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 #if defined(TOOLKIT_GTK) 27 #include <gdk/gdk.h> 28 #endif 29 30 namespace gfx { 31 32 namespace { 33 34 // Marker for accelerators in the text. 35 const gunichar kAcceleratorChar = '&'; 36 37 // Multiply by the text height to determine how much text should be faded 38 // when elliding. 39 const double kFadeWidthFactor = 1.5; 40 41 // End state of the elliding fade. 42 const double kFadeFinalAlpha = 0.15; 43 44 // Return |cairo_font_options|. If needed, allocate and update it. 45 // TODO(derat): Return font-specific options: http://crbug.com/125235 46 cairo_font_options_t* GetCairoFontOptions() { 47 // Font settings that we initialize once and then use when drawing text. 48 static cairo_font_options_t* cairo_font_options = NULL; 49 if (cairo_font_options) 50 return cairo_font_options; 51 52 cairo_font_options = cairo_font_options_create(); 53 54 const FontRenderParams& params = GetDefaultFontRenderParams(); 55 FontRenderParams::SubpixelRendering subpixel = params.subpixel_rendering; 56 if (!params.antialiasing) { 57 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_NONE); 58 } else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_NONE) { 59 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY); 60 } else { 61 cairo_font_options_set_antialias(cairo_font_options, 62 CAIRO_ANTIALIAS_SUBPIXEL); 63 cairo_subpixel_order_t cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_DEFAULT; 64 if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_RGB) 65 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_RGB; 66 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_BGR) 67 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_BGR; 68 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VRGB) 69 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VRGB; 70 else if (subpixel == FontRenderParams::SUBPIXEL_RENDERING_VBGR) 71 cairo_subpixel_order = CAIRO_SUBPIXEL_ORDER_VBGR; 72 else 73 NOTREACHED() << "Unhandled subpixel rendering type " << subpixel; 74 cairo_font_options_set_subpixel_order(cairo_font_options, 75 cairo_subpixel_order); 76 } 77 78 if (params.hinting == FontRenderParams::HINTING_NONE || 79 params.subpixel_positioning) { 80 cairo_font_options_set_hint_style(cairo_font_options, 81 CAIRO_HINT_STYLE_NONE); 82 cairo_font_options_set_hint_metrics(cairo_font_options, 83 CAIRO_HINT_METRICS_OFF); 84 } else { 85 cairo_hint_style_t cairo_hint_style = CAIRO_HINT_STYLE_DEFAULT; 86 if (params.hinting == FontRenderParams::HINTING_SLIGHT) 87 cairo_hint_style = CAIRO_HINT_STYLE_SLIGHT; 88 else if (params.hinting == FontRenderParams::HINTING_MEDIUM) 89 cairo_hint_style = CAIRO_HINT_STYLE_MEDIUM; 90 else if (params.hinting == FontRenderParams::HINTING_FULL) 91 cairo_hint_style = CAIRO_HINT_STYLE_FULL; 92 else 93 NOTREACHED() << "Unhandled hinting style " << params.hinting; 94 cairo_font_options_set_hint_style(cairo_font_options, cairo_hint_style); 95 cairo_font_options_set_hint_metrics(cairo_font_options, 96 CAIRO_HINT_METRICS_ON); 97 } 98 99 return cairo_font_options; 100 } 101 102 // Returns the number of pixels in a point. 103 // - multiply a point size by this to get pixels ("device units") 104 // - divide a pixel size by this to get points 105 float GetPixelsInPoint() { 106 static float pixels_in_point = 1.0; 107 static bool determined_value = false; 108 109 if (!determined_value) { 110 // http://goo.gl/UIh5m: "This is a scale factor between points specified in 111 // a PangoFontDescription and Cairo units. The default value is 96, meaning 112 // that a 10 point font will be 13 units high. (10 * 96. / 72. = 13.3)." 