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
18namespace gfx {
19class Canvas;
20}
21
22namespace views {
23
24class Painter;
25class 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/////////////////////////////////////////////////////////////////////////////
39class 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_
112