GIF patent expired in US

I've just come across a report that the GIF patent has expired in the US
- though apparently in Europe, Canada and Japan it still continues until
2004.

What effect, if any, does this have on the relative preferences for GIF
or PNG graphics?

--
Stephen Poley

http://www.xs4all.nl/~sbpoley/webmatters/

Mark Tranchant wrote:

In summary, PNG is superior, and the only reason to use GIF is for
animation.

What about filesizes? I have tried to create PNG images, but the PNG

files turned out to be significant bigger in size than their GIF
equivalents. Since I want my pages to load as fast as possible, I
decided to stay with GIF.
BTW I used Paint Shop Pro 7, maybe other programs achieve better
filesizes....

--
Jeroen Sangers \/
/\ Be Alert...
http://www.jeroensangers.com \/
http://www.fimcap.org /\ The world needs more Lerts!

Jeroen Sangers <nntp (AT) jeroensangers (DOT) com> writes:

What about filesizes? I have tried to create PNG images, but the PNG
files turned out to be significant bigger in size than their GIF
equivalents. Since I want my pages to load as fast as possible, I
decided to stay with GIF.
BTW I used Paint Shop Pro 7, maybe other programs achieve better
filesizes....

Odd, likewise using PSP7 [1] I get smaller file sizes with PNG than GIF
*except* where the image is 16-colour or fewer (or in a few cases
where the image is really small). Any chance you could put some
example images on the web where PNG larger than GIF?

[1] Similar results with ImageMagick and Photoshop, though.

--
Chris

Le 25/06/2003 17:40, Jeroen Sangers a écrit :

Mark Tranchant wrote:


In summary, PNG is superior, and the only reason to use GIF is for
animation.

What about filesizes? I have tried to create PNG images, but the PNG
files turned out to be significant bigger in size than their GIF
equivalents. Since I want my pages to load as fast as possible, I
decided to stay with GIF.
BTW I used Paint Shop Pro 7, maybe other programs achieve better
filesizes....

2 possibilities :
- you are using photoshop which has a pathetic PNG plugin. Solution,
install the free SuperPng plugin :
http://www.fnordware.com/superpng/

- you are saving a palette based image in PNG 24 bits instead of PNG 8 bits.

Even with superPNG, processing images with a PNG optimizing tool usually
decreases the file size by 20%.

PNG optimisers :
- http://pmt.sourceforge.net/pngcrush/ the best tool but it is console
based, no UI

- http://www.psydk.org/PngOptimizer.php a good tool but it has few
options and can't deal (yet) with some PNG images, specifically
interlaced PNG images

Pascal

--
FAQ Mozilla/Netscape 7 en français : http://pascal.chevrel.free.fr/
There are 10 kinds of people; those who understand binary, and those who
don't.

Chris Sharman wrote:

The trailing edge provides a severe constraint against the latest &
greatest technology, and I don't see PNG being worthwhile until 90-95%
have graceful behaviour for Alpha transparency.

Why not?! Even as PNG8 with binary (or no) transparency, it's still
better than GIF: all but the most trivial images compress better with PNG.

It's a bit of a vicious circle. If the whole world goes back to GIF,
then the impetus to provide decent PNG support will drop. Try to prevent
this by using PNG for all non-photographic still images.

All of my sites are GIF-free, and I've never had anyone complain they
can't see the images. Even Netscape 4.x supports PNG. I don't see why
you're so keen to stick with GIF.

--
Mark.
http://www.tranchant.freeserve.co.uk/

On Thu, 26 Jun 2003 09:57:32 +0100, Mark Tranchant <mtranch2 (AT) ford (DOT) com>
wrote:

Chris Sharman wrote:

The trailing edge provides a severe constraint against the latest &
greatest technology, and I don't see PNG being worthwhile until 90-95%
have graceful behaviour for Alpha transparency.

Why not?! Even as PNG8 with binary (or no) transparency, it's still
better than GIF: all but the most trivial images compress better with PNG.

It's a bit of a vicious circle. If the whole world goes back to GIF,
then the impetus to provide decent PNG support will drop. Try to prevent
this by using PNG for all non-photographic still images.

At the risk of exposing my ignorance (and perhaps being off-topic): when
I export PNG's from Corel Draw I get a result which looks fine in Opera
but has an ugly grey block in IE6 - I infer that it is producing alpha
transparency. Any suggestions how I could either persuade Corel Draw to
produce binary transparency (I had a look round the options, but there
was nothing obvious - I'm already using Palletted/8-bit) or to convert
the PNG file to binary transparency after I've produced it?

I've tried pngcrush, but so far only managed to replace the solid grey
block with a solid white block.

I have also tried writing PNG files from Microsoft Paint. (OK, you can
get up from the floor when you've finished laughing.)

--
Stephen Poley

http://www.xs4all.nl/~sbpoley/webmatters/

Mark Tranchant <mtranch2 (AT) ford (DOT) com> wrote

Stephen Poley wrote:

Any suggestions how I could either persuade Corel Draw to
produce binary transparency (I had a look round the options, but there
was nothing obvious - I'm already using Palletted/8-bit) or to convert
the PNG file to binary transparency after I've produced it?

Recent versions of ImageMagick or GraphicsMagick can do it:

convert transparent.png -ordered-dither opacity 2x2 binary.png

Glenn

On Thu, 26 Jun 2003 16:23:07 +0100, Mark Tranchant <mtranch2 (AT) ford (DOT) com>
wrote:

Stephen Poley wrote:

Any suggestions how I could either persuade Corel Draw to
produce binary transparency (I had a look round the options, but there
was nothing obvious - I'm already using Palletted/8-bit) or to convert
the PNG file to binary transparency after I've produced it?

I don't know about Corel Draw, but the GIMP does the job for me.
Whenever I create an indexed PNG, I get binary transparency.

I've tried pngcrush, but so far only managed to replace the solid grey
block with a solid white block.

IE will display the stored background colour in place of alpha
transparency. I guess you're deleting Draw's default grey and IE is
adding a default white.

That could be it.

Anyway (several Google searches and several megabytes of downloads
later) I seem to have cracked it: export the drawing as a GIF and
convert it with the gif2png tool.

The results look pretty good: 25% to 50% size reduction compared to the
GIF.

--
Stephen Poley

http://www.xs4all.nl/~sbpoley/webmatters/

On 27 Jun 2003 04:39:51 -0700, randeg (AT) alum (DOT) rpi.edu (Glenn
Randers-Pehrson) wrote:

Mark Tranchant <mtranch2 (AT) ford (DOT) com> wrote

Stephen Poley wrote:

Any suggestions how I could either persuade Corel Draw to
produce binary transparency (I had a look round the options, but there
was nothing obvious - I'm already using Palletted/8-bit) or to convert
the PNG file to binary transparency after I've produced it?

Recent versions of ImageMagick or GraphicsMagick can do it:

convert transparent.png -ordered-dither opacity 2x2 binary.png

OK, thanks. I'll file that as a fall-back in case I hit problems with
gif2png.

--
Stephen Poley

http://www.xs4all.nl/~sbpoley/webmatters/