56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
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#include <gint/gray.h>
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#include <gint/defs/util.h>
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#include <display/common.h>
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/* gline(): Bresenham line drawing algorithm
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Remotely adapted from MonochromeLib code by Pierre "PerriotLL" Le Gall.
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Relies on grect() for optimized situations.
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@x1 @y1 @x2 @y2 Coordinates of endpoints of line (included)
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@color Any color */
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void gline(int x1, int y1, int x2, int y2, color_t color)
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{
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/* Trivial optimizations */
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if(x1 == x2 || y1 == y2)
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{
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grect(x1, y1, x2, y2, color);
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return;
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}
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/* Brensenham line drawing algorithm */
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int i, x = x1, y = y1, cumul;
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int dx = x2 - x1, dy = y2 - y1;
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int sx = sgn(dx), sy = sgn(dy);
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dx = abs(dx), dy = abs(dy);
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gpixel(x1, y1, color);
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if(dx >= dy)
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{
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/* Start with a non-zero cumul to even the overdue between the
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two ends of the line (for more regularity) */
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cumul = dx >> 1;
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for(i = 1; i < dx; i++)
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{
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x += sx;
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cumul += dy;
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if(cumul > dx) cumul -= dx, y += sy;
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gpixel(x, y, color);
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}
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}
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else
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{
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cumul = dy >> 1;
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for(i = 1; i < dy; i++)
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{
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y += sy;
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cumul += dx;
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if(cumul > dy) cumul -= dy, x += sx;
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gpixel(x, y, color);
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}
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}
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gpixel(x2, y2, color);
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}
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