Add new property imageSmoothingEnabled to the layer. some ts fixes.

src/BaseLayer.ts

@@ -35,6 +35,9 @@ export abstract class BaseLayer extends Container<Group | Shape> {
     super(config);
     this.on('visibleChange', this._checkVisibility);
     this._checkVisibility();
+
+    this.on('imageSmoothingEnabledChange', this._checkSmooth);
+    this._checkSmooth();
   }
   // for nodejs?
   createPNGStream() {
@@ -206,6 +209,10 @@ export abstract class BaseLayer extends Container<Group | Shape> {
       this.canvas._canvas.style.display = 'none';
     }
   }
+
+  _checkSmooth() {
+    this.getContext()._context.imageSmoothingEnabled = this.imageSmoothingEnabled();
+  }
   /**
    * get/set width of layer.getter return width of stage. setter doing nothing.
    * if you want change width use `stage.width(value);`
@@ -275,10 +282,30 @@ export abstract class BaseLayer extends Container<Group | Shape> {
   }
 
   clearBeforeDraw: GetSet<boolean, this>;
+  imageSmoothingEnabled: GetSet<boolean, this>;
 }
 
 BaseLayer.prototype.nodeType = 'BaseLayer';
 
+/**
+ * get/set imageSmoothingEnabled flag
+ * For more info see https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/imageSmoothingEnabled
+ * @name Konva.BaseLayer#imageSmoothingEnabled
+ * @method
+ * @param {Boolean} imageSmoothingEnabled
+ * @returns {Boolean}
+ * @example
+ * // get imageSmoothingEnabled flag
+ * var imageSmoothingEnabled = layer.imageSmoothingEnabled();
+ *
+ * // disable clear before draw
+ * layer.imageSmoothingEnabled(false);
+ *
+ * // enable clear before draw
+ * layer.imageSmoothingEnabled(true);
+ */
+Factory.addGetterSetter(BaseLayer, 'imageSmoothingEnabled', true);
+
 /**
  * get/set clearBeforeDraw flag which determines if the layer is cleared or not
  *  before drawing

src/Context.ts

@@ -62,7 +62,8 @@ var CONTEXT_PROPERTIES = [
   'textAlign',
   'textBaseline',
   'globalAlpha',
-  'globalCompositeOperation'
+  'globalCompositeOperation',
+  'imageSmoothingEnabled'
 ];
 
 // TODO: document all context methods

src/FastLayer.ts

@@ -31,6 +31,7 @@ export class FastLayer extends BaseLayer {
   }
   _setCanvasSize(width, height) {
     this.canvas.setSize(width, height);
+    this._checkSmooth();
   }
   hitGraphEnabled() {
     return false;

src/Group.ts

@@ -16,7 +16,7 @@ import { Shape } from './Shape';
  * var group = new Konva.Group();
  */
 export class Group extends Container<Group | Shape> {
-  _validateAdd(child: Group | Shape) {
+  _validateAdd(child: Node) {
     var type = child.getType();
     if (type !== 'Group' && type !== 'Shape') {
       Util.throw('You may only add groups and shapes to groups.');

src/Layer.ts

@@ -53,6 +53,7 @@ export class Layer extends BaseLayer {
   _setCanvasSize(width, height) {
     this.canvas.setSize(width, height);
     this.hitCanvas.setSize(width, height);
+    this._checkSmooth();
   }
   _validateAdd(child) {
     var type = child.getType();

src/Node.ts

@@ -157,7 +157,8 @@ var ABSOLUTE_OPACITY = 'absoluteOpacity',
   ].join(SPACE),
   SCALE_CHANGE_STR = ['scaleXChange.konva', 'scaleYChange.konva'].join(SPACE);
 
-const emptyChildren: Collection<Node> = new Collection();
+// TODO: can we remove children from node?
+const emptyChildren: Collection<any> = new Collection();
 
 let idCounter = 1;
 
@@ -183,7 +184,7 @@ export abstract class Node<Config extends NodeConfig = NodeConfig> {
   } = {};
   attrs: any = {};
   index = 0;
-  parent: Container<Node> | undefined = undefined;
+  parent: Container<Node> | null = null;
   _cache: Map<string, any> = new Map<string, any>();
   _lastPos: Point = null;
   _attrsAffectingSize!: string[];