ref: 1b7e120c090af2f8f0e17a664ba0e5e5d7f261a0
dir: /sys/src/libmemdraw/unload.c/
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>
int
unloadmemimage(Memimage *i, Rectangle r, uchar *data, int ndata)
{
int y, l;
uchar *q;
if(badrect(r) || !rectinrect(r, i->r))
return -1;
l = bytesperline(r, i->depth);
if(ndata < l*Dy(r))
return -1;
ndata = l*Dy(r);
q = byteaddr(i, r.min);
for(y=r.min.y; y<r.max.y; y++){
memmove(data, q, l);
q += i->width*sizeof(ulong);
data += l;
}
return ndata;
}