| 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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| Re: IDL 6.2 IDLgrImage SUB_RECT and TILING [message #46280 is a reply to message #45970] |
Thu, 10 November 2005 08:35  |
Steven Houston
Messages: 5
Registered: November 2005
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Junior Member |
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Hi,
What you are seeing is correct. When you set the SUB_RECT property the
image is resized to only include the SubRect area. In your diagram if
you set the SUB_RECT to cover tile 3, the image is resized and all the
tiles outside tile 3 are discarded.
If you wish to keep the other tiles but prevent them being visible in
case your user pans you could look at using CLIP_PLANES on the
IDLgrModel containing the image.
Regards,
Steve.
Robbie Barnett wrote:
> 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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