DRAW-RECT(2) DRAW-RECT(2)
NAME
Rect - rectangular portion of the plane
SYNOPSIS
include "draw.m";
draw := load Draw Draw->PATH;
Rect: adt
{
min: Point;
max: Point;
canon: fn(r: self Rect): Rect;
dx: fn(r: self Rect): int;
dy: fn(r: self Rect): int;
eq: fn(r: self Rect, s: Rect): int;
Xrect: fn(r: self Rect, s: Rect): int;
inrect: fn(r: self Rect, s: Rect): int;
clip: fn(r: self Rect, s: Rect): (Rect, int);
combine: fn(r: self Rect, s: Rect): Rect;
contains: fn(r: self Rect, p: Point): int;
addpt: fn(r: self Rect, p: Point): Rect;
subpt: fn(r: self Rect, p: Point): Rect;
inset: fn(r: self Rect; n: int): Rect;
};
DESCRIPTION
The type Rect defines a rectangular portion of the integer
grid.
min, max These members define the upper left (min) and
lower right (max) points for the rectangle. The
rectangle contains the pixels min.x _< x < max.x
and min.y _< y < max.y. In general, Rect coordi-
nates should be in canonical form: min.x _< max.x
and min.y _< max.y. Some functions give undefined
results if the input rectangles are not canonical.
r.canon() Returns a canonical rectangle by sorting the coor-
dinates of r.
r.dx() Returns the horizontal dimension of r.
r.dy() Returns the vertical dimension of r.
r.eq(s) Returns non-zero if the rectangles r and s have
the same coordinates and zero otherwise.
r.Xrect(s)
Returns non-zero if the rectangles r and s
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DRAW-RECT(2) DRAW-RECT(2)
intersect and zero otherwise. Intersection means
the rectangles share at least one pixel; zero-
sized rectangles do not intersect.
r.inrect(s)
Returns non-zero if r is completely inside s and
zero otherwise. Rectangles with equal coordinates
are considered to be inside each other. Zero-
sized rectangles contain no rectangles.
r.clip(s) Computes the intersection between r and s. If the
input rectangles intersect, clip returns the
resulting rectangle and a non-zero integer value.
If the rectangles do not intersect, clip returns r
and a zero value.
r.combine(s)
Returns the smallest rectangle sufficient to cover
all the pixels of r and s.
r.contains(p)
Returns non-zero if the rectangle r contains the
pixel with the coordinates of p and zero other-
wise. Zero-sized rectangles contain no points.
r.addpt(p)
Returns the rectangle (r.min.add(p),
r.max.add(p)).
r.subpt(p)
Returns the rectangle (r.min.sub(p),
r.max.sub(p)).
r.inset(n)
Returns the rectangle (r.min.add((n, n)),
r.max.sub((n, n)). The result will not be in
canonical form if the inset amount is too large
for the rectangle.
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