Home | History | Annotate | Download | only in views 
      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_BACKGROUND_H_
      6 #define UI_VIEWS_BACKGROUND_H_
      7 
      8 #include "build/build_config.h"
      9 
     10 #if defined(OS_WIN)
     11 #include <windows.h>
     12 #endif  // defined(OS_WIN)
     13 
     14 #include "base/basictypes.h"
     15 #include "third_party/skia/include/core/SkColor.h"
     16 #include "ui/views/views_export.h"
     17 
     18 namespace gfx {
     19 class Canvas;
     20 }
     21 
     22 namespace views {
     23 
     24 class Painter;
     25 class View;
     26 
     27 /////////////////////////////////////////////////////////////////////////////
     28 //
     29 // Background class
     30 //
     31 // A background implements a way for views to paint a background. The
     32 // background can be either solid or based on a gradient. Of course,
     33 // Background can be subclassed to implement various effects.
     34 //
     35 // Any View can have a background. See View::SetBackground() and
     36 // View::OnPaintBackground()
     37 //
     38 /////////////////////////////////////////////////////////////////////////////
     39 class VIEWS_EXPORT Background {
     40  public:
     41   Background();
     42   virtual ~Background();
     43 
     44   // Creates a background that fills the canvas in the specified color.
     45   static Background* CreateSolidBackground(SkColor color);
     46 
     47   // Creates a background that fills the canvas in the specified color.
     48   static Background* CreateSolidBackground(int r, int g, int b) {
     49     return CreateSolidBackground(SkColorSetRGB(r, g, b));
     50   }
     51 
     52   // Creates a background that fills the canvas in the specified color.
     53   static Background* CreateSolidBackground(int r, int g, int b, int a) {
     54     return CreateSolidBackground(SkColorSetARGB(a, r, g, b));
     55   }
     56 
     57   // Creates a background that contains a vertical gradient that varies
     58   // from |color1| to |color2|
     59   static Background* CreateVerticalGradientBackground(SkColor color1,
     60                                                       SkColor color2);
     61 
     62   // Creates a background that contains a vertical gradient. The gradient can
     63   // have multiple |colors|. The |pos| array contains the relative positions of
     64   // each corresponding color. |colors| and |pos| must be the same size. The
     65   // first element in |pos| must be 0.0 and the last element must be 1.0.
     66   // |count| contains the number of elements in |colors| and |pos|.
     67   static Background* CreateVerticalMultiColorGradientBackground(SkColor* colors,
     68                                                                 SkScalar* pos,
     69                                                                 size_t count);
     70 
     71   // Creates Chrome's standard panel background
     72   static Background* CreateStandardPanelBackground();
     73 
     74   // Creates a Background from the specified Painter. If owns_painter is
     75   // true, the Painter is deleted when the Border is deleted.
     76   static Background* CreateBackgroundPainter(bool owns_painter,
     77                                              Painter* painter);
     78 
     79   // Render the background for the provided view
     80   virtual void Paint(gfx::Canvas* canvas, View* view) const = 0;
     81 
     82   // Set a solid, opaque color to be used when drawing backgrounds of native
     83   // controls.  Unfortunately alpha=0 is not an option.
     84   void SetNativeControlColor(SkColor color);
     85 
     86   // Returns the "background color".  This is equivalent to the color set in
     87   // SetNativeControlColor().  For solid backgrounds, this is the color; for
     88   // gradient backgrounds, it's the midpoint of the gradient; for painter
     89   // backgrounds, this is not useful (returns a default color).
     90   SkColor get_color() const { return color_; }
     91 
     92 #if defined(OS_WIN)
     93   // TODO(port): Make GetNativeControlBrush portable (currently uses HBRUSH).
     94 
     95   // Get the brush that was specified by SetNativeControlColor
     96   HBRUSH GetNativeControlBrush() const;
     97 #endif  // defined(OS_WIN)
     98 
     99  private:
    100   SkColor color_;
    101 #if defined(OS_WIN)
    102   // TODO(port): Create portable replacement for HBRUSH.
    103   mutable HBRUSH native_control_brush_;
    104 #endif  // defined(OS_WIN)
    105 
    106   DISALLOW_COPY_AND_ASSIGN(Background);
    107 };
    108 
    109 }  // namespace views
    110 
    111 #endif  // UI_VIEWS_BACKGROUND_H_
    112