Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?

PNG Group Unconcerned About Apple's Patent 137

melquiades writes: "A recent story raised concerns that Apple's patent on some forms of alpha compositing was blocking the development of PNG, MNG and SVG. Not so, says Greg Roelofs, a member of the PNG group: 'The PNG group did discuss the Apple patent several weeks ago, and we decided it was completely irrelevant to PNG itself, almost certainly irrelevant to the pnmtopng utility and to PNGs animated extension, MNG, and probably irrelevant to SVG as well.' Here's the article on OS Opinion. So if it's not a big deal, why was there a general call for prior art to overturn Apple's patent? It looks like some PNG developers got worried, but the core team thinks there's no problem. Is this just a case of the right hand not knowing that the left hand is paranoid?" Once bitten, twice shy?
This discussion has been archived. No new comments can be posted.

PNG Group Unconcerned About Apple's Patent

Comments Filter:
  • ...I'm sure they would have said *something* by now.
  • Leftover Paranoia (Score:5, Insightful)

    by rsimmons ( 248005 ) on Tuesday November 20, 2001 @04:26PM (#2591892) Homepage
    Its just leftover paranoia from the problem Unisys had with people using the GIF format. The PNG group seems to have a good understanding of the Apple patent, from what I read in the article.
  • Does anyone really use that format? I haven't heard too much about it lately after it was supposed to be the next greatest format for pictures ever. Anyone out there using them?
    • Re:PNG's (Score:4, Funny)

      by szomb ( 318129 ) on Tuesday November 20, 2001 @04:29PM (#2591908)
      Uh, sorry, what? Is anyone out there still *not* using PNG?
      • Slashdot. At least they are still using GIFs.
      • Re:PNG's (Score:4, Interesting)

        by Dionysus ( 12737 ) on Tuesday November 20, 2001 @05:00PM (#2592123) Homepage
        Sites that don't use PNG:,,,,,, and of course,

        So, who is using PNG?
        • Re:PNG's (Score:2, Informative)

          by Zed Pobre ( 160035 )

          Remove [] from your list. It does use .png images (and there are half a dozen of them on the main page, at least), just not exclusively.For that matter, including [] is somewhat unfair, as they pretty much only use the one image on the entire site, and although it's in jpeg format on the main page, it is also available in .png (in fact, the high resolution version is only available in .png). See [].

          So who is using PNG? Some of the people you list as not using PNG.

          (... mutter mutter ... moderators that don't check claims ... mutter mutter ...)

        • Me! :-)
      • Uh, sorry, what? Is anyone out there still *not* using PNG?

        In my job as a web scripter, we can't use PNG, as policy dictates that we be compatible with as many browsers as possible. Netscape 4.x isn't compatible without a plugin, so it's a no go. That browser has caused more grief than all the others combines.

        On the flip side, we can't use GD to generate GIFs, as there's no GIF support, so all we're left with are JPEGs with calculated backgrounds. No transparencies.

        • In my job as a web scripter, we can't use PNG, as policy dictates that we be compatible with as many browsers as possible. Netscape 4.x isn't compatible without a plugin, so it's a no go. That browser has caused more grief than all the others combines.

          Ding! Wrong.

          Communicator (4.76 anyway) does support PNGs. I know this because I can view my Webalizer output just fine with it. ;)

    • Re:PNG's (Score:4, Insightful)

      by mediadiva ( 537906 ) on Tuesday November 20, 2001 @04:33PM (#2591940) Homepage
      I use PNG's everyday, as it is the file formate that firework's (macromedia) uses. It contains a "web layer" and when created in firworks you can create "slice guides" and rules. Similair to how a PSD contains layer. The only difference is, I can open a PNG in IE, though I wont see the layers, and it will be a REALLY big file, compared to what it would be if it was exported out as a gif or jpg or I guess a flat PNG.
    • Re:PNG's (Score:3, Insightful)

      by Vicegrip ( 82853 )
      yes.. and if you do a bit of investigation you'll notice all browsers support them, including IE. In fact, you'll also notice that hordes of websites also use PNGs.

      There is practically no decent reason for any website to still be using GIF files as the conversion of both the html and files is pretty easy...

      PNGs are also way technically better.
      • I agree.
        i stopped using Gif except where I needed transparency (and considering gif's lousy attempt at transparency that wasn't often) several years ago, as soon as IE started to work properly with PNG I abandoned GIF alltogether.

