preview speed? e.g. "Light/Shadow"

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lutz
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preview speed? e.g. "Light/Shadow"

Post by lutz » Thu 19 Oct 2006 08:42

I am just testing the new version 13.1 and had the impression that overall photoline had become snappier and that it starts faster.
However, I have serious problems with my patience waiting for the generation of the previews in several tools, for example the Light/Shadow filter.
After one or two adjustments the further adjustments seem to take quite a bit longer than the rendering of the full size image. Even just changing the size of the preview seems to last quite a bit longer than the final calculation. I had this problem with the very slow preview on both, a single core and a dual core WinXP Pro machine.

Because of the lack of speed it seems also irritating that photoline starts calculating the preview as soon as I start to move a slider and hereby slowing down the responsiveness of the whole program. This makes it actually difficult to set the value for which I am aiming. At the moment I wish photoline would start its calculation only after I drop the slider.

Are there some recommended settings which I could use to improve the responsiveness? Thanks

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Koyaanis
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Post by Koyaanis » Fri 20 Oct 2006 08:40

I've noticed some slow-downs in some tools, the one you name in particular. But my slow-downs usually stem from using the "Full Preview" option checked in each filter. It takes much longer to process the whole image. This is why having a scaled-down, adjustable-size preview in all filters can be so valuable. Some of them don't have that fully implemented.

What really seems to slow down some tools or filters, is that not only will I have the "Full Preview" option checked but I almost always have the separate Histogram dialog panel open too. So I can see an after-effect of what the filter is doing mathematically to an image. If you have the Histogram view selected to calculate "All Layers" as well, there's another huge chunk of calculations. I can watch a filter take its effect on the full-preview, and then I notice there's quite a bit of delay before the Histogram window will be refreshed after that.

I don't think there's much that can be done in some instances if both of these options (Full Preview and Histogram dialog) are in use at all times. Because not only is the Histogram window trying to calculate the results of the new filter effects from the Full Preview, but it's also dealing with a high resolution 16-bit image. That's a lot of calculating that needs to be done. In cases where I see it is slowing down my work-flow then I'll disable the "Full Preview" option, or close the Histogram dialog. Some filters don't allow for a larger preview so I have to rely on using the more CPU intensive options. It's an either-or balancing act sometimes.

I don't know if I'd like a filter to not calculate something until after I have released the slider adjustment. For some filters it's almost necessary. For example, the one for chromatic aberration, it tends to depend on having a real-time preview as you focus the color layers where they need to be.

Check for those 2 things, "Full Preview" and Histogram dialog. They might be what are slowing down some of your work-flow. Use them only when necessary on a slower computer. Being a newer user to the program I may not know of other helpful tips, but those seem to work for me. Oh, and you can never have too much RAM! :-)

lutz
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Post by lutz » Fri 20 Oct 2006 09:56

Hello Koyaanis,

thanks for the suggestions and explanations. I have checked them on my work PC but the settings were already "least" demanding as described by you: no histogram and no full preview. My test pic is just an 8 MP jpeg, so not even 16-bit and single layer. The symptoms are the same as before. The program needs tremendous time to create the preview - especially after the 2nd or 3rd adjustment.
This PC has only 1 gig of RAM but no other demanding apps are running. My tray utility indicates that 99% of the processor is used during the peak of the preview generation.
At the moment the preview is quite far away from being "real-time" so that the attempt of instant calculation slows down the reaction of the slider.
The problem is the most obvious when the complete image is viewed zoomed out in the preview. Then memory usage goes up to 250 Mb and everything becomes very slow.

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Koyaanis
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Post by Koyaanis » Fri 20 Oct 2006 19:19

Well it seems the most obvious solution at this time, until the authors optimize that particular filter in some way, would be to try and select a smaller representative section of your photo/image. An area that has the darkest values next to some mid-range tones. Or vice-versa, an area with highlights next to mid-tones. Keep only that area zoomed-in in your preview so the filter doesn't have to perform its calculations on the whole image. I've done this in the past when experimenting with this filter. It seems to help on some of my larger 16-bit images.

Before selecting the filter keep your main image zoomed out for a full over-view, and only apply the "Full Preview" option to the main image after you have made some selections in the zoomed-in preview in the filter. This way you can adjust the options more quickly. If you're not satisfied with the full-image view, then uncheck "Full Preview" and try some new settings, then select "Full Preview" on the filter's options again. I've used the same method in other editors with elaborate noise and halo-removal filters. PL32 is not alone in this problem when trying to apply an advanced math-hungry filter or effect to a larger image. (It's just the nature of the beast. Problems in the past were on editing 640x480 pixel images, today's image files are 16 to 32 or even more times larger. Nowadays we expect advanced filters to run at 60 frames per second or faster on 1024x768 videos in real-time. We're spoiled. :-))

Martin Huber
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Post by Martin Huber » Tue 24 Oct 2006 15:43

lutz wrote:My test pic is just an 8 MP jpeg, so not even 16-bit and single layer.
Light/Shadow internally always works with 16-bit, so there should be no performance difference between 8- und 16-bit images.
lutz wrote:The problem is the most obvious when the complete image is viewed zoomed out in the preview.
I think this is the problem. The preview is fast as long as you don't zoom out. If the complete image is visible in the preview, Light/shadow is applied to the complete image, too.
We are going to see, what we can do to solve this problem.

Martin