geometry.hpp

   1 // Copyright 2005-6 Ben Hutchings <ben@decadent.org.uk>.
   2 // See the file "COPYING" for licence details.
   3
   4 #ifndef INC_GEOMETRY_HPP
   5 #define INC_GEOMETRY_HPP
   6
   7 struct rectangle
   8 {
   9     int left, top;     // inclusive
  10     int right, bottom; // exclusive
  11
  12     rectangle operator|=(const rectangle & other)
  13         {
  14             if (other.empty())
  15             {
  16                 // use current extents unchanged
  17             }
  18             else if (empty())
  19             {
  20                 // use other extents
  21                 *this = other;
  22             }
  23             else
  24             {
  25                 // find rectangle enclosing both extents
  26                 left = std::min(left, other.left);
  27                 top = std::min(top, other.top);
  28                 right = std::max(right, other.right);
  29                 bottom = std::max(bottom, other.bottom);
  30             }
  31
  32             return *this;
  33         }
  34
  35     rectangle operator&=(const rectangle & other)
  36         {
  37             // find rectangle enclosed in both extents
  38             left = std::max(left, other.left);
  39             top = std::max(top, other.top);
  40             right = std::max(left, std::min(right, other.right));
  41             bottom = std::max(top, std::min(bottom, other.bottom));
  42             return *this;
  43         }
  44
  45     bool empty() const
  46         {
  47             return left == right || bottom == top;
  48         }
  49 };
  50
  51 #endif // !INC_GEOMETRY_HPP