1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "ui/gfx/pango_util.h" 6 7 #include <cairo/cairo.h> 8 #include <fontconfig/fontconfig.h> 9 #include <pango/pango.h> 10 #include <pango/pangocairo.h> 11 #include <string> 12 13 #include <algorithm> 14 #include <map> 15 #include <vector> 16 17 #include "base/logging.h" 18 #include "base/strings/utf_string_conversions.h" 19 #include "ui/gfx/canvas.h" 20 #include "ui/gfx/font.h" 21 #include "ui/gfx/font_render_params_linux.h" 22 #include "ui/gfx/platform_font_pango.h" 23 #include "ui/gfx/rect.h" 24 #include "ui/gfx/text_utils.h" 25 26 namespace gfx { 27 28 namespace { 29 30 // Marker for accelerators in the text. 31 const gunichar kAcceleratorChar = '&'; 32 33 // Return |cairo_font_options|. If needed, allocate and update it. 34 // TODO(derat): Return font-specific options: http://crbug.com/125235 35 cairo_font_options_t* GetCairoFontOptions() { 36 // Font settings that we initialize once and then use when drawing text. 37 static cairo_font_options_t* cairo_font_options = NULL; 38 if (cairo_font_options) 39 return cairo_font_options; 40 41 cairo_font_options = cairo_font_options_create(); 42 43 const FontRenderParams& params = GetDefaultFontRenderParams(); 44 FontRenderParams::SubpixelRendering subpixel = params.subpixel_rendering; 45 if (!params.antialiasing) { 46 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_NONE); 47 } else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_NONE) { 48 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY); 49 } else { 50 cairo_font_options_set_antialias(cairo_font_options, 51 CAIRO_ANTIALIAS_SUBPIXEL); 52 cairo_subpixel_order_t cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT; 53 if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_RGB) 54 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_RGB; 55 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_BGR) 56 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_BGR; 57 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VRGB) 58 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VRGB; 59 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VBGR) 60 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VBGR; 61 else 62 NOTREACHED() << "Unhandled subpixel rendering type " << subpixel; 63 cairo_font_options_set_subpixel_order(cairo_font_options, 64 cairo_subpixel_order); 65 } 66 67 if (params.hinting == FontRenderParams::HINTING_NONE || 68 params.subpixel_positioning) { 69 cairo_font_options_set_hint_style(cairo_font_options, 70 CAIRO_HINT_STYLE_NONE); 71 cairo_font_options_set_hint_metrics(cairo_font_options, 72 CAIRO_HINT_METRICS_OFF); 73 } else { 74 cairo_hint_style_t cairo_hint_style = CAIRO_HINT_STYLE_DEFAULT; 75 if (params.hinting == FontRenderParams::HINTING_SLIGHT) 76 cairo_hint_style = CAIRO_HINT_STYLE_SLIGHT; 77 else if (params.hinting == FontRenderParams::HINTING_MEDIUM) 78 cairo_hint_style = CAIRO_HINT_STYLE_MEDIUM; 79 else if (params.hinting == FontRenderParams::HINTING_FULL) 80 cairo_hint_style = CAIRO_HINT_STYLE_FULL; 81 else 82 NOTREACHED() << "Unhandled hinting style " << params.hinting; 83 cairo_font_options_set_hint_style(cairo_font_options, cairo_hint_style); 84 cairo_font_options_set_hint_metrics(cairo_font_options, 85 CAIRO_HINT_METRICS_ON); 86 } 87 88 return cairo_font_options; 89 } 90 91 // Returns the number of pixels in a point. 