The Old New Thing

Scrollbars, part 3: Optimizing the paint cycle

Raymond Chen July 29, 2003 Jul 29, 2003 07/29/03

Observe that we paint all 100 lines in our paint handler, even though most of them aren't visible. This is a problem if there are a large number of items, or if painting an item is time-consuming. So instead, we optimize our paint cycle so as to paint only the elements which intersect the...

Why doesn't Windows have an "expert mode"?

Raymond Chen July 28, 2003 Jul 28, 2003 07/28/03

We often get requests like this: There should be a slider bar somewhere, say on the Performance Tab, that ranges from Novice to Advanced. At the highest level, all the geek settings are turned on. At the Novice level, all the settings for beginners are turned on. In between, we can gradually enable stuff...

Scrollbars, part 2

Raymond Chen July 25, 2003 Jul 25, 2003 07/25/03

Managing scrollbars is not hard in principle. The basic idea is not that difficult, but there are a lot of small details that need to be ironed out. If you don't get the details just right, your program will feel odd in a strange way that you often can't pinpoint, much like a subtle background hum that ...

More terse Q&A on Tweak UI 2.10

Raymond Chen July 24, 2003 Jul 24, 2003 07/24/03

I'm going to try to alternate between programming entries (where I actually try to teach something) and random entries (where I get to spout off or go into storytelling mode). So here's another random entry. Why does Tweak UI put up a totally incomprehensible error message ("Cannot locate...

The scratch program

Raymond Chen July 23, 2003 Jul 23, 2003 07/23/03

Occasionally, there is need to illustrate a point with a full program. To avoid reproducing the boring parts of the program, let's agree on using the following template for our sample programs. For expository purposes, I won't use a C++ class. I'll just keep all my variables global. In a real program, of course, instance data would be ...

Why do you have to click the Start button to shut down?

Raymond Chen July 22, 2003 Jul 22, 2003 07/22/03

Short answer: The same reason you turn the ignition key to shut off your car. Long answer: Back in the early days, the taskbar didn't have a Start button. (In a future history column, you'll learn that back in the early days, the taskbar wasn't called the taskbar.) Instead of ...

Tweak UI 2.10

Raymond Chen July 21, 2003 Jul 21, 2003 07/21/03

What are you talking about? Tweak UI is part of the Windows XP PowerToys. It was recently updated to version 2.10. What OS is required? Windows XP Service Pack 1 (or higher) or Windows Server 2003 (all versions). Not supported: Windows XP RTM, Windows...