1/*
2 * Copyright © 2011  Google, Inc.
3 *
4 *  This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod
25 */
26
27#include "view-cairo.hh"
28
29#include <assert.h>
30
31
32void
33view_cairo_t::render (const font_options_t *font_opts)
34{
35  bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
36  int vert  = vertical ? 1 : 0;
37  int horiz = vertical ? 0 : 1;
38
39  int x_sign = font_opts->font_size_x < 0 ? -1 : +1;
40  int y_sign = font_opts->font_size_y < 0 ? -1 : +1;
41
42  hb_font_t *font = font_opts->get_font();
43  hb_font_extents_t extents;
44  hb_font_get_extents_for_direction (font, direction, &extents);
45
46  double ascent = y_sign * scalbn ((double) extents.ascender, scale_bits);
47  double descent = y_sign * -scalbn ((double) extents.descender, scale_bits);
48  double font_height = y_sign * scalbn ((double) extents.ascender - extents.descender + extents.line_gap, scale_bits);
49  double leading = font_height + view_options.line_space;
50
51  /* Calculate surface size. */
52  double w, h;
53  (vertical ? w : h) = (int) lines->len * leading - view_options.line_space;
54  (vertical ? h : w) = 0;
55  for (unsigned int i = 0; i < lines->len; i++) {
56    helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);
57    double x_advance, y_advance;
58    line.get_advance (&x_advance, &y_advance);
59    if (vertical)
60      h =  MAX (h, y_sign * y_advance);
61    else
62      w =  MAX (w, x_sign * x_advance);
63  }
64
65  cairo_scaled_font_t *scaled_font = helper_cairo_create_scaled_font (font_opts);
66
67  /* See if font needs color. */
68  cairo_content_t content = CAIRO_CONTENT_ALPHA;
69  if (helper_cairo_scaled_font_has_color (scaled_font))
70    content = CAIRO_CONTENT_COLOR;
71
72  /* Create surface. */
73  cairo_t *cr = helper_cairo_create_context (w + view_options.margin.l + view_options.margin.r,
74					     h + view_options.margin.t + view_options.margin.b,
75					     &view_options, &output_options, content);
76  cairo_set_scaled_font (cr, scaled_font);
77
78  /* Setup coordinate system. */
79  cairo_translate (cr, view_options.margin.l, view_options.margin.t);
80  if (vertical)
81    cairo_translate (cr,
82		     w /* We stack lines right to left */
83		     -font_height * .5 /* "ascent" for vertical */,
84		     y_sign < 0 ? h : 0);
85  else
86   {
87    cairo_translate (cr,
88		     x_sign < 0 ? w : 0,
89		     y_sign < 0 ? descent : ascent);
90   }
91
92  /* Draw. */
93  cairo_translate (cr, +vert * leading, -horiz * leading);
94  for (unsigned int i = 0; i < lines->len; i++)
95  {
96    helper_cairo_line_t &l = g_array_index (lines, helper_cairo_line_t, i);
97
98    cairo_translate (cr, -vert * leading, +horiz * leading);
99
100    if (view_options.annotate) {
101      cairo_save (cr);
102
103      /* Draw actual glyph origins */
104      cairo_set_source_rgba (cr, 1., 0., 0., .5);
105      cairo_set_line_width (cr, 5);
106      cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
107      for (unsigned i = 0; i < l.num_glyphs; i++) {
108	cairo_move_to (cr, l.glyphs[i].x, l.glyphs[i].y);
109	cairo_rel_line_to (cr, 0, 0);
110      }
111      cairo_stroke (cr);
112
113      cairo_restore (cr);
114    }
115
116    if (0 && cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) {
117      /* cairo_show_glyphs() doesn't support subpixel positioning */
118      cairo_glyph_path (cr, l.glyphs, l.num_glyphs);
119      cairo_fill (cr);
120    } else if (l.num_clusters)
121      cairo_show_text_glyphs (cr,
122			      l.utf8, l.utf8_len,
123			      l.glyphs, l.num_glyphs,
124			      l.clusters, l.num_clusters,
125			      l.cluster_flags);
126    else
127      cairo_show_glyphs (cr, l.glyphs, l.num_glyphs);
128  }
129
130  /* Clean up. */
131  helper_cairo_destroy_context (cr);
132  cairo_scaled_font_destroy (scaled_font);
133}
134