NEWLAYER(9.2) NEWLAYER(9.2)
NAME
newlayer, dellayer, lbitblt, lpoint, lrectf, lsegment,
ltexture, upfront - layer control and graphics
SYNOPSIS
#include <jerq.h>
Layer *newlayer(r); Rectangle r;
void dellayer(l) Layer *l;
void lbitblt(sl, r, dl, p, f) Layer *sl, *dl; Rectangle r;
Point p; Code f;
void lpoint(l, p, f) Layer *l; Point p; Code f;
void lrectf(l, r, f) Layer *l; Rectangle r; Code f;
void segment(l, p, q, f) Layer *l; Point p, q; Code f;
void ltexture(l, r, t, f) Layer *l; Rectangle r; Texture *t;
Code f;
DESCRIPTION
Newlayer creates a layer in Rectangle r in the physical dis-
play bitmap, and returns its address, or 0 on failure.
Newproc(9.2) explains how to attach a process to a layer.
Dellayer de-allocates a layer; the associated process must
also be freed (see newproc(9.2)).
The routines lbitblt, lpoint, lsegment and ltexture are
equivalent to their bitblt(9.3) counterparts except that
they never inhibit the mouse cursor, so they are mainly use-
ful only for implementation of efficient composite graphics
operations such as circle-drawing. Because of the duality
of Bitmaps and Layers, arguments of either type may be
passed freely to any of the graphics primitives.
SEE ALSO
bitblt(9.3), newproc(9.2)
Graphics in Overlapping Bitmap Layers, Rob Pike, ACM Trans.
on Graphics, April 1983.