Automated screen/window capture with Applescript?

Question

Is it possible to automate screen capture in an automated, non-interactive way, using Applescript?
I know it is possible to use the terminal screencapture command in an Applescript to capture the whole screen, but the screencapture options to either select an area of the screen or a particular window require user interaction at run time to select the screen area or the target window.
What I need is to be able to specify - in the script itself - the area of the screen to capture, or the name of the window to capture, and have this happen without user interaction.
Is this possible? Are the undocumented ways of passing area or window information to screencapture? Or some other Finder/System way of doing it?
(with some research I found references to an app called FreeSnap which is allegedly scriptable - but it had been removed from all the usual sources as well as the original developer site. If there's no direct Applescript/Finder/System way to do the above, are there any third-party scriptable screenshot Apps which can do it?)
Thanks.

Answer 1

Hi brendan
Here is the code:
set tmpPath to ((POSIX path of (path to desktop)) & "screenpic.png") as string
do shell script "screencapture " & quoted form of tmpPath
delay 1.5
set this_file to tmpPath
try
tell application "Image Events"
launch
set this_image to open this_file
set {docWidth, docHeight} to the dimensions of this_image
crop this_image to dimensions {400, 200}
save this_image with icon
close this_image
end tell
on error error_message
display dialog error_message
end try
Hope this helps