        There are still lots of people who haven't heard of PNG, even in the web design and graphic arts fields, but for at least the artists just mentioning PNG's transparency abilities is enough to convert them.
        (I really can't believe we put up with GIF as long as we did)
    • We used them in a project. It supports 24bit color and lossless compression.
    • Well, KDE and GNOME use them for icons on most apps.
    • Try a "find / -iname *.png" on your Linux box and see for yourself.
      • Re:PNG's (Score:3, Interesting)

        by utoddl ( 263055 )

        Just for the record (not that this is scientific or anything) my current ~/.netscape/cache has

        • 65 PNGs,
        • 1,188 GIFs, and
        • 170 JPGs
        in it. I suspect that might be a little higher than average in the PNG department because I tend to frequent sites run by rabid free software rebels. YMMV
    • Some keenspot comics use PNGs. In particular, I remember Superosity [] and Ubersoft [] both announcing when they switched. Both mentioned a space saving of about 30% on images after the switch.
    • I not only use them everyday since they are all over KDE/Gnome, but in my projects as well - the lossless compression is great, especially for generating images from vector data (which I do a lot for various stuff) - far better quality and size than JPEG and none of GIF's patent absurdness.
    • I tried, but unfortunately the space taken up in comparison to slightly-compressed JPGs made me bail on the idea.
      • Re:PNG's (Score:3, Interesting)

        by lordpixel ( 22352 )
        What were you compressing? Photographs?

        They're not intended to replace JPEG[*] they're best suited for application where you would use a GIF. As with GIF the compression is lossless and best for compressing line art and simple computer generated stuff.

        In addition to GIF you also get:

        * > 256 colours
        * Full 8 bit alpha channel (but not in IE on Windows :(

        Then there's MNG - for animated PNGs like animated GIFs and [*] JNG which in a PNG which internally uses uses JPEG compression and thus is pretty good with photos. These are more obscure though. I think JNG might allow transparency/alpha channel, which would be cool, as regular JPEG does not.
    • Guess I got a response.....I wasn't bashing PNG's. I've been a "web-developer" (i shudder at my own title in disgust) for quite some time now. I don't use PNG's. No real reason, I don't spend much time on graphics, more time coding. I know there are a lot of sites out there that also don't use them. I do know they have some spiffy features and advantages over what I would still perceive as the standards, GIF and JPEG. I know they are supported by all major browsers. I was just wondering if anyone had any insight into why they aren't being used more on the web (or maybe they are and I'm just a nitwit). Just trying to explain myself a little as I saw some hostility in some of those replies.
      • Re:PNG's (Score:4, Insightful)

        by Doomdark ( 136619 ) on Tuesday November 20, 2001 @06:15PM (#2592615) Homepage Journal
        Well, the main reasons why PNG hasn't replaced GIFs:
        • People are slow in changing their habits; they are used to GIFs, they (still) use GIFs. If it ain't broken don't fix it (that's of course assuming you haven't been harassed by Unisys. :-))
        • Some old browsers did not support PNGs at all. Shouldn't be a big problem nowadays, though (esp. since much of Javascript stuff in use would break them anyway)
        • PNG doesn't have animation, for cheap-ass simple animation GIF is the choice (MNG would replace it, but it's bit of obscurity, being rather ambitious format project)
        • Although PNG has really cool features (full alpha channel is _really_ nice for blending image borders, neat translucency effects etc), many browsers (NS 4.x series, IE on Windows at least until 5.5) still only implement 'GIF-level' features, ie. on/off transparency, no gamma correction etc. Mozilla has good support, and IE on Mac too (no idea why; usually windows version is more advanced).
    • Microsoft uses them all over Luna. (That's Windows XP's candy-coated UI redesign.) I've been hacking with it a little, and it looks like they're using the alpha channel for cheap anti-aliasing on frequently scaled bitmaps. Other places, they fall back on the traditional .bmp format with "magic pink" transparency masks.
    • Re:PNG's (Score:2, Interesting)

      by Dracos ( 107777 )

      PNG is stealthily gaining acceptance. I think there are three reasons why PNG hasn't gone as far as it should have by now:

      • Content managers (or whoever ranks above the actual content authors) may not know or care about PNG. Until all the graphic artists start selling it up the ladder as a solution, PNG will continue to flounder.
      • PNG's are generally a bit bigger (file wise) than an identical GIF or JPG. Not much bigger in most cases (and smaller sometimes), but some sites prefer to bloat their pages with badly formatted css and invalid HTML instead of a next generation gfx format.
      • MSIE's PNG support blows goats. I haven't seen a final of IE6 in action, but a late beta I saw still used a plugin to display PNG's instead of native code. Pull up an RBGA PNG in IE and witness the dark rectangle clearly defining the size of the image. (But if it works on Mac IE, then someone at MS has a clue).
    • I'm a storm chaser, and an amateur astronomer, and I use PNG to save all my images. It's much better than JPEG in terms of quality.

