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/*
* Copyright (C) 2008 Alp Toker <alp@atoker.com>
* Copyright (C) 2010 Igalia S.L.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "FontCache.h"
#include "CString.h"
#include "Font.h"
#include "OwnPtrCairo.h"
#include "PlatformRefPtrCairo.h"
#include "SimpleFontData.h"
#include <cairo-ft.h>
#include <cairo.h>
#include <fontconfig/fcfreetype.h>
#include <wtf/Assertions.h>
namespace WebCore {
void FontCache::platformInit()
{
// It's fine to call FcInit multiple times per the documentation.
if (!FcInit())
ASSERT_NOT_REACHED();
}
const SimpleFontData* FontCache::getFontDataForCharacters(const Font& font, const UChar* characters, int length)
{
FcResult fresult;
FontPlatformData* prim = const_cast<FontPlatformData*>(&font.primaryFont()->platformData());
// FIXME: This should not happen, apparently. We are null-checking
// for now just to avoid crashing.
if (!prim || !prim->m_pattern)
return 0;
if (!prim->m_fallbacks)
prim->m_fallbacks = FcFontSort(0, prim->m_pattern.get(), FcTrue, 0, &fresult);
FcFontSet* fs = prim->m_fallbacks;
for (int i = 0; i < fs->nfont; i++) {
PlatformRefPtr<FcPattern> fin = adoptPlatformRef(FcFontRenderPrepare(0, prim->m_pattern.get(), fs->fonts[i]));
cairo_font_face_t* fontFace = cairo_ft_font_face_create_for_pattern(fin.get());
FontPlatformData alternateFont(fontFace, font.fontDescription().computedPixelSize(), false, false);
cairo_font_face_destroy(fontFace);
alternateFont.m_pattern = fin;
SimpleFontData* sfd = getCachedFontData(&alternateFont);
if (sfd->containsCharacters(characters, length))
return sfd;
}
return 0;
}
SimpleFontData* FontCache::getSimilarFontPlatformData(const Font& font)
{
return 0;
}
SimpleFontData* FontCache::getLastResortFallbackFont(const FontDescription& fontDescription)
{
// We want to return a fallback font here, otherwise the logic preventing FontConfig
// matches for non-fallback fonts might return 0. See isFallbackFontAllowed.
static AtomicString timesStr("serif");
return getCachedFontData(fontDescription, timesStr);
}
void FontCache::getTraitsInFamily(const AtomicString& familyName, Vector<unsigned>& traitsMasks)
{
}
static CString getFamilyNameStringFromFontDescriptionAndFamily(const FontDescription& fontDescription, const AtomicString& family)
{
// If we're creating a fallback font (e.g. "-webkit-monospace"), convert the name into
// the fallback name (like "monospace") that fontconfig understands.
if (family.length() && !family.startsWith("-webkit-"))
return family.string().utf8();
switch (fontDescription.genericFamily()) {
case FontDescription::StandardFamily:
case FontDescription::SerifFamily:
return "serif";
case FontDescription::SansSerifFamily:
return "sans-serif";
case FontDescription::MonospaceFamily:
return "monospace";
case FontDescription::CursiveFamily:
return "cursive";
case FontDescription::FantasyFamily:
return "fantasy";
case FontDescription::NoFamily:
default:
return "";
}
}
static bool isFallbackFontAllowed(const CString& familyName)
{
return !strcasecmp(familyName.data(), "sans")
|| !strcasecmp(familyName.data(), "sans-serif")
|| !strcasecmp(familyName.data(), "serif")
|| !strcasecmp(familyName.data(), "monospace");
}
FontPlatformData* FontCache::createFontPlatformData(const FontDescription& fontDescription, const AtomicString& family)
{
// The CSS font matching algorithm (http://www.w3.org/TR/css3-fonts/#font-matching-algorithm)
// says that we must find an exact match for font family, slant (italic or oblique can be used)
// and font weight (we only match bold/non-bold here).
PlatformRefPtr<FcPattern> pattern = adoptPlatformRef(FcPatternCreate());
CString familyNameString = getFamilyNameStringFromFontDescriptionAndFamily(fontDescription, family);
if (!FcPatternAddString(pattern.get(), FC_FAMILY, reinterpret_cast<const FcChar8*>(familyNameString.data())))
return 0;
bool italic = fontDescription.italic();
if (!FcPatternAddInteger(pattern.get(), FC_SLANT, italic ? FC_SLANT_ITALIC : FC_SLANT_ROMAN))
return 0;
bool bold = fontDescription.weight() >= FontWeightBold;
if (!FcPatternAddInteger(pattern.get(), FC_WEIGHT, bold ? FC_WEIGHT_BOLD : FC_WEIGHT_NORMAL))
return 0;
if (!FcPatternAddDouble(pattern.get(), FC_PIXEL_SIZE, fontDescription.computedPixelSize()))
return 0;
// The following comment and strategy are originally from Skia (src/ports/SkFontHost_fontconfig.cpp):
// Font matching:
// CSS often specifies a fallback list of families:
// font-family: a, b, c, serif;
// However, fontconfig will always do its best to find *a* font when asked
// for something so we need a way to tell if the match which it has found is
// "good enough" for us. Otherwise, we can return null which gets piped up
// and lets WebKit know to try the next CSS family name. However, fontconfig
// configs allow substitutions (mapping "Arial -> Helvetica" etc) and we
// wish to support that.
//
// Thus, if a specific family is requested we set @family_requested. Then we
// record two strings: the family name after config processing and the
// family name after resolving. If the two are equal, it's a good match.
//
// So consider the case where a user has mapped Arial to Helvetica in their
// config.
// requested family: "Arial"
// post_config_family: "Helvetica"
// post_match_family: "Helvetica"
// -> good match
//
// and for a missing font:
// requested family: "Monaco"
// post_config_family: "Monaco"
// post_match_family: "Times New Roman"
// -> BAD match
//
FcConfigSubstitute(0, pattern.get(), FcMatchPattern);
FcDefaultSubstitute(pattern.get());
FcChar8* familyNameAfterConfiguration;
FcPatternGetString(pattern.get(), FC_FAMILY, 0, &familyNameAfterConfiguration);
FcResult fontConfigResult;
PlatformRefPtr<FcPattern> resultPattern = adoptPlatformRef(FcFontMatch(0, pattern.get(), &fontConfigResult));
if (!resultPattern) // No match.
return 0;
// Properly handle the situation where Fontconfig gives us a font that has a different family than we requested.
FcChar8* familyNameAfterMatching;
FcPatternGetString(resultPattern.get(), FC_FAMILY, 0, &familyNameAfterMatching);
if (strcasecmp(reinterpret_cast<char*>(familyNameAfterConfiguration),
reinterpret_cast<char*>(familyNameAfterMatching)) && !isFallbackFontAllowed(familyNameString))
return 0;
return new FontPlatformData(resultPattern.get(), fontDescription);
}
}
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