ui/gfx/rect_base.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 // A template for a simple rectangle class.  The containment semantics
   6 // are array-like; that is, the coordinate (x, y) is considered to be
   7 // contained by the rectangle, but the coordinate (x + width, y) is not.
   8 // The class will happily let you create malformed rectangles (that is,
   9 // rectangles with negative width and/or height), but there will be assertions
  10 // in the operations (such as Contains()) to complain in this case.
  11
  12 #ifndef UI_GFX_RECT_BASE_H_
  13 #define UI_GFX_RECT_BASE_H_
  14
  15 #include <string>
  16
  17 #include "base/compiler_specific.h"
  18
  19 namespace gfx {
  20
  21 template<typename Class,
  22          typename PointClass,
  23          typename SizeClass,
  24          typename InsetsClass,
  25          typename VectorClass,
  26          typename Type>
  27 class UI_EXPORT RectBase {
  28  public:
  29   Type x() const { return origin_.x(); }
  30   void set_x(Type x) { origin_.set_x(x); }
  31
  32   Type y() const { return origin_.y(); }
  33   void set_y(Type y) { origin_.set_y(y); }
  34
  35   Type width() const { return size_.width(); }
  36   void set_width(Type width) { size_.set_width(width); }
  37
  38   Type height() const { return size_.height(); }
  39   void set_height(Type height) { size_.set_height(height); }
  40
  41   const PointClass& origin() const { return origin_; }
  42   void set_origin(const PointClass& origin) { origin_ = origin; }
  43
  44   const SizeClass& size() const { return size_; }
  45   void set_size(const SizeClass& size) { size_ = size; }
  46
  47   Type right() const { return x() + width(); }
  48   Type bottom() const { return y() + height(); }
  49
  50   PointClass top_right() const { return PointClass(right(), y()); }
  51   PointClass bottom_left() const { return PointClass(x(), bottom()); }
  52   PointClass bottom_right() const { return PointClass(right(), bottom()); }
  53
  54   VectorClass OffsetFromOrigin() const {
  55     return VectorClass(x(), y());
  56   }
  57
  58   void SetRect(Type x, Type y, Type width, Type height);
  59
  60   // Shrink the rectangle by a horizontal and vertical distance on all sides.
  61   void Inset(Type horizontal, Type vertical) {
  62     Inset(horizontal, vertical, horizontal, vertical);
  63   }
  64
  65   // Shrink the rectangle by the given insets.
  66   void Inset(const InsetsClass& insets);
  67
  68   // Shrink the rectangle by the specified amount on each side.
  69   void Inset(Type left, Type top, Type right, Type bottom);
  70
  71   // Move the rectangle by a horizontal and vertical distance.
  72   void Offset(Type horizontal, Type vertical);
  73   void Offset(const VectorClass& distance) {
  74     Offset(distance.x(), distance.y());
  75   }
  76   void operator+=(const VectorClass& offset);
  77   void operator-=(const VectorClass& offset);
  78
  79   InsetsClass InsetsFrom(const Class& inner) const {
  80     return InsetsClass(inner.y() - y(),
  81                        inner.x() - x(),
  82                        bottom() - inner.bottom(),
  83                        right() - inner.right());
  84   }
  85
  86   // Returns true if the area of the rectangle is zero.
  87   bool IsEmpty() const { return size_.IsEmpty(); }
  88
  89   // A rect is less than another rect if its origin is less than
  90   // the other rect's origin. If the origins are equal, then the
  91   // shortest rect is less than the other. If the origin and the
  92   // height are equal, then the narrowest rect is less than.
  93   // This comparison is required to use Rects in sets, or sorted
  94   // vectors.
  95   bool operator<(const Class& other) const;
  96
  97   // Returns true if the point identified by point_x and point_y falls inside
  98   // this rectangle.  The point (x, y) is inside the rectangle, but the
  99   // point (x + width, y + height) is not.
 100   bool Contains(Type point_x, Type point_y) const;
 101
 102   // Returns true if the specified point is contained by this rectangle.
 103   bool Contains(const PointClass& point) const {
 104     return Contains(point.x(), point.y());
 105   }
 106
 107   // Returns true if this rectangle contains the specified rectangle.
 108   bool Contains(const Class& rect) const;
 109
 110   // Returns true if this rectangle intersects the specified rectangle.
 111   // An empty rectangle doesn't intersect any rectangle.
 112   bool Intersects(const Class& rect) const;
 113
 114   // Computes the intersection of this rectangle with the given rectangle.
 115   void Intersect(const Class& rect);
 116
 117   // Computes the union of this rectangle with the given rectangle.  The union
 118   // is the smallest rectangle containing both rectangles.
 119   void Union(const Class& rect);
 120
 121   // Computes the rectangle resulting from subtracting |rect| from |*this|,
 122   // i.e. the bounding rect of |Region(*this) - Region(rect)|.
 123   void Subtract(const Class& rect);
 124
 125   // Fits as much of the receiving rectangle into the supplied rectangle as
 126   // possible, becoming the result. For example, if the receiver had
 127   // a x-location of 2 and a width of 4, and the supplied rectangle had
 128   // an x-location of 0 with a width of 5, the returned rectangle would have
 129   // an x-location of 1 with a width of 4.
 130   void AdjustToFit(const Class& rect);
 131
 132   // Returns the center of this rectangle.
 133   PointClass CenterPoint() const;
 134
 135   // Becomes a rectangle that has the same center point but with a size capped
 136   // at given |size|.
 137   void ClampToCenteredSize(const SizeClass& size);
 138
 139   // Splits |this| in two halves, |left_half| and |right_half|.
 140   void SplitVertically(Class* left_half, Class* right_half) const;
 141
 142   // Returns true if this rectangle shares an entire edge (i.e., same width or
 143   // same height) with the given rectangle, and the rectangles do not overlap.
 144   bool SharesEdgeWith(const Class& rect) const;
 145
 146  protected:
 147   RectBase(const PointClass& origin, const SizeClass& size)
 148       : origin_(origin), size_(size) {}
 149   explicit RectBase(const SizeClass& size)
 150       : size_(size) {}
 151   explicit RectBase(const PointClass& origin)
 152       : origin_(origin) {}
 153   // Destructor is intentionally made non virtual and protected.
 154   // Do not make this public.
 155   ~RectBase() {}
 156
 157  private:
 158   PointClass origin_;
 159   SizeClass size_;
 160 };
 161
 162 }  // namespace gfx
 163
 164 #endif  // UI_GFX_RECT_BASE_H_