Forum OpenACS Development: Re: Photo-Album Includelet for Xowiki

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Posted by Richard Hamilton on
Further to earlier post, I have been playing around with the files and have discovered that most of the data in these thumbnails is color profile data.

If I vary the -quality parameter, the image size doesn't change much, but if I remove the colour profile information my 28KB thumbnail drops to 2.5KB as expected.

An embedded profile in a thumbnail is really not necessary, however the CR and xowiki code is designed to work at any image size. I wonder therefore if it be handy to be able to pass through to the image resize proc whether or not to remove the color profile. Certainly, this could then be supported as a parameter in the yui-carousel includelet.

My version of ImageMagick is old and so I have to do:

convert +profile '' -quality 45% in.jpg out.jpg

For newer versions you can use the -strip parameter.

I will try compiling GraphicsMagick as Torben suggested because ImageMagick won't compile on my (rather old!) linux distribution.

Regards
Richard

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Posted by Dave Bauer on
OK, here is what I recommend.

Change the return style from image::convert_to_sizes to return something like this:

[list [list thumbnail {-strip -resize 150x150} view {-strip -resize 500x500]]

and fix the callers to intepret the new format. Since this is a private procedure and it is only called in two places, and only one place actually uses the dimensions part of the size specification.

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Posted by Richard Hamilton on
Dave,

That sounds like a good suggestion. The only problem I foresee with that is that putting -strip in there will cause an error on earlier versions of ImageMagick.

It would also be useful to apply a change to the xowiki specific image resizing code.

Regards
Richard