  • Now, the call for prior art is a totally separate issue. Even though the PNG format is not threatened by the Apple patent, it would still be a good idea to come up with prior art and destroy the patent.
  • by Millennium ( 2451 ) on Tuesday November 20, 2001 @04:30PM (#2591912)
    It looks to me like the patent covers alpha-masking, not alpha-blending.

    As I recall, PNG and SVG both use alpha channels. That is, transparency data is stored as a part of the image's color encoding.

    Alpha-masking is different. In this case, an image is defined in the "normal" RGB fashion. Along with it, a second image is stored, which has only alpha information in it, not color. You could say that an alpha channel is inline, whereas an alpha mask is not.

    Is the patent ridiculous? Of course it is. But I don't think it would affect PNG and SVG anyway, because they use a different method of storing transparency information.
    • The whole point of this patent is that it actually does not represent an alpha mask, but each pixel in the mask represents a blending value seperatly for each channel. Usually it is used in the form A*I + B*(1-I), where A and B are the images to be blended and I is the blending value.

      This technique is used to get those fancy transition effects in Final Cut and iMovie. It allows to implement a wide range of effects like wipes, fades, color effects etc. It can represent most effects which do not require pixel displacement. The big advantage is that you actually precompute the effects and then simply feed the resulting animated blending mask and the two video sources to some highly optimized code/hardware without the need of specific code for each effect.

    • by Doomdark ( 136619 ) on Tuesday November 20, 2001 @07:06PM (#2593074) Homepage Journal
      I thought so too, after first glance at the patent. However, after reading it through second time, I understood what the patent really is about.

      What it is is doing 'compontent-sensitive' image blending. Instead of using single alpha mask or channel for all colour components, it uses a full mask image, that is then used for blending images component by component. When mask image is a gray-scale image, this effectively degenerates to 'normal' alpha blending. However, when using non-gray colours, blending is not linear (as with alpha blending) for the components. In RGB, for example, you could take red value from source, green from destination, and blend blue 50-50 from both, and get... um... probably interesting results?

      What I would like to know is if this is useful? What kind of effects can be achieved by using non-grayscale mask images? Potentially it might produce interesting effects... But are those just curiosities?

      ... and no, obviously this doesn't cause any problems for PNG, which 'only' uses embedded alpha channels.

      • Maybe it is for transparent materials for composites. Think about like a blue screen or green screen with a translucent white/grey piece of paper. The paper is going to have some blue (or green) in it, so you would want to reduce the blue more (not the over all color). Because you will get a white-blue reducing it down with a single scalar (alpha) would produce grey-blue or dark-gray-blue, instead you want to reduce the blue down more then the others so you have to use 2 or 3 scalars (red-alpha, green-alpha, blue-alpha).
      • First, IANAPL but I have written a few patents in the graphics field.

        My understanding too was that the mask image (i.e. equivalent of the alpha) could be a multi-channel ARGB signal wherein each channel of the "source" and "destination" could be individually blended by their respective channels. This is an extension over standard alpha blending.

        As for the possible existence of "Prior Art", at least with respect to the first claim in that patent, does anyone have a date for the SGI's
        "Graphics Library Programming Guide Version 2.0"? I have a copy here but it doesn't have any dates. Note that this is the GL before it was "opened". I think this document dates from the early 1990s but an exact date would be useful.

        The reason I ask is that it contained a lot of the facilities that are in OpenGL, and if you look at the section 15.2 "Blending" you will see that it is possible to do a channel by channel blend by selecting calling

        blendfunction(BF_SC, BF_MSC)

        along with a texturing operation. I believe this may encapsulate all the functionality described in the 5379129 patent. Since that patent was filed in 1992, there is a good chance that the SGI documentation may consititute full prior art.

        • On second thoughts, it might be difficult to use three different textures in with this interface unless you can write to an intermediate storage as done in the multitexturing facilities of today's graphics hardware.

