Function makeClippedPolygon

src/plots/polar/helpers.js:122–170

(r, a0, a1, vangles)

}

function makeClippedPolygon(r, a0, a1, vangles) {
    var len = vangles.length;
    var vertices = [];
    var i, j;

    function a2xy(a) {
        return [r * Math.cos(a), r * Math.sin(a)];
    }

    function findXY(va0, va1, s) {
        return findIntersectionXY(va0, va1, s, a2xy(va0));
    }

    function cycleIndex(ind) {
        return Lib.mod(ind, len);
    }

    function isInside(v) {
        return isAngleInsideSector(v, [a0, a1]);
    }

    // find index in sector closest to a0
    // use it to find intersection of v[i0] <-> v[i0-1] edge with sector radius
    var i0 = findIndexOfMin(vangles, function(v) {
        return isInside(v) ? angleDist(v, a0) : Infinity;
    });
    var xy0 = findXY(vangles[i0], vangles[cycleIndex(i0 - 1)], a0);
    vertices.push(xy0);

    // fill in in-sector vertices
    for(i = i0, j = 0; j < len; i++, j++) {
        var va = vangles[cycleIndex(i)];
        if(!isInside(va)) break;
        vertices.push(a2xy(va));
    }

    // find index in sector closest to a1,
    // use it to find intersection of v[iN] <-> v[iN+1] edge with sector radius
    var iN = findIndexOfMin(vangles, function(v) {
        return isInside(v) ? angleDist(v, a1) : Infinity;
    });
    var xyN = findXY(vangles[iN], vangles[cycleIndex(iN + 1)], a1);
    vertices.push(xyN);

    vertices.push([0, 0]);
    vertices.push(vertices[0].slice());

    return vertices;
}

function makePolygon(r, a0, a1, vangles) {
    return Lib.isFullCircle([a0, a1]) ?