Gregory Pittman wrote: > This is of interest, and worth figuring out. It's not clear to me that > this is entirely in Adobe's interest to restrict this usage -- > encourages someone to develop a more open forms format. > Probably not. What's likely to happen in the long run is that as other PDF readers are enhanced they'll gain full forms support, like Adobe Reader but without requiring the same unlocking signature. Some of the Linux-based ones are already moving in that direction - and with KDE 4 the KDE PDF viewer is likely to be ported to Mac OS X and Windows too. So it's probably not going to be too long before users with non-Adobe PDF readers can handle forms quite well.
Adobe's advantage is their user base. Their app is bundled on driver and app installer CDs, pushed by websites, etc. An alternative form option would have to provide the same sort of utility and resulting ubiquity that Adobe Reader has to be really interesting. That's why they can sell the ability to unlock extra form features in Reader to people - because it's *already* on a user's machine. Alternative open forms formats would not have that, and wouldn't be any better than telling the user to download some other PDF utility. Web forms are of course the main alternative, and just fine almost all the time. I don't see saved PDF forms as hugely interesting except when combined with digital signatures and widely accepted certificate infrastructure, as is found within governments and large corporations, where archival and attestation is very important. Unsurprisingly, this is the market that the Adobe PDF enhancements stuff is targeted at. I'm not really sure why people bother with this stuff for use with the general public. If they're going to fill the form out, save it, and email/upload it back to you without using a digital signature why not use a web form? They can already fill it out and print it with Reader without any special enabling, so that doesn't justify it. Reader also supports web submit (with JavaScript and HTTP POST) from a form without any sort of feature enabling signature, and that's the only other reason I can think of to use it. The latter case is just an alternative user interface for a web form anyway. > I've always felt that this is one of the big ways that proprietary > formats are very wrong -- I take *my* data, *my* creative input, and it > gets held hostage in a format I do not have complete rights over -- very > very wrong. > It's a bit different in this case, in that PDF *is* an open format, it's fully documented, and you can do basically whatever you want with it. You can include your own enabling signature, for example. The only difference is that Adobe's free Reader product (hardly the only PDF reader in town) chooses not to honour feature enabling signatures from people who're not authorized by Adobe. What's happening here is a little different to the usual "proprietary extensions" stuff that many companies like to get up to. Adobe has fully documented the reader enabling mechanism, the only thing missing is the private key required to use it. It's a backwards way of selling licenses to Adobe Reader, where the license sold is to the ability to enable extra features on Reader on a user's machine rather than the direct rights to use Reader, and is paid for by the form creator rather than the end user. It's not, in my view, hugely different from requiring a license for products like Acrobat Pro and Acrobat Server, which operate on PDF but are not free. It's not restricting what other PDF viewer apps can do, nor what PDF creators can do to interact with other viewers and it doesn't hide any data away in non-standard ways. In a way I guess it *is* getting around the open standard nature of PDF to provide enhanced features for Adobe products talking to Adobe products. I don't much like it for that reason, but I do see it as very different from using undocumented extensions to break compatibility in a format or similar nastiness. There are no secret APIs or undocumented binary blobs here. -- Craig Ringer
