added hight and width to canvas

src/lib/ui/Canvas.hx

@@ -40,6 +40,21 @@ abstract Canvas(Array<Array<Pixel>>) to Array<Array<Pixel>> {
 			this[y][x] = value;
 		}
 	}
+
+	public function hight(): Int {
+		return this.length;
+	}
+
+	public function maxWidth() {
+		var max = 0;
+		for (i in 0...this.length){
+			if (this[i].length > max){
+				max = this[i].length;
+			}
+		}
+
+		return max;
+	}
 }
 
 class CanvasKeyValueIterator{