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 coordinates 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 coordinates 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 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 otherwise. 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.