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// Copyright (c) 2010 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 GFX_PLATFORM_FONT_WIN_
#define GFX_PLATFORM_FONT_WIN_
#pragma once
#include "base/ref_counted.h"
#include "gfx/platform_font.h"
namespace gfx {
class PlatformFontWin : public PlatformFont {
public:
PlatformFontWin();
explicit PlatformFontWin(const Font& other);
explicit PlatformFontWin(NativeFont native_font);
PlatformFontWin(const std::wstring& font_name,
int font_size);
// Dialog units to pixels conversion.
// See http://support.microsoft.com/kb/145994 for details.
int horizontal_dlus_to_pixels(int dlus) const {
return dlus * font_ref_->dlu_base_x() / 4;
}
int vertical_dlus_to_pixels(int dlus) const {
return dlus * font_ref_->height() / 8;
}
// Callback that returns the minimum height that should be used for
// gfx::Fonts. Optional. If not specified, the minimum font size is 0.
typedef int (*GetMinimumFontSizeCallback)();
static GetMinimumFontSizeCallback get_minimum_font_size_callback;
// Callback that adjusts a LOGFONT to meet suitability requirements of the
// embedding application. Optional. If not specified, no adjustments are
// performed other than clamping to a minimum font height if
// |get_minimum_font_size_callback| is specified.
typedef void (*AdjustFontCallback)(LOGFONT* lf);
static AdjustFontCallback adjust_font_callback;
// Overridden from PlatformFont:
virtual Font DeriveFont(int size_delta, int style) const;
virtual int GetHeight() const;
virtual int GetBaseline() const;
virtual int GetAverageCharacterWidth() const;
virtual int GetStringWidth(const std::wstring& text) const;
virtual int GetExpectedTextWidth(int length) const;
virtual int GetStyle() const;
virtual const std::wstring& GetFontName() const;
virtual int GetFontSize() const;
virtual NativeFont GetNativeFont() const;
private:
virtual ~PlatformFontWin() {}
// Chrome text drawing bottoms out in the Windows GDI functions that take an
// HFONT (an opaque handle into Windows). To avoid lots of GDI object
// allocation and destruction, Font indirectly refers to the HFONT by way of
// an HFontRef. That is, every Font has an HFontRef, which has an HFONT.
//
// HFontRef is reference counted. Upon deletion, it deletes the HFONT.
// By making HFontRef maintain the reference to the HFONT, multiple
// HFontRefs can share the same HFONT, and Font can provide value semantics.
class HFontRef : public base::RefCounted<HFontRef> {
public:
// This constructor takes control of the HFONT, and will delete it when
// the HFontRef is deleted.
HFontRef(HFONT hfont,
int height,
int baseline,
int ave_char_width,
int style,
int dlu_base_x);
// Accessors
HFONT hfont() const { return hfont_; }
int height() const { return height_; }
int baseline() const { return baseline_; }
int ave_char_width() const { return ave_char_width_; }
int style() const { return style_; }
int dlu_base_x() const { return dlu_base_x_; }
const std::wstring& font_name() const { return font_name_; }
private:
friend class base::RefCounted<HFontRef>;
~HFontRef();
const HFONT hfont_;
const int height_;
const int baseline_;
const int ave_char_width_;
const int style_;
// Constants used in converting dialog units to pixels.
const int dlu_base_x_;
std::wstring font_name_;
DISALLOW_COPY_AND_ASSIGN(HFontRef);
};
// Initializes this object with a copy of the specified HFONT.
void InitWithCopyOfHFONT(HFONT hfont);
// Initializes this object with the specified font name and size.
void InitWithFontNameAndSize(const std::wstring& font_name,
int font_size);
// Returns the base font ref. This should ONLY be invoked on the
// UI thread.
static HFontRef* GetBaseFontRef();
// Creates and returns a new HFONTRef from the specified HFONT.
static HFontRef* CreateHFontRef(HFONT font);
// Creates a new PlatformFontWin with the specified HFontRef. Used when
// constructing a Font from a HFONT we don't want to copy.
explicit PlatformFontWin(HFontRef* hfont_ref);
// Reference to the base font all fonts are derived from.
static HFontRef* base_font_ref_;
// Indirect reference to the HFontRef, which references the underlying HFONT.
scoped_refptr<HFontRef> font_ref_;
};
} // namespace gfx
#endif // GFX_PLATFORM_FONT_WIN_
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