I am using opencv.js and my code is based on the intelligent scissors tutorial:

let src = cv.imread('canvasInput');
//cv.resize(src, src, new cv.Size(1024, 1024));
cv.imshow('canvasOutput', src);

let tool = new cv.segmentation_IntelligentScissorsMB();
tool.setEdgeFeatureCannyParameters(32, 100);
tool.setGradientMagnitudeMaxLimit(200);
tool.applyImage(src);

let hasMap = false;

let canvas = document.getElementById('canvasOutput');
canvas.addEventListener('click', e => {
    let startX = e.offsetX, startY = e.offsetY; console.log(startX, startY);
    if (startX < src.cols && startY < src.rows)
    {
        console.time('buildMap');
        tool.buildMap(new cv.Point(startX, startY));
        console.timeEnd('buildMap');
        hasMap = true;
    }
});
canvas.addEventListener('mousemove', e => {
    let x = e.offsetX, y = e.offsetY; //console.log(x, y);
    let dst = src.clone();
    if (hasMap && x >= 0 && x < src.cols && y >= 0 && y < src.rows)
    {
        let contour = new cv.Mat();
        tool.getContour(new cv.Point(x, y), contour);
        let contours = new cv.MatVector();
        contours.push_back(contour);
        let color = new cv.Scalar(0, 255, 0, 255);  // RGBA
        cv.polylines(dst, contours, false, color, 1, cv.LINE_8);
        contours.delete(); contour.delete();
    }
    cv.imshow('canvasOutput', dst);
    dst.delete();
});
canvas.addEventListener('dispose', e => {
    src.delete();
    tool.delete();
});

Instead of drawing the polylines of the contour to the canvas with the cv.polylines(dst, contours, false, color, 1, cv.LINE_8); method, I want to convert the contours into an array of screen points (width, height). [[w0, h0], ... [wi, hi]]

When I inspect the contour variable after calling the tool.getContour(new cv.Point(x, y), contour); I see this: