BITBLT(9.3) BITBLT(9.3)
NAME
Code, addr, bitblt, point, rectf, screenswap, segment,
texture - graphics functions
SYNOPSIS
#include <jerq.h>
typedef int Code;
Code F_STORE, F_XOR, F_OR, F_CLR;
Word *addr(b, p) Bitmap *b; Point p;
void bitblt(sb, r, db, p, f) Bitmap *sb, *db; Rectangle r;
Point p; Code f;
void point(b, p, f) Bitmap *b; Point p; Code f;
void rectf(b, r, f) Bitmap *b; Rectangle r; Code f;
void screenswap(b, r, s) Bitmap *b; Rectangle r, s;
void segment(b, p, q, f) Bitmap *b; Point p, q; Code f;
void texture(b, r, t, f) Bitmap *b; Rectangle r; Texture *t;
Code f;
DESCRIPTION
The type Code tells the graphics primitives what operation
perform. The possible values are:
F_STORE target = source
F_OR target |= source
F_XOR target ^= source
F_CLR target &= ~source
In other words, if a Rectangle is copied to another place
with Code F_OR, the result will be the bitwise OR of the
contents of the source Rectangle and the target area. For
operations with no explicit source, such as line drawing,
the source is taken to be an infinite bitmap with zeros
everywhere except on the object (e.g. line) generated by the
operator, with coordinates aligned with the destination bit-
map. F_STORE is the same as F_OR for non-rectangular opera-
tions.
Addr returns the address of the Word containing the bit at
Point p in the Bitmap b.
Bitblt (bit-block transfer) copies the data in Rectangle r
in Bitmap sb to the congruent Rectangle with origin p in
BITBLT(9.3) BITBLT(9.3)
Bitmap db. The nature of the copy is specified by the Code
f.
Point draws the pixel at location p in the Bitmap b accord-
ing to Code f.
Screenswap does an in-place exchange of the on-screen Rect-
angle s and the Rectangle r within the Bitmap b. Its action
is undefined if r and s are not congruent. The Rectangle s
is not clipped to the Bitmap b, only to the screen.
Segment draws a line segment in Bitmap b from Point p to q,
with Code f. The segment is half-open: p is the first point
of the segment and q is the first point beyond the segment,
so adjacent segments sharing endpoints abut. Like all the
other graphics operations, segment clips the line so that
only the portion of the line intersecting the bitmap is dis-
played.
Texture draws, with function f in the Rectangle r in Bitmap
b, the Texture specified by t. The texture is replicated to
cover r. Rectf is equivalent to texture with *t set to all
one's.
In the above definitions, the type Bitmap may be replaced
with Layer anywhere; see newlayer(9.2).
SEE ALSO
types(9.5)