      • This (RGBR'G'B' compositing) is actually extremely useful, but almost nobody actually does it because (a) most current software doesn't support it, (b) it takes more storage - 6xwidthxheight rather than 4xwidthxheight, and (c) it's slower. But if you do premultiplied compositing, it lets you have "stained glass" effects which are impossible otherwise. It's definitely not just a curiosity.
        • Ok, thanks for info. I also think that this method might have uses in some other colour spaces, like HSV. Perhaps better anti-aliasing could be obtained by certain combinations of masks for colour (Hue) and the other two components?
          Hmmh. I'm almost tempted to start doing some gfx testing again... been a while. :-)
  • by marmoset ( 3738 ) on Tuesday November 20, 2001 @04:30PM (#2591916) Homepage Journal
    The OSOpinion article refers to Greg Roelofs'
    forum post []. My favorite part of the Roelofs' post is this classic line:

    " So I nominate this for the 2001 tempest-in-a-teapot award... But since the /. crowd lives for this stuff, I wouldn't presume to imagine that my comments will have any discernable effect on the (flame)festivities. :-) "

    How many posts did that article get the other day? :)
  • by YouAreFatMan ( 470882 ) on Tuesday November 20, 2001 @04:31PM (#2591920) Homepage
    Unfortunately, this, like many patent issues, can't be decided except by a court. Just because someone says "we don't infringe on Apple's patent", that doesn't stop Apple from suing or a judge from ruling that it does infringe.

    That's why the call for prior art goes on. Deny that Apple has a case, but build a strong defense against their case. It's the cover-your-bases approach, and, sadly, the only wise one available in the current intellectual property age.

    • by Nindalf ( 526257 ) on Tuesday November 20, 2001 @05:05PM (#2592155)
      While we're at it, let's spend all our time and effort preparing to defend PNG against patents on automated shoe manufacturing and quack magnetic therapy devices. After all, "only a court can decide" whether PNG software infringes on those, too.

      The patent itself specifically contrasts what it covers with the use of an alpha channel, such as is used by PNG. It is obviously not a threat to anyone who bothers to read the patent.

      Aside from that, PNG was designed to avoid patent issues by people who knew what they were doing, in an drawn-out open process where anyone could have pointed out weaknesses. It's based on well-established techniques with a long history of prior art. Your first assumption should be that any patent either doesn't affect PNG, or is so blatantly invalid that nobody would ever dare take it to court, not that there's trouble ahead because a one-line description of a patent sounds vaguely like something PNG does.

      You can't live your life shrieking in terror every time someone whispers "patent."
  • by gorilla ( 36491 ) on Tuesday November 20, 2001 @04:31PM (#2591921)
    What's actually relevent is what Apple's lawyers think. It's going to be expensive to fight a legal battle, so expensive that anyone who's been harassed by Unisys has folded, even though there is a fair chance that their patent would be declared invalid if it came up in court.
  • by Anixamander ( 448308 ) on Tuesday November 20, 2001 @04:32PM (#2591935) Journal
    A while back Apple posted this [] to their web site. It seems they are against RAND licensing fees. I assume that would also include their own technology, but I am really not sure how all this fits together.
  • Here [] is an article about this issue on LinuxToday [].
  • by Anonymous Coward
    Apparently the patent only covers compositing of images that start from several sources. This is all very well for PNG images, as all the data is stored in one file. However, once the PNG is in a web browser, it may get composited with other images from another source. If the page has a background image and an alpha'd PNG on top of it, surely that would then infringe the patent?

    Probably not a problem for Microsoft with IE - they would probably just have a little patent fight with Apple - but for free browsers this could be a problem.

    There's a few [] interesting [] threads [] on []
    usenet [] about it as well.
    • Well considering IE doesn't alpha composite PNGs on background graphics I don't think Microsoft has anything to worry about either.

      So far Mozilla is the only browser I've seen that does proper alpha compositing of PNGs.
      • Lots of Mac browsers do, including OmniWeb [], iCab [], and the Mac version of IE. I doubt Apple has any desire at all to sue over it.
      • Actually, IE on Mac does composition pretty nicely (it also does remarkable job with gamma correction, resizing based on pixel size defs and lots of other 'advanced' stuff).

