Rect - rectangular portion of the plane .EX 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; }; The type Rect defines a rectangular portion of the integer grid.

10 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.