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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 <string>
#include "base/memory/ref_counted.h"
#include "base/optional.h"
#include "build/build_config.h"
#include "third_party/skia/include/core/SkRefCnt.h"
#include "third_party/skia/include/core/SkTypeface.h"
#include "ui/gfx/font.h"
#include "ui/gfx/font_render_params.h"
#include "ui/gfx/gfx_export.h"
#include "ui/gfx/native_widget_types.h"
namespace gfx {
class GFX_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
// The size of the font returned by CreateDefault() on a "default" platform
// configuration. This allows UI that wants to target a particular size of font
// to obtain that size for the majority of users, while still compensating for a
// user preference for a larger or smaller font.
#if defined(OS_MACOSX)
static constexpr int kDefaultBaseFontSize = 13;
static constexpr int kDefaultBaseFontSize = 12;
// Creates an appropriate PlatformFont implementation.
static PlatformFont* CreateDefault();
#if defined(OS_MACOSX) || defined(OS_IOS)
static PlatformFont* CreateFromNativeFont(NativeFont native_font);
// Creates a PlatformFont implementation with the specified |font_name|
// (encoded in UTF-8) and |font_size| in pixels.
static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
int font_size);
// Creates a PlatformFont instance from the provided SkTypeface, ideally by
// just wrapping it without triggering a new font match. Implemented for
// PlatformFontWin and PlatformFontSkia, where only the latter provides true
// wrapping of the provided SkTypeface, while PlatformFontWin creates a
// PlatformFont object by extracting the family name and falls back to
// CreateFromNameAndSize(). The FontRenderParams can be provided or they
// will be determined by using gfx::GetFontRenderParams(...) otherwise.
static PlatformFont* CreateFromSkTypeface(
sk_sp<SkTypeface> typeface,
int font_size,
const base::Optional<FontRenderParams>& params);
// Returns a new Font derived from the existing font.
// |size_delta| is the size in pixels to add to the current font.
// The style parameter specifies the new style for the font, and is a
// bitmask of the values: ITALIC and UNDERLINE.
// The weight parameter specifies the desired weight of the font.
virtual Font DeriveFont(int size_delta,
int style,
Font::Weight weight) const = 0;
// Returns the number of vertical pixels needed to display characters from
// the specified font. This may include some leading, i.e. height may be
// greater than just ascent + descent. Specifically, the Windows and Mac
// implementations include leading and the Linux one does not. This may
// need to be revisited in the future.
virtual int GetHeight() = 0;
// Returns the font weight.
virtual Font::Weight GetWeight() const = 0;
// Returns the baseline, or ascent, of the font.
virtual int GetBaseline() = 0;
// Returns the cap height of the font.
virtual int GetCapHeight() = 0;
// Returns the expected number of horizontal pixels needed to display the
// specified length of characters. Call GetStringWidth() to retrieve the
// actual number.
virtual int GetExpectedTextWidth(int length) = 0;
// Returns the style of the font.
virtual int GetStyle() const = 0;
// Returns the specified font name in UTF-8.
virtual const std::string& GetFontName() const = 0;
// Returns the actually used font name in UTF-8.
virtual std::string GetActualFontName() const = 0;
// Returns the font size in pixels.
virtual int GetFontSize() const = 0;
// Returns an object describing how the font should be rendered.
virtual const FontRenderParams& GetFontRenderParams() = 0;
#if defined(OS_MACOSX) || defined(OS_IOS)
// Returns the native font handle.
virtual NativeFont GetNativeFont() const = 0;
// Returns the underlying Skia typeface if this PlatformFont instance is
// backed by PlatformFontSkia, returns nullptr otherwise. Used in
// RenderTextHarfBuzz for having access to the exact Skia typeface returned by
// font fallback, as we would otherwise lose the handle to the correct
// platform font instance.
virtual sk_sp<SkTypeface> GetNativeSkTypefaceIfAvailable() const = 0;
virtual ~PlatformFont() {}
friend class base::RefCounted<PlatformFont>;
} // namespace gfx