content/child/browser_font_resource_trusted.cc

   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 "content/child/browser_font_resource_trusted.h"
   6
   7 #include "base/strings/string_util.h"
   8 #include "base/strings/utf_string_conversions.h"
   9 #include "content/public/common/web_preferences.h"
  10 #include "ppapi/c/dev/ppb_font_dev.h"
  11 #include "ppapi/proxy/connection.h"
  12 #include "ppapi/shared_impl/ppapi_preferences.h"
  13 #include "ppapi/shared_impl/var.h"
  14 #include "ppapi/thunk/enter.h"
  15 #include "ppapi/thunk/ppb_image_data_api.h"
  16 #include "ppapi/thunk/thunk.h"
  17 #include "skia/ext/platform_canvas.h"
  18 #include "third_party/WebKit/public/platform/WebCanvas.h"
  19 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
  20 #include "third_party/WebKit/public/platform/WebFloatRect.h"
  21 #include "third_party/WebKit/public/platform/WebRect.h"
  22 #include "third_party/WebKit/public/web/WebFont.h"
  23 #include "third_party/WebKit/public/web/WebFontDescription.h"
  24 #include "third_party/WebKit/public/web/WebTextRun.h"
  25 #include "third_party/icu/source/common/unicode/ubidi.h"
  26 #include "third_party/skia/include/core/SkRect.h"
  27
  28 using ppapi::StringVar;
  29 using ppapi::thunk::EnterResourceNoLock;
  30 using ppapi::thunk::PPB_ImageData_API;
  31 using blink::WebFloatPoint;
  32 using blink::WebFloatRect;
  33 using blink::WebFont;
  34 using blink::WebFontDescription;
  35 using blink::WebRect;
  36 using blink::WebTextRun;
  37 using blink::WebCanvas;
  38
  39 namespace content {
  40
  41 namespace {
  42
  43 // Same as WebPreferences::kCommonScript. I'd use that directly here, but get an
  44 // undefined reference linker error.
  45 const char kCommonScript[] = "Zyyy";
  46
  47 base::string16 GetFontFromMap(const ScriptFontFamilyMap& map,
  48                               const std::string& script) {
  49   ScriptFontFamilyMap::const_iterator it = map.find(script);
  50   if (it != map.end())
  51     return it->second;
  52   return base::string16();
  53 }
  54
  55 // Splits a PP_BrowserFont_Trusted_TextRun into a sequence or LTR and RTL
  56 // WebTextRuns that can be used for WebKit. Normally WebKit does this for us,
  57 // but the font drawing and measurement routines we call happen after this
  58 // step. So for correct rendering of RTL content, we need to do it ourselves.
  59 class TextRunCollection {
  60  public:
  61   explicit TextRunCollection(const PP_BrowserFont_Trusted_TextRun& run)
  62       : bidi_(NULL),
  63         num_runs_(0) {
  64     StringVar* text_string = StringVar::FromPPVar(run.text);
  65     if (!text_string)
  66       return;  // Leave num_runs_ = 0 so we'll do nothing.
  67     text_ = base::UTF8ToUTF16(text_string->value());
  68
  69     if (run.override_direction) {
  70       // Skip autodetection.
  71       num_runs_ = 1;
  72       override_run_ = WebTextRun(text_, PP_ToBool(run.rtl), true);
  73     } else {
  74       bidi_ = ubidi_open();
  75       UErrorCode uerror = U_ZERO_ERROR;
  76       ubidi_setPara(bidi_, text_.data(), text_.size(), run.rtl, NULL, &uerror);
  77       if (U_SUCCESS(uerror))
  78         num_runs_ = ubidi_countRuns(bidi_, &uerror);
  79     }
  80   }
  81
  82   ~TextRunCollection() {
  83     if (bidi_)
  84       ubidi_close(bidi_);
  85   }
  86
  87   const base::string16& text() const { return text_; }
  88   int num_runs() const { return num_runs_; }
  89
  90   // Returns a WebTextRun with the info for the run at the given index.
