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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 UI_GFX_PLATFORM_FONT_WIN_
+#define UI_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 string16& 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 string16& text) const;
+ virtual int GetExpectedTextWidth(int length) const;
+ virtual int GetStyle() const;
+ virtual string16 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 string16& 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_;
+ string16 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 string16& 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 // UI_GFX_PLATFORM_FONT_WIN_
+