Transparent PNG images

It seems as if PNG icons aren't rendered with the alpha channel intact. Is there any way to get IBrowse 2.4 to do that?

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That would seem to be possible using OS 4.0 Final, since MultiView renders PNG graphics with their alpha-channels.

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It is working fine with a standard setup (OS4final + IBrowse 2.4 OEM).

@hnl_dk

Doesn't work here. The alpha channel is stripped.

See example here:

http://orgin.org/~orgin/icons/ibexample.png

@orgin

Doesn't work here either using the IBrowse OEM version (haven't changed any settings or such).

Works in AWeb though, and that's the browser I use.

Ah, that'll be down to IBrowse.

IBrowse doesn't yet support full alpha channels. Basically, It takes the alpha channel at 50% & cuts it. i.e. The image shows up either solid, or transparent with no gradual alpha calculated in between.

AFAIK, there's no way around this until something gets updates with IBrowse. Changing the IB settings so that it uses an "external" image decoder for PNG's doesn't even sort it, even though we know the datatype supports alpha channels fully.

Sadly, for nice shaded/antialiased images on our web pages via IBrowse, we'll have to wait a bit.

FuZion.

@FuZion

I'll have to check with Oliver again as I can never remember the correct answer to this one, but I believe its the lack of alpha blitting functions in the OS which is the cause of the problem. This was something I mentioned to Oliver a million times during 2.4's development cycle, and I think they added some alpha functions to OS4.0 right near the end so we never got the chance to alter IB to take advantage of them when running under OS4.

I'll check with Oliver again anyway :)

@Vader

Cheers Vader. I don't know the technical side of what you guys go through but here's a link that may have some info too.

http://os4depot.net/index.php?functio ... lopment/library/ablit.lha

FuZion.

@FuZion

Ok, spoke to Oliver IBrowse uses the graphics.library routines to draw the images, and those (at least for 68k programs) support only a 1-bit maskplane.

We will need to add support directly for the full 8-bit alpha channel of RGBA images.

The functions added to OS4.0 final to support 32-bit imagery were a) added right near the end which was too late for 2.4 as we were finalising more important issues (like crashes ) and b) were not sufficently documented at the time.

Hope that clears things up - and I will now go and add an FAQ

@Vader

Cheers for the info guys. You catch that Origin

FuZion.