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 PANGO_DEFINE_TYPE_ABSTRACT (PangoEngine, pango_engine,
  29                             NULL, NULL,
  30                             G_TYPE_OBJECT)
  31
  32 PANGO_DEFINE_TYPE_ABSTRACT (PangoEngineLang, pango_engine_lang,
  33                             NULL, NULL,
  34                             PANGO_TYPE_ENGINE)
  35
  36 static PangoCoverageLevel
  37 pango_engine_shape_real_covers (PangoEngineShape *engine G_GNUC_UNUSED,
  38                                 PangoFont        *font,
  39                                 PangoLanguage    *language,
  40                                 gunichar          wc)
  41 {
  42
  43   PangoCoverage *coverage = pango_font_get_coverage (font, language);
  44   PangoCoverageLevel result = pango_coverage_get (coverage, wc);
  45
  46   pango_coverage_unref (coverage);
  47
  48   return result;
  49 }
  50
  51 static void
  52 pango_engine_shape_class_init (PangoEngineShapeClass *class)
  53 {
  54   class->covers = pango_engine_shape_real_covers;
  55 }
  56
  57 PANGO_DEFINE_TYPE_ABSTRACT (PangoEngineShape, pango_engine_shape,
  58                             pango_engine_shape_class_init, NULL,
  59                             PANGO_TYPE_ENGINE)
  60
  61 void
  62 _pango_engine_shape_shape (PangoEngineShape *engine,
  63                            PangoFont        *font,
  64                            const char       *text,
  65                            int               length,
  66                            const PangoAnalysis *analysis,
  67                            PangoGlyphString *glyphs)
  68 {
  69   glyphs->num_glyphs = 0;
  70
  71   PANGO_ENGINE_SHAPE_GET_CLASS (engine)->script_shape (engine,
  72                                                        font,
  73                                                        text, length,
  74                                                        analysis,
  75                                                        glyphs);
  76 }
  77
  78 PangoCoverageLevel
  79 _pango_engine_shape_covers (PangoEngineShape *engine,
  80                             PangoFont        *font,
  81                             PangoLanguage    *language,
  82                             gunichar          wc)
  83 {
  84   g_return_val_if_fail (PANGO_IS_ENGINE_SHAPE (engine), PANGO_COVERAGE_NONE);
  85   g_return_val_if_fail (PANGO_IS_FONT (font), PANGO_COVERAGE_NONE);
  86
  87   return PANGO_ENGINE_SHAPE_GET_CLASS (engine)->covers (engine,
  88                                                         font,
  89                                                         language,
  90                                                         wc);
  91 }
  92
  93 /* No extra fields needed */
  94 typedef PangoEngineShape PangoFallbackEngine;
  95 typedef PangoEngineShapeClass PangoFallbackEngineClass;
  96
  97 static void
  98 fallback_engine_shape (PangoEngineShape *engine G_GNUC_UNUSED,
  99                        PangoFont        *font G_GNUC_UNUSED,
 100                        const char       *text,
 101                        gint              length,
 102                        const PangoAnalysis *analysis,
 103                        PangoGlyphString *glyphs)
 104 {
 105   int n_chars;
 106   const char *p;
 107   int cluster = 0;
 108   int i;
 109
 110   n_chars = text ? pango_utf8_strlen (text, length) : 0;
 111
 112   pango_glyph_string_set_size (glyphs, n_chars);
 113
 114   p = text;
 115   for (i = 0; i < n_chars; i++)
 116     {
 117       gunichar wc;
 118       PangoGlyph glyph;
 119       PangoRectangle logical_rect;
 120
 121       wc = g_utf8_get_char (p);
 122
 123       if (g_unichar_type (wc) != G_UNICODE_NON_SPACING_MARK)
 124         cluster = p - text;
 125
 126       if (pango_is_zero_width (wc))
 127         glyph = PANGO_GLYPH_EMPTY;
 128       else
 129         glyph = PANGO_GET_UNKNOWN_GLYPH (wc);
 130
 131       pango_font_get_glyph_extents (analysis->font, glyph, NULL, &logical_rect);
 132
 133       glyphs->glyphs[i].glyph = glyph;
 134
 135       glyphs->glyphs[i].geometry.x_offset = 0;
 136       glyphs->glyphs[i].geometry.y_offset = 0;
 137       glyphs->glyphs[i].geometry.width = logical_rect.width;
 138
 139       glyphs->log_clusters[i] = cluster;
 140
 141       p = g_utf8_next_char (p);
 142     }
 143
 144   if (analysis->level & 1)
 145     pango_glyph_string_reverse_range (glyphs, 0, glyphs->num_glyphs);
 146 }
 147
 148 static PangoCoverageLevel
 149 fallback_engine_covers (PangoEngineShape *engine G_GNUC_UNUSED,
 150                         PangoFont        *font G_GNUC_UNUSED,
 151                         PangoLanguage    *lang G_GNUC_UNUSED,
 152                         gunichar          wc G_GNUC_UNUSED)
 153 {
 154   return PANGO_COVERAGE_NONE;
 155 }
 156
 157 static void
 158 fallback_engine_class_init (PangoEngineShapeClass *class)
 159 {
 160   class->covers = fallback_engine_covers;
 161   class->script_shape = fallback_engine_shape;
 162 }
 163
 164 static PANGO_DEFINE_TYPE (PangoFallbackEngine, pango_fallback_engine,
 165                           fallback_engine_class_init, NULL,
 166                           PANGO_TYPE_ENGINE_SHAPE)
 167
 168 PangoEngineShape *
 169 _pango_get_fallback_shaper (void)
 170 {
 171   static PangoEngineShape *fallback_shaper = NULL;
 172   if (!fallback_shaper)
 173     fallback_shaper = g_object_new (pango_fallback_engine_get_type (), NULL);
 174
 175   return fallback_shaper;
 176 }
 177