ref: 661c14037cfc65a1fcd828faedcb40f6ea0d6a5b
parent: 1c0b2d238dc7e76735f240c1877afe7b6c991cf9
author: rodri <rgl@antares-labs.eu>
date: Wed Jan 28 12:50:30 EST 2026
libmemdraw: finish the special handling of horizontal and vertical lines in memimageline(2) This allows purely horizontal and vertical lines with line ends other than Endsquare to use the optimized code to rasterize the line. It also fixes an error in the optimized path where the rectangle describing the line would be one pixel off in the max.x or max.y coordinate, for purely horizontal and vertical lines respectively.
--- a/sys/src/libmemdraw/line.c
+++ b/sys/src/libmemdraw/line.c
@@ -11,15 +11,6 @@
Arrow3 = 3,
};
-static
-int
-lmax(int a, int b)
-{- if(a > b)
- return a;
- return b;
-}
-
static Memimage*
membrush(int radius)
{@@ -38,8 +29,7 @@
return brush;
}
-static
-void
+static void
discend(Point p, int radius, Memimage *dst, Memimage *src, Point dsrc, int op)
{Memimage *disc;
@@ -51,12 +41,11 @@
r.min.y = p.y - radius;
r.max.x = p.x + radius+1;
r.max.y = p.y + radius+1;
- memdraw(dst, r, src, addpt(r.min, dsrc), disc, Pt(0,0), op);
+ memdraw(dst, r, src, addpt(r.min, dsrc), disc, ZP, op);
}
}
-static
-void
+static void
arrowend(Point tip, Point *pp, int end, int sin, int cos, int radius)
{int x1, x2, x3;
@@ -89,15 +78,17 @@
pp->y = tip.y+((2*radius+1)*cos/2-x1*sin);
}
+/*
+ * NOTE: Clipping is a little peculiar. We can't use Sutherland-Cohen
+ * clipping because lines are wide. But this is probably just fine:
+ * we do all math with the original p0 and p1, but clip when deciding
+ * what pixels to draw. This means the layer code can call this routine,
+ * using clipr to define the region being written, and get the same set
+ * of pixels regardless of the dicing.
+ */
void
_memimageline(Memimage *dst, Point p0, Point p1, int end0, int end1, int radius, Memimage *src, Point sp, Rectangle clipr, int op)
{- /*
- * BUG: We should really really pick off purely horizontal and purely
- * vertical lines and handle them separately with calls to memimagedraw
- * on rectangles.
- */
-
int hor;
int sin, cos, dx, dy, t;
Rectangle oclipr, r;
@@ -114,16 +105,7 @@
return;
if((src->flags&Frepl)==0 && rectclip(&clipr, rectsubpt(src->r, d))==0)
return;
- /* this means that only verline() handles degenerate lines (p0==p1) */
hor = (abs(p1.x-p0.x) > abs(p1.y-p0.y));
- /*
- * Clipping is a little peculiar. We can't use Sutherland-Cohen
- * clipping because lines are wide. But this is probably just fine:
- * we do all math with the original p0 and p1, but clip when deciding
- * what pixels to draw. This means the layer code can call this routine,
- * using clipr to define the region being written, and get the same set
- * of pixels regardless of the dicing.
- */
if((hor && p0.x>p1.x) || (!hor && p0.y>p1.y)){q = p0;
p0 = p1;
@@ -133,26 +115,58 @@
end1 = t;
}
- if((p0.x == p1.x || p0.y == p1.y) && (end0&0x1F) == Endsquare && (end1&0x1F) == Endsquare){+ /* handle purely vertical or horizontal lines */
+ if(p0.x == p1.x || p0.y == p1.y){r.min = p0;
- r.max = p1;
+ r.max = addpt(p1, Pt(1, 1));
if(p0.x == p1.x){r.min.x -= radius;
- r.max.x += radius+1;
+ r.max.x += radius;
+ cos = 0; sin = ICOSSCALE;
}
else{r.min.y -= radius;
- r.max.y += radius+1;
+ r.max.y += radius;
+ cos = ICOSSCALE; sin = 0;
}
oclipr = dst->clipr;
- sp = addpt(r.min, d);
dst->clipr = clipr;
+ switch(end0 & 0x1F){+ case Enddisc:
+ discend(p0, radius, dst, src, d, op);
+ break;
+ case Endarrow:
+ q.x = ICOSSCALE*p0.x+ICOSSCALE/2-cos/2;
+ q.y = ICOSSCALE*p0.y+ICOSSCALE/2-sin/2;
+ arrowend(q, pts, end0, -sin, -cos, radius);
+ _memfillpolysc(dst, pts, 5, ~0, src, addpt(pts[0], mulpt(d, ICOSSCALE)), 1, 10, op);
+ if(cos)
+ r.min.x = pts[0].x >> 10;
+ else
+ r.min.y = pts[0].y >> 10;
+ break;
+ }
+ switch(end1 & 0x1F){+ case Enddisc:
+ discend(p1, radius, dst, src, d, op);
+ break;
+ case Endarrow:
+ q.x = ICOSSCALE*p1.x+ICOSSCALE/2+cos/2;
+ q.y = ICOSSCALE*p1.y+ICOSSCALE/2+sin/2;
+ arrowend(q, pts, end1, sin, cos, radius);
+ _memfillpolysc(dst, pts, 5, ~0, src, addpt(pts[0], mulpt(d, ICOSSCALE)), 1, 10, op);
+ if(cos)
+ r.max.x = pts[0].x >> 10;
+ else
+ r.max.y = pts[0].y >> 10;
+ break;
+ }
+ sp = addpt(r.min, d);
memimagedraw(dst, r, src, sp, memopaque, sp, op);
dst->clipr = oclipr;
return;
}
-/* Hard: */
/* draw thick line using polygon fill */
icossin2(p1.x-p0.x, p1.y-p0.y, &cos, &sin);
dx = (sin*(2*radius+1))/2;
@@ -217,8 +231,7 @@
* Simple-minded conservative code to compute bounding box of line.
* Result is probably a little larger than it needs to be.
*/
-static
-void
+static void
addbbox(Rectangle *r, Point p)
{if(r->min.x > p.x)
@@ -243,6 +256,14 @@
else
x3 = (end>>23) & 0x1FF;
return x3;
+}
+
+static int
+lmax(int a, int b)
+{+ if(a > b)
+ return a;
+ return b;
}
Rectangle
--
⑨