Re: PerlMagick Fast Image Loading

Are you talking about browsing via konqueror (KDE) or nautilus (Gnome)- or even gqview etc?

What you describe sounds like jpeg 'progressive' scanning. That has nothing to do with the viewer, but the way the images were created.

The other possibility is that you're actually talking about thumbnails- not the actual images. And the thumbnails are cached in ~/.thumbnails (if you're using shared cache, across apps).

Handling image data is a ****. The faster the machines get the more we will abuse them.

Comment on Re: PerlMagick Fast Image Loading

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Re^2: PerlMagick Fast Image Loading by jethro (Monsignor) on Jul 15, 2008 at 12:07 UTC
There is a third possibility. A JPEG picture tile consists of a linear combination of 64 standard tiles. If you only compute a few of them you could display an approximation of the picture somewhat faster. This is (if I understand it correctly) similar to the method in progressive encoding only that with this method you have to read in the whole file. With progressive encoding the coefficients of the standard tiles are grouped together so that you only have to read part of the file to display a first approximation of the picture. That presumes that displaying the pictures is not completely IO-bound. Just tested it on my machine, konqueror showing only thumbnails of hundreds of pictures got to 72% CPU usage, so I think showing the full pictures could be stressing out the CPU.	[reply]

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Re^2: PerlMagick Fast Image Loading
by jethro (Monsignor) on Jul 15, 2008 at 12:07 UTC

This is (if I understand it correctly) similar to the method in progressive encoding only that with this method you have to read in the whole file. With progressive encoding the coefficients of the standard tiles are grouped together so that you only have to read part of the file to display a first approximation of the picture.

That presumes that displaying the pictures is not completely IO-bound. Just tested it on my machine, konqueror showing only thumbnails of hundreds of pictures got to 72% CPU usage, so I think showing the full pictures could be stressing out the CPU.

[reply]