ref: 901dd9c361590f17f29ad5145845c8f070d1d2a9
parent: 4819125f8871bab19a4058f14b56bd933d78a357
author: qwx <qwx@sciops.net>
date: Wed Mar 11 19:24:41 EDT 2020
drw: refactor drawpic, make it more comprehensible
--- a/drw.c
+++ b/drw.c
@@ -74,60 +74,62 @@
}
}
+static int
+boundpic(Rectangle *r)
+{+ r->min.x -= pan.x / scale;
+ r->min.y -= pan.y / scale;
+ if(r->min.x + r->max.x < 0 || r->min.x >= fbw / scale
+ || r->min.y + r->max.y < 0 || r->min.y >= fbh)
+ return -1;
+ if(r->min.x < 0){+ r->max.x += r->min.x;
+ r->min.x = 0;
+ }else if(r->min.x + r->max.x > fbw / scale)
+ r->max.x = fbw / scale - r->min.x;
+ if(r->min.y < 0){+ r->max.y += r->min.y;
+ r->min.y = 0;
+ }else if(r->min.y + r->max.y > fbh)
+ r->max.y = fbh - r->min.y;
+ r->min.x *= scale;
+ r->max.x *= scale;
+ return 0;
+}
+
static void
drawpic(int x, int y, Pic *pic)
{- int n, k, w, pw, s, off;
- u32int v, *pp, *ip;
+ int n, w, Δp, Δq;
+ u32int v, *p, *q;
+ Rectangle r;
- /* FIXME: naming here sucks and is very confusing */
- off = 0;
- ip = pic->p;
- pw = pic->w;
- n = pic->h;
- x -= pic->dx;
- y -= pic->dy;
- x -= pan.x / scale;
- y -= pan.y / scale;
- x *= scale;
- if(x + pw * scale < 0 || x > fbw
- || y + n < 0 || y > fbh)
+ r = Rect(x - pic->dx, y - pic->dy, pic->w, pic->h);
+ if(boundpic(&r) < 0)
return;
- if(y < 0){- ip -= y * pw;
- n += y;
- y = 0;
+ q = pic->p;
+ Δq = 0;
+ if(r.max.x < pic->w){+ Δq = pic->w - r.max.x;
+ if(r.min.x == 0)
+ q += Δq;
}
- if(x < 0){- ip -= x / scale;
- off += pw;
- pw += x / scale;
- off -= pw;
- x = 0;
- }
- pp = fb + y * fbw + x;
- if(pp >= fbe)
- return;
- if(x + pw * scale > fbw){- off += pw;
- pw = (fbw - x) / scale;
- off -= pw;
- }
- if(y + n > fbh)
- n = fbh - y;
- w = fbw - pw * scale;
- while(n-- > 0){- k = pw;
- while(k-- > 0){- v = *ip++;
+ if(r.max.y < pic->h && r.min.y == 0)
+ q += pic->w * (pic->h - r.max.y);
+ p = fb + r.min.y * fbw + r.min.x;
+ Δp = fbw - r.max.x * scale;
+ while(r.max.y-- > 0){+ w = r.max.x;
+ while(w-- > 0){+ v = *q++;
if(v & 0xff << 24){- for(s=0; s<scale; s++)
- *pp++ = v;
+ for(n=0; n<scale; n++)
+ *p++ = v;
}else
- pp += scale;
+ p += scale;
}
- ip += off;
- pp += w;
+ q += Δq;
+ p += Δp;
}
}