Fix color filter.

Runtime/painting/decoration_image.cs

             Paint paint = new Paint();
             if (colorFilter != null) {
                 paint.colorFilter = colorFilter;
+                paint.color = colorFilter.color;
+                paint.blendMode = colorFilter.blendMode;
             }
 
             if (sourceSize != destinationSize) {

Runtime/rendering/image.cs

             this._alignment = alignment ?? Alignment.center;
             this._invertColors = invertColors;
             this._filterMode = filterMode;
+            this._updateColorFilter();
         }
 
         Image _image;
                 }
 
                 this._color = value;
+                this._updateColorFilter();
                 this.markNeedsPaint();
             }
         }
                 }
 
                 this._colorBlendMode = value;
+                this._updateColorFilter();
                 this.markNeedsPaint();
             }
         }