Chapter 17. GDI

Chapter 17. GDI+

A picture is worth a thousand wordsor several thousand lines of source code, if you're generating a bitmap image of it. Writing code to manipulate images of varying color depths, or to trace out multi-layer vector art, can be a nightmare of geometric contortions and linear algebra. It makes one yearn for those days of pre-screen computers. The first programming class I took used a DECWriter, a printer-based terminal that had no screen, and included the graphics capabilities of a jellyfish. It was perfect for me. I couldn't draw a straight line anyway, and I didn't need some fancy schmancy "video display terminal" reminding me of it.

The graphics included in early display systems weren't much better. "Dumb terminals," like the popular VT100, included some simple character graphics that displayed basic lines and blocks. Each graphic part was exactly one character in size, and any images you sought to display had to fit in a clunky 80 by 24 grid.

Fortunately for art aficionados everywhere, computers have come a long way in the graphics department. GDI+ includes complex drawing features that would make a DECWriter cry. Built upon the older Windows' Graphics Device Interface (GDI) technology, GDI+ includes commands for drawing lines, text, and images in the Picasso-enhanced world of 2D graphics.