CreateJS/EaselJS — pull request #447 by abtv (2014-05-16 13:39:00+00:00)
Title: Incorrect using reference was fixed

Hello. I'm started using easeljs and modified one of your examples. In particular case (with stroke = 1 and green color on white background) line looks less smoothly than in my variant. This is not a problem in your example because you have really thick pen, but you may fix it. You incorrectly initialized object with a reference instead of creating an object.
You may replace
oldPt = new createjs.Point(stage.mouseX, stage.mouseY);
oldMidPt = oldPt;
with
oldPt = new createjs.Point(stage.mouseX, stage.mouseY);
oldMidPt = new createjs.Point(oldPt.x, oldPt.y);

You can modify handleMouseMove by adding console.log("oldMidPt are equals oldPt: " + (oldMidPt === oldPt)) as here and you'll see the problem:

function handleMouseMove(event) {
var midPt = new createjs.Point(oldPt.x + stage.mouseX>>1, oldPt.y+stage.mouseY>>1);

drawingCanvas.graphics.clear().setStrokeStyle(stroke, 'round', 'round').beginStroke(color).moveTo(midPt.x, midPt.y).curveTo(oldPt.x, oldPt.y, oldMidPt.x, oldMidPt.y);

oldPt.x = stage.mouseX;
oldPt.y = stage.mouseY;

oldMidPt.x = midPt.x;
oldMidPt.y = midPt.y;

console.log("oldMidPt are equals oldPt: " + (oldMidPt === oldPt));

stage.update();
}