| IDL 6.2 IDLgrImage SUB_RECT and TILING [message #45970] |
Sun, 23 October 2005 16:37  |
Robert Barnett
Messages: 70
Registered: May 2004
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Member |
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G'Day,
Has anyone been experimenting with the new properties available in
IDLgrImage?
I've been using the new image tiling features in IDL 6.2 for generating
fast and memory efficent slicing and animations. To render an animation
I store all frames from an animation sequence side-by-side in a single
image.
There is an (semi) explanatory diagram at
http://www.zipworld.com.au/~retsil/idl/news/slicing.png
I use the TILING keyword for extra efficiency. This is for when I only
want to compute frames as they are rendered and/or only cache frames
when graphics memory is available. In fact, this allows me to render
animation or slicing sequences which are larger than what can fit into
graphics memory.
When I want to animate, I move the current transfer matrix (CTM) so it
displays each frame in sequence. However, I would prefer to use the
SUB_RECT
property to crop the image display (a neat way to prevent the user
using a pan/zoom
tool to view adjacent frames), however, SUB_RECT does not behave in the
way which I would expect. Instead the SUB_RECT keyword deletes all of
my
cached tiles each time the property is changed. At the same time I get
floating point errors from the IDLgrWindow::Draw method.
Given the lack of documentation on the SUB_RECT property, what do you
think?
Bug or feature?
(Note: This has been lodged as an RSI Incident #197686)
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