auto-accept/www/js/svg.js

function getPathShapeBetweenPoints(p1, p2, corners) {
    let cornerPoints = [/*[p1.x,p1.y]*/];
    if(corners == 4){
            // draw inbetween p1 & p2.
    // let d = `M ${p1.x},${p1.y} L `;
    //     d += ` ${p1.x},${p2.y} ${p2.x},${p2.y}  ${p2.x},${p1.y}  ${p1.x},${p1.y} `;
        cornerPoints.push([p1.x, p1.y]);
        cornerPoints.push([p1.x, p2.y]);
        cornerPoints.push([p2.x, p2.y]);
        cornerPoints.push([p2.x, p1.y]);
    }
    else{
        // find center of circle that describes the polygon of which p1 and p2 are part
        // it's _not_ the center between the two points, as p1 and p2 are corners on the shape


        // distance between p1 and p2
        const length = Math.sqrt(Math.pow(p1.x-p2.x,2)+ Math.pow(p1.y - p2.y, 2));

        const segmentAngle = Math.PI * 2 / corners;
        // TODO: can we find a way to draw not from the first 3 segments, but have the 
        // cursor span as many segment as possible 
        // const segmentsAngle = Math.floor(180/segmentAngle) * segmentAngle;

        const radius = (length*.5)/Math.sin(segmentAngle);

        const rotation = Math.atan2((p2.y -p1.y),(p2.x - p1.x)) + (Math.PI/2-segmentAngle);

        const dx = Math.cos(rotation) * radius;// * Math.sign(p2.x - p1.x);
        const dy = Math.sin(rotation) * radius;// * Math.sign(p2.y - p1.y);
        // we now have the center:
        const cx = p2.x - dx;
        const cy = p2.y - dy;

        // startpoint in relation to circle
        const sx = cx - p1.x;
        const sy = cy - p1.y;

        let startRot = Math.asin(sx / radius);
        if(sy>0){startRot = -1 * startRot + Math.PI;}
        
        for (let a = 0; a < Math.PI*2; a += segmentAngle) {
            let x = radius * Math.sin(a-startRot) + cx;
            let y = radius * Math.cos(a-startRot) + cy;
            cornerPoints.push([x,y])
            // d += ` ${x},${y}`;

            // d += ` A 50 50 100 1 1 ${x} ${y+0.1} L `
        }

    }


    // teken punten tussen alle punten
    let allCornerPoints = [];
    for (let index = 0; index < cornerPoints.length; index++) {
        const c = cornerPoints[index];
        const nextC = cornerPoints[(index+1)%cornerPoints.length];
        allCornerPoints.push(c);
        allCornerPoints.push([.5*(nextC[0]+c[0]), .5*(nextC[1]+c[1])]);
    }
    cornerPoints = allCornerPoints;

    
    // create d:
    let d = "";
    const r = 10;
    for (let index = 0; index < cornerPoints.length; index++) {
        const c = cornerPoints[index];
        const nextC = cornerPoints[(index+1)%cornerPoints.length];

        const angle = Math.atan2(nextC[1] - c[1], nextC[0] - c[0]);

        const dx = Math.cos(angle) * r;
        const dy = Math.sin(angle) * r;

        d += ` M ${c[0]+dx},${c[1]+dy} L `
        d += ` ${nextC[0]-dx},${nextC[1]-dy}`;
        // Thanks Anthony: https://stackoverflow.com/a/10477334
        d += ` a ${r} ${r} 0 1,0 ${dx*2},${dy*2}`;
        d += ` a ${r} ${r} 0 1,0 ${-dx*2},${-dy*2}`;
        
    }
        

    // console.log(d);
    return d + ' Z';
}

export {getPathShapeBetweenPoints};