        However, I think the original writer's worries about browsers are probably unfounded; if the patent only covers composites based on separate masks, it doesn't sound at all like what browsers really do. If they use masks (instead of just drawing layered images), those masks are dynamically generated, not read from files (or external sources). Additionally, when rendering images that have real alpha channel, mask aren't all that useful in the first place. They are just for poor man's transparency. :-)
        Would be nice to have de-lawyerized patent text available to be sure, of course.

  • Unfortunately, the article referenced does not seem to give any details for why people think this isn't "relevant"; there is no analysis of the claims.

    Apple itself identified the patent as relevant to SVG and at some point asked for non-discriminatory royalty payments. They apparently have backed off from those requirements by now, but Apple still hasn't dedicated the patent to the public domain, leaving some legal uncertainty hanging over open source projects.

    If the Apple patent were valid, I think it could be a problem and might have to be overturned. In that sense, it is "relevant", and it makes a lot of sense to collect prior art.

    It's also relevant in a different sense: it tells us about what Apple is up to, what their attitude is towards free and open source software, and the intellectual and research standards at the company.

    • If the Apple patent were valid, I think it could be a problem and might have to be overturned. In that sense, it is "relevant", and it makes a lot of sense to collect prior art.

      No, if the Apple patent were valid it would not be overturned. Anyone wanting to use the technology would have to pay licensing fees.

      It's also relevant in a different sense: it tells us about what Apple is up to, what their attitude is towards free and open source software, and the intellectual and research standards at the company.

      I don't understand your point. Are you happy with Apple because they are no longer requiring royalty payments, or are you complaining that they didn't give the patent to the public domain all together? Please explain what Apple is "up to."

    • by jthill ( 303417 )
      READ THE PATENT. And not just the claims, the whole thing. It specifically disclaims alpha-blending, mentioning it as a well known and inferior precursor.
      • GodDAMN I had to scroll down a long way to find this. People, we just went over this shit a few days ago: the patent contrasts the technique in question with alpha-blending. This is a non-issue.

        I'm well beyond being amused by all the lawyers jumping into this story to demonstrate their wisdom and knowledge without ever fucking reading the patent being discussed. Please let's shoot this one and put it out of its misery.
      • I did read the whole patent before posting. The authors mention alpha blending, but they mischaracterize it. Go back to the textbook reference I gave before flaming.

        The fact remains that these people tried to patent what was already a standard textbook technique at the time. Whether they deliberately mischaracterized and ignored prior art, or whether they were simply ignorant you will have to decide for yourself.

  • So if it's not a big deal, why was there a general call for prior art to overturn Apple's patent?

    is there a problem with this? with the average IQ of a patent lawyer at about 35 these days, you can't be too careful. mark my words, the future of Open Source depends upon it.
    • Exactly. A bad patent is a bad patent is a bad patent. Just because it doesn't seem to affect $OPEN_SOURCE_PROJECT_DU_JOUR at this moment in time, doesn't mean that it will never do so, or that it doesn't set an unpleasant precedent, or that it will not affect $FUTURE_OPEN_SOURCE_PROJECT.
  • Why, you ask? (Score:5, Insightful)

    by Lars T. ( 470328 ) <> on Tuesday November 20, 2001 @04:43PM (#2592023) Journal
    From the the article on OS Opinion: (my emphasis)
    Earlier this year, the World Wide Web Consortium (W3C) asked interested parties to submit information about patents they own that
    might potentially infringe upon the development of scalable vector graphics (SVG).
    So Apple reported one of their patents that could in the future conflict with the development of SVG. Sombody read that, combined the two evil buzz-words "Apple" and "patent", and paranoia kicked in. He then scanned through the patent, found "alpha channel", and thought his worst fears had come true. So he called up some buddies and started the usual anti "evil/stupid patent" actions.

    All in all, simply self induced FUD.

  • by Compulawyer ( 318018 ) on Tuesday November 20, 2001 @04:47PM (#2592046)
    I know this is Open Source, but I generally thought that most Open Source software was better engineered than much of the commercial stuff out there. One of the key components in a feasibility study BEFORE other development work begins is legal feasibility . If you don't believe me, dust off your copies of Pressman's Software Engineering and see what HE says. I'm not just making this up.

    Part of a legal feasibility study has to be a patent infringement analysis. Whether you agree kthat software should be patentable or not, the fact it that in the US it IS patentable. If someone else made it first and was granted the exclusive right to make that product, then you will infringe on their rights if you make the product.

