Grabbug is a utility for grabbing screen dumps. Grabbug is hard to use, consumes lots of memory and doesn’t have many advanced features. Its sole redeeming feature is that it can grab the screen at any time, even interrupt time. Cool huh?
Salient features:
• MacsBug dcmd for grabbing
• Application for dumping grabs.
• Requires System 7.5 or later.
• Requires MacsBug 6.5d10 or later.
• Source code included.
Background Information
Grabbug was written because I had a hard time capturing zoom rects. I was writing a web page on some of the more subtle features of the Macintosh human interface and I wanted to grab them in action. Unfortunately neither the Macintosh built-in screen capture utility nor the Flash-It (which I highly recommend by the way) can capture the screen in the middle of a zoom rectangle sequence. I then went searching on the net and found the Snapz utility. This claimed to be able to grab the screen at any time, including in the middle of arcade games that don’t give time to other processes. Unfortunately Snapz, while it was most probably capable of grabbing the zoom rects, didn’t have the temporal precision to grab something as ephemeral as a zoom rect.
I needed bigger guns!
Grabbug is a two part solution to this problem. The first part is a MacsBug plug-in (known as a 'dcmd', or debugger command) that loads at startup time and allocates the a temporary buffer that stores the screen dump. When you invoke this dcmd from MacsBug it captures the screen to the temporary buffer. The second part of Grabbug is a little application called “Grabbug Dump”. When you run this it dumps the most recent screen dump to a file in the root directory of your boot disk.
When you get the package you will find a file called “MacsBug”. Put this file in your System Folder (not in the Extensions folder!) and restart. When you restart you’re Mac should say “Debugger Installed” shortly after saying “Welcome to Macintosh”.
2. Use ResEdit to Install the dcmd
In the Grabbug distribution there is a resource file called “Grabbug”. Inside that file is a 'dcmd' resource also called “Grabbug”.
If you also have a Debugger Prefs file, simply use ResEdit (also available at the location given above) to copy the Grabbug dcmd into your Debugger Prefs file. It’s safe to renumber it if its ID clashes with an existing dcmd.
If you don’t have a Debugger Prefs file you should use ResEdit to create one in your System Folder (not in the Preferences folder!) and call it “Debugger Prefs” (use that name exactly). You can then copy the Grabbug dcmd into your newly created file.
3. Drop into MacsBug and Run Grabbug
When you want to take a screen shot drop into MacsBug and type Grabbug. Grabbug will respond with Snap! to let you know that it has grabbed the screen shot.
You can drop into MacsBug in a variety of ways. The most obvious is to hit the Mac’s Interrupt button, usually on the front of the machine near the Reset button. [Don’t mix them up!] Alternatively many Macs support the command-power combination to enter MacsBug. Finally you can use all your programming skill to set MacsBug break
