kinetic.js stage.getDragLayer method

Question

I am trying to learn some kinetic.js. I heve some problem with following example:

http://www.html5canvastutorials.com/labs/html5-canvas-modify-curves-with-anchor-points-using-kineticjs/

What does this part actually do:

stage.getDragLayer().beforeDraw(function() {
      drawCurves(curveLayer.getCanvas(), layer.quad, layer.bezier);
      updateDottedLines(layer);
    });

I mean getDragLayer() method and beforeDraw() method.

Answer 1

KineticJS builds a specialized layer that handles drag/drops.

getDragLayer() gets a reference to this layer.

beforeDraw() allows a function to be executed before any drawing related to the drag/drop are started. In this case, drawCurves() and updateDottedLines() are called--these 2 functions are defined in the demo you're learning.