Exercise 1:  C# Application, Painting Tool

The goal of this homework is to gain experience in developing user interfaces using the C# programming language.  The basic principles learned here in C# will carry over to many other GUI programming languages.

Develop a simple graffiti application that enables users to paint pictures using the mouse.  User required features are:

• painting using a paintbrush tool (by click-and-drag on the painting canvas).
• controlling the color of the paint for the paintbrush;  multiple colors can be used in a single picture.
• controlling the width of the paintbrush with a slider.
• unlimited "undo" of paint actions.
• selective deletion of paint actions -- clicking on/near previous paint actions deletes them (this is the hard one, save for last).
• clearing the canvas.
• show an "About" popup dialog box that displays your name.

Also, the application window containing the paint canvas must:

• be resizable (with the paint canvas resizing to fill the available window space).
• not lose the current painted picture when the window is resized or manipulated in any way.