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 "ppapi/c/dev/ppb_font_dev.h"
  10 #include "ppapi/proxy/connection.h"
  11 #include "ppapi/shared_impl/ppapi_preferences.h"
  12 #include "ppapi/shared_impl/var.h"
  13 #include "ppapi/thunk/enter.h"
  14 #include "ppapi/thunk/ppb_image_data_api.h"
  15 #include "ppapi/thunk/thunk.h"
  16 #include "skia/ext/platform_canvas.h"
  17 #include "third_party/WebKit/public/platform/WebCanvas.h"
  18 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
  19 #include "third_party/WebKit/public/platform/WebFloatRect.h"
  20 #include "third_party/WebKit/public/platform/WebRect.h"
  21 #include "third_party/WebKit/public/web/WebFont.h"
  22 #include "third_party/WebKit/public/web/WebFontDescription.h"
  23 #include "third_party/WebKit/public/web/WebTextRun.h"
  24 #include "third_party/icu/source/common/unicode/ubidi.h"
  25 #include "third_party/skia/include/core/SkRect.h"
  26
  27 using ppapi::StringVar;
  28 using ppapi::thunk::EnterResourceNoLock;
  29 using ppapi::thunk::PPB_ImageData_API;
  30 using WebKit::WebFloatPoint;
  31 using WebKit::WebFloatRect;
  32 using WebKit::WebFont;
  33 using WebKit::WebFontDescription;
  34 using WebKit::WebRect;
  35 using WebKit::WebTextRun;
  36 using WebKit::WebCanvas;
  37
  38 namespace content {
  39
  40 namespace {
  41
  42 // Same as WebPreferences::kCommonScript. I'd use that directly here, but get an
  43 // undefined reference linker error.
  44 const char kCommonScript[] = "Zyyy";
  45
  46 string16 GetFontFromMap(
  47     const webkit_glue::ScriptFontFamilyMap& map,
  48     const std::string& script) {
  49   webkit_glue::ScriptFontFamilyMap::const_iterator it =
  50       map.find(script);
  51   if (it != map.end())
  52     return it->second;
  53   return string16();
  54 }
  55
  56 // Splits a PP_BrowserFont_Trusted_TextRun into a sequence or LTR and RTL
  57 // WebTextRuns that can be used for WebKit. Normally WebKit does this for us,
  58 // but the font drawing and measurement routines we call happen after this
  59 // step. So for correct rendering of RTL content, we need to do it ourselves.
  60 class TextRunCollection {
  61  public:
  62   explicit TextRunCollection(const PP_BrowserFont_Trusted_TextRun& run)
  63       : bidi_(NULL),
  64         num_runs_(0) {
  65     StringVar* text_string = StringVar::FromPPVar(run.text);
  66     if (!text_string)
  67       return;  // Leave num_runs_ = 0 so we'll do nothing.
  68     text_ = UTF8ToUTF16(text_string->value());
  69
  70     if (run.override_direction) {
  71       // Skip autodetection.
  72       num_runs_ = 1;
  73       override_run_ = WebTextRun(text_, PP_ToBool(run.rtl), true);
  74     } else {
  75       bidi_ = ubidi_open();
  76       UErrorCode uerror = U_ZERO_ERROR;
  77       ubidi_setPara(bidi_, text_.data(), text_.size(), run.rtl, NULL, &uerror);
  78       if (U_SUCCESS(uerror))
  79         num_runs_ = ubidi_countRuns(bidi_, &uerror);
  80     }
  81   }
  82
  83   ~TextRunCollection() {
  84     if (bidi_)
  85       ubidi_close(bidi_);
  86   }
  87
  88   const string16& text() const { return text_; }
  89   int num_runs() const { return num_runs_; }
  90
  91   // Returns a WebTextRun with the info for the run at the given index.
  92   // The range covered by the run is in the two output params.
  93   WebTextRun GetRunAt(int index, int32_t* run_start, int32_t* run_len) const {
  94     DCHECK(index < num_runs_);
  95     if (bidi_) {
  96       bool run_rtl = !!ubidi_getVisualRun(bidi_, index, run_start, run_len);
  97       return WebTextRun(string16(&text_[*run_start], *run_len),
  98                         run_rtl, true);
  99     }
 100
 101     // Override run, return the single one.
