testsuite/FuzzyPixel.h

   1 /*
   2  *   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  *
  18  */
  19
  20 #ifndef GNASH_FUZZYPIXEL_H
  21 #define GNASH_FUZZYPIXEL_H
  22
  23 #include "Range2d.h"
  24 #include "GnashKey.h" // for namespace key
  25 #include "RGBA.h" // for rgba class (composition)
  26
  27 #include <iostream>
  28
  29 namespace gnash {
  30
  31 /// An utility class used to compare rgba values with a given tolerance
  32 //
  33 /// This is simply a wrapper around an rgba value, with an associated
  34 /// tolerance used when comparing with another FuzzyPixel.
  35 ///
  36 /// Currently (but we might change this in the future), the tolerance is
  37 /// used to compare red, green, blue and alpha values.
  38 ///
  39 /// A negative tolerance may be used to mark the FuzzyPixel as
  40 /// an "invalid" one, which is a FuzzyPixel that will never be equal
  41 /// to any other. Intollerant FuzzyPixel.
  42 ///
  43 /// See operator== for more info.
  44 ///
  45 class FuzzyPixel
  46 {
  47
  48 public:
  49
  50         friend std::ostream& operator<< (std::ostream& o, const FuzzyPixel& p);
  51
  52         /// Construct an Intollerant FuzzyPixel.
  53         //
  54         /// Intollerant means that any comparison will fail.
  55         /// Actual value of the pixel doesn't make much sense.
  56         ///
  57         FuzzyPixel()
  58                 :
  59                 _col(0,0,0,0),
  60                 _tol(-1)
  61         {
  62         }
  63
  64         /// Construct a FuzzyPixel with given color and tolerance
  65         //
  66         /// @param color
  67         ///     The color value
  68         ///
  69         /// @param tolerance
  70         ///     The tolerance to use in comparisons.
  71         ///
  72         FuzzyPixel(const rgba& color, short unsigned tolerance=0)
  73                 :
  74                 _col(color),
  75                 // From short unsigned to signed we hopefully never swap sign.
  76                 // Use the default constructor to build intolerant fuzzy pixels.
  77                 _tol(int(tolerance))
  78         {
  79         }
  80
  81         /// Construct a FuzzyPixel with given values and 0 tolerance.
  82         //
  83         /// Use setTolerance to modify the tolerance value.
  84         ///
  85         /// @param r
  86         ///     The red value.
  87         ///
  88         /// @param g
  89         ///     The green value.
  90         ///
  91         /// @param b
  92         ///     The blue value.
  93         ///
  94         /// @param a
  95         ///     The alpha value.
  96         ///
  97         FuzzyPixel(boost::uint8_t r, boost::uint8_t g, boost::uint8_t b, boost::uint8_t a)
  98                 :
  99                 _col(r, g, b, a),
 100                 _tol(0)
 101         {
 102         }
 103
 104         /// Set the tolerance to use in comparisons
 105         //
 106         /// @param tol
 107         ///     The tolerance to use in comparisons.
 108         ///
 109         void setTolerance(unsigned short tol)
 110         {
 111                 _tol = int(tol);
 112         }
 113
 114         /// Make this fuzzy pixel intolerant
 115         void setIntolerant()
 116         {
 117                 _tol = -1;
 118         }
 119
 120         /// Compare two FuzzyPixel using the tolerance of the most tolerant of the two
 121         //
 122         /// Note that if any of the two operands is intolerant, any equality
 123         /// comparison will fail.
 124         ///
 125         /// See default constructor and setIntolerant for more info.
 126         ///
 127         bool operator==(const FuzzyPixel& other) const;
 128
 129         /// Return true if a and b are below a given tolerance
 130         static bool fuzzyEqual(int a, int b, int tol)
 131         {
 132                 return abs(a-b) <= tol;
 133         }
 134
 135 private:
 136
 137         // actual color
 138         rgba _col;
 139
 140         // tolerance value
 141         int _tol;
 142
 143 };
 144
 145 } // namespace gnash
 146
 147 #endif // _GNASH_FUZZYPIXEL_H