    There is simply no excuse for not doing this analysis. Yes, there is some up-front cost to a patent attorney. However, with a large enough development group, this cost can easily be absorbed by the group at a nominal level per member. The potential consequence is that every developer can find themselves defending a patent infringement suit. The last estimate of which I am aware placed the cost of litigating an "average" infringement suit at just around $500,000.00. If the case is deemed "exceptional," the infringers could potentially have to pay the patentee's legal costs as well as their own, on top of paying damages for the patentee's lost profits.

    Bottom line: all this can be avoided by getting a noninfringement opinion by a reputable and competent patent attorney. This is a basic software engineering step and should be performed at the very beginning of the development process. The attorney will even be able to suggest ways you can still go forward with the project, but do so in a way that does not infringe on someone else's rights.

    • Getting a noninfringement opinion at the beginning of the development is often of dubious value, because at the early stages all you can determine is roughly what areas are heavily protected by patents. You aren't going to pay an attorney to give you an opinion on every patent in a given area, so you're going to need to make some decisions about what technology you plan to use in developing your project before you can get any kind of meaningful feedback.

      At this point though, the PNG developers would be absolutely foolish not to get an opinion from a competent patent attorney. If they are found to be infringing Apple's patent after they knew about it, and declined to get an attorney's opinion, they are going to be found to be willful infringers which might mean treble damages and attorney's fees if they lose.
      • I have to disagree with your assertion that a noninfringement opinion is of "dubious value." At the beginning statges of development, you should have a decent draft of the program's requirements and some conception of its structure. It is at this point that a noninfringement opinion should be sought.

        Patents on software protect functionality and to a certain extent, the structure that provides that functionality. If your project is not sufficiently developed so that an infringement analysis is possible or useful, the attorney giving the opinion will tell you that he does not have enough information to give the opinion. For those skeptics who are thinking "yeah, right" on this point, remember this: it is the attorney's reputation and malpractice policy on the line if he doesn't do his job right in giving the opinion.

        • "I have to disagree with your assertion that a noninfringement opinion is of "dubious value." At
          the beginning statges of development, you should have a decent draft of the program's requirements and some conception of its structure. It is at this point that a noninfringement opinion should be sought."

          Maybe. But the original post said before ANY other development activity, so your statement is already more conservative than the original one. I never said that noninfringing opinions were of dubious value. I said pre development opinions were often (not always, not even usually) of dubious value.

          PNG/MNG is a good example of a situation where an early opinion might have been a good idea, because the major reason for the projects existence was to work around a troublesome patent.
    • I know this is Open Source, but I generally thought that most Open Source software was better engineered than much of the commercial stuff out there.

      What gave you that idea? Open source efforts may or may not be better engineered than non-open source stuff, but they are not guaranteed to be better. It all has to do with the number of people working on the project, the quality of the project, the project administration, etc.

      Look at it this way, if you have a well-funded, well-organized, large commercial effort then it will most likely beat the pants off of a free, badly organized open-source effort with only a couple of developers. The reverse is true also.

      Is open source better than commercial? Well, the result is free and it has the potential to produce a good product, but many times projects take a long time to develop, end up rough around the edges, are largely unsupported, and require a good knowledge of the product to operate it. If this was how a piece of commercial software turned out then it would tend to wither and die off (with some [] exceptions), because no one would pay for it.

      There are some great open source efforts and some great commercial products, but you have to choose them on a case-by-case basis. I certainly prefer open source to commercial, all other factors being equal.

      • What gave me that idea (that generally open source is better engineered than commercial) is my experience with software on both ends of the spectrum, my CS education, and actually seeing the development efforts made on both open source projects and various commercial projects. It is just my opinion, but it is based on facts I have personally observed. The comment was not meant to be read as some fanciful speculation.
    • The key weakness in your argument is "a large enough development group."

      While a legal feasability study is certainly a Good Thing that any major Open Source project should do, remember that many projects start out as a few people hacking away. There is no large group that can put up the cash for these sorts of legal costs. It just doesn't exist. A lot of these projects start out as hobbies. I don't know about you, but I most certainly don't want to pay a lawyer thousands of dollars to figure out what I can do in my spare time.

      In some cases, it is obviously rather daft to go anywhere with a project without paying a lawyer lots of money first (e.g., Ogg Vorbis), and probably later too (Good luck to the Vorbis team!).

