ui/views/layout/box_layout.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_LAYOUT_BOX_LAYOUT_H_
   6 #define UI_VIEWS_LAYOUT_BOX_LAYOUT_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/compiler_specific.h"
  10 #include "ui/gfx/insets.h"
  11 #include "ui/views/layout/layout_manager.h"
  12
  13 namespace gfx {
  14 class Rect;
  15 class Size;
  16 }
  17
  18 namespace views {
  19
  20 class View;
  21
  22 // A Layout manager that arranges child views vertically or horizontally in a
  23 // side-by-side fashion with spacing around and between the child views. The
  24 // child views are always sized according to their preferred size. If the
  25 // host's bounds provide insufficient space, child views will be clamped.
  26 // Excess space will not be distributed.
  27 class VIEWS_EXPORT BoxLayout : public LayoutManager {
  28  public:
  29   enum Orientation {
  30     kHorizontal,
  31     kVertical,
  32   };
  33
  34   // This specifies where along the main axis the children should be laid out.
  35   // e.g. a horizontal layout of MAIN_AXIS_ALIGNMENT_END will result in the
  36   // child views being right-aligned.
  37   enum MainAxisAlignment {
  38     MAIN_AXIS_ALIGNMENT_START,
  39     MAIN_AXIS_ALIGNMENT_CENTER,
  40     MAIN_AXIS_ALIGNMENT_END,
  41
  42     // This distributes extra space among the child views. This increases the
  43     // size of child views along the main axis rather than the space between
  44     // them.
  45     MAIN_AXIS_ALIGNMENT_FILL,
  46     // TODO(calamity): Add MAIN_AXIS_ALIGNMENT_JUSTIFY which spreads blank space
  47     // in-between the child views.
  48   };
  49
  50   // This specifies where along the cross axis the children should be laid out.
  51   // e.g. a horizontal layout of CROSS_AXIS_ALIGNMENT_END will result in the
  52   // child views being bottom-aligned.
  53   enum CrossAxisAlignment {
  54     // This causes the child view to stretch to fit the host in the cross axis.
  55     CROSS_AXIS_ALIGNMENT_STRETCH,
  56     CROSS_AXIS_ALIGNMENT_START,
  57     CROSS_AXIS_ALIGNMENT_CENTER,
  58     CROSS_AXIS_ALIGNMENT_END,
  59   };
  60
  61   // Use |inside_border_horizontal_spacing| and
  62   // |inside_border_vertical_spacing| to add additional space between the child
  63   // view area and the host view border. |between_child_spacing| controls the
  64   // space in between child views.
  65   BoxLayout(Orientation orientation,
  66             int inside_border_horizontal_spacing,
  67             int inside_border_vertical_spacing,
  68             int between_child_spacing);
  69   virtual ~BoxLayout();
  70
  71   void set_main_axis_alignment(MainAxisAlignment main_axis_alignment) {
  72     main_axis_alignment_ = main_axis_alignment;
  73   }
  74
  75   void set_cross_axis_alignment(CrossAxisAlignment cross_axis_alignment) {
  76     cross_axis_alignment_ = cross_axis_alignment;
  77   }
  78
  79   void set_inside_border_insets(const gfx::Insets& insets) {
  80     inside_border_insets_ = insets;
  81   }
  82
  83   // Overridden from views::LayoutManager:
  84   virtual void Layout(View* host) OVERRIDE;
  85   virtual gfx::Size GetPreferredSize(const View* host) const OVERRIDE;
  86   virtual int GetPreferredHeightForWidth(const View* host,
  87                                          int width) const OVERRIDE;
  88
  89  private:
  90   // Returns the size and position along the main axis of |rect|.
  91   int MainAxisSize(const gfx::Rect& rect) const;
  92   int MainAxisPosition(const gfx::Rect& rect) const;
  93
  94   // Sets the size and position along the main axis of |rect|.
  95   void SetMainAxisSize(int size, gfx::Rect* rect) const;
  96   void SetMainAxisPosition(int position, gfx::Rect* rect) const;
  97
  98   // Returns the size and position along the cross axis of |rect|.
  99   int CrossAxisSize(const gfx::Rect& rect) const;
 100   int CrossAxisPosition(const gfx::Rect& rect) const;
 101
 102   // Sets the size and position along the cross axis of |rect|.
 103   void SetCrossAxisSize(int size, gfx::Rect* rect) const;
 104   void SetCrossAxisPosition(int size, gfx::Rect* rect) const;
 105
 106   // Returns the main axis size for the given view. |child_area_width| is needed
 107   // to calculate the height of the view when the orientation is vertical.
 108   int MainAxisSizeForView(const View* view, int child_area_width) const;
 109
 110   // Returns the cross axis size for the given view.
 111   int CrossAxisSizeForView(const View* view) const;
 112
 113   // The preferred size for the dialog given the width of the child area.
 114   gfx::Size GetPreferredSizeForChildWidth(const View* host,
 115                                           int child_area_width) const;
 116
 117   // The amount of space the layout requires in addition to any space for the
 118   // child views.
 119   gfx::Size NonChildSize(const View* host) const;
 120
 121   const Orientation orientation_;
 122
 123   // Spacing between child views and host view border.
 124   gfx::Insets inside_border_insets_;
 125
 126   // Spacing to put in between child views.
 127   const int between_child_spacing_;
 128
 129   // The alignment of children in the main axis. This is
 130   // MAIN_AXIS_ALIGNMENT_START by default.
 131   MainAxisAlignment main_axis_alignment_;
 132
 133   // The alignment of children in the cross axis. This is
 134   // CROSS_AXIS_ALIGNMENT_STRETCH by default.
 135   CrossAxisAlignment cross_axis_alignment_;
 136
 137   DISALLOW_IMPLICIT_CONSTRUCTORS(BoxLayout);
 138 };
 139
 140 } // namespace views
 141
 142 #endif  // UI_VIEWS_LAYOUT_BOX_LAYOUT_H_