113 double pango_dpi = GetPangoResolution(); 114 if (pango_dpi <= 0) 115 pango_dpi = 96.0; 116 pixels_in_point = pango_dpi / 72.0; // 72 points in an inch 117 determined_value = true; 118 } 119 120 return pixels_in_point; 121 } 122 123 } // namespace 124 125 PangoContext* GetPangoContext() { 126 #if defined(TOOLKIT_GTK) 127 return gdk_pango_context_get(); 128 #else 129 PangoFontMap* font_map = pango_cairo_font_map_get_default(); 130 return pango_font_map_create_context(font_map); 131 #endif 132 } 133 134 double GetPangoResolution() { 135 static double resolution; 136 static bool determined_resolution = false; 137 if (!determined_resolution) { 138 determined_resolution = true; 139 PangoContext* default_context = GetPangoContext(); 140 resolution = pango_cairo_context_get_resolution(default_context); 141 g_object_unref(default_context); 142 } 143 return resolution; 144 } 145 146 void DrawTextOntoCairoSurface(cairo_t* cr, 147 const base::string16& text, 148 const gfx::Font& font, 149 const gfx::Rect& bounds, 150 const gfx::Rect& clip, 151 SkColor text_color, 152 int flags) { 153 PangoLayout* layout = pango_cairo_create_layout(cr); 154 base::i18n::TextDirection text_direction = 155 base::i18n::GetFirstStrongCharacterDirection(text); 156 DCHECK(!bounds.IsEmpty()); 157 158 gfx::SetupPangoLayout( 159 layout, text, font, bounds.width(), text_direction, flags); 160 161 pango_layout_set_height(layout, bounds.height() * PANGO_SCALE); 162 163 cairo_save(cr); 164 cairo_rectangle(cr, clip.x(), clip.y(), clip.width(), clip.height()); 165 cairo_clip(cr); 166 167 int width = 0, height = 0; 168 pango_layout_get_pixel_size(layout, &width, &height); 169 Rect text_rect(bounds.x(), bounds.y(), width, height); 170 // Vertically center |text_rect| in |bounds|. 171 text_rect += gfx::Vector2d(0, (bounds.height() - text_rect.height()) / 2); 172 173 DrawPangoLayout(cr, layout, font, bounds, text_rect, 174 text_color, text_direction, flags); 175 176 cairo_restore(cr); 177 g_object_unref(layout); 178 } 179 180 // Pass a width greater than 0 to force wrapping and eliding. 181 static void SetupPangoLayoutWithoutFont( 182 PangoLayout* layout, 183 const base::string16& text, 184 int width, 185 base::i18n::TextDirection text_direction, 186 int flags) { 187 cairo_font_options_t* cairo_font_options = GetCairoFontOptions(); 188 189 // If we got an explicit request to turn off subpixel rendering, disable it on 190 // a copy of the static font options object. 191 bool copied_cairo_font_options = false; 192 if ((flags & Canvas::NO_SUBPIXEL_RENDERING) && 193 (cairo_font_options_get_antialias(cairo_font_options) == 194 CAIRO_ANTIALIAS_SUBPIXEL)) { 195 cairo_font_options = cairo_font_options_copy(cairo_font_options); 196 copied_cairo_font_options = true; 197 cairo_font_options_set_antialias(cairo_font_options, CAIRO_ANTIALIAS_GRAY); 198 } 199 200 // This needs to be done early on; it has no effect when called just before 201 // pango_cairo_show_layout(). 202 pango_cairo_context_set_font_options( 203 pango_layout_get_context(layout), cairo_font_options); 204 205 if (copied_cairo_font_options) { 206 cairo_font_options_destroy(cairo_font_options); 207 cairo_font_options = NULL; 208 } 209 210 // Set Pango's base text direction explicitly from |text_direction|. 211 pango_layout_set_auto_dir(layout, FALSE); 212 pango_context_set_base_dir(pango_layout_get_context(layout), 213 (text_direction == base::i18n::RIGHT_TO_LEFT ? 