October 2010 | The Old New Thing

It's the Great Pumpkin, Charlie Brown: The world of competitive pumpkin-growing

Raymond ChenOctober 29, 2010Oct 29, 201010/29/10

Bill Littlefield of NPR's sports program Only a Game interviews Susan Warren about competitive pumpkin-growing. [Direct link - Real format] An excerpt from her book Backyard Giants was printed in The Wall Street Journal: The Race to Break the Squash Barrier, the quest to grow a one-ton pumpkin. I'm fascinated by these subcultures of ...

Debugging walkthrough: Diagnosing a __purecall failure

Raymond ChenOctober 29, 2010Oct 29, 201010/29/10

Prerequisite: Understanding what __purecall means. I was asked to help diagnose an issue in which a program managed to stumble into the __purecall function. The stack at the point of failure looked like this: The line at XYZ!CViewFrame::SetFrame that called the mystic __purecall was a simple AddRef: From what we know of __purecall...

Why is there an LVN_ODSTATECHANGED notification when there's already a perfectly good LVN_ITEMCHANGED notification?

Raymond ChenOctober 28, 2010Oct 28, 201010/28/10

If you work with owner-data listviews, you take the responsibility for managing the data associated with each item in the list view. The list view control itself only knows how many items there are; when it needs information about an item, it asks you for it. It's the fancy name for a "virtual list view" control. When you use an ownerdata ...

How do I programmatically invoke Aero Peek on a window?

Raymond ChenOctober 27, 2010Oct 27, 201010/27/10

A customer wanted to know if there was a way for their application to invoke the Aero Peek feature so that their window appeared and all the other windows on the system turned transparent. No, there is no such programmatic interface exposed. Aero Peek is a feature for the user to invoke, not a feature for applications to invoke so they can ...

Hacking Barney the dinosaur for fun (no profit)

Raymond ChenOctober 26, 2010Oct 26, 201010/26/10

Many years ago, Microsoft produced a collection of interactive toys called ActiMates, and one of the features was that television programs could broadcast an encoded signal which would enable the toy to interact with the program. The idea would be that the Barney doll would do something that was coordinated with what was happening on Barney...

Belated happy first birthday, Windows 7

Raymond ChenOctober 25, 2010Oct 25, 201010/25/10

On Friday, the marketing folks informed me that they decided to put me on the Microsoft Careers United States home page in recognition of Windows 7's first birthday. It's an honor and to be honest a bit scary to be chosen to be the face of Windows on a day of such significance. (They told me that had narrowed it down to me and "some ...

When you call a function, your code doesn't resume execution until that function returns

Raymond ChenOctober 25, 2010Oct 25, 201010/25/10

Consider this code fragment: When foo calls bar(), and bar has not yet returned, does foo continue executing? Does baz get called before bar returns? No, it does not. The basic structure of the C/C++ language imposes sequential execution. Control does not return to the foo function until bar returns control, either by reaching the end ...

The evolution of the ICO file format, part 4: PNG images

Raymond ChenOctober 22, 2010Oct 22, 201010/22/10

We finish our tour of the evolution of the ICO file format with the introduction of PNG-compressed images in Windows Vista. The natural way of introducing PNG support for icon images would be to allow the biCompression field of the BITMAPINFOHEADER to take the value BI_PNG, in which case the image would be represented not by a ...

The evolution of the ICO file format, part 3: Alpha-blended images

Raymond ChenOctober 21, 2010Oct 21, 201010/21/10

Windows XP introduced the ability to provide icon images which contain an 8-bit alpha channel. Up until this point, you had only a 1-bit alpha channel, represented by a mask. The representation of an alpha-blended image in your ICO file is pretty straightforward. Recall that the old ICO format supports 0RGB 32bpp bitmaps. To use an alpha...

How do I get the dimensions of a cursor or icon?

Raymond ChenOctober 20, 2010Oct 20, 201010/20/10

Given a HICON or a HCURSOR, how do you get the dimensions of the icon or cursor? The GetIconInfo function gets you most of the way there, returning you an ICONINFO structure which gives you the mask and color bitmaps (and the hotspot, if a cursor). You can then use the GetObject function to get the attributes of the bitmap. And then here's ...

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