Adobe Animate Canvas

hello! I want to use bitmap image as masked object from shape that is generated by user input:

// Load the image
var image = new Image();
image.src="image.jpg";
var bitmap = new createjs.Bitmap(image);
bitmap.cache(0, 0, image.width, image.height);
var drawingShape = new createjs.Shape();


// Handle user input for drawing
stage.addEventListener("stagemousedown", startDrawing);
stage.addEventListener("stagemousemove", continueDrawing);
stage.addEventListener("stagemouseup", stopDrawing);

var isDrawing = false;
var lastX, lastY;

function startDrawing(event) {
    isDrawing = true;
    var pt = drawingShape.globalToLocal(event.stageX, event.stageY);
    lastX = pt.x;
    lastY = pt.y;
	updateCanvas();
}

function continueDrawing(event) {
    if (!isDrawing) return;

    var pt = drawingShape.globalToLocal(event.stageX, event.stageY);

    // Draw a line segment
    drawingShape.graphics.setStrokeStyle(40, "round").beginStroke("#000").moveTo(lastX, lastY).lineTo(pt.x, pt.y).endStroke();

    lastX = pt.x;
    lastY = pt.y;

    updateCanvas();
}

function stopDrawing(event) {
    isDrawing = false;
}


function updateCanvas() {
	stage.addChild(bitmap);
	bitmap.mask = drawingShape;
	stage.addChild(drawingShape);
	stage.update();
}

updateCanvas()

But image not showing on top, where might be a problem?