good day jorge,

here is a page you may be interested in.

http://people.mozilla.com/~dolske/apng/demo.html

Mate, I too agree that a 'proper' animated file type will be preferable. However... show me *one* programme that will allow me to create animations and save them to APNG (and please, don't say GIMP).
In any case, you can see where I'm going. While the current implementation is simply stitching frames into one long strip of a PNG, the alternative is to require yet another tool. Well... I don't know, mate... I mean, technically, even APNG *is* multiple PNG data blocks into the same signature-header-end block, with a frame-control block to separate it from the other frameheader-framedata blocks. Our current solution is simply one big PNG, one sig-hdr-end block, no frame control blocks, and the data cascaded per scan line into the same data block. The only possible advantage I can see, is that the creator can control the animation speed and maybe create smaller files, by using smaller frame sizes and using the offset and/or blend and/or disposal options that APNG offers; however, the two latter can be compensated by the creator.
Is it really worth the trouble?

skagon i only posted it because i thought people might be interest in reading about it. you read something in to my post that was simply not there.

Hey, man, peace! I wasn't trying to pick a fight or anything.
I was just thinking "aloud", not trying to ground your idea. I've just spent quite some time trying to see pros and cons for PNG animation, and I essentially end up in what the PNG group came up with: either something really elaborate, but CPU intensive and code-heavy (see MNG), or something easy and light, but more limited (see APNG), and finally, both ideas depend heavily on support, both from applications and editors.
Anyway... just saying... I didn't *accuse* you of anything, I just thought I'd write my thoughts here, since you mentioned it, and maybe hear Jorge's thoughts on the subject, since we're talking.

If we had the possibility of a single animated icon Jorge would have used GIFs as they were out since long time ago and they're suitable for our needs. To me though there's only one advantage in using an animated image instead of an image strip, and that would be that you would have smaller Width images instead of those huge strips.
For the image size, no, there wouldn't be any bit of size difference as PNG maintains information for each pixel (exception for 8-bit PNGs) and having a long strip or multiple images in one file wouldn't make the difference (actually, I'm event thinking that APNG isn't even something really new...did they copy the GIF concept?).

Anyway, these are my thoughts. I'd like to know the other's

Actually, I don't quite know what you're trying to say here, mate. "If we had the possibility of a single animated icon" ? We do! GIFs are hugely inefficient nowadays, simply because they don't support alpha channel transparency and they don't support more than 256 colours. Once upon a time, that was no problem, but now, I doubt you'd want your icons to be 8-bit and with jagged edges due to 1-bit transparency.
Incidentally, PNG may be lossless, but it *does* compress the data; it's not raw bitmap.
And I'm not certain what you mean by saying "did they copy the GIF concept". What concept is that?

i have to agree with skagon on all points on this one. now as for copying the gif consept, no. if i remember right what can be done with gif files hasn't changed in years if ever. apng or something similar should of been the next step for gif files, but the creator of the gif never took it any further. skagon am i right with using a strip affords the creator the ability to do anything they would normally do in a static image versus being limited like with gifs and the apng format? if so then my vote would to use the strips for any app that uses animated icons.

Well, since it's a single image, yes, the creator can do any damn thing they want on it. GIF and APNG (in part) can be very troublesome. What I mean is that both GIFs and APNGs can contain a full copy of each frame, in which case, the application that renders them can also do anything. However, both GIFs and even more so APNGs can include "slimmed down" frames, for the obvious reason, to conserve space. For instance, GIF frames can only include *changed* pixels. APNG can do that as well, but also define a smaller rectangle, which not only will be rendered accordingly (GIFs can theoretically do that too), but also change position within the original PNG frame.
The only case in which an APNG (well, ok, *and* a GIF) would be preferable, would be a variable showtime case. Like, if you want one frame to be shown for, say, 100msec and another one for 10msec. In such cases, the only thing that a creator can do is decide on some frame's (or frames') minimum showtime, and duplicate frames with longer showtimes accordingly. Let me explain that: assume you've make an animation with four frames. You decide that the first frame should be shown for 20msec, the second for 100, the third for 30 and the last one for 50msec. In that case, which I've purposefully made as bad as it gets, the greatest common divisor is 10. So, if we had APNG we'd simply input the 20, 100, 30 and 50 as "runtimes" for each frame. Since there's no such facility in a plain PNG strip, we'd have to make two copies of frame 0, ten copies of frame 1, three copies of frame 2 and five copies of frame 3. So, in the end, we'd have 20 frames instead of only four. Plain vanilla PNG strips do not have runtimes, so... you'd get a 5x increase in size, just so that you'd get a proper animation. Plus, a PNG strip also lacks of any runtime specification, so it's up to the user to make it as fast or as slow as they want. Any proper animation spec would 'nail' the animation to the framerate intended by its creator (much like GIFs do).
So, you can see that it's not all roses with the PNG strip solution. Actually, since APNG decoding is relatively easy to implement, I can't help but wonder if Jorge can include that, on top of PNG strips (since that one already exists).
On second thought, I don't know of any 'serious' APNG editor, so it's a rather moot point. He might as well include support for ABMP32. Don't google it, that thing DOESN'T exist, so there's no editor for that either.

By "single animated icon" I meant a file containing an animated icon like GIF.

Multiple frames into a single image, to make an animated icon.
I hope it's more clear now what I meant


If by A you meant ALPHA, then it does exist and it's free. It's called Paint.NET (you can find it here: http://www.getpaint.net ), you'll only need the BMP32 plugin ( http://forums.getpaint.net/index.php?showtopic=11201 )

No, actually it was a (bad, apparently) pun playing with the A like APNG = Animated PNG, ABMP32 would be Animated BMP32.
If I may be pedantic here, officially there's no such thing as an ABMP32 (meaning Alpha), since BMP32 can mean a whole lot of different things, *including* alpha channel. The correct acronym would be ARGB BMP32.

jAPNG editor. I make all my APNGs with this, and it's working like a charm. By the way, people always talk about transparency and number of colours, but another big advantage of APNG vs. GIF is the ability to set the delay between 2 frames in milliseconds. That was the reason why I switched to APNG, I needed a millisecond precision.

Now if what you mean is a graphics software that would allow you to save as APNG, I don't know. I think you have to create the frames separately and then compile them with jAPNG. https://www.reto-hoehener.ch/japng

Another very powerful tool is VirtualDub APNG mod. It allows you to directly convert AVI to APNG. http://sourceforge.net/projects/vdubapngmod
It optimizes the file, avoiding redundant image data.

Another very convenient tool to remove redundant image data is APNG optimizer
http://sourceforge.net/projects/apng/fi ... imizer/1.0

Yeah, I'm sorry but that's Java. I don't have a Java engine on my PC and I frankly don't want to have one. Java sucks. Sorry.
The VirtualDub mod is nice, but most (if not all) video formats are lossy, which pretty much makes the resulting quality bad. Very bad. For an icon, that is.
The optimiser is nice, but you have to make one first, in order to optimise it. Kinda moot point.
By the way, you can set delays in GIFs too. I don't know how precise you wanted it to be, but we're talking about simple animated icons here, not atomic clocks stored in APNG format...

In GIFs you can set hundredths of second, not milliseconds. And yes I need that sort of precision for what I'm doing.

It's too bad you're angry with Java, because jAPNG is a great program, and it never bugs.