  91   // The range covered by the run is in the two output params.
  92   WebTextRun GetRunAt(int index, int32_t* run_start, int32_t* run_len) const {
  93     DCHECK(index < num_runs_);
  94     if (bidi_) {
  95       bool run_rtl = !!ubidi_getVisualRun(bidi_, index, run_start, run_len);
  96       return WebTextRun(base::string16(&text_[*run_start], *run_len),
  97                         run_rtl, true);
  98     }
  99
 100     // Override run, return the single one.
 101     DCHECK(index == 0);
 102     *run_start = 0;
 103     *run_len = static_cast<int32_t>(text_.size());
 104     return override_run_;
 105   }
 106
 107  private:
 108   // Will be null if we skipped autodetection.
 109   UBiDi* bidi_;
 110
 111   // Text of all the runs.
 112   base::string16 text_;
 113
 114   int num_runs_;
 115
 116   // When the content specifies override_direction (bidi_ is null) then this
 117   // will contain the single text run for WebKit.
 118   WebTextRun override_run_;
 119
 120   DISALLOW_COPY_AND_ASSIGN(TextRunCollection);
 121 };
 122
 123 bool PPTextRunToWebTextRun(const PP_BrowserFont_Trusted_TextRun& text,
 124                            WebTextRun* run) {
 125   StringVar* text_string = StringVar::FromPPVar(text.text);
 126   if (!text_string)
 127     return false;
 128
 129   *run = WebTextRun(base::UTF8ToUTF16(text_string->value()),
 130                     PP_ToBool(text.rtl),
 131                     PP_ToBool(text.override_direction));
 132   return true;
 133 }
 134
 135 // The PP_* version lacks "None", so is just one value shifted from the
 136 // WebFontDescription version. These values are checked in
 137 // PPFontDescToWebFontDesc to make sure the conversion is correct. This is a
 138 // macro so it can also be used in the COMPILE_ASSERTS.
 139 #define PP_FAMILY_TO_WEB_FAMILY(f) \
 140   static_cast<WebFontDescription::GenericFamily>(f + 1)
 141
 142 // Assumes the given PP_FontDescription has been validated.
 143 WebFontDescription PPFontDescToWebFontDesc(
 144     const PP_BrowserFont_Trusted_Description& font,
 145     const ppapi::Preferences& prefs) {
 146   // Verify that the enums match so we can just static cast.
 147   COMPILE_ASSERT(static_cast<int>(WebFontDescription::Weight100) ==
 148                  static_cast<int>(PP_BROWSERFONT_TRUSTED_WEIGHT_100),
 149                  FontWeight100);
 150   COMPILE_ASSERT(static_cast<int>(WebFontDescription::Weight900) ==
 151                  static_cast<int>(PP_BROWSERFONT_TRUSTED_WEIGHT_900),
 152                  FontWeight900);
 153   COMPILE_ASSERT(WebFontDescription::GenericFamilyStandard ==
 154                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_DEFAULT),
 155                  StandardFamily);
 156   COMPILE_ASSERT(WebFontDescription::GenericFamilySerif ==
 157                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_SERIF),
 158                  SerifFamily);
 159   COMPILE_ASSERT(WebFontDescription::GenericFamilySansSerif ==
 160                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_SANSSERIF),
 161                  SansSerifFamily);
 162   COMPILE_ASSERT(WebFontDescription::GenericFamilyMonospace ==
 163                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_MONOSPACE),
 164                  MonospaceFamily);
 165
 166   StringVar* face_name = StringVar::FromPPVar(font.face);  // Possibly null.
 167
 168   WebFontDescription result;
 169   base::string16 resolved_family;
 170   if (!face_name || face_name->value().empty()) {
 171     // Resolve the generic family.
