Mac OS X Screenshot Secrets
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Shadow Hack

One byproduct of the OS X window design is that Finder windows lose their borders when you collapse the title bar (see Figures 5A and 5B).

Figure 5A. When you shoot an expanded Finder window in window-capture mode, it has a meaty metallic border, although there's no drop shadow.

Figure 5B. Collapsing a Finder window's title bar removes the bottom and left borders, which makes for a strange screenshot. (The borders are normally defined by drop shadow.)

I've come up with two ways to work around that disappearing border. The first is to fire up Screenshot Helper, set the background to white, and drag-shoot the window I want plus enough blank space around it to capture the drop shadow. I then open the screenshot in my image editor (Macromedia Fireworks), select the white space with the Magic Wand tool, and delete it (see Figure 6).

Sometimes, though, I want to use a drop-shadowed window on a non-white background. For that, I'll shoot the window normally, then add drop shadow in the image editor. Figure 7 shows the values I came up with. They're not exactly the same as the Finder shadow, but they're close enough.

Figure 7. To add Finder-like drop shadow to a naked window, I use these values in Fireworks.

You can compare the real and imitation drop shadow in Figures 8A and 8B.

Figure 8A. True Finder drop shadow.

Figure 8B. "Aftermarket" drop shadow, created in Fireworks.

Figure 9 shows how the Fireworks drop shadow makes the same window stand out on different textured backgrounds.

Figure 9. By shooting only the raw window and adding drop shadow later, you get more design options.

Capturing a DVD

If you try to use the Mac's standard Command+Shift+3 or +4 functions to capture a frame from a DVD, you'll be stymied by the following error:

Fortunately, there are several easy ways around this limitation, although they may not work on all Macs. Both the Screenshot Plus widget and SnapNDrag will capture DVD stills, although I found the quality was better with SnapNDrag (see Figure 10). The powerful Snapz Pro ($69 edition) can even capture DVD motion and audio, and save the result as a QuickTime movie.

Figure 10. Note the pixelation in the inset image, which I grabbed from a DVD with Screenshot Plus. The larger image, captured with SnapNDrag, is baby-smooth. Both shots were made at 100%.

Thanks to a coder named Jack, here's an even simpler way to grab DVD stills on the fly: paste the following line into a new AppleScript document and save the script as DVD Screenshot in the directory ~/Library/Application Support/DVD Player/Scripts.

do shell script "screencapture ~/Desktop/DVD-screenshot.png"

When you find a scene you want to grab in DVD Player, pause playback and select DVD Screenshot from the Scripts menu. The script will create a PNG image of the entire screen on your desktop and name it DVD-screenshot.png.

If you want to shoot just part of the image, create a second AppleScript document called DVD Selection Screenshot, containing the following line:

do shell script "screencapture -i ~/Desktop/dvd-select.png"

When you select that script from the DVD Player menu, you'll get the familiar crosshair cursor, which you can drag to select the area you want. Releasing the mouse button triggers the screen grab.

To capture only the window, use the following syntax:

do shell script "screencapture -iW ~/Desktop/dvd-window.png"

Oddly, I noticed that like Screenshot Plus, this method generates pixelation when using the window command.

He Shoots ... He Scores!

From documenting a verbose error message to quickly assembling tutorial illustrations or even cover images for a DVD you're making, there are untold applications for screenshots. I hope this article has demystified the process and given you some ideas.

David Battino is the audio editor for O’Reilly’s Digital Media site, the co-author of The Art of Digital Music, and on the steering committee for the Interactive Audio Special Interest Group (IASIG). He also writes, publishes, and performs Japanese kamishibai storycards.

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