      In the case of PNG, it would have been a good idea, because we were doing this to get away from exactly this sort of thing in the first place!
      • On the contrary, you have not spotted a weakness in my argument but rather an obstacle in development. If you want to develop software for your own personal use "as a hobby," then by all means do so. I do. But as soon as you want to release your software to the public, you have to play by the rules that govern public actions -- including the patent laws.
  • keep cool (Score:2, Interesting)

    by kylant ( 527449 )
    Don't worry, everything is fine.
    Nothing's wrong with the patent


    At least not for several years until the PNG-format is used all over the internet and apple can make a fortune by taking it out of the drawer.

  • The idea of a patent, is for the inventor of a technology, idea, whatever to have rights over it for 20 years.

    We all know Apple wasn't the first, and therefor they shouldn't have the patent. I'm not worried about it either, but I would like another stupid patent overturned.
    • Actually, if I remember correctly, the original intent was that you couldn't patent an "idea" but you had to patent a specific device (which makes perfect sense, in preventing just this sort of thing) - of course they didn't have software to consider back then, which is just as easily described as either an idea or a "device" (which it usually is for the purposes of patenting)
    • its all good and nice to claim that we all know Apple wasn't the first but what proof do you have?

      I am not claiming I know either way and certainly would like to see these software patents squashed but we need some proof that there was prior art!
  • This shows what the slashdot community thinks of software patents. I agree that they need to go, kinda, but for slightly different reasons. But what they do today is only to hinder development, forcing new names and similar techniques just to stay out of trouble for things that I think should be free for anyone to use. Isn't there a better way to pay inventors (because they should be paid I think) instead of this horrible system.

    Socialistic capitalism ;)
    • by glwtta ( 532858 )
      The problem isn't just that the system isn't great (or designed with software development in mind, and therefore ill suited for it), but also that the system is horribly implemented, with those deciding on validity of patents being filed, knowing very little about them and generally ending up granting them.

      Of course inventors should be paid - but what's an invention? The theme right now seems to be "quick, patent it before everyone else thinks of it" whereas it was supposed to be "patent it so others don't steal it from you."

      There is absolutely no reason one the first company to patent an obvious thing should have exclusivity to it. (and of course the whole thing is weighted very heavily against open source development, but that's a different issue)
  • by Ogerman ( 136333 ) on Tuesday November 20, 2001 @05:16PM (#2592216)
    One way that the Open Source community could help fight software patents is to establish a database of prior art. When issues like this come up, relavant prior art would be hyperlinked to the supposed patent.
  • So if it's not a big deal, why was there a general call for prior art to overturn Apple's patent?

    The big deal with this patent is not its implications for PNG, MNG, or SVG - it's the abundance of *published* prior art, from way earlier than the patent was applied for. It's a blatantly obvious case of the USPTO not doing its homework.

  • by Anonymous Coward
    Patents aren't what you think they are. All patents make broad claims that can not be defended in court. The patent writer knows this -- they are really trying to patent something that is specific and unique that other people aren't doing.

    There are lots of patents that discuss alpha blending. They don't affect PNG.

    The important thing to remember about patents is "don't go looking for trouble". Don't worry about new patents that come out -- wait until the patent owner comes looking for you. If you look far enough in the patent database, you will certianly find patents that can be interpreted to cover your idea. Unless you bring it to their attention, or are a direct competitor, most patent owners won't care about you. Most companies view patents as a defensive play -- they don't really care about them, they just grab the patents so that if a competitor sues them for patent infringement, they can sue back. E.g. Via countersuing Intel on patents.

  • by BeBoxer ( 14448 )
    If you read the patent, it's an almost textbook example of a painfully obvious 'invention'. The patent clearly admits that the use of a special transparent 'color' in one image is an old technique for blending two images. Next it admits that using a 1-bit alpha mask is a known technique for combining two images. Then it admits that an 8-bit alpha mask has been used to smoothly blend two images in the compositing process! Finally, it admits the 'invention': Let's use a full color image instead of a grayscale image for the alpha mask! Wow! How do they think of these things! What a genius it takes to think that maybe after first using black and white masks, then greyscale, you might try color!

    The real clincher is that they go on to list all of these wonderous things you can do with full color mask. But most of their examples only require a good old fasioned greyscale map! Somebody at Apple pulled a fast one at the patent office. The entire 'Fig 1.' shows an example which doesn't even use Apple's 'invention'! It just uses good old fashioned greyscale alpha masks which Apple lists as prior art! Then two of the claims list anti-aliased text! Does anybody do this with color alpha masks? No font renderer spits out multi-color images! They spit out greyscale which is used to merge the text color/pattern with the background! Once again, they claim their invention is needed to do something which everyone does with the prior art method!