 172     switch (font.family) {
 173       case PP_BROWSERFONT_TRUSTED_FAMILY_SERIF:
 174         resolved_family = GetFontFromMap(prefs.serif_font_family_map,
 175                                          kCommonScript);
 176         break;
 177       case PP_BROWSERFONT_TRUSTED_FAMILY_SANSSERIF:
 178         resolved_family = GetFontFromMap(prefs.sans_serif_font_family_map,
 179                                          kCommonScript);
 180         break;
 181       case PP_BROWSERFONT_TRUSTED_FAMILY_MONOSPACE:
 182         resolved_family = GetFontFromMap(prefs.fixed_font_family_map,
 183                                          kCommonScript);
 184         break;
 185       case PP_BROWSERFONT_TRUSTED_FAMILY_DEFAULT:
 186       default:
 187         resolved_family = GetFontFromMap(prefs.standard_font_family_map,
 188                                          kCommonScript);
 189         break;
 190     }
 191   } else {
 192     // Use the exact font.
 193     resolved_family = base::UTF8ToUTF16(face_name->value());
 194   }
 195   result.family = resolved_family;
 196
 197   result.genericFamily = PP_FAMILY_TO_WEB_FAMILY(font.family);
 198
 199   if (font.size == 0) {
 200     // Resolve the default font size, using the resolved family to see if
 201     // we should use the fixed or regular font size. It's difficult at this
 202     // level to detect if the requested font is fixed width, so we only apply
 203     // the alternate font size to the default fixed font family.
 204     if (base::StringToLowerASCII(resolved_family) ==
 205         base::StringToLowerASCII(GetFontFromMap(prefs.fixed_font_family_map,
 206                                                 kCommonScript)))
 207       result.size = static_cast<float>(prefs.default_fixed_font_size);
 208     else
 209       result.size = static_cast<float>(prefs.default_font_size);
 210   } else {
 211     // Use the exact size.
 212     result.size = static_cast<float>(font.size);
 213   }
 214
 215   result.italic = font.italic != PP_FALSE;
 216   result.smallCaps = font.small_caps != PP_FALSE;
 217   result.weight = static_cast<WebFontDescription::Weight>(font.weight);
 218   result.letterSpacing = static_cast<short>(font.letter_spacing);
 219   result.wordSpacing = static_cast<short>(font.word_spacing);
 220   return result;
 221 }
 222
 223 }  // namespace
 224
 225 // static
 226 bool BrowserFontResource_Trusted::IsPPFontDescriptionValid(
 227     const PP_BrowserFont_Trusted_Description& desc) {
 228   // Check validity of string. We can't check the actual text since we could
 229   // be on the wrong thread and don't know if we're in the plugin or the host.
 230   if (desc.face.type != PP_VARTYPE_STRING &&
 231       desc.face.type != PP_VARTYPE_UNDEFINED)
 232     return false;
 233
 234   // Check enum ranges.
 235   if (static_cast<int>(desc.family) < PP_BROWSERFONT_TRUSTED_FAMILY_DEFAULT ||
 236       static_cast<int>(desc.family) > PP_BROWSERFONT_TRUSTED_FAMILY_MONOSPACE)
 237     return false;
 238   if (static_cast<int>(desc.weight) < PP_BROWSERFONT_TRUSTED_WEIGHT_100 ||
 239       static_cast<int>(desc.weight) > PP_BROWSERFONT_TRUSTED_WEIGHT_900)
 240     return false;
 241
 242   // Check for excessive sizes which may cause layout to get confused.
