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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 "FontCustomPlatformData.h"
#include "FontPlatformData.h"
#include "SharedBuffer.h"
#include <cairo-ft.h>
#include <cairo.h>
namespace WebCore {
static void releaseCustomFontData(void* data)
{
static_cast<SharedBuffer*>(data)->deref();
}
FontCustomPlatformData::FontCustomPlatformData(FT_Face freeTypeFace, SharedBuffer& buffer)
: m_fontFace(cairo_ft_font_face_create_for_ft_face(freeTypeFace, FT_LOAD_FORCE_AUTOHINT))
{
// FT_LOAD_FORCE_AUTOHINT prohibits use of the font's native hinting. This
// is a safe option for custom fonts because (a) some such fonts may have
// broken hinting, which site admins may not notice if other browsers do not
// use the native hints, and (b) allowing native hints exposes the FreeType
// bytecode interpreter to potentially-malicious input. Treating web fonts
// differently than system fonts is non-ideal, but the result of autohinting
// is always decent, whereas native hints sometimes look terrible, and
// unlike system fonts where Fontconfig may change the hinting settings on a
// per-font basis, the same settings are used for all web fonts. Note that
// Chrome is considering switching from autohinting to native hinting in
// https://code.google.com/p/chromium/issues/detail?id=173207 but this is
// more risk than we want to assume for now. See
// https://bugs.webkit.org/show_bug.cgi?id=140994 before changing this.
buffer.ref(); // This is balanced by the buffer->deref() in releaseCustomFontData.
static cairo_user_data_key_t bufferKey;
cairo_font_face_set_user_data(m_fontFace, &bufferKey, &buffer,
static_cast<cairo_destroy_func_t>(releaseCustomFontData));
// Cairo doesn't do FreeType reference counting, so we need to ensure that when
// this cairo_font_face_t is destroyed, it cleans up the FreeType face as well.
static cairo_user_data_key_t freeTypeFaceKey;
cairo_font_face_set_user_data(m_fontFace, &freeTypeFaceKey, freeTypeFace,
reinterpret_cast<cairo_destroy_func_t>(FT_Done_Face));
}
FontCustomPlatformData::~FontCustomPlatformData()
{
cairo_font_face_destroy(m_fontFace);
}
FontPlatformData FontCustomPlatformData::fontPlatformData(const FontDescription& description, bool bold, bool italic)
{
return FontPlatformData(m_fontFace, description, bold, italic);
}
std::unique_ptr<FontCustomPlatformData> createFontCustomPlatformData(SharedBuffer& buffer)
{
static FT_Library library;
if (!library && FT_Init_FreeType(&library)) {
library = nullptr;
return nullptr;
}
FT_Face freeTypeFace;
if (FT_New_Memory_Face(library, reinterpret_cast<const FT_Byte*>(buffer.data()), buffer.size(), 0, &freeTypeFace))
return nullptr;
return std::make_unique<FontCustomPlatformData>(freeTypeFace, buffer);
}
bool FontCustomPlatformData::supportsFormat(const String& format)
{
return equalLettersIgnoringASCIICase(format, "truetype")
|| equalLettersIgnoringASCIICase(format, "opentype")
#if USE(WOFF2)
|| equalLettersIgnoringASCIICase(format, "woff2")
#endif
|| equalLettersIgnoringASCIICase(format, "woff");
}
}
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