问使用paperJS绘制多个圆

EN

// path we are currently drawing
var path = null;

// array to store paths (so paper.js would still draw them)
var circles = [];
function onMouseDrag(event) {
    // The radius is the distance between the position
    // where the user clicked and the current position
    // of the mouse.
    path = new Path.Circle({
        center: event.downPoint,
        radius: (event.downPoint - event.point).length,
        fillColor: null,
        strokeColor: 'black',
        strokeWidth: 10
    });

    // Remove this path on the next drag event:
    path.removeOnDrag();

};

function onMouseUp(event) {
    // if mouseUp event fires, save current path into the array
    circles.push(path);
};