shithub: plan9front

ref: 7dcc3eb27a449eb72a66a915b18d7376c8d0e0e9
dir: /sys/src/libmemdraw/unload.c/

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#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;
}