91 lines
No EOL
3 KiB
JavaScript
91 lines
No EOL
3 KiB
JavaScript
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function getPathShapeBetweenPoints(p1, p2, corners) {
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let cornerPoints = [/*[p1.x,p1.y]*/];
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if(corners == 4){
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// draw inbetween p1 & p2.
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// let d = `M ${p1.x},${p1.y} L `;
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// d += ` ${p1.x},${p2.y} ${p2.x},${p2.y} ${p2.x},${p1.y} ${p1.x},${p1.y} `;
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cornerPoints.push([p1.x, p1.y]);
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cornerPoints.push([p1.x, p2.y]);
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cornerPoints.push([p2.x, p2.y]);
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cornerPoints.push([p2.x, p1.y]);
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}
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else{
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// find center of circle that describes the polygon of which p1 and p2 are part
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// it's _not_ the center between the two points, as p1 and p2 are corners on the shape
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// distance between p1 and p2
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const length = Math.sqrt(Math.pow(p1.x-p2.x,2)+ Math.pow(p1.y - p2.y, 2));
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const segmentAngle = Math.PI * 2 / corners;
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// TODO: can we find a way to draw not from the first 3 segments, but have the
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// cursor span as many segment as possible
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// const segmentsAngle = Math.floor(180/segmentAngle) * segmentAngle;
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const radius = (length*.5)/Math.sin(segmentAngle);
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const rotation = Math.atan2((p2.y -p1.y),(p2.x - p1.x)) + (Math.PI/2-segmentAngle);
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const dx = Math.cos(rotation) * radius;// * Math.sign(p2.x - p1.x);
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const dy = Math.sin(rotation) * radius;// * Math.sign(p2.y - p1.y);
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// we now have the center:
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const cx = p2.x - dx;
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const cy = p2.y - dy;
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// startpoint in relation to circle
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const sx = cx - p1.x;
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const sy = cy - p1.y;
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let startRot = Math.asin(sx / radius);
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if(sy>0){startRot = -1 * startRot + Math.PI;}
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for (let a = 0; a < Math.PI*2; a += segmentAngle) {
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let x = radius * Math.sin(a-startRot) + cx;
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let y = radius * Math.cos(a-startRot) + cy;
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cornerPoints.push([x,y])
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// d += ` ${x},${y}`;
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// d += ` A 50 50 100 1 1 ${x} ${y+0.1} L `
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}
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}
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// teken punten tussen alle punten
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let allCornerPoints = [];
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for (let index = 0; index < cornerPoints.length; index++) {
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const c = cornerPoints[index];
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const nextC = cornerPoints[(index+1)%cornerPoints.length];
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allCornerPoints.push(c);
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allCornerPoints.push([.5*(nextC[0]+c[0]), .5*(nextC[1]+c[1])]);
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}
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cornerPoints = allCornerPoints;
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// create d:
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let d = "";
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const r = 10;
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for (let index = 0; index < cornerPoints.length; index++) {
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const c = cornerPoints[index];
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const nextC = cornerPoints[(index+1)%cornerPoints.length];
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const angle = Math.atan2(nextC[1] - c[1], nextC[0] - c[0]);
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const dx = Math.cos(angle) * r;
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const dy = Math.sin(angle) * r;
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d += ` M ${c[0]+dx},${c[1]+dy} L `
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d += ` ${nextC[0]-dx},${nextC[1]-dy}`;
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// Thanks Anthony: https://stackoverflow.com/a/10477334
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d += ` a ${r} ${r} 0 1,0 ${dx*2},${dy*2}`;
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d += ` a ${r} ${r} 0 1,0 ${-dx*2},${-dy*2}`;
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}
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// console.log(d);
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return d + ' Z';
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}
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export {getPathShapeBetweenPoints}; |