sys/src/libmemlayer/line.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <draw.h>
   4 #include <memdraw.h>
   5 #include <memlayer.h>
   6
   7 struct Lline
   8 {
   9         Point                   p0;
  10         Point                   p1;
  11         Point                   delta;
  12         int                     end0;
  13         int                     end1;
  14         int                     radius;
  15         Point                   sp;
  16         Memlayer                *dstlayer;
  17         Memimage        *src;
  18         int                     op;
  19 };
  20
  21 static void llineop(Memimage*, Rectangle, Rectangle, void*, int);
  22
  23 static
  24 void
  25 _memline(Memimage *dst, Point p0, Point p1, int end0, int end1, int radius, Memimage *src, Point sp, Rectangle clipr, int op)
  26 {
  27         Rectangle r;
  28         struct Lline ll;
  29         Point d;
  30         int srcclipped;
  31         Memlayer *dl;
  32
  33         if(radius < 0)
  34                 return;
  35         if(src->layer)  /* can't draw line with layered source */
  36                 return;
  37         srcclipped = 0;
  38
  39    Top:
  40         dl = dst->layer;
  41         if(dl == nil){
  42                 _memimageline(dst, p0, p1, end0, end1, radius, src, sp, clipr, op);
  43                 return;
  44         }
  45         if(!srcclipped){
  46                 d = subpt(sp, p0);
  47                 if(rectclip(&clipr, rectsubpt(src->clipr, d)) == 0)
  48                         return;
  49                 if((src->flags&Frepl)==0 && rectclip(&clipr, rectsubpt(src->r, d))==0)
  50                         return;
  51                 srcclipped = 1;
  52         }
  53
  54         /* dst is known to be a layer */
  55         p0.x += dl->delta.x;
  56         p0.y += dl->delta.y;
  57         p1.x += dl->delta.x;
  58         p1.y += dl->delta.y;
  59         clipr.min.x += dl->delta.x;
  60         clipr.min.y += dl->delta.y;
  61         clipr.max.x += dl->delta.x;
  62         clipr.max.y += dl->delta.y;
  63         if(dl->clear){
  64                 dst = dst->layer->screen->image;
  65                 goto Top;
  66         }
  67
  68         /* can't use sutherland-cohen clipping because lines are wide */
  69         r = memlinebbox(p0, p1, end0, end1, radius);
  70         /*
  71          * r is now a bounding box for the line;
  72          * use it as a clipping rectangle for subdivision
  73          */
  74         if(rectclip(&r, clipr) == 0)
  75                 return;
  76         ll.p0 = p0;
  77         ll.p1 = p1;
  78         ll.end0 = end0;
  79         ll.end1 = end1;
  80         ll.sp = sp;
  81         ll.dstlayer = dst->layer;
  82         ll.src = src;
  83         ll.radius = radius;
  84         ll.delta = dl->delta;
  85         ll.op = op;
  86         _memlayerop(llineop, dst, r, r, &ll);
  87 }
  88
  89 static
  90 void
  91 llineop(Memimage *dst, Rectangle screenr, Rectangle clipr, void *etc, int insave)
  92 {
  93         struct Lline *ll;
  94         Point p0, p1;
  95
  96         USED(screenr.min.x);
  97         ll = etc;
  98         if(insave && ll->dstlayer->save==nil)
  99                 return;
 100         if(!rectclip(&clipr, screenr))
 101                 return;
 102         if(insave){
 103                 p0 = subpt(ll->p0, ll->delta);
 104                 p1 = subpt(ll->p1, ll->delta);
 105                 clipr = rectsubpt(clipr, ll->delta);
 106         }else{
 107                 p0 = ll->p0;
 108                 p1 = ll->p1;
 109         }
 110         _memline(dst, p0, p1, ll->end0, ll->end1, ll->radius, ll->src, ll->sp, clipr, ll->op);
 111 }
 112
 113 void
 114 memline(Memimage *dst, Point p0, Point p1, int end0, int end1, int radius, Memimage *src, Point sp, int op)
 115 {
 116         _memline(dst, p0, p1, end0, end1, radius, src, sp, dst->clipr, op);
 117 }