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/* drawline using simple DDA */
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void DrawLine(int x1, int y1, int x2, int y2)
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{
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int x, y, hm=1, vm=1, sw=0, t;
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double dx, edx, dy, edy, eps;
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x = x2-x1;
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y = y2-y1;
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if (x < 0)
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{
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x = -x;
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hm = -1;
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}
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if (y < 0)
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{
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y = -y;
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vm = -1;
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}
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if (x < y)
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{
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sw = 1;
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t = x;
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x = y;
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y = t;
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}
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eps = 1./x;
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edx = eps*x;
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edy = eps*y;
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dx = dy = 0.5;
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if (sw == 0)
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SetPixel((int)dx*hm+x1, (int)dy*vm+y1);
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else
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SetPixel((int)dy*hm+x1, (int)dx*vm+y1);
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while (dx < x)
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{
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dx += edx;
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dy += edy;
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if (sw == 0)
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SetPixel((int)dx*hm+x1, (int)dy*vm+y1);
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else
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SetPixel((int)dy*hm+x1, (int)dx*vm+y1);
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}
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}
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