Files
blockly/core/utils/rect.ts
2024-08-21 21:02:07 +00:00

128 lines
3.4 KiB
TypeScript

/**
* @license
* Copyright 2019 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/**
* Utility methods for rectangle manipulation.
* These methods are not specific to Blockly, and could be factored out into
* a JavaScript framework such as Closure.
*
* @class
*/
// Former goog.module ID: Blockly.utils.Rect
import {Coordinate} from './coordinate.js';
/**
* Class for representing rectangular regions.
*/
export class Rect {
/**
* @param top Top.
* @param bottom Bottom.
* @param left Left.
* @param right Right.
*/
constructor(
public top: number,
public bottom: number,
public left: number,
public right: number,
) {}
/**
* Creates a new copy of this rectangle.
*
* @returns A copy of this Rect.
*/
clone(): Rect {
return new Rect(this.top, this.bottom, this.left, this.right);
}
/** Returns the height of this rectangle. */
getHeight(): number {
return this.bottom - this.top;
}
/** Returns the width of this rectangle. */
getWidth(): number {
return this.right - this.left;
}
/**
* Tests whether this rectangle contains a x/y coordinate.
*
* @param x The x coordinate to test for containment.
* @param y The y coordinate to test for containment.
* @returns Whether this rectangle contains given coordinate.
*/
contains(x: number, y: number): boolean {
return (
x >= this.left && x <= this.right && y >= this.top && y <= this.bottom
);
}
/**
* Tests whether this rectangle intersects the provided rectangle.
* Assumes that the coordinate system increases going down and left.
*
* @param other The other rectangle to check for intersection with.
* @returns Whether this rectangle intersects the provided rectangle.
*/
intersects(other: Rect): boolean {
// The following logic can be derived and then simplified from a longer form symmetrical check
// of verifying each rectangle's borders with the other rectangle by checking if either end of
// the border's line segment is contained within the other rectangle. The simplified version
// used here can be logically interpreted as ensuring that each line segment of 'this' rectangle
// is not outside the bounds of the 'other' rectangle (proving there's an intersection).
return (
this.left <= other.right &&
this.right >= other.left &&
this.bottom >= other.top &&
this.top <= other.bottom
);
}
/**
* Compares bounding rectangles for equality.
*
* @param a A Rect.
* @param b A Rect.
* @returns True iff the bounding rectangles are equal, or if both are null.
*/
static equals(a?: Rect | null, b?: Rect | null): boolean {
if (a === b) {
return true;
}
if (!a || !b) {
return false;
}
return (
a.top === b.top &&
a.bottom === b.bottom &&
a.left === b.left &&
a.right === b.right
);
}
/**
* Creates a new Rect using a position and supplied dimensions.
*
* @param position The upper left coordinate of the new rectangle.
* @param width The width of the rectangle, in pixels.
* @param height The height of the rectangle, in pixels.
* @returns A newly created Rect using the provided Coordinate and dimensions.
*/
static createFromPoint(
position: Coordinate,
width: number,
height: number,
): Rect {
const left = position.x;
const top = position.y;
return new Rect(top, top + height, left, left + width);
}
}