PNG gamma chunk removal for custom panel PNG images?

[joerattz]

I created a couple custom containers but stumbled on a problem regarding PNG gamma chunk information, specifically with PNGs rendered in IE. The result is that the colors in the PNG file don't match the color specified in the custom widget's .js file. I know this problem/issue is not the fault of Profound but since I don't see this issue with the Profound provided panels, I believe Profound is using some solution for this.

Can anyone there tell me what Profound is doing to combat this PNG gamma issue? I see some utilities for removing the gamma correction chunk and am wondering if that is what you are doing and if so, what utility are you using?

Thanks!

[joerattz]

FYI, I have found TweakPNG which seems to work:

http://entropymine.com/jason/tweakpng/

But I would still like to know how Profound is doing it.

Thanks.

[David]

Sorry for the late reply here.

I checked this with one of the developers. The developer doesn't remember any special tool being used, or any special handling that was required.

The images were produced using Adobe Photoshop, and the developer says that it just "seemed to work" automatically without anything special being done.

Sorry if this is not too helpful.

[joerattz]

Thanks for responding. I just checked some of the images for the built-in panels that ProfoundUI provides and they didn't have a gamma chunk. I am guessing that Photoshop must have taken care of that for you.

In case others run into this issue, the way it manifests itself is that when you create the left, right, bottomleft, bottommiddle, and bottomright images for a custom panel, if those images contain the same color you are specifying as the background color for the panel, they won't actually match. So if for example your background color for the panel is #53A09C and that color is in the images and specified as the background color, they won't appear the same and you will be able to clearly see where the image begins/ends and the background with the specified background color is.

This is due to the gamma (gAMA) chunk in the PNG file. There are utilities that can remove this chunk for you. I used the one I specified in my previous post and it worked fine.

You can see some examples of the issues caused by the gamma chunk by checking out the link below. Notice that every color box isn't affected but that the ones that are, show two different colors, one for the borders of the image and a slightly different color for the inside where the PNG image is. Be sure to glance at several rows of color boxes because not every color is affected by this problem.

http://www.libpng.org/pub/png/colorcube ... mma22.html