 102     DCHECK(index == 0);
 103     *run_start = 0;
 104     *run_len = static_cast<int32_t>(text_.size());
 105     return override_run_;
 106   }
 107
 108  private:
 109   // Will be null if we skipped autodetection.
 110   UBiDi* bidi_;
 111
 112   // Text of all the runs.
 113   string16 text_;
 114
 115   int num_runs_;
 116
 117   // When the content specifies override_direction (bidi_ is null) then this
 118   // will contain the single text run for WebKit.
 119   WebTextRun override_run_;
 120
 121   DISALLOW_COPY_AND_ASSIGN(TextRunCollection);
 122 };
 123
 124 bool PPTextRunToWebTextRun(const PP_BrowserFont_Trusted_TextRun& text,
 125                            WebTextRun* run) {
 126   StringVar* text_string = StringVar::FromPPVar(text.text);
 127   if (!text_string)
 128     return false;
 129
 130   *run = WebTextRun(UTF8ToUTF16(text_string->value()),
 131                     PP_ToBool(text.rtl),
 132                     PP_ToBool(text.override_direction));
 133   return true;
 134 }
 135
 136 // The PP_* version lacks "None", so is just one value shifted from the
 137 // WebFontDescription version. These values are checked in
 138 // PPFontDescToWebFontDesc to make sure the conversion is correct. This is a
 139 // macro so it can also be used in the COMPILE_ASSERTS.
 140 #define PP_FAMILY_TO_WEB_FAMILY(f) \
 141   static_cast<WebFontDescription::GenericFamily>(f + 1)
 142
 143 // Assumes the given PP_FontDescription has been validated.
 144 WebFontDescription PPFontDescToWebFontDesc(
 145     const PP_BrowserFont_Trusted_Description& font,
 146     const ppapi::Preferences& prefs) {
 147   // Verify that the enums match so we can just static cast.
 148   COMPILE_ASSERT(static_cast<int>(WebFontDescription::Weight100) ==
 149                  static_cast<int>(PP_BROWSERFONT_TRUSTED_WEIGHT_100),
 150                  FontWeight100);
 151   COMPILE_ASSERT(static_cast<int>(WebFontDescription::Weight900) ==
 152                  static_cast<int>(PP_BROWSERFONT_TRUSTED_WEIGHT_900),
 153                  FontWeight900);
 154   COMPILE_ASSERT(WebFontDescription::GenericFamilyStandard ==
 155                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_DEFAULT),
 156                  StandardFamily);
 157   COMPILE_ASSERT(WebFontDescription::GenericFamilySerif ==
 158                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_SERIF),
 159                  SerifFamily);
 160   COMPILE_ASSERT(WebFontDescription::GenericFamilySansSerif ==
 161                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_SANSSERIF),
 162                  SansSerifFamily);
 163   COMPILE_ASSERT(WebFontDescription::GenericFamilyMonospace ==
 164                  PP_FAMILY_TO_WEB_FAMILY(PP_FONTFAMILY_MONOSPACE),
 165                  MonospaceFamily);
 166
 167   StringVar* face_name = StringVar::FromPPVar(font.face);  // Possibly null.
 168
 169   WebFontDescription result;
 170   string16 resolved_family;
 171   if (!face_name || face_name->value().empty()) {
 172     // Resolve the generic family.
 173     switch (font.family) {
 174       case PP_BROWSERFONT_TRUSTED_FAMILY_SERIF:
 175         resolved_family = GetFontFromMap(prefs.serif_font_family_map,
 176                                          kCommonScript);
 177         break;
 178       case PP_BROWSERFONT_TRUSTED_FAMILY_SANSSERIF:
 179         resolved_family = GetFontFromMap(prefs.sans_serif_font_family_map,
 180                                          kCommonScript);
 181         break;
 182       case PP_BROWSERFONT_TRUSTED_FAMILY_MONOSPACE:
 183         resolved_family = GetFontFromMap(prefs.fixed_font_family_map,
 184                                          kCommonScript);
 185         break;
 186       case PP_BROWSERFONT_TRUSTED_FAMILY_DEFAULT:
 187       default:
 188         resolved_family = GetFontFromMap(prefs.standard_font_family_map,
 189                                          kCommonScript);
 190         break;
 191     }
 192   } else {
 193     // Use the exact font.
