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import Point from '@mapbox/point-geometry';
export default clipLine;
/**
* Returns the part of a multiline that intersects with the provided rectangular box.
*
* @param lines
* @param x1 the left edge of the box
* @param y1 the top edge of the box
* @param x2 the right edge of the box
* @param y2 the bottom edge of the box
* @returns lines
* @private
*/
function clipLine(lines: Array<Array<Point>>, x1: number, y1: number, x2: number, y2: number): Array<Array<Point>> {
const clippedLines = [];
for (let l = 0; l < lines.length; l++) {
const line = lines[l];
let clippedLine;
for (let i = 0; i < line.length - 1; i++) {
let p0 = line[i];
let p1 = line[i + 1];
if (p0.x < x1 && p1.x < x1) {
continue;
} else if (p0.x < x1) {
p0 = new Point(x1, p0.y + (p1.y - p0.y) * ((x1 - p0.x) / (p1.x - p0.x)))._round();
} else if (p1.x < x1) {
p1 = new Point(x1, p0.y + (p1.y - p0.y) * ((x1 - p0.x) / (p1.x - p0.x)))._round();
}
if (p0.y < y1 && p1.y < y1) {
continue;
} else if (p0.y < y1) {
p0 = new Point(p0.x + (p1.x - p0.x) * ((y1 - p0.y) / (p1.y - p0.y)), y1)._round();
} else if (p1.y < y1) {
p1 = new Point(p0.x + (p1.x - p0.x) * ((y1 - p0.y) / (p1.y - p0.y)), y1)._round();
}
if (p0.x >= x2 && p1.x >= x2) {
continue;
} else if (p0.x >= x2) {
p0 = new Point(x2, p0.y + (p1.y - p0.y) * ((x2 - p0.x) / (p1.x - p0.x)))._round();
} else if (p1.x >= x2) {
p1 = new Point(x2, p0.y + (p1.y - p0.y) * ((x2 - p0.x) / (p1.x - p0.x)))._round();
}
if (p0.y >= y2 && p1.y >= y2) {
continue;
} else if (p0.y >= y2) {
p0 = new Point(p0.x + (p1.x - p0.x) * ((y2 - p0.y) / (p1.y - p0.y)), y2)._round();
} else if (p1.y >= y2) {
p1 = new Point(p0.x + (p1.x - p0.x) * ((y2 - p0.y) / (p1.y - p0.y)), y2)._round();
}
if (!clippedLine || !p0.equals(clippedLine[clippedLine.length - 1])) {
clippedLine = [p0];
clippedLines.push(clippedLine);
}
clippedLine.push(p1);
}
}
return clippedLines;
}
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