Bug: Transparent Gifs Outputting Black

[CaliKat]

My transparent-backed animated gif is outputting with a black background at Redux, Koya and Arbor IM's today.

I know there was a problem yesterday with black rendering as transparent. Now we have transparent outputting black.

[magick]

As always, we can't fix a problem unless we can reproduce it. Post a URL to your image and exactly what we must do to reproduce the problem.

[CaliKat]

Take this gif:
http://wordtiller.lbbhost.com/tempdiv2.gif

Input it at Redux IM. Click the output folder tab. Leave it as a multi-file gif and press the output button.

On the next page is a black-backed animated gif with three transparent looking gifs below it. Whether I click onto the black-backed gif or the left of the three below it, what I end upwith is a black-backed animated gif instead of the transparent back that I inputted.

[magick]

We can reproduce the problem you posted and will have a fix within a day or two. Thanks.

[CaliKat]

Thank you.

Also, thank you for all the great features we have to choose from at Image Magick. Just when I think it can't get any better, you all add something else new. IM rocks!

[viki4short]

My transparent backed gif is outputting a black background at Redux and Arbor. I put "9999" in the fuzz box, "replace" in the method box, and "matte" in the paint type box. I''ve always used this method and it worked well about a week ago. No matter what I do, it doesn't make my image transparent. Any help would be appreciated, maybe I'm doing something wrong.

[CaliKat]

My transparent backed gif is outputting a black background at Redux and Arbor. I put "9999" in the fuzz box, "replace" in the method box, and "matte" in the paint type box. I''ve always used this method and it worked well about a week ago. No matter what I do, it doesn't make my image transparent. Any help would be appreciated, maybe I'm doing something wrong.

Hi - i just took a transparent gif to Arbor, drew an ellipse on it and outputted - the transparent areas remained transparent so I was not able to reproduce your problem. If you are still having a problem today, please post the url of the image you are using, along with the steps you take so I or someone else can try to reproduce the problem.

[ahigerd]

I think I'm reproducing this bug using <http://greenmaw.com/trans-bug.png>. If I invoke "convert trans-bug.png trans-bug.mng" I get a solid black image. I see this behavior using http://www.imagemagick.org/MagickStudio ... Studio.cgi as well. I tried this with some other transparent PNG files and I didn't see the problem, so perhaps this example will help.

[fmw42]

I get the same behavior in command line IM 6.6.3.0 Q16 Mac OSX Tiger.

HOWEVER, if you convert it first to GIF and then from GIF to MNG it looks fine.

convert trans-bug.png GIF:- | convert - trans-bug.mng

I am not an expert on MNG. Does MNG support 8-bit alpha that is in your PNG file?

[ahigerd]

If you convert it to GIF first you lose the alpha transparency and get some nasty stairstepping.

MNG is an extension of the PNG standard and as such supports everything PNG supports and then some (like JPEG-based frames), so yes, it supports 8-bit alpha.

[fmw42]

If you feel this is then incorrect behaviour, you should then cross post to the Bugs forum to get the best attention.