rough/bin/utils/hachure.js

import { Segment } from '../geometry';
export class HachureIterator {
    constructor(top, bottom, left, right, gap, sinAngle, cosAngle, tanAngle) {
        this.deltaX = 0;
        this.hGap = 0;
        this.top = top;
        this.bottom = bottom;
        this.left = left;
        this.right = right;
        this.gap = gap;
        this.sinAngle = sinAngle;
        this.tanAngle = tanAngle;
        if (Math.abs(sinAngle) < 0.0001) {
            this.pos = left + gap;
        }
        else if (Math.abs(sinAngle) > 0.9999) {
            this.pos = top + gap;
        }
        else {
            this.deltaX = (bottom - top) * Math.abs(tanAngle);
            this.pos = left - Math.abs(this.deltaX);
            this.hGap = Math.abs(gap / cosAngle);
            this.sLeft = new Segment([left, bottom], [left, top]);
            this.sRight = new Segment([right, bottom], [right, top]);
        }
    }
    nextLine() {
        if (Math.abs(this.sinAngle) < 0.0001) {
            if (this.pos < this.right) {
                const line = [this.pos, this.top, this.pos, this.bottom];
                this.pos += this.gap;
                return line;
            }
        }
        else if (Math.abs(this.sinAngle) > 0.9999) {
            if (this.pos < this.bottom) {
                const line = [this.left, this.pos, this.right, this.pos];
                this.pos += this.gap;
                return line;
            }
        }
        else {
            let xLower = this.pos - this.deltaX / 2;
            let xUpper = this.pos + this.deltaX / 2;
            let yLower = this.bottom;
            let yUpper = this.top;
            if (this.pos < (this.right + this.deltaX)) {
                while (((xLower < this.left) && (xUpper < this.left)) || ((xLower > this.right) && (xUpper > this.right))) {
                    this.pos += this.hGap;
                    xLower = this.pos - this.deltaX / 2;
                    xUpper = this.pos + this.deltaX / 2;
                    if (this.pos > (this.right + this.deltaX)) {
                        return null;
                    }
                }
                const s = new Segment([xLower, yLower], [xUpper, yUpper]);
                if (this.sLeft && s.intersects(this.sLeft)) {
                    xLower = s.xi;
                    yLower = s.yi;
                }
                if (this.sRight && s.intersects(this.sRight)) {
                    xUpper = s.xi;
                    yUpper = s.yi;
                }
                if (this.tanAngle > 0) {
                    xLower = this.right - (xLower - this.left);
                    xUpper = this.right - (xUpper - this.left);
                }
                const line = [xLower, yLower, xUpper, yUpper];
                this.pos += this.hGap;
                return line;
            }
        }
        return null;
    }
}