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About the PNG Format

Posted: 08 Feb 2010, 17:56
by bcs86
[PNG Homepage]

I'm posting this because I think many people are not familiar with Portable Network Graphics and are therefore afraid of it.
The Mana World uses the Portable Networks Graphics format for all sprites.

One thing that I would like to make clear is that PNGs are lossless. They use zlib compression (like in gzip).
It will not mess up your image to compress it.

Another thing to make clear is that PNGs support full 24 and 32bit color. You will not lose colors upon saving.

PNG graphics can be optimized up to 256 colors, good for pixel art. It requires some tweaking to do losslessly,
but it saves space when you know how.

Unlike GIF, PNG has an entire alpha channel. Images can have areas that are partially see-through.

Fully compressed PNG files do not benefit any from being put in compressed archives. They go nicely in non-compressed tape archives (tar). You can mount tape archives and browse the images inside, or change the .tar suffix to .cbt for viewing in comic book readers.

The best speed to compression ratio is 6. PNGs that are fully compressed (9) are slower to unpack. I don't know how this affects gameplay. Nine is best for larger files that will take some time to display anyhow.

PNG is best for icons and sprites, not photos. It replaces the need for unanimated gif, and .bmp (don't rely on MSPaint for it's .png support though)

I hope this helps avert paranoia about the PNG format. I'll try to answer any questions if asked.

Re: About the PNG Format

Posted: 08 Feb 2010, 18:10
by Jaxad0127
I've made this a sticky. The platform (mana) supports many different formats, but TMW has chosen to only use PNG for world data (other formats are needed for other, special areas, like program icon). Other projects can do what they want, like use GIF or JPEG or whatever. But TMW will only accept PNG (except for those aforementioned special images).

Re: About the PNG Format

Posted: 09 Feb 2010, 06:27
by Crush
It was also suggested to use TGA for some images in the past. TGA supports everything PNG supports. The difference is that TGA files are not as small as PNG but it is considerably faster to unpack resulting in reduced load times on systems with slow CPUs.

But for TMW I would still advise to stick to a single image format to make life easier for contributors and maintainers.

Re: About the PNG Format

Posted: 05 Mar 2010, 04:25
by bcs86
* Added information about compression in the 7th paragraph.

Re: About the PNG Format

Posted: 21 Jun 2010, 03:45
by Senretsu
I've relied heavily on Png's, and never been let down, for the better half of my spriting career.
Two thumbs up.

Re: About the PNG Format

Posted: 07 Oct 2011, 06:51
by New
I love pixel art.

Re: About the PNG Format

Posted: 07 Oct 2011, 10:20
by Freeyorp101
New wrote:I love pixel art.
You seriously bumped a year old thread just to say that?


---Freeyorp

Re: About the PNG Format

Posted: 07 Oct 2011, 13:36
by yubabax116
If you look at most of his posts he does it to many.