, font_size); |
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font_options = cairo_font_options_create (); |
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cairo_font_options_set_hint_style (font_options, CAIRO_HINT_STYLE_NONE); |
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cairo_font_options_set_hint_metrics (font_options, CAIRO_HINT_METRICS_OFF); |
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cairo_scaled_font_t *scaled_font = cairo_scaled_font_create (cairo_face, |
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&font_matrix, |
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&ctm, |
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font_options); |
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cairo_font_options_destroy (font_options); |
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cairo_font_face_destroy (cairo_face); |
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static cairo_user_data_key_t key; |
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if (cairo_scaled_font_set_user_data (scaled_font, |
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&key, |
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(void *) font, |
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(cairo_destroy_func_t) hb_font_destroy)) |
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hb_font_destroy (font); |
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return scaled_font; |
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} |
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struct finalize_closure_t { |
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void (*callback)(finalize_closure_t *); |
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cairo_surface_t *surface; |
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cairo_write_func_t write_func; |
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void *closure; |
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}; |
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static cairo_user_data_key_t finalize_closure_key; |
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#ifdef CAIRO_HAS_PNG_FUNCTIONS |
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static void |
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finalize_png (finalize_closure_t *closure) |
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{ |
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cairo_status_t status; |
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status = cairo_surface_write_to_png_stream (closure->surface, |
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closure->write_func, |
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closure->closure); |
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if (status != CAIRO_STATUS_SUCCESS) |
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fail (FALSE, "Failed to write output: %s", |
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cairo_status_to_string (status)); |
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} |
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static cairo_surface_t * |
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_cairo_png_surface_create_for_stream (cairo_write_func_t write_func, |
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void *closure, |
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double width, |
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double height, |
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cairo_content_t content) |
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{ |
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cairo_surface_t *surface; |
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int w = ceil (width); |
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int h = ceil (height); |
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switch (content) { |
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case CAIRO_CONTENT_ALPHA: |
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surface = cairo_image_surface_create (CAIRO_FORMAT_A8, w, h); |
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break; |
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default: |
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case CAIRO_CONTENT_COLOR: |
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surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, w, h); |
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break; |
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case CAIRO_CONTENT_COLOR_ALPHA: |
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, w, h); |
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break; |
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} |
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cairo_status_t status = cairo_surface_status (surface); |
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if (status != CAIRO_STATUS_SUCCESS) |
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fail (FALSE, "Failed to create cairo surface: %s", |
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cairo_status_to_string (status)); |
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finalize_closure_t *png_closure = g_new0 (finalize_closure_t, 1); |
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png_closure->callback = finalize_png; |
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png_closure->surface = surface; |
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png_closure->write_func = write_func; |
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png_closure->closure = closure; |
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if (cairo_surface_set_user_data (surface, |
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&finalize_closure_key, |
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(void *) png_closure, |
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(cairo_destroy_func_t) g_free)) |
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g_free ((void *) closure); |
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return surface; |
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} |
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#endif |
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void |
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view_cairo_t::render (const font_options_t *font_opts) |
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{ |
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cairo_scaled_font_t *scaled_font = create_scaled_font (font_opts); |
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double w, h; |
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get_surface_size (scaled_font, &w, &h); |
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cairo_t *cr = create_context (w, h); |
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cairo_set_scaled_font (cr, scaled_font); |
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cairo_scaled_font_destroy (scaled_font); |
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draw (cr); |
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finalize_closure_t *closure = (finalize_closure_t *) |
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cairo_surface_get_user_data (cairo_get_target (cr), |
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&finalize_closure_key); |
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if (closure) |
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closure->callback (closure); |
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cairo_status_t status = cairo_status (cr); |
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if (status != CAIRO_STATUS_SUCCESS) |
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fail (FALSE, "Failed: %s", |
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cairo_status_to_string (status)); |
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cairo_destroy (cr); |
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} |
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static cairo_status_t |
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stdio_write_func (void *closure, |
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const unsigned char *data, |
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unsigned int size) |
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{ |
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FILE *fp = (FILE *) closure; |
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while (size) { |
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size_t ret = fwrite (data, 1, size, fp); |
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size -= ret; |
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data += ret; |
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if (size && ferror (fp)) |
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fail (FALSE, "Failed to write output: %s", strerror (errno)); |
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} |
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return CAIRO_STATUS_SUCCESS; |
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} |
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cairo_t * |
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view_cairo_t::create_context (double w, double h) |
