Initial revision
diff --git a/src/libdraw/ml-ltorear.c b/src/libdraw/ml-ltorear.c
new file mode 100644
index 0000000..d53e8cc
--- /dev/null
+++ b/src/libdraw/ml-ltorear.c
@@ -0,0 +1,69 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <memlayer.h>
+
+void
+_memltorear(Memimage *i, Memimage *rear)
+{
+ Memlayer *l;
+ Memscreen *s;
+ Memimage *f, *r, *rr;
+ Rectangle x;
+ int overlap;
+
+ l = i->layer;
+ s = l->screen;
+ while(l->rear != rear){
+ r = l->rear;
+ x = l->screenr;
+ overlap = rectclip(&x, r->layer->screenr);
+ if(overlap){
+ memlhide(i, x);
+ l->clear = 0;
+ }
+ /* swap l and r in screen's list */
+ rr = r->layer->rear;
+ f = l->front;
+ if(rr == nil)
+ s->rearmost = i;
+ else
+ rr->layer->front = i;
+ if(f == nil)
+ s->frontmost = r;
+ else
+ f->layer->rear = r;
+ l->rear = rr;
+ l->front = r;
+ r->layer->rear = i;
+ r->layer->front = f;
+ if(overlap)
+ memlexpose(r, x);
+ }
+}
+
+void
+memltorear(Memimage *i)
+{
+ _memltorear(i, nil);
+ _memlsetclear(i->layer->screen);
+}
+
+void
+memltorearn(Memimage **ip, int n)
+{
+ Memimage *i, *rear;
+ Memscreen *s;
+
+ if(n == 0)
+ return;
+ rear = nil;
+ while(--n >= 0){
+ i = *ip++;
+ _memltorear(i, rear);
+ rear = i;
+ }
+ s = rear->layer->screen;
+ _memlsetclear(s);
+}
