Simple Paint

Technical interview question for CANImmunize.

You can try it here.

Instructions

Your task is to create an extremely simple version of the Microsoft Paint application. The application has the following requirements:

• It must be built using React and run in the browser.
• The app should support two tools: pencil, and flood fill.
• Those tools will need to support some kind of color picker. We would suggest using an open source package for this.
• The canvas should be made up of squares, and be of configurable size. The user should be able to input their desired dimensions for the canvas. You aren’t required to maintain the drawing state when the user changes the canvas size.
• The user should be able to use the pencil tool to colour individual squares by clicking on them.
• You do not need to implement any kind of drag-to-colour feature like is supported by the real pencil tool. (The user will have to click on each square to colour it.)
• The flood fill tool, should allow the user to fill in all connected squares of the same colour with another colour.