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{ |
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cairo_surface_t *(*constructor) (cairo_write_func_t write_func, |
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void *closure, |
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double width, |
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double height) = NULL; |
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cairo_surface_t *(*constructor2) (cairo_write_func_t write_func, |
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void *closure, |
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double width, |
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double height, |
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cairo_content_t content) = NULL; |
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const char *extension = output_format; |
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if (!extension) |
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extension = "png"; |
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if (0) |
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; |
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#ifdef CAIRO_HAS_PNG_FUNCTIONS |
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else if (0 == strcasecmp (extension, "png")) |
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constructor2 = _cairo_png_surface_create_for_stream; |
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#endif |
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#ifdef CAIRO_HAS_SVG_SURFACE |
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else if (0 == strcasecmp (extension, "svg")) |
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constructor = cairo_svg_surface_create_for_stream; |
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#endif |
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#ifdef CAIRO_HAS_PDF_SURFACE |
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else if (0 == strcasecmp (extension, "pdf")) |
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constructor = cairo_pdf_surface_create_for_stream; |
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#endif |
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#ifdef CAIRO_HAS_PS_SURFACE |
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else if (0 == strcasecmp (extension, "ps")) |
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constructor = cairo_ps_surface_create_for_stream; |
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#ifdef HAS_EPS |
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else if (0 == strcasecmp (extension, "eps")) |
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constructor = _cairo_eps_surface_create_for_stream; |
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#endif |
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#endif |
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unsigned int fr, fg, fb, fa, br, bg, bb, ba; |
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br = bg = bb = ba = 255; |
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sscanf (back + (*back=='#'), "%2x%2x%2x%2x", &br, &bg, &bb, &ba); |
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fr = fg = fb = 0; fa = 255; |
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sscanf (fore + (*fore=='#'), "%2x%2x%2x%2x", &fr, &fg, &fb, &fa); |
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cairo_content_t content; |
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if (!annotate && ba == 255 && br == bg && bg == bb && fr == fg && fg == fb) |
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content = CAIRO_CONTENT_ALPHA; |
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else if (ba == 255) |
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content = CAIRO_CONTENT_COLOR; |
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else |
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content = CAIRO_CONTENT_COLOR_ALPHA; |
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cairo_surface_t *surface; |
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FILE *f = get_file_handle (); |
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if (constructor) |
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surface = constructor (stdio_write_func, f, w, h); |
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else if (constructor2) |
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surface = constructor2 (stdio_write_func, f, w, h, content); |
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else |
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fail (FALSE, "Unknown output format `%s'", extension); |
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cairo_t *cr = cairo_create (surface); |
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content = cairo_surface_get_content (surface); |
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switch (content) { |
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case CAIRO_CONTENT_ALPHA: |
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cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE); |
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cairo_set_source_rgba (cr, 1., 1., 1., br / 255.); |
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cairo_paint (cr); |
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cairo_set_source_rgba (cr, 1., 1., 1., |
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(fr / 255.) * (fa / 255.) + (br / 255) * (1 - (fa / 255.))); |
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break; |
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default: |
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case CAIRO_CONTENT_COLOR: |
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case CAIRO_CONTENT_COLOR_ALPHA: |
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cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE); |
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cairo_set_source_rgba (cr, br / 255., bg / 255., bb / 255., ba / 255.); |
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cairo_paint (cr); |
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cairo_set_operator (cr, CAIRO_OPERATOR_OVER); |
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cairo_set_source_rgba (cr, fr / 255., fg / 255., fb / 255., fa / 255.); |
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break; |
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} |
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cairo_surface_destroy (surface); |
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return cr; |
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} |
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void |
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view_cairo_t::draw (cairo_t *cr) |
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{ |
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cairo_save (cr); |
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cairo_font_extents_t font_extents; |
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cairo_font_extents (cr, &font_extents); |
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cairo_translate (cr, margin.l, margin.t); |
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for (unsigned int i = 0; i < lines->len; i++) |
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{ |
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line_t &l = g_array_index (lines, line_t, i); |
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if (i) |
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cairo_translate (cr, 0, line_space); |
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cairo_translate (cr, 0, font_extents.ascent); |
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if (annotate) { |
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cairo_save (cr); |
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/* Draw actual glyph origins */ |
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cairo_set_source_rgba (cr, 1., 0., 0., .5); |
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cairo_set_line_width (cr, 5); |
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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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} |
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if (cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) { |
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/* cairo_show_glyphs() doesn't support subpixel positioning */ |
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cairo_glyph_path (cr, l.glyphs, l.num_glyphs); |
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cairo_fill (cr); |
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} else 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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cairo_show_glyphs (cr, l.glyphs, l.num_glyphs); |
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cairo_translate (cr, 0, font_extents.height - font_extents.ascent); |
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} |
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cairo_restore (cr); |
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}
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