fix image size detection on zero values. fix #774

CHANGELOG.md

@@ -5,6 +5,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Not released:
 
+* Add ability to use `width = 0` and `height = 0` for `Konva.Image`.
+
 ## 4.1.0 - 2019-12-23
 
 * Make events work on some CSS transforms

src/shapes/Image.ts

@@ -92,11 +92,11 @@ export class Image extends Shape<ImageConfig> {
   }
   getWidth() {
     var image = this.image();
-    return this.attrs.width || (image ? image.width : 0);
+    return this.attrs.width ?? (image ? image.width : 0);
   }
   getHeight() {
     var image = this.image();
-    return this.attrs.height || (image ? image.height : 0);
+    return this.attrs.height ?? (image ? image.height : 0);
   }
 
   /**

test/unit/shapes/Image-test.js

@@ -368,4 +368,23 @@ suite('Image', function() {
       done();
     });
   });
+
+  test.only('check zero values', function(done) {
+    var stage = addStage();
+    var layer = new Konva.Layer();
+    stage.add(layer);
+    var src = 'assets/darth-vader.jpg';
+    Konva.Image.fromURL(src, function(image) {
+      layer.add(image);
+      layer.draw();
+
+      image.width(0);
+      image.height(0);
+      layer.draw();
+
+      assert.equal(image.width(), 0);
+      assert.equal(image.height(), 0);
+      done();
+    });
+  });
 });