TODOs:

• Save and load drawing
• Record each action to restore Canvas state when a drawing is opened
• Retrieve drawing output as png or jpg
• Add circle color picker instead of static color wheel
• Add option to open an image and draw on it
• Add option to display layout grid
• Add option to draw text with properties
• Add option to draw shapes like circle, rectangle or polygons
• Add BitmapShader for different type of pencils