92 // - multiply a point size by this to get pixels ("device units") 93 // - divide a pixel size by this to get points 94 float GetPixelsInPoint() { 95 static float pixels_in_point = 1.0; 96 static bool determined_value = false; 97 98 if (!determined_value) { 99 // http://goo.gl/UIh5m: "This is a scale factor between points specified in 100 // a PangoFontDescription and Cairo units. The default value is 96, meaning 101 // that a 10 point font will be 13 units high. (10 * 96. / 72. = 13.3)." 102 double pango_dpi = GetPangoResolution(); 103 if (pango_dpi <= 0) 104 pango_dpi = 96.0; 105 pixels_in_point = pango_dpi / 72.0; // 72 points in an inch 106 determined_value = true; 107 } 108 109 return pixels_in_point; 110 } 111 112 } // namespace 113 114 PangoContext* GetPangoContext() { 115 PangoFontMap* font_map = pango_cairo_font_map_get_default(); 116 return pango_font_map_create_context(font_map); 117 } 118 119 double GetPangoResolution() { 120 static double resolution; 121 static bool determined_resolution = false; 122 if (!determined_resolution) { 123 determined_resolution = true; 124 PangoContext* default_context = GetPangoContext(); 125 resolution = pango_cairo_context_get_resolution(default_context); 126 g_object_unref(default_context); 127 } 128 return resolution; 129 } 130 131 // Pass a width greater than 0 to force wrapping and eliding. 132 static void SetupPangoLayoutWithoutFont( 133 PangoLayout* layout, 134 const base::string16& text, 135 int width, 136 base::i18n::TextDirection text_direction, 137 int flags) { 138 cairo_font_options_t* cairo_font_options = GetCairoFontOptions(); 139 140 // If we got an explicit request to turn off subpixel rendering, disable it on 141 // a copy of the static font options object. 142 bool copied_cairo_font_options = false; 143 if ((flags & Canvas::NO_SUBPIXEL_RENDERING) && 144 (cairo_font_options_get_antialias(cairo_font_options) == 145 CAIRO_ANTIALIAS_SUBPIXEL)) { 146 cairo_font_options = cairo_font_options_copy(cairo_font_options); 147 copied_cairo_font_options = true; 148 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY); 149 } 150 151 // This needs to be done early on; it has no effect when called just before 152 // pango_cairo_show_layout(). 153 pango_cairo_context_set_font_options( 154 pango_layout_get_context(layout), cairo_font_options); 155 156 if (copied_cairo_font_options) { 157 cairo_font_options_destroy(cairo_font_options); 158 cairo_font_options = NULL; 159 } 160 161 // Set Pango's base text direction explicitly from |text_direction|. 162 pango_layout_set_auto_dir(layout, FALSE); 163 pango_context_set_base_dir(pango_layout_get_context(layout), 164 (text_direction == base::i18n::RIGHT_TO_LEFT ? 165 PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR)); 166 167 if (width > 0) 168 pango_layout_set_width(layout, width * PANGO_SCALE); 169 170 if (flags & Canvas::TEXT_ALIGN_CENTER) { 171 // We don't support center aligned w/ eliding. 172 DCHECK(gfx::Canvas::NO_ELLIPSIS); 173 pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER); 174 } else if (flags & Canvas::TEXT_ALIGN_RIGHT) { 175 pango_layout_set_alignment(layout, PANGO_ALIGN_RIGHT); 176 } 177 178 if (flags & Canvas::NO_ELLIPSIS) { 179 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE); 180 if (flags & Canvas::MULTI_LINE) { 181 pango_layout_set_wrap(layout, 182 (flags & Canvas::CHARACTER_BREAK) ? 183 PANGO_WRAP_WORD_CHAR : PANGO_WRAP_WORD); 184 } 185 } else if (text_direction == base::i18n::RIGHT_TO_LEFT) { 186 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_END); 187 } else { 188 // Fading the text will be handled in the draw operation. 