214 PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR)); 215 216 if (width > 0) 217 pango_layout_set_width(layout, width * PANGO_SCALE); 218 219 if (flags & Canvas::TEXT_ALIGN_CENTER) { 220 // We don't support center aligned w/ eliding. 221 DCHECK(gfx::Canvas::NO_ELLIPSIS); 222 pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER); 223 } else if (flags & Canvas::TEXT_ALIGN_RIGHT) { 224 pango_layout_set_alignment(layout, PANGO_ALIGN_RIGHT); 225 } 226 227 if (flags & Canvas::NO_ELLIPSIS) { 228 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE); 229 if (flags & Canvas::MULTI_LINE) { 230 pango_layout_set_wrap(layout, 231 (flags & Canvas::CHARACTER_BREAK) ? 232 PANGO_WRAP_WORD_CHAR : PANGO_WRAP_WORD); 233 } 234 } else if (text_direction == base::i18n::RIGHT_TO_LEFT) { 235 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_END); 236 } else { 237 // Fading the text will be handled in the draw operation. 238 // Ensure that the text is only on one line. 239 pango_layout_set_ellipsize(layout, PANGO_ELLIPSIZE_NONE); 240 pango_layout_set_width(layout, -1); 241 } 242 243 // Set the resolution to match that used by Gtk. If we don't set the 244 // resolution and the resolution differs from the default, Gtk and Chrome end 245 // up drawing at different sizes. 246 double resolution = GetPangoResolution(); 247 if (resolution > 0) { 248 pango_cairo_context_set_resolution(pango_layout_get_context(layout), 249 resolution); 250 } 251 252 // Set text and accelerator character if needed. 253 if (flags & Canvas::SHOW_PREFIX) { 254 // Escape the text string to be used as markup. 255 std::string utf8 = UTF16ToUTF8(text); 256 gchar* escaped_text = g_markup_escape_text(utf8.c_str(), utf8.size()); 257 pango_layout_set_markup_with_accel(layout, 258 escaped_text, 259 strlen(escaped_text), 260 kAcceleratorChar, NULL); 261 g_free(escaped_text); 262 } else { 263 std::string utf8; 264 265 // Remove the ampersand character. A double ampersand is output as 266 // a single ampersand. 267 if (flags & Canvas::HIDE_PREFIX) { 268 DCHECK_EQ(1, g_unichar_to_utf8(kAcceleratorChar, NULL)); 269 base::string16 accelerator_removed = 270 RemoveAcceleratorChar(text, static_cast<char16>(kAcceleratorChar), 271 NULL, NULL); 272 utf8 = UTF16ToUTF8(accelerator_removed); 273 } else { 274 utf8 = UTF16ToUTF8(text); 275 } 276 277 pango_layout_set_text(layout, utf8.data(), utf8.size()); 278 } 279 } 280 281 void SetupPangoLayout(PangoLayout* layout, 282 const base::string16& text, 283 const Font& font, 284 int width, 285 base::i18n::TextDirection text_direction, 286 int flags) { 287 SetupPangoLayoutWithoutFont(layout, text, width, text_direction, flags); 288 289 ScopedPangoFontDescription desc(font.GetNativeFont()); 290 pango_layout_set_font_description(layout, desc.get()); 291 } 292 293 void SetupPangoLayoutWithFontDescription( 294 PangoLayout* layout, 295 const base::string16& text, 296 const std::string& font_description, 297 int width, 298 base::i18n::TextDirection text_direction, 299 int flags) { 300 SetupPangoLayoutWithoutFont(layout, text, width, text_direction, flags); 301 302 ScopedPangoFontDescription desc( 303 pango_font_description_from_string(font_description.c_str())); 304 pango_layout_set_font_description(layout, desc.get()); 305 } 306 307 void DrawPangoLayout(cairo_t* cr, 308 PangoLayout* layout, 309 const Font& font, 310 const gfx::Rect& bounds, 311 const gfx::Rect& text_rect, 312 SkColor text_color, 313 base::i18n::TextDirection text_direction, 314 int flags) { 315 double r = SkColorGetR(text_color) / 255.0, 316 g = SkColorGetG(text_color) / 255.0, 317 b = SkColorGetB(text_color) / 255.0, 318 a = SkColorGetA(text_color) / 255.0; 319 320 cairo_pattern_t* pattern = NULL; 321 322 cairo_save(cr); 323 324 // If we're not eliding, use a fixed color. 