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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 "base/memory/scoped_ptr.h"
11 #include "third_party/skia/include/core/SkColor.h"
12 #include "ui/views/views_export.h"
13 
14 namespace gfx {
15 class Canvas;
16 class ImageSkia;
17 class Insets;
18 class Rect;
19 class Size;
20 }
21 
22 // A macro to define arrays of IDR constants used with CreateImageGridPainter.
23 #define IMAGE_GRID(x) { x ## _TOP_LEFT,    x ## _TOP,    x ## _TOP_RIGHT, \
24                         x ## _LEFT,        x ## _CENTER, x ## _RIGHT, \
25                         x ## _BOTTOM_LEFT, x ## _BOTTOM, x ## _BOTTOM_RIGHT, }
26 
27 namespace views {
28 
29 class View;
30 
31 // Painter, as the name implies, is responsible for painting in a particular
32 // region. Think of Painter as a Border or Background that can be painted
33 // in any region of a View.
34 class VIEWS_EXPORT Painter {
35  public:
36   Painter();
37   virtual ~Painter();
38 
39   // A convenience method for painting a Painter in a particular region.
40   // This translates the canvas to x/y and paints the painter.
41   static void PaintPainterAt(gfx::Canvas* canvas,
42                              Painter* painter,
43                              const gfx::Rect& rect);
44 
45   // Convenience that paints |focus_painter| only if |view| HasFocus() and
46   // |focus_painter| is non-NULL.
47   static void PaintFocusPainter(View* view,
48                                 gfx::Canvas* canvas,
49                                 Painter* focus_painter);
50 
51   // Creates a painter that draws a gradient between the two colors.
52   static Painter* CreateHorizontalGradient(SkColor c1, SkColor c2);
53   static Painter* CreateVerticalGradient(SkColor c1, SkColor c2);
54 
55   // Creates a painter that draws a multi-color gradient. |colors| contains the
56   // gradient colors and |pos| the relative positions of the colors. The first
57   // element in |pos| must be 0.0 and the last element 1.0. |count| contains
58   // the number of elements in |colors| and |pos|.
59   static Painter* CreateVerticalMultiColorGradient(SkColor* colors,
60                                                    SkScalar* pos,
61                                                    size_t count);
62 
63   // Creates a painter that divides |image| into nine regions. The four corners
64   // are rendered at the size specified in insets (eg. the upper-left corner is
65   // rendered at 0 x 0 with a size of insets.left() x insets.top()). The center
66   // and edge images are stretched to fill the painted area.
67   static Painter* CreateImagePainter(const gfx::ImageSkia& image,
68                                      const gfx::Insets& insets);
69 
70   // Creates a painter that paints images in a scalable grid. The images must
71   // share widths by column and heights by row. The corners are painted at full
72   // size, while center and edge images are stretched to fill the painted area.
73   // The center image may be zero (to be skipped). This ordering must be used:
74   // Top-Left/Top/Top-Right/Left/[Center]/Right/Bottom-Left/Bottom/Bottom-Right.
75   static Painter* CreateImageGridPainter(const int image_ids[]);
76 
77   // Factory methods for creating painters intended for rendering focus.
78   static scoped_ptr<Painter> CreateDashedFocusPainter();
79   static scoped_ptr<Painter> CreateDashedFocusPainterWithInsets(
80       const gfx::Insets& insets);
81   static scoped_ptr<Painter> CreateSolidFocusPainter(SkColor color,
82                                                      const gfx::Insets& insets);
83 
84   // Returns the minimum size this painter can paint without obvious graphical
85   // problems (e.g. overlapping images).
86   virtual gfx::Size GetMinimumSize() const = 0;
87 
88   // Paints the painter in the specified region.
89   virtual void Paint(gfx::Canvas* canvas, const gfx::Size& size) = 0;
90 
91  private:
92   DISALLOW_COPY_AND_ASSIGN(Painter);
93 };
94 
95 // HorizontalPainter paints 3 images into a box: left, center and right. The
96 // left and right images are drawn to size at the left/right edges of the
97 // region. The center is tiled in the remaining space. All images must have the
98 // same height.
99 class VIEWS_EXPORT HorizontalPainter : public Painter {
100  public:
101   // Constructs a new HorizontalPainter loading the specified image names.
102   // The images must be in the order left, right and center.
103   explicit HorizontalPainter(const int image_resource_names[]);
104   virtual ~HorizontalPainter();
105 
106   // Painter:
107   virtual gfx::Size GetMinimumSize() const OVERRIDE;
108   virtual void Paint(gfx::Canvas* canvas, const gfx::Size& size) OVERRIDE;
109 
110  private:
111   // The image chunks.
112   enum BorderElements {
113     LEFT,
114     CENTER,
115     RIGHT
116   };
117 
118   // NOTE: the images are owned by ResourceBundle. Don't free them.
119   const gfx::ImageSkia* images_[3];
120 
121   DISALLOW_COPY_AND_ASSIGN(HorizontalPainter);
122 };
123 
124 }  // namespace views
125 
126 #endif  // UI_VIEWS_PAINTER_H_
127