#123: Support alphachannel PNGs
- Contents
- Proposed by
- Alexander Limi
- Proposal type
- User interface
- State
- being-discussed
Motivation
Currently, there is no way to use PNG images with alpha channel information in Plone running on Internet Explorer.
We'd like to switch Plone's default icon format to PNG — but before we can do that, we need to implement one of the workaround implementations that already exist.
Proposal
We should look at something like Dean Edwards' IE7 or a different solutions to fix this problem.
I'd like to include IE7 wholesale in Plone, but our last attempt at this resulted in a massive slowdown on loading a page, so we'll have to re-evaluate and do some tweaking if we want to include it.
Risks
- Fixing this for all the icons on a standard page might turn out as too slow.
- We should make sure this works with images in the CSS classes too (background images etc)
IE7 still slow
In any case, I hope to be able to rewrite the Plone CSS for 3.0, making it more efficient. Not sure if it will be fast enough to make use of IE7, though.
+1 for this PLIP
so I'm eager to see pictures in my plone site are made using PNG format.
More IE6 png alpha resources
On IE6, the alpha for PNG has some quirks. Twinhelix's fix for this is instructive.
http://www.twinhelix.com/css/iepngfix/
Please note the "sizingMethod" attribute the AlphaImageLoader is using. It is set to sizingMethod='scale'. "Scale" in this case refers to the IMG attributes height and width. If these attributes are not present on the PNG image element, the scale sizingMethod will not work.
The Twinhelix fix also takes care of background-images.
http://webfx.eae.net/dhtml/pngbehavior/pngbehavior.html
More (explanatory) detail under "Troubleshooting" at http://homepage.ntlworld.com/bobosola/pnginfo.htm
IE7 library needs PHP rewritten to Python
Source, this thread: https://sourceforge.net/forum/forum.php?thread_id=1664215&forum_id=379297
IE7 library needs PHP rewritten to Python
Source, this thread: https://sourceforge.net/forum/forum.php?thread_id=1664215&forum_id=379297
8bit PNG
http://www.sitepoint.com/blogs/2007/09/18/png8-the-clear-winner/
Yup, as detailed on the Plone logo page
http://plone.org/about/logo has the details.
Too slow?
Limi, at one point I remember you toying with IE7 and saying it was far to slow to be useful to Plone. Has something changed here? Also, I seem to recall certain versions of Safari doing unacceptable things to PNG's when trying to auto-correct gamma sutff. Isn't this still the case?