C# 4 and .NET 4

OC48 ❘ ChaPTer 48 GrAphics with Gdi+
figure 48-20
summary
This chapter covered the realm of GDI+ — the area of drawing to a display device, where the drawing is
done by your code rather than by some predefined control or dialog box. GDI+ is a powerful tool, and
there are many .NET base classes available to help you draw to a device. You have seen that the process of
drawing is actually relatively simple. In most cases, you can draw text or sophisticated figures or display
images with just a couple of C# statements. However, managing your drawing — the behind-the-scenes
work involving working out what to draw, where to draw it, and what does or does not need repainting
in any given situation — is far more complex and requires careful algorithm design. For this reason, it is
also important to have a good understanding of how GDI+ works and what actions Windows takes to
get something drawn. In particular, because of the architecture of Windows, it is important that, where
possible, drawing should be done by invalidating areas of the window and relying on Windows to respond
by issuing a Paint event.
Many more .NET classes can be used for drawing than there is space to cover in this chapter. However,
if you have worked through it and understood the principles involved in drawing, then you will be in an
excellent position to explore these classes by looking at their lists of methods in the SDK documentation and
instantiating instances of them to see what they do. In the end, drawing, as with almost any other aspect of
programming, requires logic, careful thought, and clear algorithms if you want to go beyond the standard
controls. Your software will benefit in both user-friendliness and visual appearance if it is well thought out.
Many applications out there rely entirely on controls for their user interface. Although this can be effective,
such applications very quickly end up resembling each other. By adding some GDI+ code to do some custom
drawing you can mark out your software as distinct and make it appear more original, which can only help
increase your sales!
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