fix: correclty handle color property change

Author: farfromrefug

Diff for: src/canvas.common.ts

@@ -1,4 +1,4 @@
-import { ChangedData, Observable, ObservableArray, Property, Screen, View, booleanConverter } from '@nativescript/core';
+import { ChangedData, Observable, ObservableArray, Property, Screen, View, booleanConverter, colorProperty } from '@nativescript/core';
 import { layout } from '@nativescript/core/utils/utils';
 import { Canvas, Rect, RectF } from './canvas';
 import Shape from './shapes/shape';
@@ -161,6 +161,12 @@ export abstract class CanvasBase extends View {
         shape.off(Observable.propertyChangeEvent, this.onShapePropertyChange, this);
     }
 
+    [colorProperty.setNative](value) {
+        if (!!this._shapes) {
+            this.requestDrawShapes();
+        }
+    }
+
     [densityProperty.setNative](value) {
         if (!!this._shapes) {
             this.requestDrawShapes();

Diff for: src/canvas.ios.ts

@@ -1106,6 +1106,7 @@ export class Paint implements IPaint {
         } else {
             this.alpha = 255;
         }
+        this._textAttribs = null;
     }
     getColor(): Color {
         return this._color;