 243   if (desc.size > 200)
 244     return false;
 245
 246   return true;
 247 }
 248
 249 BrowserFontResource_Trusted::BrowserFontResource_Trusted(
 250     ppapi::proxy::Connection connection,
 251     PP_Instance instance,
 252     const PP_BrowserFont_Trusted_Description& desc,
 253     const ppapi::Preferences& prefs)
 254     : PluginResource(connection, instance),
 255       font_(WebFont::create(PPFontDescToWebFontDesc(desc, prefs))) {
 256 }
 257
 258 BrowserFontResource_Trusted::~BrowserFontResource_Trusted() {
 259 }
 260
 261 ppapi::thunk::PPB_BrowserFont_Trusted_API*
 262 BrowserFontResource_Trusted::AsPPB_BrowserFont_Trusted_API() {
 263   return this;
 264 }
 265
 266 PP_Bool BrowserFontResource_Trusted::Describe(
 267     PP_BrowserFont_Trusted_Description* description,
 268     PP_BrowserFont_Trusted_Metrics* metrics) {
 269   if (description->face.type != PP_VARTYPE_UNDEFINED)
 270     return PP_FALSE;
 271
 272   // While converting the other way in PPFontDescToWebFontDesc we validated
 273   // that the enums can be casted.
 274   WebFontDescription web_desc = font_->fontDescription();
 275   description->face =
 276       StringVar::StringToPPVar(base::UTF16ToUTF8(web_desc.family));
 277   description->family =
 278       static_cast<PP_BrowserFont_Trusted_Family>(web_desc.genericFamily);
 279   description->size = static_cast<uint32_t>(web_desc.size);
 280   description->weight = static_cast<PP_BrowserFont_Trusted_Weight>(
 281       web_desc.weight);
 282   description->italic = web_desc.italic ? PP_TRUE : PP_FALSE;
 283   description->small_caps = web_desc.smallCaps ? PP_TRUE : PP_FALSE;
 284   description->letter_spacing = static_cast<int32_t>(web_desc.letterSpacing);
 285   description->word_spacing = static_cast<int32_t>(web_desc.wordSpacing);
 286
 287   metrics->height = font_->height();
 288   metrics->ascent = font_->ascent();
 289   metrics->descent = font_->descent();
 290   metrics->line_spacing = font_->lineSpacing();
 291   metrics->x_height = static_cast<int32_t>(font_->xHeight());
 292
 293   // Convert the string.
 294   return PP_TRUE;
 295 }
 296
 297 PP_Bool BrowserFontResource_Trusted::DrawTextAt(
 298     PP_Resource image_data,
 299     const PP_BrowserFont_Trusted_TextRun* text,
 300     const PP_Point* position,
 301     uint32_t color,
 302     const PP_Rect* clip,
 303     PP_Bool image_data_is_opaque) {
 304   PP_Bool result = PP_FALSE;
 305   // Get and map the image data we're painting to.
 306   EnterResourceNoLock<PPB_ImageData_API> enter(image_data, true);
 307   if (enter.failed())
 308     return result;
 309
 310   PPB_ImageData_API* image = static_cast<PPB_ImageData_API*>(
 311       enter.object());
 312   SkCanvas* canvas = image->GetPlatformCanvas();
 313   bool needs_unmapping = false;
 314   if (!canvas) {
 315     needs_unmapping = true;
 316     image->Map();
 317     canvas = image->GetPlatformCanvas();
 318     if (!canvas)
 319       return result;  // Failure mapping.
 320   }
 321
 322   DrawTextToCanvas(canvas, *text, position, color, clip, image_data_is_opaque);
 323
 324   if (needs_unmapping)
 325     image->Unmap();
 326   return PP_TRUE;
 327 }
 328
 329 int32_t BrowserFontResource_Trusted::MeasureText(
 330     const PP_BrowserFont_Trusted_TextRun* text) {
 331   WebTextRun run;
 332   if (!PPTextRunToWebTextRun(*text, &run))
 333     return -1;
 334   return font_->calculateWidth(run);
 335 }
 336
 337 uint32_t BrowserFontResource_Trusted::CharacterOffsetForPixel(
 338     const PP_BrowserFont_Trusted_TextRun* text,
 339     int32_t pixel_position) {
 340   TextRunCollection runs(*text);
 341   int32_t cur_pixel_offset = 0;
 342   for (int i = 0; i < runs.num_runs(); i++) {
 343     int32_t run_begin = 0;
 344     int32_t run_len = 0;
 345     WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
 346     int run_width = font_->calculateWidth(run);
 347     if (pixel_position < cur_pixel_offset + run_width) {
 348       // Offset is in this run.
