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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/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   virtual ~HorizontalPainter();
    101 
    102   // Painter:
    103   virtual gfx::Size GetMinimumSize() const OVERRIDE;
    104   virtual 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_
    123