Move app/gfx/canvas and app/gfx/font to gfx/.

TBR=darin
BUG=none
TEST=none

Review URL: http://codereview.chromium.org/1132006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42312 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 287 insertions, 0 deletions

diff --git a/gfx/font.h b/gfx/font.h
new file mode 100644
index 0000000..7395a4d
--- /dev/null
+++ b/gfx/font.h
@@ -0,0 +1,287 @@
+// Copyright (c) 2006-2008 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_FONT_H_
+#define GFX_FONT_H_
+
+#include "build/build_config.h"
+
+#include <string>
+
+#if defined(OS_WIN)
+typedef struct HFONT__* HFONT;
+#elif !defined(OS_MACOSX)
+#include "third_party/skia/include/core/SkRefCnt.h"
+class SkPaint;
+class SkTypeface;
+#endif
+
+#if defined(OS_WIN)
+typedef struct HFONT__* NativeFont;
+#elif defined(OS_MACOSX)
+#ifdef __OBJC__
+@class NSFont;
+#else
+class NSFont;
+#endif
+typedef NSFont* NativeFont;
+#else
+typedef struct _PangoFontDescription PangoFontDescription;
+class SkTypeface;
+typedef SkTypeface* NativeFont;
+#endif
+
+#include "base/basictypes.h"
+#include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
+
+namespace gfx {
+
+// Font provides a wrapper around an underlying font. Copy and assignment
+// operators are explicitly allowed, and cheap.
+class Font {
+ public:
+  // The following constants indicate the font style.
+  enum {
+    NORMAL = 0,
+    BOLD = 1,
+    ITALIC = 2,
+    UNDERLINED = 4,
+  };
+
+  // Creates a Font given font name (e.g. arial), font size (e.g. 12).
+  // Skia actually expects a family name and not a font name.
+  static Font CreateFont(const std::wstring& font_name, int font_size);
+
+  ~Font() { }
+
+  // Returns a new Font derived from the existing font.
+  // size_deta is the size to add to the current font. For example, a value
+  // of 5 results in a font 5 units bigger than this font.
+  Font DeriveFont(int size_delta) const {
+    return DeriveFont(size_delta, style());
+  }
+
+  // Returns a new Font derived from the existing font.
+  // size_delta is the size to add to the current font. See the single
+  // argument version of this method for an example.
+  // The style parameter specifies the new style for the font, and is a
+  // bitmask of the values: BOLD, ITALIC and UNDERLINED.
+  Font DeriveFont(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 height() const;
+
+  // Returns the baseline, or ascent, of the font.
+  int baseline() const;
+
+  // Returns the average character width for the font.
+  int ave_char_width() const;
+
+  // Returns the number of horizontal pixels needed to display the specified
+  // string.
+  int GetStringWidth(const std::wstring& text) const;
+
+  // Returns the expected number of horizontal pixels needed to display
+  // the specified length of characters.
+  // Call GetStringWidth() to retrieve the actual number.
+  int GetExpectedTextWidth(int length) const;
+
+  // Returns the style of the font.
+  int style() const;
+
+  // Font Name.
+  // It is actually a font family name, because Skia expects a family name
+  // and not a font name.
+  const std::wstring& FontName() const;
+
+  // Font Size.
+  int FontSize();
+
+  NativeFont nativeFont() const;
+
+  // Creates a font with the default name and style.
+  Font();
+
+#if defined(OS_WIN)
+  // Creates a Font from the specified HFONT. The supplied HFONT is effectively
+  // copied.
+  static Font CreateFont(HFONT hfont);
+
+  // Returns the handle to the underlying HFONT. This is used by gfx::Canvas to
+  // draw text.
+  HFONT hfont() const { return font_ref_->hfont(); }
+
+  // Dialog units to pixels conversion.
+  // See http://support.microsoft.com/kb/145994 for details.
+  int horizontal_dlus_to_pixels(int dlus) {
+    return dlus * font_ref_->dlu_base_x() / 4;
+  }
+  int vertical_dlus_to_pixels(int dlus) {
+    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;
+
+#elif !defined(OS_MACOSX)
+  static Font CreateFont(PangoFontDescription* desc);
+  // We need a copy constructor and assignment operator to deal with
+  // the Skia reference counting.
+  Font(const Font& other);
+  Font& operator=(const Font& other);
+  // Setup a Skia context to use the current typeface
+  void PaintSetup(SkPaint* paint) const;
+
+  // Converts |gfx_font| to a new pango font. Free the returned font with
+  // pango_font_description_free().
+  static PangoFontDescription* PangoFontFromGfxFont(const gfx::Font& gfx_font);
+
+  // Position as an offset from the height of the drawn text, used to draw
+  // an underline. This is a negative number, so the underline would be
+  // drawn at y + height + underline_position;
+  double underline_position() const;
+  // The thickness to draw the underline.
+  double underline_thickness() const;
+#endif
+
+ private:
+
+#if defined(OS_WIN)
+  // 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);
+  };
+
+  // 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);
+
+  explicit Font(HFontRef* font_ref) : font_ref_(font_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_;
+#elif !defined(OS_MACOSX)
+  explicit Font(SkTypeface* typeface, const std::wstring& name,
+                int size, int style);
+  // Calculate and cache the font metrics.
+  void calculateMetrics();
+  // Make |this| a copy of |other|.
+  void CopyFont(const Font& other);
+
+  // The default font, used for the default constructor.
+  static Font* default_font_;
+
+  // Return the scale factor for fonts that account for DPI.  We clamp the
+  // max DPI to prevent large fonts from overflowing UI elements.
+  static float GetPangoScaleFactor();
+
+  // The average width of a character, initialized and cached if needed.
+  double avg_width() const;
+
+  // Potentially slow call to get pango metrics (avg width, underline info).
+  void InitPangoMetrics();
+
+  // These two both point to the same SkTypeface. We use the SkAutoUnref to
+  // handle the reference counting, but without @typeface_ we would have to
+  // cast the SkRefCnt from @typeface_helper_ every time.
+  scoped_ptr<SkAutoUnref> typeface_helper_;
+  SkTypeface *typeface_;
+
+  // Additional information about the face
+  // Skia actually expects a family name and not a font name.
+  std::wstring font_family_;
+  int font_size_;
+  int style_;
+
+  // Cached metrics, generated at construction
+  int height_;
+  int ascent_;
+
+  // The pango metrics are much more expensive so we wait until we need them
+  // to compute them.
+  bool pango_metrics_inited_;
+  double avg_width_;
+  double underline_position_;
+  double underline_thickness_;
+#else  // OS_MACOSX
+  explicit Font(const std::wstring& font_name, int font_size, int style);
+
+  // Calculate and cache the font metrics.
+  void calculateMetrics();
+
+  std::wstring font_name_;
+  int font_size_;
+  int style_;
+
+  // Cached metrics, generated at construction
+  int height_;
+  int ascent_;
+  int avg_width_;
+#endif
+
+};
+
+}  // namespace gfx
+
+#endif  // GFX_FONT_H_