astro-ghostcms/.pnpm-store/v3/files/e5/fc764b04e6a7be9e356086e2203...

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2024-02-14 14:10:47 +00:00
// The Bounding Box object
function derive(v0, v1, v2, v3, t) {
return Math.pow(1 - t, 3) * v0 +
3 * Math.pow(1 - t, 2) * t * v1 +
3 * (1 - t) * Math.pow(t, 2) * v2 +
Math.pow(t, 3) * v3;
}
/**
* A bounding box is an enclosing box that describes the smallest measure within which all the points lie.
* It is used to calculate the bounding box of a glyph or text path.
*
* On initialization, x1/y1/x2/y2 will be NaN. Check if the bounding box is empty using `isEmpty()`.
*
* @exports opentype.BoundingBox
* @class
* @constructor
*/
function BoundingBox() {
this.x1 = Number.NaN;
this.y1 = Number.NaN;
this.x2 = Number.NaN;
this.y2 = Number.NaN;
}
/**
* Returns true if the bounding box is empty, that is, no points have been added to the box yet.
*/
BoundingBox.prototype.isEmpty = function() {
return isNaN(this.x1) || isNaN(this.y1) || isNaN(this.x2) || isNaN(this.y2);
};
/**
* Add the point to the bounding box.
* The x1/y1/x2/y2 coordinates of the bounding box will now encompass the given point.
* @param {number} x - The X coordinate of the point.
* @param {number} y - The Y coordinate of the point.
*/
BoundingBox.prototype.addPoint = function(x, y) {
if (typeof x === 'number') {
if (isNaN(this.x1) || isNaN(this.x2)) {
this.x1 = x;
this.x2 = x;
}
if (x < this.x1) {
this.x1 = x;
}
if (x > this.x2) {
this.x2 = x;
}
}
if (typeof y === 'number') {
if (isNaN(this.y1) || isNaN(this.y2)) {
this.y1 = y;
this.y2 = y;
}
if (y < this.y1) {
this.y1 = y;
}
if (y > this.y2) {
this.y2 = y;
}
}
};
/**
* Add a X coordinate to the bounding box.
* This extends the bounding box to include the X coordinate.
* This function is used internally inside of addBezier.
* @param {number} x - The X coordinate of the point.
*/
BoundingBox.prototype.addX = function(x) {
this.addPoint(x, null);
};
/**
* Add a Y coordinate to the bounding box.
* This extends the bounding box to include the Y coordinate.
* This function is used internally inside of addBezier.
* @param {number} y - The Y coordinate of the point.
*/
BoundingBox.prototype.addY = function(y) {
this.addPoint(null, y);
};
/**
* Add a Bézier curve to the bounding box.
* This extends the bounding box to include the entire Bézier.
* @param {number} x0 - The starting X coordinate.
* @param {number} y0 - The starting Y coordinate.
* @param {number} x1 - The X coordinate of the first control point.
* @param {number} y1 - The Y coordinate of the first control point.
* @param {number} x2 - The X coordinate of the second control point.
* @param {number} y2 - The Y coordinate of the second control point.
* @param {number} x - The ending X coordinate.
* @param {number} y - The ending Y coordinate.
*/
BoundingBox.prototype.addBezier = function(x0, y0, x1, y1, x2, y2, x, y) {
// This code is based on http://nishiohirokazu.blogspot.com/2009/06/how-to-calculate-bezier-curves-bounding.html
// and https://github.com/icons8/svg-path-bounding-box
const p0 = [x0, y0];
const p1 = [x1, y1];
const p2 = [x2, y2];
const p3 = [x, y];
this.addPoint(x0, y0);
this.addPoint(x, y);
for (let i = 0; i <= 1; i++) {
const b = 6 * p0[i] - 12 * p1[i] + 6 * p2[i];
const a = -3 * p0[i] + 9 * p1[i] - 9 * p2[i] + 3 * p3[i];
const c = 3 * p1[i] - 3 * p0[i];
if (a === 0) {
if (b === 0) continue;
const t = -c / b;
if (0 < t && t < 1) {
if (i === 0) this.addX(derive(p0[i], p1[i], p2[i], p3[i], t));
if (i === 1) this.addY(derive(p0[i], p1[i], p2[i], p3[i], t));
}
continue;
}
const b2ac = Math.pow(b, 2) - 4 * c * a;
if (b2ac < 0) continue;
const t1 = (-b + Math.sqrt(b2ac)) / (2 * a);
if (0 < t1 && t1 < 1) {
if (i === 0) this.addX(derive(p0[i], p1[i], p2[i], p3[i], t1));
if (i === 1) this.addY(derive(p0[i], p1[i], p2[i], p3[i], t1));
}
const t2 = (-b - Math.sqrt(b2ac)) / (2 * a);
if (0 < t2 && t2 < 1) {
if (i === 0) this.addX(derive(p0[i], p1[i], p2[i], p3[i], t2));
if (i === 1) this.addY(derive(p0[i], p1[i], p2[i], p3[i], t2));
}
}
};
/**
* Add a quadratic curve to the bounding box.
* This extends the bounding box to include the entire quadratic curve.
* @param {number} x0 - The starting X coordinate.
* @param {number} y0 - The starting Y coordinate.
* @param {number} x1 - The X coordinate of the control point.
* @param {number} y1 - The Y coordinate of the control point.
* @param {number} x - The ending X coordinate.
* @param {number} y - The ending Y coordinate.
*/
BoundingBox.prototype.addQuad = function(x0, y0, x1, y1, x, y) {
const cp1x = x0 + 2 / 3 * (x1 - x0);
const cp1y = y0 + 2 / 3 * (y1 - y0);
const cp2x = cp1x + 1 / 3 * (x - x0);
const cp2y = cp1y + 1 / 3 * (y - y0);
this.addBezier(x0, y0, cp1x, cp1y, cp2x, cp2y, x, y);
};
export default BoundingBox;