painter.h revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d 
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_PAINTER_H_
6#define UI_VIEWS_PAINTER_H_
7
8#include "base/basictypes.h"
9#include "base/compiler_specific.h"
10#include "third_party/skia/include/core/SkColor.h"
11#include "ui/views/views_export.h"
12
13namespace gfx {
14class Canvas;
15class ImageSkia;
16class Insets;
17class Rect;
18class Size;
19}
20
21// A macro to define arrays of IDR constants used with CreateImageGridPainter.
22#define IMAGE_GRID(x) { x ## _TOP_LEFT,    x ## _TOP,    x ## _TOP_RIGHT, \
23                        x ## _LEFT,        x ## _CENTER, x ## _RIGHT, \
24                        x ## _BOTTOM_LEFT, x ## _BOTTOM, x ## _BOTTOM_RIGHT, }
25
26namespace views {
27
28// Painter, as the name implies, is responsible for painting in a particular
29// region. Think of Painter as a Border or Background that can be painted
30// in any region of a View.
31class VIEWS_EXPORT Painter {
32 public:
33  // A convenience method for painting a Painter in a particular region.
34  // This translates the canvas to x/y and paints the painter.
35  static void PaintPainterAt(gfx::Canvas* canvas,
36                             Painter* painter,
37                             const gfx::Rect& rect);
38
39  // Creates a painter that draws a gradient between the two colors.
40  static Painter* CreateHorizontalGradient(SkColor c1, SkColor c2);
41  static Painter* CreateVerticalGradient(SkColor c1, SkColor c2);
42
43  // Creates a painter that draws a multi-color gradient. |colors| contains the
44  // gradient colors and |pos| the relative positions of the colors. The first
45  // element in |pos| must be 0.0 and the last element 1.0. |count| contains
46  // the number of elements in |colors| and |pos|.
47  static Painter* CreateVerticalMultiColorGradient(SkColor* colors,
48                                                   SkScalar* pos,
49                                                   size_t count);
50
51  // Creates a painter that divides |image| into nine regions. The four corners
52  // are rendered at the size specified in insets (eg. the upper-left corner is
53  // rendered at 0 x 0 with a size of insets.left() x insets.top()). The center
54  // and edge images are stretched to fill the painted area.
55  static Painter* CreateImagePainter(const gfx::ImageSkia& image,
56                                     const gfx::Insets& insets);
57
58  // Creates a painter that paints images in a scalable grid. The images must
59  // share widths by column and heights by row. The corners are painted at full
60  // size, while center and edge images are stretched to fill the painted area.
61  // The center image may be zero (to be skipped). This ordering must be used:
62  // Top-Left/Top/Top-Right/Left/[Center]/Right/Bottom-Left/Bottom/Bottom-Right.
63  static Painter* CreateImageGridPainter(const int image_ids[]);
64
65  virtual ~Painter() {}
66
67  // Paints the painter in the specified region.
68  virtual void Paint(gfx::Canvas* canvas, const gfx::Size& size) = 0;
69};
70
71// HorizontalPainter paints 3 images into a box: left, center and right. The
72// left and right images are drawn to size at the left/right edges of the
73// region. The center is tiled in the remaining space. All images must have the
74// same height.
75class VIEWS_EXPORT HorizontalPainter : public Painter {
76 public:
77  // Constructs a new HorizontalPainter loading the specified image names.
78  // The images must be in the order left, right and center.
79  explicit HorizontalPainter(const int image_resource_names[]);
80
81  virtual ~HorizontalPainter() {}
82
83  // Paints the images.
84  virtual void Paint(gfx::Canvas* canvas, const gfx::Size& size) OVERRIDE;
85
86  // Height of the images.
87  int height() const { return height_; }
88
89 private:
90  // The image chunks.
91  enum BorderElements {
92    LEFT,
93    CENTER,
94    RIGHT
95  };
96
97  // The height.
98  int height_;
99  // NOTE: the images are owned by ResourceBundle. Don't free them.
100  const gfx::ImageSkia* images_[3];
101
102  DISALLOW_COPY_AND_ASSIGN(HorizontalPainter);
103};
104
105}  // namespace views
106
107#endif  // UI_VIEWS_PAINTER_H_
108