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# csplugincommon/canvas/draw_line.h

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    00001 /*
    00002     Copyright (C) 2004 by Jorrit Tyberghein
    00003               (C) 2004 by Frank Richter
    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
    00020 #ifndef __CS_CSPLUGINCOMMON_CANVAS_DRAW_LINE_H__
    00021 #define __CS_CSPLUGINCOMMON_CANVAS_DRAW_LINE_H__
    00022
    00027 #include "csplugincommon/canvas/draw_common.h"
    00028 #include "csqint.h"
    00029
    00034
    00035 template<class Tpixel, class Tpixmixer>
    00036 class csG2DDrawLine
    00037 {
    00038 public:
    00040   static void DrawLine (csGraphics2D* G2D, float x1, float y1, float x2, float y2,
    00041     Tpixel color, uint8 alpha)
    00042   {
    00043     Tpixmixer mixer (G2D, color, alpha);
    00044     unsigned char* Memory = G2D->Memory;
    00045     const int* LineAddress = G2D->LineAddress;
    00046
    00047     int fx1 = csQint (x1), fx2 = csQint (x2),
    00048         fy1 = csQint (y1), fy2 = csQint (y2);
    00049
    00050     if (fy1 == fy2)
    00051     {
    00052       if (fx2 - fx1)
    00053       {
    00054         if (fx1 > fx2) { int tmp = fx1; fx1 = fx2; fx2 = tmp; }
    00055         int count = fx2 - fx1 + 1;
    00056         register Tpixel* dest = (Tpixel*)G2D->GetPixelAt (fx1, fy1);
    00057         while (count--) mixer.Mix (*dest++);
    00058       }
    00059       else
    00060         mixer.Mix (*((Tpixel*)G2D->GetPixelAt (fx1, fy1)));
    00061     }
    00062     else if (abs (fx2 - fx1) > abs (fy2 - fy1))
    00063     {
    00064       // Transform floating-point format to 16.16 fixed-point
    00065       fy1 = csQfixed16 (y1); fy2 = csQfixed16 (y2);
    00066
    00067       if (fx1 > fx2)
    00068       {
    00069         int tmp = fx1; fx1 = fx2; fx2 = tmp;
    00070         tmp = fy1; fy1 = fy2; fy2 = tmp;
    00071       }
    00072
    00073       // delta Y can be negative
    00074       int deltay = (fy2 - fy1) / (fx2 - fx1 + 1);
    00075
    00076       {
    00077         int x, y;
    00078         for (x = fx1, y = fy1 + deltay / 2; x <= fx2; x++)
    00079         {
    00080           Tpixel* p = (Tpixel*)(Memory +
    00081             (x * sizeof (Tpixel) + LineAddress [y >> 16]));
    00082           mixer.Mix (*p); y += deltay;
    00083         }
    00084       }
    00085     }
    00086     else
    00087     {
    00088       // Transform floating-point format to 16.16 fixed-point
    00089       fx1 = csQfixed16 (x1); fx2 = csQfixed16 (x2);
    00090
    00091       if (fy1 > fy2)
    00092       {
    00093         int tmp = fy1; fy1 = fy2; fy2 = tmp;
    00094         tmp = fx1; fx1 = fx2; fx2 = tmp;
    00095       }
    00096
    00097       // delta X can be negative
    00098       int deltax = (fx2 - fx1) / (fy2 - fy1 + 1);
    00099
    00100       {
    00101         int x, y;
    00102         for (x = fx1 + deltax / 2, y = fy1; y <= fy2; y++)
    00103         {
    00104           Tpixel* p = (Tpixel*)(Memory +
    00105             ((x >> 16) * sizeof (Tpixel) + LineAddress [y]));
    00106           mixer.Mix (*p); x += deltax;
    00107         }
    00108       }
    00109     }
    00110
    00111   }
    00112 };
    00113
    00116 #endif // __CS_CSPLUGINCOMMON_CANVAS_DRAW_LINE_H__