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# csgfx/rgbpixel.h

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    00001 /*
    00002     Copyright (C) 1998 by Jorrit Tyberghein
    00003     Contributions made by Ivan Avramovic <ivan@avramovic.com>
    00004
    00005     This library is free software; you can redistribute it and/or
    00006     modify it under the terms of the GNU Library General Public
    00007     License as published by the Free Software Foundation; either
    00008     version 2 of the License, or (at your option) any later version.
    00009
    00010     This library is distributed in the hope that it will be useful,
    00011     but WITHOUT ANY WARRANTY; without even the implied warranty of
    00012     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00013     Library General Public License for more details.
    00014
    00015     You should have received a copy of the GNU Library General Public
    00016     License along with this library; if not, write to the Free
    00017     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    00018 */
    00019
    00026 //-----------------------------------------------------------------------------
    00027 // Implementation Note: Eric Sunshine <sunshine@sunshineco.com>      1999/02/09
    00028 //
    00029 // Certain portions of the Crystal Space code have strict requirements about
    00030 // the sizes of the structures csRGBcolor and csRGBpixel.  In particular, some
    00031 // pieces of code make these assumptions:
    00032 //
    00033 //    sizeof(csRGBcolor) == 3  (byte:rgb)
    00034 //    sizeof(csRGBpixel) == 4  (byte:rgb + byte:alpha)
    00035 //
    00036 // Originally, csRGBpixel was implemented as a subclasse of csRGBcolor and
    00037 // added a byte-sized "alpha" variable.  Thus, the original implementation made
    00038 // the assumption that the compiler would not pad out the csRGBcolor structure.
    00039 //
    00040 // Unfortunately in some environments (such as the NextStep compiler on M68K
    00041 // hardware) the compiler does pad csRGBcolor thus breaking the original
    00042 // assumptions about structure sizes.  In such cases, csRGBcolor is padded out
    00043 // to 4 bytes instead of 3 and csRGBpixel is padded out to 6 bytes instead of
    00044 // 4.  This padding results in problems in code which makes assumptions about
    00045 // the sizes of each structure.  In practice, problems were observed in code
    00046 // which expected csRGBpixel to be 4 bytes.
    00047 //
    00048 // To work around this problem, csRGBpixel has been re-implemented so that it
    00049 // is no longer derived from csRGBcolor.  An unfortunate side-effect of this
    00050 // re-implementation is that code is no longer inherited, and is thus
    00051 // duplicated in each class.  However, except for this minor point, the size of
    00052 // each structure should now be more stable between various compilers.
    00053 //-----------------------------------------------------------------------------
    00054
    00055 #ifndef __CS_RGBPIXEL_H__
    00056 #define __CS_RGBPIXEL_H__
    00057
    00058 #include "csextern.h"
    00059 #include "csutil/comparator.h"
    00060
    00061
    00066 CS_STRUCT_ALIGN_4BYTE_BEGIN
    00067 struct csRGBcolor
    00068 {
    00070   unsigned char red, green, blue;
    00072   csRGBcolor () : red(0), green(0), blue(0) {}
    00074   csRGBcolor (unsigned char r, unsigned char g, unsigned char b) :
    00075     red(r), green(g), blue(b) {}
    00077   void Set (unsigned char r, unsigned char g, unsigned char b)
    00078   { red = r; green = g; blue = b; }
    00080   bool operator == (const csRGBcolor& c) const
    00081   { return (c.red == red) && (c.green == green) && (c.blue == blue); }
    00083   bool operator != (const csRGBcolor& c) const
    00084   { return !operator == (c); }
    00086   csRGBcolor operator + (const csRGBcolor& c) const
    00087   { return csRGBcolor (
    00088     (unsigned char)(c.red + red),
    00089     (unsigned char)(c.green + green),
    00090     (unsigned char)(c.blue + blue)); }
    00094   void UnsafeAdd (const csRGBcolor& c)
    00095   {
    00096     red   = (unsigned char)(red   + c.red  );
    00097     green = (unsigned char)(green + c.green);
    00098     blue  = (unsigned char)(blue  + c.blue );
    00099   }
    00103   void SafeAdd (const csRGBcolor& c)
