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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/font_render_params_linux.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "ui/gfx/display.h"
#include "ui/gfx/switches.h"
#include <fontconfig/fontconfig.h>
#if defined(OS_LINUX) && defined(USE_AURA) && !defined(OS_CHROMEOS)
#include "ui/gfx/linux_font_delegate.h"
#endif
namespace gfx {
namespace {
bool SubpixelPositioningRequested(bool renderer) {
const CommandLine* cl = CommandLine::ForCurrentProcess();
if (renderer) {
// Text rendered by Blink in high-DPI mode is poorly-hinted unless subpixel
// positioning is used (as opposed to each glyph being individually snapped
// to the pixel grid).
return cl->HasSwitch(switches::kEnableWebkitTextSubpixelPositioning) ||
(Display::HasForceDeviceScaleFactor() &&
Display::GetForcedDeviceScaleFactor() != 1.0);
}
return cl->HasSwitch(switches::kEnableBrowserTextSubpixelPositioning);
}
// Initializes |params| with the system's default settings. |renderer| is true
// when setting WebKit renderer defaults.
void LoadDefaults(FontRenderParams* params, bool renderer) {
// For non-GTK builds (read: Aura), just use reasonable hardcoded values.
params->antialiasing = true;
params->autohinter = true;
params->use_bitmaps = true;
params->hinting = FontRenderParams::HINTING_SLIGHT;
// Fetch default subpixel rendering settings from FontConfig.
FcPattern* pattern = FcPatternCreate();
FcConfigSubstitute(NULL, pattern, FcMatchPattern);
FcDefaultSubstitute(pattern);
FcResult result;
FcPattern* match = FcFontMatch(0, pattern, &result);
DCHECK(match);
int fc_rgba = FC_RGBA_RGB;
FcPatternGetInteger(match, FC_RGBA, 0, &fc_rgba);
FcPatternDestroy(pattern);
FcPatternDestroy(match);
switch (fc_rgba) {
case FC_RGBA_RGB:
params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_RGB;
break;
case FC_RGBA_BGR:
params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_BGR;
break;
case FC_RGBA_VRGB:
params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VRGB;
break;
case FC_RGBA_VBGR:
params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VBGR;
break;
default:
params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
}
#if defined(OS_LINUX) && defined(USE_AURA) && !defined(OS_CHROMEOS)
const LinuxFontDelegate* delegate = LinuxFontDelegate::instance();
if (delegate) {
params->antialiasing = delegate->UseAntialiasing();
params->hinting = delegate->GetHintingStyle();
params->subpixel_rendering = delegate->GetSubpixelRenderingStyle();
}
#endif
params->subpixel_positioning = SubpixelPositioningRequested(renderer);
// To enable subpixel positioning, we need to disable hinting.
if (params->subpixel_positioning)
params->hinting = FontRenderParams::HINTING_NONE;
}
} // namespace
const FontRenderParams& GetDefaultFontRenderParams() {
static bool loaded_defaults = false;
static FontRenderParams default_params;
if (!loaded_defaults)
LoadDefaults(&default_params, /* renderer */ false);
loaded_defaults = true;
return default_params;
}
const FontRenderParams& GetDefaultWebKitFontRenderParams() {
static bool loaded_defaults = false;
static FontRenderParams default_params;
if (!loaded_defaults)
LoadDefaults(&default_params, /* renderer */ true);
loaded_defaults = true;
return default_params;
}
bool GetDefaultWebkitSubpixelPositioning() {
return SubpixelPositioningRequested(true);
}
} // namespace gfx
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