 194     resolved_family = UTF8ToUTF16(face_name->value());
 195   }
 196   result.family = resolved_family;
 197
 198   result.genericFamily = PP_FAMILY_TO_WEB_FAMILY(font.family);
 199
 200   if (font.size == 0) {
 201     // Resolve the default font size, using the resolved family to see if
 202     // we should use the fixed or regular font size. It's difficult at this
 203     // level to detect if the requested font is fixed width, so we only apply
 204     // the alternate font size to the default fixed font family.
 205     if (StringToLowerASCII(resolved_family) ==
 206         StringToLowerASCII(GetFontFromMap(prefs.fixed_font_family_map,
 207                                           kCommonScript)))
 208       result.size = static_cast<float>(prefs.default_fixed_font_size);
 209     else
 210       result.size = static_cast<float>(prefs.default_font_size);
 211   } else {
 212     // Use the exact size.
 213     result.size = static_cast<float>(font.size);
 214   }
 215
 216   result.italic = font.italic != PP_FALSE;
 217   result.smallCaps = font.small_caps != PP_FALSE;
 218   result.weight = static_cast<WebFontDescription::Weight>(font.weight);
 219   result.letterSpacing = static_cast<short>(font.letter_spacing);
 220   result.wordSpacing = static_cast<short>(font.word_spacing);
 221   return result;
 222 }
 223
 224 }  // namespace
 225
 226 // static
 227 bool BrowserFontResource_Trusted::IsPPFontDescriptionValid(
 228     const PP_BrowserFont_Trusted_Description& desc) {
 229   // Check validity of string. We can't check the actual text since we could
 230   // be on the wrong thread and don't know if we're in the plugin or the host.
 231   if (desc.face.type != PP_VARTYPE_STRING &&
 232       desc.face.type != PP_VARTYPE_UNDEFINED)
 233     return false;
 234
 235   // Check enum ranges.
 236   if (static_cast<int>(desc.family) < PP_BROWSERFONT_TRUSTED_FAMILY_DEFAULT ||
 237       static_cast<int>(desc.family) > PP_BROWSERFONT_TRUSTED_FAMILY_MONOSPACE)
 238     return false;
 239   if (static_cast<int>(desc.weight) < PP_BROWSERFONT_TRUSTED_WEIGHT_100 ||
 240       static_cast<int>(desc.weight) > PP_BROWSERFONT_TRUSTED_WEIGHT_900)
 241     return false;
 242
 243   // Check for excessive sizes which may cause layout to get confused.
 244   if (desc.size > 200)
 245     return false;
 246
 247   return true;
 248 }
 249
 250 BrowserFontResource_Trusted::BrowserFontResource_Trusted(
 251     ppapi::proxy::Connection connection,
 252     PP_Instance instance,
 253     const PP_BrowserFont_Trusted_Description& desc,
 254     const ppapi::Preferences& prefs)
 255     : PluginResource(connection, instance),
 256       font_(WebFont::create(PPFontDescToWebFontDesc(desc, prefs))) {
 257 }
 258
 259 BrowserFontResource_Trusted::~BrowserFontResource_Trusted() {
 260 }
 261
 262 ppapi::thunk::PPB_BrowserFont_Trusted_API*
 263 BrowserFontResource_Trusted::AsPPB_BrowserFont_Trusted_API() {
 264   return this;
 265 }
 266
 267 PP_Bool BrowserFontResource_Trusted::Describe(
 268     PP_BrowserFont_Trusted_Description* description,
 269     PP_BrowserFont_Trusted_Metrics* metrics) {
 270   if (description->face.type != PP_VARTYPE_UNDEFINED)
 271     return PP_FALSE;
 272
 273   // While converting the other way in PPFontDescToWebFontDesc we validated
 274   // that the enums can be casted.
 275   WebFontDescription web_desc = font_->fontDescription();
 276   description->face = StringVar::StringToPPVar(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