    00104   {
    00105     int color = red + c.red;
    00106     red   = (unsigned char)(color > 255 ? 255 : color);
    00107     color = green + c.green;
    00108     green = (unsigned char)(color > 255 ? 255 : color);
    00109     color = blue + c.blue;
    00110     blue  = (unsigned char)(color > 255 ? 255 : color);
    00111   }
    00112 } CS_STRUCT_ALIGN_4BYTE_END;
    00113
    00114
    00118 template<>
    00119 class csComparator<csRGBcolor, csRGBcolor>
    00120 {
    00121 public:
    00122   static int Compare (csRGBcolor const& r1, csRGBcolor const& r2)
    00123   {
    00124     if (r1.red != r2.red)
    00125       return (int)r1.red - (int)r2.red;
    00126     if (r1.green != r2.green)
    00127       return (int)r1.green - (int)r2.green;
    00128     if (r1.blue != r2.blue)
    00129       return (int)r1.blue - (int)r2.blue;
    00130     return 0;
    00131   }
    00132 };
    00133
    00138 template<>
    00139 class csComparator<csRGBcolor*, csRGBcolor*>
    00140 {
    00141 public:
    00142   static int Compare (csRGBcolor* const& r1, csRGBcolor* const& r2)
    00143   { return csComparator<csRGBcolor, csRGBcolor>::Compare (*r1, *r2); }
    00144 };
    00145
    00151 CS_STRUCT_ALIGN_4BYTE_BEGIN
    00152 struct csRGBpixel
    00153 {
    00155   unsigned char red, green, blue, alpha;
    00157   csRGBpixel () : red(0), green(0), blue(0), alpha(255) {}
    00159   csRGBpixel (const csRGBpixel& p) :
    00160     red (p.red), green (p.green), blue (p.blue), alpha (p.alpha) {}
    00162   csRGBpixel (const csRGBcolor& c) :
    00163     red (c.red), green (c.green), blue (c.blue), alpha (255) {}
    00165   csRGBpixel (int r, int g, int b, int a = 255) :
    00166     red ((unsigned char)r),
    00167     green ((unsigned char)g),
    00168     blue ((unsigned char)b),
    00169     alpha ((unsigned char)a) {}
    00171   bool operator == (const csRGBcolor& c) const
    00172   { return (c.red == red) && (c.green == green) && (c.blue == blue); }
    00174   bool operator == (const csRGBpixel& p) const
    00175   { return (p.red == red) && (p.green == green) && (p.blue == blue); }
    00177   bool operator != (const csRGBcolor& c) const
    00178   { return !operator == (c); }
    00183   bool operator != (const csRGBpixel& p) const
    00184   { return !operator == (p); }
    00186   operator csRGBcolor () const
    00187   { return csRGBcolor (red, green, blue); }
    00189   bool eq (const csRGBpixel& p) const
    00190   { return operator==(p); }
    00192   int Intensity () const
    00193   { return (red + green + blue) / 3; }
    00195   unsigned char Luminance () const
    00196   {
    00197     return (unsigned char)(((int)red*30 + (int)green*59 + (int)blue*11) / 100);
    00198   }
    00200   void Set (const int r, const int g, const int b, const int a = 255)
    00201   {
    00202     red = (unsigned char)r;
    00203     green = (unsigned char)g;
    00204     blue = (unsigned char)b;
    00205     alpha = (unsigned char)a;
    00206   }
    00208   void Set (const csRGBpixel& p)
    00209   { red = p.red; green = p.green; blue = p.blue; alpha = p.alpha; }
    00211   void operator += (const csRGBcolor& c)
    00212   {
    00213       red   = (unsigned char)(red   + c.red  );
    00214       green = (unsigned char)(green + c.green);
    00215       blue  = (unsigned char)(blue  + c.blue );
    00216   }
    00221   void UnsafeAdd (const csRGBpixel& c)
    00222   {
    00223     red   = (unsigned char)(red   + c.red  );
    00224     green = (unsigned char)(green + c.green);
    00225     blue  = (unsigned char)(blue  + c.blue );
    00226   }
    00231   void SafeAdd (const csRGBpixel& c)
    00232   {
    00233     int color = red + c.red;
    00234     red   = (unsigned char)(color > 255 ? 255 : color);
    00235     color = green + c.green;
    00236     green = (unsigned char)(color > 255 ? 255 : color);
    00237     color = blue + c.blue;
    00238     blue  = (unsigned char)(color > 255 ? 255 : color);
    00239   }
    00240 } CS_STRUCT_ALIGN_4BYTE_END;
    00241
    00242
    00249
    00250 #define R_COEF          173
    00252 #define G_COEF          242
    00254 #define B_COEF          107
    00255
    00258
    00259 #define R_COEF_SQ       299
    00261 #define G_COEF_SQ       587
    00263 #define B_COEF_SQ       114
    00264
    00268 #endif // __CS_RGBPIXEL_H__