    On the plus side, it's such a silly invention it's trivial to work around. Here's an idea: use three different alpha masks! One per channel! I wonder if Apple managed to get a patent on that. Hey, here's another nifty idea! Generate the three alpha masks from the three channels of a color image! I bet Apple never thought of that! Only a genius like me could think of that. What an invention! I'll make millions!

    Man, this patent is the worst. Check out Claim 3: A method as in claim 1 further comprising displaying the result image. Whoh Nellie! Your going to display the image! Man, that's adds a whole new level of complexity. Usually, I composite images and then just free the memory. But actually displaying an image you've generated! Man, what incredible insight!
  • by 90XDoubleSide ( 522791 ) <ninetyxdoublesid ... t ['ail' in gap]> on Tuesday November 20, 2001 @06:36PM (#2592795)
    From the article:

    "Fear Itself

    Misinformation on this matter has caused many open-source advocates to incorrectly accuse Apple of holding back Open Web technologies.

    Let's hope that cooler heads prevail and that fear-debunking articles such as this one are more widely read."

    It is amazing how worked up everyone got in November when they learned that a company that supports web standards and has a public policy of royalty-free licensing for them (as of October) had responded in June to a call to disclose all patents to the PNG group that they should be aware of for infringement issues in the future.

  • by JoeBuck ( 7947 ) on Tuesday November 20, 2001 @06:44PM (#2592875) Homepage

    If Apple's patent is valid, nothing put out by the PNG group infringes. However, when an application, say, Mozilla, displays a PNG in front of some other graphic and uses the PNG's alpha mask to do partial transparency, that would infringe. Similarly, when a Gnome or KDE desktop displays a PNG icon and uses the partial transparency to have a smooth and not a jagged edge, that would infringe. But just storing the alpha mask in the file doesn't collide with anything in the patent.

    In practice, there's so much prior art that the patent will be dead meat once it hits a court. Traditionally, the patent holder deals with this by licensing for a fee small enough that it's cheaper to pay than fight, and in this case, perhaps giving an out to the free software folks, while possibly trying to get a bit of cash from others. But in this case, I suspect that even that strategy is not going to work.

    • No. They didn't patent single-channel alpha blending. They patented 'multi-channel blend'. That is; blending is done by using mask image, not mask (alpha) channel. Each colour component is blended separately; only if mask image uses grayscale (ie. all components have same value) pixels this degenerates to normal alpha-blending.

      So, like PNG gurus said, this doesn't relate to PNG; PNG 'only' supports alpha channel (although it's questionable whether full alpha-'image' would be an improvement... but that's what Apple patented).

    • This post [] did a good job of answering the root question of why they have a patent they don't intend to enforce. Go look through their 1500-odd patents; you will see many interesting ideas that they tend to protect, but also many of the kind of patents that poster was describing. No ones seems to worried about getting sued for using a Graphical user interface having sound effects for operating control elements and dragging objects [] ;)
      • Here's the Abstract. The weird thing is that if you read the patent, you have to admit that no one else ever used that, because it's too annoying to hear a continuous sound while you drag something...
        Systems and methods for providing an enhanced auditory behavior to a graphical user interface are described. Control elements portrayed by the graphical user interface on a display are associated with at least two states. When transitioning between states, a sound effect specified for that transition can be provided to provide further user or designer customization of the interface appearance. Movement of objects can be accompanied by a repeated sound effect. Characteristics of both sound effects can be easily adjusted in volume, pitch and frequency.

        - Benad
        • But the patent also covers "control elements" that are operated over a period of time, such as scroll arrows, which do have sounds in many products. But in any event I'm sure if you cared to read all the patents (of any company, for that matter) you'd find many more of this kind.
  • Well, the patent most certainly looks like a standard mask-like image manipulation. So I understand people to get paranoid about this (given that PNG uses a mask for its alpha transparancy). I still doubt if the GIMP wouldn't be influenced by this patent.

"The eleventh commandment was `Thou Shalt Compute' or `Thou Shalt Not Compute' -- I forget which." -- Epigrams in Programming, ACM SIGPLAN Sept. 1982