189 // Ensure that the text is only on one line. 190 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE); 191 pango_layout_set_width(layout, -1); 192 } 193 194 // Set the resolution to match that used by Gtk. If we don't set the 195 // resolution and the resolution differs from the default, Gtk and Chrome end 196 // up drawing at different sizes. 197 double resolution = GetPangoResolution(); 198 if (resolution > 0) { 199 pango_cairo_context_set_resolution(pango_layout_get_context(layout), 200 resolution); 201 } 202 203 // Set text and accelerator character if needed. 204 if (flags & Canvas::SHOW_PREFIX) { 205 // Escape the text string to be used as markup. 206 std::string utf8 = base::UTF16ToUTF8(text); 207 gchar* escaped_text = g_markup_escape_text(utf8.c_str(), utf8.size()); 208 pango_layout_set_markup_with_accel(layout, 209 escaped_text, 210 strlen(escaped_text), 211 kAcceleratorChar, NULL); 212 g_free(escaped_text); 213 } else { 214 std::string utf8; 215 216 // Remove the ampersand character. A double ampersand is output as 217 // a single ampersand. 218 if (flags & Canvas::HIDE_PREFIX) { 219 DCHECK_EQ(1, g_unichar_to_utf8(kAcceleratorChar, NULL)); 220 base::string16 accelerator_removed = 221 RemoveAcceleratorChar(text, 222 static_cast<base::char16>(kAcceleratorChar), 223 NULL, NULL); 224 utf8 = base::UTF16ToUTF8(accelerator_removed); 225 } else { 226 utf8 = base::UTF16ToUTF8(text); 227 } 228 229 pango_layout_set_text(layout, utf8.data(), utf8.size()); 230 } 231 } 232 233 void SetupPangoLayout(PangoLayout* layout, 234 const base::string16& text, 235 const Font& font, 236 int width, 237 base::i18n::TextDirection text_direction, 238 int flags) { 239 SetupPangoLayoutWithoutFont(layout, text, width, text_direction, flags); 240 241 ScopedPangoFontDescription desc(font.GetNativeFont()); 242 pango_layout_set_font_description(layout, desc.get()); 243 } 244 245 void SetupPangoLayoutWithFontDescription( 246 PangoLayout* layout, 247 const base::string16& text, 248 const std::string& font_description, 249 int width, 250 base::i18n::TextDirection text_direction, 251 int flags) { 252 SetupPangoLayoutWithoutFont(layout, text, width, text_direction, flags); 253 254 ScopedPangoFontDescription desc( 255 pango_font_description_from_string(font_description.c_str())); 256 pango_layout_set_font_description(layout, desc.get()); 257 } 258 259 size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font) { 260 size_t size_in_pixels = pango_font_description_get_size(pango_font); 261 if (pango_font_description_get_size_is_absolute(pango_font)) { 262 // If the size is absolute, then it's in Pango units rather than points. 263 // There are PANGO_SCALE Pango units in a device unit (pixel). 264 size_in_pixels /= PANGO_SCALE; 265 } else { 266 // Otherwise, we need to convert from points. 267 size_in_pixels = size_in_pixels * GetPixelsInPoint() / PANGO_SCALE; 268 } 269 return size_in_pixels; 270 } 271 272 PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc) { 273 static std::map<int, PangoFontMetrics*>* desc_to_metrics = NULL; 274 static PangoContext* context = NULL; 275 276 if (!context) { 277 context = GetPangoContext(); 278 pango_context_set_language(context, pango_language_get_default()); 279 } 280 281 if (!desc_to_metrics) 282 desc_to_metrics = new std::map<int, PangoFontMetrics*>(); 283 284 const int desc_hash = pango_font_description_hash(desc); 285 std::map<int, PangoFontMetrics*>::iterator i = 286 desc_to_metrics->find(desc_hash); 287 288 if (i == desc_to_metrics->end()) { 289 PangoFontMetrics* metrics = pango_context_get_metrics(context, desc, NULL); 290 desc_to_metrics->insert(std::make_pair(desc_hash, metrics)); 291 return metrics; 292 } 293 return i->second; 294 } 295 296 } // namespace gfx 297
