pango/pango-engine.c

   1 /* Pango
   2  * pango-engine.c: Engines for script and language specific processing
   3  *
   4  * Copyright (C) 2003 Red Hat Software
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Library General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Library General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Library General Public
  17  * License along with this library; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  * Boston, MA 02111-1307, USA.
  20  */
  21
  22 #include "config.h"
  23
  24 #include "pango-engine.h"
  25 #include "pango-engine-private.h"
  26 #include "pango-impl-utils.h"
  27
  28
  29 G_DEFINE_ABSTRACT_TYPE (PangoEngine, pango_engine, G_TYPE_OBJECT);
  30
  31 static void
  32 pango_engine_init (PangoEngine *self)
  33 {
  34 }
  35
  36 static void
  37 pango_engine_class_init (PangoEngineClass *klass)
  38 {
  39 }
  40
  41
  42 G_DEFINE_ABSTRACT_TYPE (PangoEngineLang, pango_engine_lang, PANGO_TYPE_ENGINE);
  43
  44 static void
  45 pango_engine_lang_init (PangoEngineLang *self)
  46 {
  47 }
  48
  49 static void
  50 pango_engine_lang_class_init (PangoEngineLangClass *klass)
  51 {
  52 }
  53
  54
  55 static PangoCoverageLevel
  56 pango_engine_shape_real_covers (PangoEngineShape *engine G_GNUC_UNUSED,
  57                                 PangoFont        *font,
  58                                 PangoLanguage    *language,
  59                                 gunichar          wc)
  60 {
  61
  62   PangoCoverage *coverage = pango_font_get_coverage (font, language);
  63   PangoCoverageLevel result = pango_coverage_get (coverage, wc);
  64
  65   pango_coverage_unref (coverage);
  66
  67   return result;
  68 }
  69
  70
  71 G_DEFINE_ABSTRACT_TYPE (PangoEngineShape, pango_engine_shape, PANGO_TYPE_ENGINE);
  72
  73 static void
  74 pango_engine_shape_init (PangoEngineShape *klass)
  75 {
  76 }
  77
  78 static void
  79 pango_engine_shape_class_init (PangoEngineShapeClass *class)
  80 {
  81   class->covers = pango_engine_shape_real_covers;
  82 }
  83
  84 void
  85 _pango_engine_shape_shape (PangoEngineShape *engine,
  86                            PangoFont        *font,
  87                            const char       *text,
  88                            int               length,
  89                            const PangoAnalysis *analysis,
  90                            PangoGlyphString *glyphs)
  91 {
  92   glyphs->num_glyphs = 0;
  93
  94   PANGO_ENGINE_SHAPE_GET_CLASS (engine)->script_shape (engine,
  95                                                        font,
  96                                                        text, length,
  97                                                        analysis,
  98                                                        glyphs);
  99 }
 100
 101 PangoCoverageLevel
 102 _pango_engine_shape_covers (PangoEngineShape *engine,
 103                             PangoFont        *font,
 104                             PangoLanguage    *language,
 105                             gunichar          wc)
 106 {
 107   g_return_val_if_fail (PANGO_IS_ENGINE_SHAPE (engine), PANGO_COVERAGE_NONE);
 108   g_return_val_if_fail (PANGO_IS_FONT (font), PANGO_COVERAGE_NONE);
 109
 110   return PANGO_ENGINE_SHAPE_GET_CLASS (engine)->covers (engine,
 111                                                         font,
 112                                                         language,
 113                                                         wc);
 114 }
 115
 116 /* No extra fields needed */
 117 typedef PangoEngineShape PangoFallbackEngine;
 118 typedef PangoEngineShapeClass PangoFallbackEngineClass;
 119
 120 static void
 121 fallback_engine_shape (PangoEngineShape *engine G_GNUC_UNUSED,
 122                        PangoFont        *font G_GNUC_UNUSED,
 123                        const char       *text,
 124                        gint              length,
 125                        const PangoAnalysis *analysis,
 126                        PangoGlyphString *glyphs)
 127 {
 128   int n_chars;
 129   const char *p;
 130   int cluster = 0;
 131   int i;
 132
 133   n_chars = text ? pango_utf8_strlen (text, length) : 0;
 134
 135   pango_glyph_string_set_size (glyphs, n_chars);
 136
 137   p = text;
 138   for (i = 0; i < n_chars; i++)
 139     {
 140       gunichar wc;
 141       PangoGlyph glyph;
 142       PangoRectangle logical_rect;
 143
 144       wc = g_utf8_get_char (p);
 145
 146       if (g_unichar_type (wc) != G_UNICODE_NON_SPACING_MARK)
 147         cluster = p - text;
 148
 149       if (pango_is_zero_width (wc))
 150         glyph = PANGO_GLYPH_EMPTY;
 151       else
 152         glyph = PANGO_GET_UNKNOWN_GLYPH (wc);
 153
 154       pango_font_get_glyph_extents (analysis->font, glyph, NULL, &logical_rect);
 155
 156       glyphs->glyphs[i].glyph = glyph;
 157
 158       glyphs->glyphs[i].geometry.x_offset = 0;
 159       glyphs->glyphs[i].geometry.y_offset = 0;
 160       glyphs->glyphs[i].geometry.width = logical_rect.width;
 161
 162       glyphs->log_clusters[i] = cluster;
 163
 164       p = g_utf8_next_char (p);
 165     }
 166
 167   if (analysis->level & 1)
 168     pango_glyph_string_reverse_range (glyphs, 0, glyphs->num_glyphs);
 169 }
 170
 171 static PangoCoverageLevel
 172 fallback_engine_covers (PangoEngineShape *engine G_GNUC_UNUSED,
 173                         PangoFont        *font G_GNUC_UNUSED,
 174                         PangoLanguage    *lang G_GNUC_UNUSED,
 175                         gunichar          wc G_GNUC_UNUSED)
 176 {
 177   return PANGO_COVERAGE_NONE;
 178 }
 179
 180
 181 static GType pango_fallback_engine_get_type (void);
 182
 183 G_DEFINE_TYPE (PangoFallbackEngine, pango_fallback_engine, PANGO_TYPE_ENGINE_SHAPE);
 184
 185 static void
 186 pango_fallback_engine_init (PangoFallbackEngine *self)
 187 {
 188 }
 189
 190 static void
 191 pango_fallback_engine_class_init (PangoFallbackEngineClass *class)
 192 {
 193   class->covers = fallback_engine_covers;
 194   class->script_shape = fallback_engine_shape;
 195 }
 196
 197 PangoEngineShape *
 198 _pango_get_fallback_shaper (void)
 199 {
 200   static PangoEngineShape *fallback_shaper = NULL;
 201   if (!fallback_shaper)
 202     fallback_shaper = g_object_new (pango_fallback_engine_get_type (), NULL);
 203
 204   return fallback_shaper;
 205 }
 206