Lephe
ef0e5e32f8
Behave like Basic's Horizontal and Vertical commands. Internal dline() optimizations are renamed gint_dhline() and gint_dvline(). Also supports ghline() and gvline() in the gray engine. Optimization cases here are amost negligible due to limiting RAM access frequencies and the very limited amount of work accomplished in the functions. Code maintainability is prioritized by using dline().
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
#include <gint/display.h>
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#include <gint/defs/util.h>
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#include <display/common.h>
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/* dline(): Bresenham line drawing algorithm
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Remotely adapted from MonochromeLib code by Pierre "PerriotLL" Le Gall.
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Relies on platform-dependent dhline() and dvline() for optimized situations.
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@x1 @y1 @x2 @y2 Coordinates of endpoints of line (included)
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@color Any color accepted by dpixel() on the platform */
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void dline(int x1, int y1, int x2, int y2, color_t color)
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{
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/* Possible optimizations */
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if(y1 == y2)
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{
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gint_dhline(x1, x2, y1, color);
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return;
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}
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if(x1 == x2)
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{
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gint_dvline(y1, y2, x1, 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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dpixel(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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dpixel(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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dpixel(x, y, color);
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}
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}
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dpixel(x2, y2, color);
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}
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