Beispiel #1
0
static SkScalar drawCharacter(SkCanvas* canvas, uint32_t character, SkScalar x,
                              SkScalar y, SkPaint& paint, SkFontMgr* fm,
                              const char* fontName, const char* bcp47[], int bcp47Count,
                              const SkFontStyle& fontStyle) {
    // find typeface containing the requested character and draw it
    SkString ch;
    ch.appendUnichar(character);
    SkTypeface* typeface = fm->matchFamilyStyleCharacter(fontName, fontStyle,
                                                         bcp47, bcp47Count, character);
    SkSafeUnref(paint.setTypeface(typeface));
    x = drawString(canvas, ch, x, y, paint) + 20;

    if (nullptr == typeface) {
        return x;
    }

    // repeat the process, but this time use the family name of the typeface
    // from the first pass.  This emulates the behavior in Blink where it
    // it expects to get the same glyph when following this pattern.
    SkString familyName;
    typeface->getFamilyName(&familyName);
    SkTypeface* typefaceCopy = fm->legacyCreateTypeface(familyName.c_str(), typeface->fontStyle());
    SkSafeUnref(paint.setTypeface(typefaceCopy));
    return drawString(canvas, ch, x, y, paint) + 20;
}
Beispiel #2
0
// Given the desired base font, this will create a SimpleFontData for a specific
// font that can be used to render the given range of characters.
PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
    const FontDescription& fontDescription,
    UChar32 character,
    const SimpleFontData* originalFontData,
    FontFallbackPriority fallbackPriority) {
  // First try the specified font with standard style & weight.
  if (fallbackPriority != FontFallbackPriority::EmojiEmoji &&
      (fontDescription.style() == FontStyleItalic ||
       fontDescription.weight() >= FontWeightBold)) {
    RefPtr<SimpleFontData> fontData =
        fallbackOnStandardFontStyle(fontDescription, character);
    if (fontData)
      return fontData;
  }

  UScriptCode script;
  const wchar_t* family = getFallbackFamily(
      character, fontDescription.genericFamily(), fontDescription.locale(),
      &script, fallbackPriority, m_fontManager.get());
  FontPlatformData* data = nullptr;
  if (family) {
    FontFaceCreationParams createByFamily(AtomicString(family, wcslen(family)));
    data = getFontPlatformData(fontDescription, createByFamily);
  }

  if ((!data || !data->fontContainsCharacter(character)) &&
      s_useSkiaFontFallback) {
    const char* bcp47Locale = nullptr;
    int localeCount = 0;
    // If the font description has a locale, use that. Otherwise, Skia will
    // fall back on the user's default locale.
    // TODO(kulshin): extract locale fallback logic from
    //   FontCacheAndroid.cpp and share that code
    if (fontDescription.locale()) {
      bcp47Locale = fontDescription.locale()->localeForSkFontMgr();
      localeCount = 1;
    }

    CString familyName = fontDescription.family().family().utf8();

    SkTypeface* typeface = m_fontManager->matchFamilyStyleCharacter(
        familyName.data(), fontDescription.skiaFontStyle(), &bcp47Locale,
        localeCount, character);
    if (typeface) {
      SkString skiaFamily;
      typeface->getFamilyName(&skiaFamily);
      FontFaceCreationParams createByFamily(AtomicString(skiaFamily.c_str()));
      data = getFontPlatformData(fontDescription, createByFamily);
    }
  }

  // Last resort font list : PanUnicode. CJK fonts have a pretty
  // large repertoire. Eventually, we need to scan all the fonts
  // on the system to have a Firefox-like coverage.
  // Make sure that all of them are lowercased.
  const static wchar_t* const cjkFonts[] = {
      L"arial unicode ms", L"ms pgothic", L"simsun", L"gulim", L"pmingliu",
      L"wenquanyi zen hei",  // Partial CJK Ext. A coverage but more widely
                             // known to Chinese users.
      L"ar pl shanheisun uni", L"ar pl zenkai uni",
      L"han nom a",  // Complete CJK Ext. A coverage.
      L"code2000"    // Complete CJK Ext. A coverage.
      // CJK Ext. B fonts are not listed here because it's of no use
      // with our current non-BMP character handling because we use
      // Uniscribe for it and that code path does not go through here.
  };

  const static wchar_t* const commonFonts[] = {
      L"tahoma", L"arial unicode ms", L"lucida sans unicode",
      L"microsoft sans serif", L"palatino linotype",
      // Six fonts below (and code2000 at the end) are not from MS, but
      // once installed, cover a very wide range of characters.
      L"dejavu serif", L"dejavu sasns", L"freeserif", L"freesans", L"gentium",
      L"gentiumalt", L"ms pgothic", L"simsun", L"gulim", L"pmingliu",
      L"code2000"};

  const wchar_t* const* panUniFonts = nullptr;
  int numFonts = 0;
  if (script == USCRIPT_HAN) {
    panUniFonts = cjkFonts;
    numFonts = WTF_ARRAY_LENGTH(cjkFonts);
  } else {
    panUniFonts = commonFonts;
    numFonts = WTF_ARRAY_LENGTH(commonFonts);
  }
  // Font returned from getFallbackFamily may not cover |character|
  // because it's based on script to font mapping. This problem is
  // critical enough for non-Latin scripts (especially Han) to
  // warrant an additional (real coverage) check with fontCotainsCharacter.
  int i;
  for (i = 0;
       (!data || !data->fontContainsCharacter(character)) && i < numFonts;
       ++i) {
    family = panUniFonts[i];
    FontFaceCreationParams createByFamily(AtomicString(family, wcslen(family)));
    data = getFontPlatformData(fontDescription, createByFamily);
  }

  // For font fallback we want to match the subpixel behavior of the original
  // font. Mixing subpixel and non-subpixel in the same text run looks really
  // odd and causes problems with preferred width calculations.
  if (data && originalFontData) {
    const FontPlatformData& platformData = originalFontData->platformData();
    data->setMinSizeForAntiAlias(platformData.minSizeForAntiAlias());
    data->setMinSizeForSubpixel(platformData.minSizeForSubpixel());
  }

  // When i-th font (0-base) in |panUniFonts| contains a character and
  // we get out of the loop, |i| will be |i + 1|. That is, if only the
  // last font in the array covers the character, |i| will be numFonts.
  // So, we have to use '<=" rather than '<' to see if we found a font
  // covering the character.
  if (i <= numFonts)
    return fontDataFromFontPlatformData(data, DoNotRetain);

  return nullptr;
}