Question about Trans. PNG

[Soquili]

I received an email today from Tony Gaylord, asking about transparent png files. In my tests to answer his question, I ran across some questions of my own.

The 24bit+alpha transparency image made in Xara X looked fine when imported into PaintShop Pro 7 and Photoshop LE. But, when opened in Internet Explorer 5.5 on a WinME machine, there was a grey rectangle as a background to the text used for the image. I then inserted the png into a Front Page 2000 page and it had a black rectange for a background. I proceeded to open the png file using IE6.0 on a Win2000 machine, same grey background. Switching to Red Hat Linux 7.2 it was opened in Netscape Communicator and Netscape Navigator 4.78 where it showed a black background rectangle. Opening the file using Galeon and Mozilla on the linux platform showed the correct transparent background.

Has anyone else experienced similar problems with transparent png files using the browser you prefer?

Thanks for your time.

Soquili

BTW transparent png files created in the other graphics programs experience the same background problem.

[Soquili]

I received an email today from Tony Gaylord, asking about transparent png files. In my tests to answer his question, I ran across some questions of my own.

The 24bit+alpha transparency image made in Xara X looked fine when imported into PaintShop Pro 7 and Photoshop LE. But, when opened in Internet Explorer 5.5 on a WinME machine, there was a grey rectangle as a background to the text used for the image. I then inserted the png into a Front Page 2000 page and it had a black rectange for a background. I proceeded to open the png file using IE6.0 on a Win2000 machine, same grey background. Switching to Red Hat Linux 7.2 it was opened in Netscape Communicator and Netscape Navigator 4.78 where it showed a black background rectangle. Opening the file using Galeon and Mozilla on the linux platform showed the correct transparent background.

Has anyone else experienced similar problems with transparent png files using the browser you prefer?

Thanks for your time.

Soquili

BTW transparent png files created in the other graphics programs experience the same background problem.

[gwpriester]

Soquili

Were you exporting a 24-bit PNG with Alpha channel transparency?

If so, you have discovered that most browsers, perhaps all, do not support 24-bit transparency. Only 8-bit.

So, what is the advantage of 24-bit plus Alpha you well might ask.

You answered the question when you brought the image into a bitmap editing application. The alpha channel travels with the image. So if in Photoshop you wish to place your image over another background and have your image's transparency maintained, you can use the Alpha channel.

To use transparency on the Web, you will need to reduce the color depth to 8-bit 256 colors.

Gary

Gary

Gary Priester

Moderator Person

<a href="http://www.gwpriester.com">
www.gwpriester.com </a>


XaraXone

[Soquili]

Ah, so browsers are not all made equal. The popular browsers for windows only support 8bit transparent png files. Thanks for letting us know this fact Gary.

It is interesting that the Galeon and Mozilla browsers for Linux do support the 24bit with transparency.

Soquili

[pduggan]

Avoiding GIFs (except for animations) as far as possible, I've used 16 and 256 colour transparent PNGs for several sites and never had any display problems in IE, Opera and Netscape 6. True colour + alpha, however, still seems to be poorly supported by comparison (my IE6 test has just produced the same results as yours). Netscape 4 (spawn of the devil!) can't display transparency in PNGs at all, but backs the 16 and 256 colour varieties with white!



Peter</p>



Peat Stack or Pete's Tack?</p>

[Soquili]

It's good to know that by reducing the number of colours the png + transparency files can be used on websites.

Soquili

[jens g.r. benthien]

you should run Opera (www.opersoftware.com) as your favorite browser - it's the only one that can handle full color plus alpha. Available for Windows, Linux, BeOS, Mac, and even the real time OS QNX Neutrino.

Sure it's not free, but very small on your hard drive, fast and extremely responsive. And of course it's the only browser that sticks to the W3C consortium standards. Many more features in there like ICQ, an import function for you MS IE hotlist etc - give it a try and forget those MS apps - they are not worth the hassle ;-}

jens

jens g.r. benthien
designer
http://jens.highspeedweb.net

----------//--
If you don't know how to dream you'll never be a designer.
----------//--

[gwpriester]

<BLOCKQUOTE><font size="-1">quote:</font><HR> you should run Opera (www.opersoftware.com) as your favorite browser - it's the only one that can handle full color plus alpha. Available for Windows, Linux, BeOS, Mac, and even the real time OS QNX Neutrino. <HR></BLOCKQUOTE>

The fact is that the world uses Internet Explorer and that is not going to go away anytime soon. When Microsoft decides to go after a market, they usually get their way. Linux as you remember was going to be a serious challenge to Windows. But what does 95% of the world use?

Just my two cents.

Gary

Gary Priester

Moderator Person

<a href="http://www.gwpriester.com">
www.gwpriester.com </a>


XaraXone

[jens g.r. benthien]

...on productivity is worht billions each year because most apps **are** a hassle for the users. The system crashes alone cause a loss of hundreds of millions each year worldwide. And if you read case studies about productivity it's amazing that the highest productivity is not achieved by users with MS apps, but by users who run applications from 'third party' developers.

Sorry, it's a sad story, but 99.9% of the users still believe the bullshit MS is spreading.

Besides this I just wanted to point the forum members to an existing and superior alternative that is the **only** standard because it really sticks to the standard. If anybody can afford to waste his/her time with hassle or display problems, that's fine with me.

BTW, I bet you are using the graphics driver from the manufacturer of your graphics card and NOT the 'original' MS driver. And I bet you've installed the printer driver that came with your printer and not the genuine MS driver for that printer. Why? Because they exploit the features of the components much better than the lousy MS stuff. So I really don't understand why 'intelligent' people use MS IE or any other MS apps that even have some well known and documented 'bugs' and backdoors programmed into it to open the systems for virus attacks. Only because it's FREE? Poor world.

No wonder that we are having so many 'successful' virus attacks now with this attitude of the users.

Welcome to the club of the constant rebooters and re-installers!

I prefer to be productive while they are messing around with their 'wanna-be-professional-and-beefed-up-to-the-limit-systems'.

And believe me, on Mars there a still little green men running around ;-}.

It's the same story as with the 'America is immune against attacks' story: September 11th 2001 led this statement ad absurdum.

jens

jens g.r. benthien
designer
http://jens.highspeedweb.net

----------//--
If you don't know how to dream you'll never be a designer.
----------//--

[Soquili]

Hi Jens,

Thanks for the advice. I did upgrade Netscape on my Linux machine to version 6.2.2 and it handles 24bit+alpha png files correctly. I haven't tried Opera for about 3 to 4 years now, back then it was only a front end that actually used the IE engine. For Windows, I prefer IE; just my personal taste. In Linux, I prefer to use Galeon. It is a very lightweight app and responds more quickly than any of the other Linux browsers I've tried.

Soquili