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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.
#ifndef UI_GFX_FONT_H_
#define UI_GFX_FONT_H_
#include <string>
#include "base/memory/ref_counted.h"
#include "base/strings/string16.h"
#include "build/build_config.h"
#include "ui/gfx/gfx_export.h"
#include "ui/gfx/native_widget_types.h"
namespace gfx {
struct FontRenderParams;
class PlatformFont;
// Font provides a wrapper around an underlying font. Copy and assignment
// operators are explicitly allowed, and cheap.
//
// Figure of font metrics:
// +--------+-------------------+------------------+
// | | | internal leading |
// | | ascent (baseline) +------------------+
// | height | | cap height |
// | |-------------------+------------------+
// | | descent (height - baseline) |
// +--------+--------------------------------------+
class GFX_EXPORT Font {
public:
// The following constants indicate the font style.
enum FontStyle {
NORMAL = 0,
BOLD = 1,
ITALIC = 2,
UNDERLINE = 4,
};
// Creates a font with the default name and style.
Font();
// Creates a font that is a clone of another font object.
Font(const Font& other);
Font& operator=(const Font& other);
#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
// Creates a font from the specified native font.
explicit Font(NativeFont native_font);
#endif
// Constructs a Font object with the specified PlatformFont object. The Font
// object takes ownership of the PlatformFont object.
explicit Font(PlatformFont* platform_font);
// Creates a font with the specified name in UTF-8 and size in pixels.
Font(const std::string& font_name, int font_size);
~Font();
// Returns a new Font derived from the existing font.
// |size_delta| is the size in pixels to add to the current font. For example,
// a value of 5 results in a font 5 pixels bigger than this font.
// The style parameter specifies the new style for the font, and is a
// bitmask of the values: BOLD, ITALIC and UNDERLINE.
Font Derive(int size_delta, int style) const;
// 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.
int GetHeight() const;
// Returns the baseline, or ascent, of the font.
int GetBaseline() const;
// Returns the cap height of the font.
int GetCapHeight() const;
// Returns the expected number of horizontal pixels needed to display the
// specified length of characters. Call gfx::GetStringWidth() to retrieve the
// actual number.
int GetExpectedTextWidth(int length) const;
// Returns the style of the font.
int GetStyle() const;
// Returns the specified font name in UTF-8.
const std::string& GetFontName() const;
// Returns the actually used font name in UTF-8.
std::string GetActualFontNameForTesting() const;
// Returns the font size in pixels.
int GetFontSize() const;
// Returns an object describing how the font should be rendered.
const FontRenderParams& GetFontRenderParams() const;
#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
// Returns the native font handle.
// Lifetime lore:
// Windows: This handle is owned by the Font object, and should not be
// destroyed by the caller.
// Mac: The object is owned by the system and should not be released.
NativeFont GetNativeFont() const;
#endif
// Raw access to the underlying platform font implementation. Can be
// static_cast to a known implementation type if needed.
PlatformFont* platform_font() const { return platform_font_.get(); }
private:
// Wrapped platform font implementation.
scoped_refptr<PlatformFont> platform_font_;
};
} // namespace gfx
#endif // UI_GFX_FONT_H_