 349       return static_cast<uint32_t>(font_->offsetForPosition(
 350               run, static_cast<float>(pixel_position - cur_pixel_offset))) +
 351           run_begin;
 352     }
 353     cur_pixel_offset += run_width;
 354   }
 355   return runs.text().size();
 356 }
 357
 358 int32_t BrowserFontResource_Trusted::PixelOffsetForCharacter(
 359     const PP_BrowserFont_Trusted_TextRun* text,
 360     uint32_t char_offset) {
 361   TextRunCollection runs(*text);
 362   int32_t cur_pixel_offset = 0;
 363   for (int i = 0; i < runs.num_runs(); i++) {
 364     int32_t run_begin = 0;
 365     int32_t run_len = 0;
 366     WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
 367     if (char_offset >= static_cast<uint32_t>(run_begin) &&
 368         char_offset < static_cast<uint32_t>(run_begin + run_len)) {
 369       // Character we're looking for is in this run.
 370       //
 371       // Here we ask WebKit to give us the rectangle around the character in
 372       // question, and then return the left edge. If we asked for a range of
 373       // 0 characters starting at the character in question, it would give us
 374       // a 0-width rect around the insertion point. But that will be on the
 375       // right side of the character for an RTL run, which would be wrong.
 376       WebFloatRect rect = font_->selectionRectForText(
 377           run, WebFloatPoint(0.0f, 0.0f), font_->height(),
 378           char_offset - run_begin, char_offset - run_begin + 1);
 379       return cur_pixel_offset + static_cast<int>(rect.x);
 380     } else {
 381       // Character is past this run, account for the pixels and continue
 382       // looking.
 383       cur_pixel_offset += font_->calculateWidth(run);
 384     }
 385   }
 386   return -1;  // Requested a char beyond the end.
 387 }
 388
 389 void BrowserFontResource_Trusted::DrawTextToCanvas(
 390     SkCanvas* destination,
 391     const PP_BrowserFont_Trusted_TextRun& text,
 392     const PP_Point* position,
 393     uint32_t color,
 394     const PP_Rect* clip,
 395     PP_Bool image_data_is_opaque) {
 396   // Convert position and clip.
 397   WebFloatPoint web_position(static_cast<float>(position->x),
 398                              static_cast<float>(position->y));
 399   WebRect web_clip;
 400   if (!clip) {
 401     // Use entire canvas. SkCanvas doesn't have a size on it, so we just use
 402     // the current clip bounds.
 403     SkRect skclip;
 404     destination->getClipBounds(&skclip);
 405     web_clip = WebRect(skclip.fLeft, skclip.fTop, skclip.fRight - skclip.fLeft,
 406                        skclip.fBottom - skclip.fTop);
 407   } else {
 408     web_clip = WebRect(clip->point.x, clip->point.y,
 409                        clip->size.width, clip->size.height);
 410   }
 411
 412   TextRunCollection runs(text);
 413   for (int i = 0; i < runs.num_runs(); i++) {
 414     int32_t run_begin = 0;
 415     int32_t run_len = 0;
 416     WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
 417     font_->drawText(destination, run, web_position, color, web_clip,
 418                     PP_ToBool(image_data_is_opaque));
 419
 420     // Advance to the next run. Note that we avoid doing this for the last run
 421     // since it's unnecessary, measuring text is slow, and most of the time
 422     // there will be only one run anyway.
 423     if (i != runs.num_runs() - 1)
 424       web_position.x += font_->calculateWidth(run);
 425   }
 426 }
 427
 428 }  // namespace content