sys/src/libdraw/unloadimage.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <draw.h>
   4
   5 int
   6 unloadimage(Image *i, Rectangle r, uchar *data, int ndata)
   7 {
   8         int bpl, n, chunk, dx, dy;
   9         uchar *a, *start;
  10         Display *d;
  11
  12         if(!rectinrect(r, i->r)){
  13                 werrstr("unloadimage: bad rectangle");
  14                 return -1;
  15         }
  16         bpl = bytesperline(r, i->depth);
  17         if(ndata < bpl*Dy(r)){
  18                 werrstr("unloadimage: buffer too small");
  19                 return -1;
  20         }
  21         start = data;
  22         d = i->display;
  23         chunk = d->bufsize;
  24         flushimage(d, 0);       /* make sure subsequent flush is for us only */
  25         while(r.min.y < r.max.y){
  26                 dx = Dx(r);
  27                 dy = chunk/bpl;
  28                 if(dy <= 0){
  29                         dy = 1;
  30                         dx = ((chunk*dx)/bpl) & ~7;
  31                         n = bytesperline(Rect(r.min.x, r.min.y, r.min.x+dx, r.min.y+dy), i->depth);
  32                         if(unloadimage(i, Rect(r.min.x+dx, r.min.y, r.max.x, r.min.y+dy), data+n, bpl-n) < 0)
  33                                 return -1;
  34                 } else {
  35                         if(dy > Dy(r))
  36                                 dy = Dy(r);
  37                         n = bpl*dy;
  38                 }
  39                 a = bufimage(d, 1+4+4*4);
  40                 if(a == nil){
  41                         werrstr("unloadimage: %r");
  42                         return -1;
  43                 }
  44                 a[0] = 'r';
  45                 BPLONG(a+1, i->id);
  46                 BPLONG(a+5, r.min.x);
  47                 BPLONG(a+9, r.min.y);
  48                 BPLONG(a+13, r.min.x+dx);
  49                 BPLONG(a+17, r.min.y+dy);
  50                 if(flushimage(d, 0) < 0)
  51                         return -1;
  52                 if(read(d->fd, data, n) < 0)
  53                         return -1;
  54                 data += bpl*dy;
  55                 r.min.y += dy;
  56         }
  57         return data - start;
  58 }