#123: Support alphachannel PNGs

Contents

by Alexander Limi — last modified Jun 11, 2006 12:21 AM

Plone should automatically work around the bugs in Internet Explorer so that we can start using transparent PNGs for the icons.

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)

Too slow?

Posted by Rocky Burt at Mar 13, 2006 01:14 PM

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?

IE7 still slow

Posted by Alexander Limi at Mar 16, 2006 10:09 PM

Yes, IE7 is still slow, but the PNG fixing code can be extracted (or use one of the standalone solutions out there).

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

Posted by Rank Lee at Mar 23, 2007 02:47 AM

the alpha channel is a great exciting image display, till now only PNG file format support it.
so I'm eager to see pictures in my plone site are made using PNG format.

More IE6 png alpha resources

Posted by Olle Jonsson at May 07, 2007 11:36 AM

Hi, just checking in on this old Ticket.

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

Posted by Olle Jonsson at May 08, 2007 10:54 AM

After skimming Dean's IE7 solution, I now know that it currently uses server-side PHP scripts to do some work, and they need to be turned into Python.

Source, this thread: https://sourceforge.net/for[…]1664215&forum_id=379297

IE7 library needs PHP rewritten to Python

Posted by Olle Jonsson at May 08, 2007 10:57 AM

8bit PNG

Posted by Darryl Dixon (Winterhouse Consulting Ltd) at Feb 26, 2008 11:05 PM

What about 8bit PNG? Especially for icons this is probably sufficient, and it degrades nicely in IE6 to no worse than current GIF support:

http://www.sitepoint.com/[…]/

Yup, as detailed on the Plone logo page

Posted by Alexander Limi at Feb 27, 2008 04:25 AM

…it is what I recommend. This PLIP needs to be updated, that's all. :)

http://plone.org/about/logo has the details.

supersleight + conditional GIFs

Posted by Jeremy McMillan at Jul 08, 2008 01:44 AM

I have had good experience working with supersleight (http://24ways.org/2007/supersleight-transparent-png-in-ie6) on Plone, even using alpha transparency on background images. I believe it could be refined for greater flexibility by generating wrapper DIVs to contain the filter renderer, and it's not too terribly slow unless there are a lot of PNGs to re-render. For small icons (16x16), the alpha effects are hardly noticeable, and these are the most likely candidates for slowing down page rendering with too many filters. Maybe it would be better to serve 8-bit PNGs or GIFs for these images? We should also consider rendering an interstitial above the page while it's loading IE5/IE6 filters encouraging an upgrade ;)

rewriting plone

Posted by sandra dorr at Aug 25, 2008 06:10 PM

Dear Alexander Limi, Help. I've just had a Plone website built for me and need to get it rewritten into html with some simpler tools that I can use (coffee cup, rapid weaver, etc.) as I'm just a one-person company and didn't need this kind of system. Do you do this or know anyone that does? Many thanks, and all good wishes for you and your work.
Sandra Dorr