ui/views/background.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_VIEWS_BACKGROUND_H_
   6 #define UI_VIEWS_BACKGROUND_H_
   7
   8 #include "build/build_config.h"
   9
  10 #if defined(OS_WIN)
  11 #include <windows.h>
  12 #endif  // defined(OS_WIN)
  13
  14 #include "base/basictypes.h"
  15 #include "third_party/skia/include/core/SkColor.h"
  16 #include "ui/views/views_export.h"
  17
  18 namespace gfx {
  19 class Canvas;
  20 }
  21
  22 namespace views {
  23
  24 class Painter;
  25 class View;
  26
  27 /////////////////////////////////////////////////////////////////////////////
  28 //
  29 // Background class
  30 //
  31 // A background implements a way for views to paint a background. The
  32 // background can be either solid or based on a gradient. Of course,
  33 // Background can be subclassed to implement various effects.
  34 //
  35 // Any View can have a background. See View::SetBackground() and
  36 // View::OnPaintBackground()
  37 //
  38 /////////////////////////////////////////////////////////////////////////////
  39 class VIEWS_EXPORT Background {
  40  public:
  41   Background();
  42   virtual ~Background();
  43
  44   // Creates a background that fills the canvas in the specified color.
  45   static Background* CreateSolidBackground(SkColor color);
  46
  47   // Creates a background that fills the canvas in the specified color.
  48   static Background* CreateSolidBackground(int r, int g, int b) {
  49     return CreateSolidBackground(SkColorSetRGB(r, g, b));
  50   }
  51
  52   // Creates a background that fills the canvas in the specified color.
  53   static Background* CreateSolidBackground(int r, int g, int b, int a) {
  54     return CreateSolidBackground(SkColorSetARGB(a, r, g, b));
  55   }
  56
  57   // Creates a background that contains a vertical gradient that varies
  58   // from |color1| to |color2|
  59   static Background* CreateVerticalGradientBackground(SkColor color1,
  60                                                       SkColor color2);
  61
  62   // Creates a background that contains a vertical gradient. The gradient can
  63   // have multiple |colors|. The |pos| array contains the relative positions of
  64   // each corresponding color. |colors| and |pos| must be the same size. The
  65   // first element in |pos| must be 0.0 and the last element must be 1.0.
  66   // |count| contains the number of elements in |colors| and |pos|.
  67   static Background* CreateVerticalMultiColorGradientBackground(SkColor* colors,
  68                                                                 SkScalar* pos,
  69                                                                 size_t count);
  70
  71   // Creates Chrome's standard panel background
  72   static Background* CreateStandardPanelBackground();
  73
  74   // Creates a Background from the specified Painter. If owns_painter is
  75   // true, the Painter is deleted when the Border is deleted.
  76   static Background* CreateBackgroundPainter(bool owns_painter,
  77                                              Painter* painter);
  78
  79   // Render the background for the provided view
  80   virtual void Paint(gfx::Canvas* canvas, View* view) const = 0;
  81
  82   // Set a solid, opaque color to be used when drawing backgrounds of native
  83   // controls.  Unfortunately alpha=0 is not an option.
  84   void SetNativeControlColor(SkColor color);
  85
  86   // Returns the "background color".  This is equivalent to the color set in
  87   // SetNativeControlColor().  For solid backgrounds, this is the color; for
  88   // gradient backgrounds, it's the midpoint of the gradient; for painter
  89   // backgrounds, this is not useful (returns a default color).
  90   SkColor get_color() const { return color_; }
  91
  92 #if defined(OS_WIN)
  93   // TODO(port): Make GetNativeControlBrush portable (currently uses HBRUSH).
  94
  95   // Get the brush that was specified by SetNativeControlColor
  96   HBRUSH GetNativeControlBrush() const;
  97 #endif  // defined(OS_WIN)
  98
  99  private:
 100   SkColor color_;
 101 #if defined(OS_WIN)
 102   // TODO(port): Create portable replacement for HBRUSH.
 103   mutable HBRUSH native_control_brush_;
 104 #endif  // defined(OS_WIN)
 105
 106   DISALLOW_COPY_AND_ASSIGN(Background);
 107 };
 108
 109 }  // namespace views
 110
 111 #endif  // UI_VIEWS_BACKGROUND_H_