duplicated code in LatticeCanvasNode and LightScreenNode

[pixelzoom]

For code review #259, identified by grunt find-duplicates.

The code below is duplicated in LatticeCanvasNode.js (lines 51-68) and LightScreenNode.js (lines 59-76).

      const height = this.lattice.height - this.lattice.dampY * 2;

      // @private
      this.directCanvas = document.createElement( 'canvas' );
      this.directCanvas.width = width;
      this.directCanvas.height = height;

      // @private
      this.directContext = this.directCanvas.getContext( '2d' );

      // @private
      this.imageData = this.directContext.createImageData( width, height );

      // Invalidate paint when model indicates changes
      const invalidateSelfListener = this.invalidatePaint.bind( this );
      lattice.changedEmitter.addListener( invalidateSelfListener );

[samreid]

Proposed fix pushed, please review.

[pixelzoom]

ImageDataRenderer looks very nice, could be useful in common code someday (maybe even in Gas Properties). With that in mind...

The first 2 lines of the constructor are:

constructor( lattice, width ) {
 const height = lattice.height - lattice.dampY * 2;

... and the lattice is never used again. How about changing to:

constructor( width, height ) {

... with call sites like:

  this.imageDataRenderer = new ImageDataRenderer( width, this.lattice.height - this.lattice.dampY * 2 );

And perhaps move the this.lattice.height - this.lattice.dampY * 2 computation into method of Lattice, so that it doesn't need to be duplicated at new ImageDataRenderer call sites.

[samreid]

Nice recommendation, thanks! I pushed one commit, please review.

[samreid]

Oops, previous commit had bad jsdoc params, fixed in an additional commit.

[pixelzoom]

👍 Closing.