325 // Otherwise, create a gradient pattern to use as the source. 326 if (text_direction == base::i18n::RIGHT_TO_LEFT || 327 (flags & gfx::Canvas::NO_ELLIPSIS) || 328 text_rect.width() <= bounds.width()) { 329 cairo_set_source_rgba(cr, r, g, b, a); 330 } else { 331 // Fade to semi-transparent to elide. 332 int fade_width = static_cast<double>(text_rect.height()) * kFadeWidthFactor; 333 if (fade_width > bounds.width() / 2) { 334 // Don't fade more than half the text. 335 fade_width = bounds.width() / 2; 336 } 337 int fade_x = bounds.x() + bounds.width() - fade_width; 338 339 pattern = cairo_pattern_create_linear( 340 fade_x, bounds.y(), bounds.x() + bounds.width(), bounds.y()); 341 cairo_pattern_add_color_stop_rgba(pattern, 0, r, g, b, a); 342 cairo_pattern_add_color_stop_rgba(pattern, 1, r, g, b, kFadeFinalAlpha); 343 cairo_set_source(cr, pattern); 344 } 345 346 cairo_move_to(cr, text_rect.x(), text_rect.y()); 347 pango_cairo_show_layout(cr, layout); 348 349 if (font.GetStyle() & gfx::Font::UNDERLINE) { 350 gfx::PlatformFontPango* platform_font = 351 static_cast<gfx::PlatformFontPango*>(font.platform_font()); 352 DrawPangoTextUnderline(cr, platform_font, 0.0, text_rect); 353 } 354 355 if (pattern) 356 cairo_pattern_destroy(pattern); 357 358 cairo_restore(cr); 359 } 360 361 void DrawPangoTextUnderline(cairo_t* cr, 362 gfx::PlatformFontPango* platform_font, 363 double extra_edge_width, 364 const Rect& text_rect) { 365 const double underline_y = 366 static_cast<double>(text_rect.y()) + text_rect.height() + 367 platform_font->underline_position(); 368 cairo_set_line_width( 369 cr, platform_font->underline_thickness() + 2 * extra_edge_width); 370 cairo_move_to(cr, 371 text_rect.x() - extra_edge_width, 372 underline_y); 373 cairo_line_to(cr, 374 text_rect.x() + text_rect.width() + extra_edge_width, 375 underline_y); 376 cairo_stroke(cr); 377 } 378 379 size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font) { 380 size_t size_in_pixels = pango_font_description_get_size(pango_font); 381 if (pango_font_description_get_size_is_absolute(pango_font)) { 382 // If the size is absolute, then it's in Pango units rather than points. 383 // There are PANGO_SCALE Pango units in a device unit (pixel). 384 size_in_pixels /= PANGO_SCALE; 385 } else { 386 // Otherwise, we need to convert from points. 387 size_in_pixels = size_in_pixels * GetPixelsInPoint() / PANGO_SCALE; 388 } 389 return size_in_pixels; 390 } 391 392 PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc) { 393 static std::map<int, PangoFontMetrics*>* desc_to_metrics = NULL; 394 static PangoContext* context = NULL; 395 396 if (!context) { 397 context = GetPangoContext(); 398 pango_context_set_language(context, pango_language_get_default()); 399 } 400 401 if (!desc_to_metrics) 402 desc_to_metrics = new std::map<int, PangoFontMetrics*>(); 403 404 const int desc_hash = pango_font_description_hash(desc); 405 std::map<int, PangoFontMetrics*>::iterator i = 406 desc_to_metrics->find(desc_hash); 407 408 if (i == desc_to_metrics->end()) { 409 PangoFontMetrics* metrics = pango_context_get_metrics(context, desc, NULL); 410 desc_to_metrics->insert(std::make_pair(desc_hash, metrics)); 411 return metrics; 412 } 413 return i->second; 414 } 415 416 } // namespace gfx 417
