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 #ifndef VIEW_CAIRO_HH
28 #define VIEW_CAIRO_HH
29
30 #include "view-options.hh"
31 #include "output-options.hh"
32 #include "helper-cairo.hh"
33
34 struct view_cairo_t : view_options_t, output_options_t<>
35 {
~view_cairo_tview_cairo_t36 ~view_cairo_t ()
37 {
38 cairo_debug_reset_static_data ();
39 }
40
add_optionsview_cairo_t41 void add_options (option_parser_t *parser)
42 {
43 parser->set_summary ("View text with given font.");
44 view_options_t::add_options (parser);
45 output_options_t::add_options (parser, helper_cairo_supported_formats);
46 }
47
initview_cairo_t48 void init (hb_buffer_t *buffer, const font_options_t *font_opts)
49 {
50 lines = g_array_new (false, false, sizeof (helper_cairo_line_t));
51 scale_bits = - (int) font_opts->subpixel_bits;
52 }
new_lineview_cairo_t53 void new_line () {}
consume_textview_cairo_t54 void consume_text (hb_buffer_t *buffer,
55 const char *text,
56 unsigned int text_len,
57 hb_bool_t utf8_clusters) {}
errorview_cairo_t58 void error (const char *message)
59 { g_printerr ("%s: %s\n", g_get_prgname (), message); }
consume_glyphsview_cairo_t60 void consume_glyphs (hb_buffer_t *buffer,
61 const char *text,
62 unsigned int text_len,
63 hb_bool_t utf8_clusters)
64 {
65 direction = hb_buffer_get_direction (buffer);
66 helper_cairo_line_t l;
67 helper_cairo_line_from_buffer (&l, buffer, text, text_len, scale_bits, utf8_clusters);
68 g_array_append_val (lines, l);
69 }
finishview_cairo_t70 void finish (hb_buffer_t *buffer, const font_options_t *font_opts)
71 {
72 render (font_opts);
73
74 for (unsigned int i = 0; i < lines->len; i++) {
75 helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);
76 line.finish ();
77 }
78 #if GLIB_CHECK_VERSION (2, 22, 0)
79 g_array_unref (lines);
80 #else
81 g_array_free (lines, TRUE);
82 #endif
83 }
84
85 protected:
86
87 void render (const font_options_t *font_opts);
88
89 hb_direction_t direction = HB_DIRECTION_INVALID; // Remove this, make segment_properties accessible
90 GArray *lines = nullptr;
91 int scale_bits = 0;
92 };
93
94 inline void
render(const font_options_t * font_opts)95 view_cairo_t::render (const font_options_t *font_opts)
96 {
97 bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
98 int vert = vertical ? 1 : 0;
99 int horiz = vertical ? 0 : 1;
100
101 int x_sign = font_opts->font_size_x < 0 ? -1 : +1;
102 int y_sign = font_opts->font_size_y < 0 ? -1 : +1;
103
104 hb_font_t *font = font_opts->font;
105
106 if (!have_font_extents)
107 {
108 hb_font_extents_t hb_extents;
109 hb_font_get_extents_for_direction (font, direction, &hb_extents);
110 font_extents.ascent = scalbn ((double) hb_extents.ascender, scale_bits);
111 font_extents.descent = -scalbn ((double) hb_extents.descender, scale_bits);
112 font_extents.line_gap = scalbn ((double) hb_extents.line_gap, scale_bits);
113 have_font_extents = true;
114 }
115
116 double ascent = y_sign * font_extents.ascent;
117 double descent = y_sign * font_extents.descent;
118 double line_gap = y_sign * font_extents.line_gap + line_space;
119 double leading = ascent + descent + line_gap;
120
121 /* Calculate surface size. */
122 double w = 0, h = 0;
123 (vertical ? w : h) = (int) lines->len * leading - (font_extents.line_gap + line_space);
124 (vertical ? h : w) = 0;
125 for (unsigned int i = 0; i < lines->len; i++) {
126 helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);
127 double x_advance, y_advance;
128 line.get_advance (&x_advance, &y_advance);
129 if (vertical)
130 h = MAX (h, y_sign * y_advance);
131 else
132 w = MAX (w, x_sign * x_advance);
133 }
134
135 cairo_scaled_font_t *scaled_font = helper_cairo_create_scaled_font (font_opts);
136
137 /* See if font needs color. */
138 cairo_content_t content = CAIRO_CONTENT_ALPHA;
139 if (helper_cairo_scaled_font_has_color (scaled_font))
140 content = CAIRO_CONTENT_COLOR;
141
142 /* Create surface. */
143 cairo_t *cr = helper_cairo_create_context (w + margin.l + margin.r,
144 h + margin.t + margin.b,
145 this,
146 this,
147 content);
148 cairo_set_scaled_font (cr, scaled_font);
149
150 /* Setup coordinate system. */
151 cairo_translate (cr, margin.l, margin.t);
152 if (vertical)
153 cairo_translate (cr,
154 w - ascent, /* We currently always stack lines right to left */
155 y_sign < 0 ? h : 0);
156 else
157 {
158 cairo_translate (cr,
159 x_sign < 0 ? w : 0,
160 y_sign < 0 ? descent : ascent);
161 }
162
163 /* Draw. */
164 cairo_translate (cr, +vert * leading, -horiz * leading);
165 for (unsigned int i = 0; i < lines->len; i++)
166 {
167 helper_cairo_line_t &l = g_array_index (lines, helper_cairo_line_t, i);
168
169 cairo_translate (cr, -vert * leading, +horiz * leading);
170
171 if (annotate) {
172 cairo_save (cr);
173
174 /* Draw actual glyph origins */
175 cairo_set_source_rgba (cr, 1., 0., 0., .5);
176 cairo_set_line_width (cr, 5);
177 cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
178 for (unsigned i = 0; i < l.num_glyphs; i++) {
179 cairo_move_to (cr, l.glyphs[i].x, l.glyphs[i].y);
180 cairo_rel_line_to (cr, 0, 0);
181 }
182 cairo_stroke (cr);
183
184 cairo_restore (cr);
185 }
186
187 if (0 && cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) {
188 /* cairo_show_glyphs() doesn't support subpixel positioning */
189 cairo_glyph_path (cr, l.glyphs, l.num_glyphs);
190 cairo_fill (cr);
191 } else if (l.num_clusters)
192 cairo_show_text_glyphs (cr,
193 l.utf8, l.utf8_len,
194 l.glyphs, l.num_glyphs,
195 l.clusters, l.num_clusters,
196 l.cluster_flags);
197 else
198 cairo_show_glyphs (cr, l.glyphs, l.num_glyphs);
199 }
200
201 /* Clean up. */
202 helper_cairo_destroy_context (cr);
203 cairo_scaled_font_destroy (scaled_font);
204 }
205
206 #endif
207