| Backing store [message #9913] |
Thu, 11 September 1997 00:00  |
thompson
Messages: 584
Registered: August 1991
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Senior Member |
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I run IDL on DEC Alpha Workstations running OSF/Digital Unix. I've noticed
that the newer machines give me more problems with backing store. In other
words, if a graphics window is covered up and then brought back to the
foreground, then the parts of the image that were obscured are lost, unless one
uses RETAIN=2. This is not a problem on the older Alpha workstations.
It seems to me that there are two possibilities. Either the problem is
associated with the newer Alpha hardware, or with the newer version of the
Operating System. So far, we have not upgraded our older machines to OSF 4.0,
so maybe that's why those machines do not give any problems.
I could put DEVICE, RETAIN=2 into the IDL startup script, but according to the
online help:
Pixmaps are a precious resource in the X server, so backing
pixmaps should only be requested for windows with contents
that must absolutely be preserved.
Has anyone else noticed this behavior under Digital Unix? Is there anything to
do to tune the system to keep this from happening?
Thank you,
William Thompson
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| Re: backing store [message #44639 is a reply to message #9913] |
Wed, 29 June 2005 08:50  |
Rick Towler
Messages: 821
Registered: August 1998
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Senior Member |
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KK T wrote:
> Will I lose the details of the bitmap using CONGRID or REBIN if I zoom
> my view to an area smaller than the orginial image?
>
> ENVI provides image, scroll and zoom window. However, those windows
> take up too much space on the desktop and I will like to combine all
> features in one window. That is, when I zoom in to the maximun, I can
> see the finest details of the bitmap, when I zoom out to the maximun, i
> can see the overall view of the bitmap. At the same time, i should be
> able to view the whole area of the bitmap at that zoom level with
> scroll bar activated.
>
> Am I too ambitious?
I'm not an image guy, nor do I act like one on the internet, but I would
use a combination of REBIN and WIDGET_DRAW with the /APP_SCROLL keyword
set. You'll keep the original image in memory and REBIN that image for
display, altering the dimensions according to your zoom level.
I have no idea if this is feasible performance wise, but it is where *I*
would start. Maybe someone else can come up with a better approach.
-Rick
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| Re: backing store [message #44644 is a reply to message #44557] |
Wed, 29 June 2005 01:45 |
KK T
Messages: 8
Registered: June 2005
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Junior Member |
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Good day,
Will I lose the details of the bitmap using CONGRID or REBIN if I zoom
my view to an area smaller than the orginial image?
ENVI provides image, scroll and zoom window. However, those windows
take up too much space on the desktop and I will like to combine all
features in one window. That is, when I zoom in to the maximun, I can
see the finest details of the bitmap, when I zoom out to the maximun, i
can see the overall view of the bitmap. At the same time, i should be
able to view the whole area of the bitmap at that zoom level with
scroll bar activated.
Am I too ambitious?
Kok Kiang
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