Import sources from 2011-03-30 iso image

sys/src/libmemlayer/lalloc.c

@@ -0,0 +1,79 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <memlayer.h>
+
+Memimage*
+memlalloc(Memscreen *s, Rectangle screenr, Refreshfn refreshfn, void *refreshptr, ulong val)
+{
+	Memlayer *l;
+	Memimage *n;
+	static Memimage *paint;
+
+	if(paint == nil){
+		paint = allocmemimage(Rect(0,0,1,1), RGBA32);
+		if(paint == nil)
+			return nil;
+		paint->flags |= Frepl;
+		paint->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
+	}
+
+	n = allocmemimaged(screenr, s->image->chan, s->image->data);
+	if(n == nil)
+		return nil;
+	l = malloc(sizeof(Memlayer));
+	if(l == nil){
+		free(n);
+		return nil;
+	}
+
+	l->screen = s;
+	if(refreshfn)
+		l->save = nil;
+	else{
+		l->save = allocmemimage(screenr, s->image->chan);
+		if(l->save == nil){
+			free(l);
+			free(n);
+			return nil;
+		}
+		/* allocmemimage doesn't initialize memory; this paints save area */
+		if(val != DNofill)
+			memfillcolor(l->save, val);
+	}
+	l->refreshfn = refreshfn;
+	l->refreshptr = nil;	/* don't set it until we're done */
+	l->screenr = screenr;
+	l->delta = Pt(0,0);
+
+	n->data->ref++;
+	n->zero = s->image->zero;
+	n->width = s->image->width;
+	n->layer = l;
+
+	/* start with new window behind all existing ones */
+	l->front = s->rearmost;
+	l->rear = nil;
+	if(s->rearmost)
+		s->rearmost->layer->rear = n;
+	s->rearmost = n;
+	if(s->frontmost == nil)
+		s->frontmost = n;
+	l->clear = 0;
+
+	/* now pull new window to front */
+	_memltofrontfill(n, val != DNofill);
+	l->refreshptr = refreshptr;
+
+	/*
+	 * paint with requested color; previously exposed areas are already right
+	 * if this window has backing store, but just painting the whole thing is simplest.
+	 */
+	if(val != DNofill){
+		memsetchan(paint, n->chan);
+		memfillcolor(paint, val);
+		memdraw(n, n->r, paint, n->r.min, nil, n->r.min, S);
+	}
+	return n;
+}