Page 238 - DCAP408_WEB_PROGRAMMING

Windows Programming

Notes 14.11 Keywords

Character Mode: In character mode, the display screen is treated as an array of blocks, each of
which can hold one ASCII character.

Device Context: A device context is a Windows data structure containing information about the
drawing attributes of a device such as a display or a printer.
Graphics mode: In graphics mode, the display screen is treated as an array of pixels, with
characters and other shapes formed by turning on combinations of pixels.
PeekMessage(): PeekMessage() looks into the message queue and checks to see if any messages
are waiting.
WM_PAINT: The WM_PAINT message is sent when the system or another application makes a
request to paint a portion of an application’s window.
14.12 Review Questions

1. Make distinction between character mode and graphic mode.
2. What is a device context? Illustrate the functions of device context.
3. Illustrate the use of WM_PAINT message.
4. Discuss the functions that are used for changing device contexts.

5. Illustrate with example the concept of Setting the Pen or Brush Color.
6. What is graphics output? Elucidate the basic controls in VB that you can use to draw
graphics on your form.

7. Make distinction between GetMessage() and PeekMessage().
8. Explicate the Structure of a PeekMessage() Loop.
9. Elucidate the use of CPaintDC objects and CClientDC objects.

10. You can load a picture at runtime by using the LoadPicture ( ) method. Comment.
Answers: Self Assessment

1. character-based 2. pixels
3. device context 4. CPaintDC
5. drop_caps 6. drop_caps
7. WM_PAINT 8. DispatchMessage

9. ChangeDisplaySettings 10. GetDCBrushColor
11. line 12. 0
13. animated 14. GetMessage()
15. PeekMessage()

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