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