Initial import.

src/libdraw/poly.c

@@ -0,0 +1,87 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+
+static
+uchar*
+addcoord(uchar *p, int oldx, int newx)
+{
+	int dx;
+
+	dx = newx-oldx;
+	/* does dx fit in 7 signed bits? */
+	if((unsigned)(dx - -0x40) <= 0x7F)
+		*p++ = dx&0x7F;
+	else{
+		*p++ = 0x80 | (newx&0x7F);
+		*p++ = newx>>7;
+		*p++ = newx>>15;
+	}
+	return p;
+}
+
+static
+void
+dopoly(int cmd, Image *dst, Point *pp, int np, int end0, int end1, int radius, Image *src, Point *sp, Drawop op)
+{
+	uchar *a, *t, *u;
+	int i, ox, oy;
+
+	if(np == 0)
+		return;
+	t = malloc(np*2*3);
+	if(t == nil)
+		return;
+	u = t;
+	ox = oy = 0;
+	for(i=0; i<np; i++){
+		u = addcoord(u, ox, pp[i].x);
+		ox = pp[i].x;
+		u = addcoord(u, oy, pp[i].y);
+		oy = pp[i].y;
+	}
+
+	_setdrawop(dst->display, op);
+
+	a = bufimage(dst->display, 1+4+2+4+4+4+4+2*4+(u-t));
+	if(a == 0){
+		free(t);
+		fprint(2, "image poly: %r\n");
+		return;
+	}
+	a[0] = cmd;
+	BPLONG(a+1, dst->id);
+	BPSHORT(a+5, np-1);
+	BPLONG(a+7, end0);
+	BPLONG(a+11, end1);
+	BPLONG(a+15, radius);
+	BPLONG(a+19, src->id);
+	BPLONG(a+23, sp->x);
+	BPLONG(a+27, sp->y);
+	memmove(a+31, t, u-t);
+	free(t);
+}
+
+void
+poly(Image *dst, Point *p, int np, int end0, int end1, int radius, Image *src, Point sp)
+{
+	dopoly('p', dst, p, np, end0, end1, radius, src, &sp, SoverD);
+}
+
+void
+polyop(Image *dst, Point *p, int np, int end0, int end1, int radius, Image *src, Point sp, Drawop op)
+{
+	dopoly('p', dst, p, np, end0, end1, radius, src, &sp, op);
+}
+
+void
+fillpoly(Image *dst, Point *p, int np, int wind, Image *src, Point sp)
+{
+	dopoly('P', dst, p, np, wind, 0, 0, src, &sp, SoverD);
+}
+
+void
+fillpolyop(Image *dst, Point *p, int np, int wind, Image *src, Point sp, Drawop op)
+{
+	dopoly('P', dst, p, np, wind, 0, 0, src, &sp, op);
+}