Ivor Horton's Beginning Visual C++ 2012

SUMMARY

After completing this chapter, you should have a good grasp of how to write message handlers for the mouse, and how to organize drawing operations in your Windows programs. You have seen how using polymorphism with the shape classes makes it possible to operate on any shape in the same way, regardless of its actual type.

EXERCISES

1. Add a menu item and Toolbar button to Sketcher for an ellipse element. Add an element type for ellipses and define a class to support drawing ellipses defined by two points on opposite corners of their enclosing rectangle.

2. Which functions must you modify to support drawing ellipses? Modify the program to draw ellipses.

3. Which functions must you modify in the example from the previous exercise so that the first point defines the center of the ellipse, and the current cursor position defines a corner of the enclosing rectangle? Modify the example to work this way. (Hint: look up the CPoint class members in Help.)

4. Add a new Pen Style menu to the menu bar to allow solid, dashed, dotted, dash-dotted, and dash-dot-dotted lines to be specified.

5. Which parts of the program need to be modified to support the operation of the menu, and the drawing of elements in the line types listed in the previous exercise?

6. Implement support for the new menu and drawing all elements in any of the line types.

WHAT YOU LEARNED IN THIS CHAPTER

TOPIC	CONCEPT
The client coordinate system	By default, Windows addresses the client area of ...