ui/views/border.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_BORDER_H_
   6 #define UI_VIEWS_BORDER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "third_party/skia/include/core/SkColor.h"
  11 #include "ui/gfx/geometry/insets.h"
  12 #include "ui/views/views_export.h"
  13
  14 namespace gfx{
  15 class Canvas;
  16 class Size;
  17 }
  18
  19 namespace views {
  20
  21 class Painter;
  22 class View;
  23
  24 ////////////////////////////////////////////////////////////////////////////////
  25 //
  26 // Border class.
  27 //
  28 // The border class is used to display a border around a view.
  29 // To set a border on a view, just call SetBorder on the view, for example:
  30 // view->SetBorder(Border::CreateSolidBorder(1, SkColorSetRGB(25, 25, 112));
  31 // Once set on a view, the border is owned by the view.
  32 //
  33 // IMPORTANT NOTE: not all views support borders at this point. In order to
  34 // support the border, views should make sure to use bounds excluding the
  35 // border (by calling View::GetLocalBoundsExcludingBorder) when doing layout and
  36 // painting.
  37 //
  38 ////////////////////////////////////////////////////////////////////////////////
  39
  40 class VIEWS_EXPORT Border {
  41  public:
  42   Border();
  43   virtual ~Border();
  44
  45   // Convenience for creating a scoped_ptr with no Border.
  46   static scoped_ptr<Border> NullBorder();
  47
  48   // Creates a border that is a simple line of the specified thickness and
  49   // color.
  50   static scoped_ptr<Border> CreateSolidBorder(int thickness, SkColor color);
  51
  52   // Creates a border for reserving space. The returned border does not
  53   // paint anything.
  54   static scoped_ptr<Border> CreateEmptyBorder(int top,
  55                                               int left,
  56                                               int bottom,
  57                                               int right);
  58
  59   // Creates a border of the specified color, and specified thickness on each
  60   // side.
  61   static scoped_ptr<Border> CreateSolidSidedBorder(int top,
  62                                                    int left,
  63                                                    int bottom,
  64                                                    int right,
  65                                                    SkColor color);
  66
  67   // Creates a Border from the specified Painter. The border owns the painter,
  68   // thus the painter is deleted when the Border is deleted.
  69   // |insets| define size of an area allocated for a Border.
  70   static scoped_ptr<Border> CreateBorderPainter(Painter* painter,
  71                                                 const gfx::Insets& insets);
  72
  73   // Renders the border for the specified view.
  74   virtual void Paint(const View& view, gfx::Canvas* canvas) = 0;
  75
  76   // Returns the border insets.
  77   virtual gfx::Insets GetInsets() const = 0;
  78
  79   // Returns the minimum size this border requires.  Note that this may not be
  80   // the same as the insets.  For example, a Border may paint images to draw
  81   // some graphical border around a view, and this would return the minimum size
  82   // such that these images would not be clipped or overlapping -- but the
  83   // insets may be larger or smaller, depending on how the view wanted its
  84   // content laid out relative to these images.
  85   virtual gfx::Size GetMinimumSize() const = 0;
  86
  87  private:
  88   DISALLOW_COPY_AND_ASSIGN(Border);
  89 };
  90
  91 }  // namespace views
  92
  93 #endif  // UI_VIEWS_BORDER_H_