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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 // 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_GEOMETRY_RECT_BASE_H_
     13 #define UI_GFX_GEOMETRY_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 GFX_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   // Returns the manhattan distance from the rect to the point. If the point is
    147   // inside the rect, returns 0.
    148   Type ManhattanDistanceToPoint(const PointClass& point) const;
    149 
    150   // Returns the manhattan distance between the contents of this rect and the
    151   // contents of the given rect. That is, if the intersection of the two rects
    152   // is non-empty then the function returns 0. If the rects share a side, it
    153   // returns the smallest non-zero value appropriate for Type.
    154   Type ManhattanInternalDistance(const Class& rect) const;
    155 
    156  protected:
    157   RectBase(const PointClass& origin, const SizeClass& size)
    158       : origin_(origin), size_(size) {}
    159   explicit RectBase(const SizeClass& size)
    160       : size_(size) {}
    161   explicit RectBase(const PointClass& origin)
    162       : origin_(origin) {}
    163   // Destructor is intentionally made non virtual and protected.
    164   // Do not make this public.
    165   ~RectBase() {}
    166 
    167  private:
    168   PointClass origin_;
    169   SizeClass size_;
    170 };
    171 
    172 }  // namespace gfx
    173 
    174 #endif  // UI_GFX_GEOMETRY_RECT_BASE_H_
    175