The Old New Thing

Scrollbars part 8 – Integral interactive resizing

Enforcing integrality solves the fractional-line problem, but notice that when you grab the top or bottom edge and resize the window, the resize feedback doesn't match the actual window you get back if you drag the window to a non-integral size. (You may need to turn off full window drag to see this effect...

Why can't I remove "for test/evaluation purposes only"?

"Why can't I remove 'for test/evaluation purposes only'? I know I'm running an evaluation edition, I don't need it rubbed in my face." This prevents unscrupulous OEMs from selling machines with the evaluation edition of the product instead of the retail version. (Yes, this has happened before. ...

Scrollbars part 7 – Integrality

If you play around with resizing the window, you can get a fractional line to appear at the bottom of the screen. This is not normally a problem until you scroll to the very end of the list, say, by pressing the key, at which point an ugly blank space appears at the bottom. This ugly blank space is ...

Answers to exercises

What is the significance of the cast in the computation of ? It isn't. I got the question wrong. The real question should have been "What is the significance of the cast in the computation of ?" The answer is to ensure that the computation is performed with signed integers ...

Why is a registry file called a "hive"?

Useless trivia day. Why is a registry file called a "hive"? Because one of the original developers of Windows NT hated bees.  So the developer who was responsible for the registry snuck in as many bee references as he could.  A registry file is called a "hive", and ...

A subtlety in the keyboard code

I neglected to call it out explicitly in the text for Part 5:  Notice that I use cRepeat to determine how many lines/pages to scroll.  This allows us to scroll the correct amount even if we are falling behind on input processing and are missing some autorepeats...

Scrollbars bart 6 – The wheel

The mouse wheel is tricky because the mouse wheel UI guidelines indicate that you should scroll by a user-specified amount for each "click" of the mouse, where one click is mouse units (called a "detent"). There are two subtle points about the above requirement: First, that the amount of scrolling is a ...

Limitations on DLL resources in Windows 95

Ancient history lesson. When Win9x loads a 32-bit DLL, it creates a shadow 16-bit DLL so 16-bit code (like USER) can access resources in it. The shadow DLL is effectively a resource-only 16-bit DLL, created by taking the 32-bit resources and converting them to 16-bit format. ...

Keyboard accessibility for scrollbars

Note that so far, the scrollbar is accessible only with the mouse. Our next step is to add keyboard access to the scrollbar. Fortunately, this is not all that difficult. We merely map some keystrokes to equivalent scrollbar actions. Note that this doesn't make our sample program fully accessible; this ...

Changing the Windows boot logo

This is the answer I give to IT people when they ask if it's okay to customize the Windows boot logo. DO NOT DO THIS ON A PRODUCTION MACHINE OR YOU WILL REGRET IT. If you hack the bitmap everything will seem fine until six months down the road when you decide to install the ...