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Implementating Transparent PNGs in IE7

Posted by timothy on from the hammers-and-tongs dept.

Brandon writes "Over at the official IE Blog, Sam Fortiner has posted some very detailed information regarding Alpha PNG Rendering in IE7. From the article: 'As the dev who implemented the support, I can state that it was neither a bug-fix nor did it require a re-write of the display engine. Instead, it ended up being somewhere in-between the two and required what I would call "feature work." Implementing transparency support for PNG images required a significant amount of modification to the image decoding and display pipeline in IE along with a significant amount of new functionality added to the PNG decoder.'"

13 of 97 comments (clear)

  1. libpng.... by __david__ · · Score: 4, Interesting

    So this implies they wrote their own PNG reading routines instead of using libpng?

    Is this some sort of NIH thing?

    libpng has a BSDish licence if I recall... So that can't be the issue...

    -David

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    1. Re:libpng.... by Chris_Jefferson · · Score: 4, Informative

      If you read the article, you'd find the main problem is that all their internal data structures and rendering system were only designed for boolean transparency.

      libpng wouldn't have helped with either of these, and this is where most of the work was.

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  2. Probably because IE displays images as they load.. by cwensley · · Score: 3, Interesting

    I'd imagine this would be why IE can show images as they download, instead of waiting for the whole thing to download like other browsers...

    I could be wrong..

  3. Monopoly by augustz · · Score: 4, Insightful

    This is a really interesting case study in monopoly behavior and the value of competition. Microsoft you will remember pretty much stopped IE development and shut down the IE team.

    Firefox came along, and whamo, all of a sudden Microsoft has developers writing things like. Very impressive. What's interesting for me is they are huge huge company by comparision to Firefox, but it took firefox to really get them to start making some improvements.

  4. You are by leonbrooks · · Score: 4, Informative

    Konqueror displays partial images as they download. The original friggin' browser in OS/2 did the same thing. It's hardly new.

    Think about it: what's the whole purpose in Progressive-mode JPEGs?

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  5. Implementating? by Atrax · · Score: 3, Funny

    put your spellchecker on danger money, baby.

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  6. Reading between the lines of the story... by leonbrooks · · Score: 3, Informative

    ...the code they're rewriting has not been substantially changed since the days when GIF was king of the images.

    AFAICT, what they've finally added is genuine translucency (not the simple yes/no transparency of yore) to MSIE's image handlng.

    Does anyone know of any other (non-text-mode) web browser which hasn't already been doing translucency for years?

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  7. Implementating? by eric.t.f.bat · · Score: 3, Informative

    Implementating? Implementating???!!!

    Something is very very wrong with the /. editors. I think it's time I spent my precious picoseconds looking at some other website.

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  8. Requires IE5, IE6 by julie-h · · Score: 3, Funny

    I have a question. When there is written

    "Requires IE5, IE6, or better"

    on a website. Does that mean Firefox?

    1. Re:Requires IE5, IE6 by FidelCatsro · · Score: 4, Funny

      to me "Best viewed in Microsoft Internet Explorer" say "Wanted , new web designer/Developer"

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      The only things certain in war are Propaganda and Death. You can never be sure which is which though
  9. Fixes by Adelbert · · Score: 3, Funny

    So IE7 will show transparent PNGs, Firefox 2.0 will render /. properly. What will I be able to complain about then?

  10. CSS support? by tryone · · Score: 5, Insightful

    Very nice. Now go fix the crappy CSS support.

  11. [OT] I just want to know why... by leonbrooks · · Score: 3, Funny

    ...when Conan32 spelt "hypocrisy" correctly, and both eraserewind and NanoGator had it right there on their screens to reply to, they both spelt it wrong?

    <thwack!>

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