1
2// Copyright (c) 2011 The Chromium Authors. All rights reserved.
3// Use of this source code is governed by a BSD-style license that can be
4// found in the LICENSE file.
5
6#ifndef UI_GFX_CANVAS_PAINT_LINUX_H_
7#define UI_GFX_CANVAS_PAINT_LINUX_H_
8
9#include "base/logging.h"
10#include "skia/ext/platform_canvas.h"
11#include "ui/gfx/canvas.h"
12#include <gdk/gdk.h>
13
14namespace gfx {
15
16// A class designed to translate skia painting into a region in a GdkWindow.
17// On construction, it will set up a context for painting into, and on
18// destruction, it will commit it to the GdkWindow.
19// Note: The created context is always inialized to (0, 0, 0, 0).
20class GFX_EXPORT CanvasSkiaPaint : public Canvas {
21 public:
22  // This constructor assumes the result is opaque.
23  explicit CanvasSkiaPaint(GdkEventExpose* event);
24  CanvasSkiaPaint(GdkEventExpose* event, bool opaque);
25  virtual ~CanvasSkiaPaint();
26
27  // Sets whether the bitmap is composited in such a way that the alpha channel
28  // is honored. This is only useful if you've enabled an RGBA colormap on the
29  // widget. The default is false.
30  void set_composite_alpha(bool composite_alpha) {
31    composite_alpha_ = composite_alpha;
32  }
33
34  // Returns true if the invalid region is empty. The caller should call this
35  // function to determine if anything needs painting.
36  bool is_empty() const {
37    return gdk_region_empty(region_);
38  }
39
40  GdkRectangle rectangle() const {
41    GdkRectangle bounds;
42    gdk_region_get_clipbox(region_, &bounds);
43    return bounds;
44  }
45
46 private:
47  void Init(bool opaque);
48
49  cairo_t* context_;
50  GdkWindow* window_;
51  GdkRegion* region_;
52  // See description above setter.
53  bool composite_alpha_;
54
55  // Disallow copy and assign.
56  CanvasSkiaPaint(const CanvasSkiaPaint&);
57  CanvasSkiaPaint& operator=(const CanvasSkiaPaint&);
58};
59
60// A class designed to translate skia painting into a region in a Cairo context.
61// On construction, it will set up a context for painting into, and on
62// destruction, it will commit it to the Cairo context. If there are any
63// transformations applied to the Cairo context, they will affect the drawing.
64class GFX_EXPORT CanvasSkiaPaintCairo : public Canvas {
65 public:
66  CanvasSkiaPaintCairo(cairo_t* cairo, Size size, bool opaque);
67  virtual ~CanvasSkiaPaintCairo();
68
69  // Sets whether the bitmap is composited in such a way that the alpha channel
70  // is honored. This is only useful if you've enabled an RGBA colormap on the
71  // widget. The default is false.
72  void set_composite_alpha(bool composite_alpha) {
73    composite_alpha_ = composite_alpha;
74  }
75
76  // Returns true if size of the drawing region is empty. The caller should call
77  // this function to determine if anything needs painting.
78  bool is_empty() const {
79    return size_.IsEmpty();
80  }
81
82  Size size() const {
83    return size_;
84  }
85
86 private:
87  void Init(bool opaque);
88
89  cairo_t* context_;
90  cairo_t* dest_;
91  Size size_;
92  // See description above setter.
93  bool composite_alpha_;
94
95  // Disallow copy and assign.
96  CanvasSkiaPaintCairo(const CanvasSkiaPaintCairo&);
97  CanvasSkiaPaintCairo& operator=(const CanvasSkiaPaintCairo&);
98};
99
100}  // namespace gfx
101
102#endif  // UI_GFX_CANVAS_PAINT_LINUX_H_
103