Page 221 - DCAP408_WEB_PROGRAMMING

Unit 13: Windows GDI

Language Barriers Notes

Of course, there is also another issue – programming languages. Once a developer learns
a programming language, he is not always eager to jump from what he knows to what he
doesn't because this involves relearning a language. Karunakaran, who is well-versed
with Java, says that he can't move to iOS because he is required to program it in Objective
C, a language that he is not familiar with. He also has no desire to move to Android, a
platform that he says he doesn't like. "Android has a lot of bugs even with basic features
like phone calls and SMS. I have an Android phone and these bugs are making it difficult
for me to use the phone," he said.

So, is the BlackBerry developer market filled with people who don't like other platforms,
or can't move away for various reasons? Mathew disagrees. "Apple is not the most popular
brand in India. That is why developers want to get on to BlackBerry." Highlighting Indian
players like MakeMyTrip, Naukri and Shaadi, she said, "They first made an appearance on
BlackBerry and only then did they get on other platforms. For developers in India, it is
BlackBerry, Android and iOS, in that order."

13.2 Summary

 GDI stands for Graphics Device Interface. It provides many functions for displaying graphics
in your Windows application.
 GDI uses the concept of Pens and Brushes. A Pen defines the style and colour that pixels
will be drawn in while a brush determines the fill colour of shapes.
 We can use CreateSolidBrush to create a solid coloured brush or CreateBrushIndirect to
create a brush with specific styles (like hatched) or even using a loaded bitmap.

 Sometimes you would like to update your window whenever you want. To do this you
have to tell Windows that your window is dirty and needs a redraw. You can do this by
using InvalidateRect.
13.3 Keywords

GDI: Graphics Device Interface
HDC: Handle to a Device Context

13.4 Review Questions

1. Windows-based applications do not access the graphics hardware directly. Explain.

2. To obtain the handle you call: BeginPaint, it takes your window handle and a pointer to a
PAINTSTRUCT that you have declared. Discuss.
3. You can also use PolyLine, PolyPolyLine, Arc etc. To explore which ones are available
look in the MSDN help. Analyze.
4. A number of the GDI drawing functions can be effected by the pen or brush chosen.
Elaborate.
5. When you create a window you can specify its size. Explain with an example.

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