diff options
| -rw-r--r-- | bezier.c | 53 |
1 files changed, 0 insertions, 53 deletions
diff --git a/bezier.c b/bezier.c deleted file mode 100644 index a8ddf05f..00000000 --- a/bezier.c +++ /dev/null @@ -1,53 +0,0 @@ -/* From http://members.chello.at/easyfilter/bresenham.html */ -#include<assert.h> -#include<stdio.h> - -void setPixel(int x, int y) { - printf("%d %d\n", x, y); -} - -void plotQuadBezierSeg(int x0, int y0, int x1, int y1, int x2, int y2) -{ - int sx = x2-x1, sy = y2-y1; - long xx = x0-x1, yy = y0-y1, xy=0; /* relative values for checks */ - double dx, dy, err, cur = xx*sy-yy*sx; /* curvature */ - - assert(xx*sx <= 0 && yy*sy <= 0); /* sign of gradient must not change */ - - printf("A sx %d sy %d xx %ld yy %ld cur %g\n", sx, sy, xx, yy, cur); - if (sx*(long)sx+sy*(long)sy > xx*xx+yy*yy) { /* begin with longer part */ - printf("swap\n"); - x2 = x0; x0 = sx+x1; y2 = y0; y0 = sy+y1; cur = -cur; /* swap P0 P2 */ - } - printf("B sx %d sy %d xx %ld yy %ld xy %ld cur %g\n", sx, sy, xx, yy, xy, cur); - if (cur != 0) { /* no straight line */ - xx += sx; xx *= sx = x0 < x2 ? 1 : -1; /* x step direction */ - yy += sy; yy *= sy = y0 < y2 ? 1 : -1; /* y step direction */ - printf("E sx %d sy %d xx %ld yy %ld xy %ld cur %g\n", sx, sy, xx, yy, xy, cur); - xy = 2*xx*yy; - printf("F sx %d sy %d xx %ld yy %ld xy %ld cur %g\n", sx, sy, xx, yy, xy, cur); - xx *= xx; yy *= yy; /* differences 2nd degree */ - printf("M sx %d sy %d xx %ld yy %ld xy %ld cur %g\n", sx, sy, xx, yy, xy, cur); - if (cur*sx*sy < 0) { /* negated curvature? */ - printf("negate\n"); - xx = -xx; yy = -yy; xy = -xy; cur = -cur; - } - printf("N sx %d sy %d xx %ld yy %ld xy %ld cur %g\n", sx, sy, xx, yy, xy, cur); - dx = 4.0*sy*cur*(x1-x0)+xx-xy; /* differences 1st degree */ - dy = 4.0*sx*cur*(y0-y1)+yy-xy; - xx += xx; yy += yy; err = dx+dy+xy; /* error 1st step */ - do { - printf("%d %d: dx %g dy %g err %g\n", x0, y0, dx, dy, err); - if (x0 == x2 && y0 == y2) return; /* last pixel -> curve finished */ - y1 = 2*err < dx; /* save value for test of y step */ - if (2*err > dy) { x0 += sx; dx -= xy; err += dy += yy; } /* x step */ - if ( y1 ) { y0 += sy; dy -= xy; err += dx += xx; } /* y step */ - } while (dy < dx ); /* gradient negates -> algorithm fails */ - } -//? plotLine(x0,y0, x2,y2); /* plot remaining part to end */ -} - -int main(void) { - plotQuadBezierSeg(0x200, 0x20, 0x180, 0x90, 0x180, 0x160); - return 0; -} |