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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 5131 | clevermous | 1 | /*! |
| 2 | \file Draw_Line.c |
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| 3 | \author Mario Palomo |
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| 4 | \author Jose M. de la Huerga Fernández |
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| 5 | \author Pepe González Mora |
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| 6 | \date 05-2002 |
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| 7 | |||
| 8 | This library is free software; you can redistribute it and/or |
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| 9 | modify it under the terms of the GNU Library General Public |
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| 10 | License as published by the Free Software Foundation; either |
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| 11 | version 2 of the License, or (at your option) any later version. |
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| 12 | |||
| 13 | This library is distributed in the hope that it will be useful, |
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| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 16 | Library General Public License for more details. |
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| 17 | |||
| 18 | You should have received a copy of the GNU Library General Public |
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| 19 | License along with this library; if not, write to the Free Foundation, |
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| 20 | Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 21 | */ |
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| 22 | #define SDL_DRAW_PUTPIXEL_BPP(A, B, C) \ |
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| 23 | *(##A##(##B##(Uint8*)super->pixels + y*super->pitch + x*SDL_DRAW_BPP))=##C##; |
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| 24 | |||
| 25 | #if SDL_DRAW_BPP == 1 |
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| 26 | #define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP(0+,0+,color) |
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| 27 | |||
| 28 | #elif SDL_DRAW_BPP == 2 |
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| 29 | #define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP((Uint16*),0+,color) |
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| 30 | |||
| 31 | #elif SDL_DRAW_BPP == 3 |
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| 32 | #define SDL_DRAW_PUTPIXEL \ |
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| 33 | SDL_DRAW_PUTPIXEL_BPP(0+,1+,(Uint8)colorbyte1) \ |
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| 34 | if (SDL_BYTEORDER == SDL_BIG_ENDIAN) { \ |
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| 35 | SDL_DRAW_PUTPIXEL_BPP(0+,0+,(Uint8)colorbyte2) \ |
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| 36 | SDL_DRAW_PUTPIXEL_BPP(0+,2+,(Uint8)colorbyte0) \ |
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| 37 | }else{ \ |
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| 38 | SDL_DRAW_PUTPIXEL_BPP(0+,0+,(Uint8)colorbyte0) \ |
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| 39 | SDL_DRAW_PUTPIXEL_BPP(0+,2+,(Uint8)colorbyte2) \ |
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| 40 | } |
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| 41 | |||
| 42 | #elif SDL_DRAW_BPP == 4 |
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| 43 | #define SDL_DRAW_PUTPIXEL SDL_DRAW_PUTPIXEL_BPP((Uint32*),0+,color) |
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| 44 | |||
| 45 | #endif /*SDL_DRAW_BPP*/ |
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| 46 | |||
| 47 | |||
| 48 | void SDL_DRAWFUNCTION(SDL_Surface *super, |
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| 49 | Sint16 x1, Sint16 y1, Sint16 x2, Sint16 y2, |
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| 50 | Uint32 color) |
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| 51 | { |
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| 52 | #if SDL_DRAW_BPP == 3 |
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| 53 | Uint8 colorbyte0 = (Uint8) (color & 0xff); |
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| 54 | Uint8 colorbyte1 = (Uint8) ((color >> 8) & 0xff); |
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| 55 | Uint8 colorbyte2 = (Uint8) ((color >> 16) & 0xff); |
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| 56 | #endif |
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| 57 | |||
| 58 | Sint16 x = x1; |
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| 59 | Sint16 y = y1; |
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| 60 | Sint16 dy = y2 - y1; |
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| 61 | Sint16 dx = x2 - x1; |
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| 62 | |||
| 63 | Sint16 G, DeltaG1, DeltaG2, minG, maxG; |
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| 64 | Sint16 swap; |
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| 65 | Sint16 inc = 1; |
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| 66 | |||
| 67 | SDL_DRAW_PUTPIXEL |
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| 68 | |||
| 69 | if (abs(dy) < abs(dx)) { /* -1 < ramp < 1 */ |
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| 70 | if (dx < 0) { |
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| 71 | dx = -dx; |
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| 72 | dy = -dy; |
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| 73 | |||
| 74 | swap = y2; |
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| 75 | y2 = y1; |
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| 76 | y1 = swap; |
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| 77 | |||
| 78 | swap = x2; |
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| 79 | x2 = x1; |
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| 80 | x1 = swap; |
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| 81 | } |
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| 82 | if (dy < 0) { |
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| 83 | dy = -dy; |
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| 84 | inc = -1; |
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| 85 | } |
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| 86 | |||
| 87 | G = 2 * dy - dx; |
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| 88 | DeltaG1 = 2 * (dy - dx); |
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| 89 | DeltaG2 = 2 * dy; |
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| 90 | |||
| 91 | while (x++ < x2) { |
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| 92 | if (G > 0) { G += DeltaG1; y += inc; } |
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| 93 | else G += DeltaG2; |
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| 94 | |||
| 95 | SDL_DRAW_PUTPIXEL |
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| 96 | }/*while*/ |
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| 97 | |||
| 98 | } else { /* ramp < -1 or ramp > 1 */ |
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| 99 | if (dy < 0) { |
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| 100 | dx = -dx; |
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| 101 | dy = -dy; |
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| 102 | |||
| 103 | swap = y2; |
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| 104 | y2 = y1; |
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| 105 | y1 = swap; |
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| 106 | |||
| 107 | swap = x2; |
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| 108 | x2 = x1; |
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| 109 | x1 = swap; |
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| 110 | } |
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| 111 | if (dx < 0) { |
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| 112 | dx = -dx; |
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| 113 | inc = -1; |
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| 114 | } |
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| 115 | |||
| 116 | G = 2 * dx - dy; |
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| 117 | minG = maxG = G; |
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| 118 | DeltaG1 = 2 * (dx - dy); |
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| 119 | DeltaG2 = 2 * dx; |
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| 120 | |||
| 121 | while (y++ < y2) { |
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| 122 | if (G > 0) { G += DeltaG1; x += inc; } |
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| 123 | else G += DeltaG2; |
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| 124 | |||
| 125 | SDL_DRAW_PUTPIXEL |
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| 126 | }/*while*/ |
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| 127 | |||
| 128 | }/*if*/ |
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| 129 | |||
| 130 | }/*Draw_Line*/ |
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| 131 | |||
| 132 | |||
| 133 | #undef SDL_DRAW_PUTPIXEL |
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| 134 | #undef SDL_DRAW_PUTPIXEL_BPP |
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| 135 |