iLiad Community iPDF - Discussion

[jharker]

Historically, many people have proposed improvements to the pdf viewer. Many different versions of the viewer have been released, each with different features. To help solve this babel of versions, I propose that we create one centralized community version of the iPDF viewer, containing as many of the patches as can be comfortably combined together.

I'll volunteer to maintain this distribution, at least to start with. If you have comments, ideas, suggestions, or discussion, please post it here. Please post ONLY comments and discussion in this thread. Submit patches in the patch thread.

I started this thread for discussion about particular patches, the project as a whole, and feedback for released versions. There is a second thread specifically for patch submissions. When the a release version is ready, I will start a third thread specifically for releases.

What do you think?

[tribble]

Great idea. That would really make our lifes easier. Thanks for your work.

[alanine]

This is actually a follow up from the other thread where I proposed a 2 column view. This afternoon I took a look at the ipdf source and partially implemented it, where "partial" means it only works with portrait view and only split the view 4 ways (for 2-column) and move in a direction like |/|. I also changed the zoom level for A4 to 300 instead of 200.

It took me a while to figure out the coordinate system, but in the end I got it to work as I intended. But I don't think I'll submit the patch because:

1. it's more of a hack than a well thought-out and well organized patch;
2. ipdf is fundamentally flawed in its way of doing zooms, and I don't think it's a good foundation to start with;
3. ipdf itself is not well designed, and the division between portrait and landscape views is also flawed, and results in redundant code for all future patches.

Seriously, I suggest someone start writing a new PDF viewer for iLiad instead of patching ipdf. Given that the size of ipdf is relatively small, just fixing 2 and 3 is almost a rewrite. While I'm at it, it'll also be super to have anti-aliased sketching like in xournal, which, by the way, allows loading and annotating PDFs, or maybe somebody like Adam should just port it to iliad :-)

I'm attaching my 2-column ipdf binary here just in case it might be useful to somebody else. Make sure you backup /usr/bin/ipdf binary before using this to replace it. Use uparrow (I re-used the same button from jharker's fullscreen patch, I'm lazy!) to toggle column view, use normal flip to go forward and backward.

[nekokami]

Would it be feasible to allow users to pick the patches they want and apply them with some sort of patch management system, or would that just be asking for trouble?

The patches I'd particularly like are the comments/bookmarks and column browsing. The full-screen thing never really mattered to me, but it would be ok if the new version has that, too, if an individual patch system doesn't make sense.

[Karel]

Nice initiative Jharker, we might be interested to make it into an iRex Community Project. This would mean that we could integrated certain features into the stock viewer.

If you are interested let me know, we are happy to provide a development iLiad and support.

[rincewind]

JHarker, excellent initiative!

First off though, do you need some of my patches again, or are you happy with them still? I guess it's really only quick erase and scribble toggles that are in at the moment.

I also agree with alanine, in that specially the landscape/portrait views are badly implemented. I do however believe it would be fairly simple to create a parent class with all but the x-y calculation humbo jumbo left out, then inherit from that one to create the specific views.

Maybe I should take a look at "evince", the Gnome document viewer. I believe it is largely a GTK app, with Gnome libs for printing (which we could manage fine without), and it supports some nice things like thumbnails, remembers last position , indexes and so on. Also, it supports more than just PDF, but you can google for evince by yourself. :-) It's a fast application, but would require integration with scribbles, hardware buttons and there is no rotate function. It does however have continous mode.

Does anyone know if xrandr is supported on the iLiad? If it was, we could just rotate the X display... The rest should be pretty automatic.

Edit: Karel, I believe you mentioned (someone at iRex at least) that you would provide a "community" SVN branch. It would be excellent to have access to the full community IPDF source in a proper environment.

Edit2: And evince can rotate documents, and it does so *very fast*. I'll se if I can figure out the dependencies and see if I can make it work.
/r

[wpd]

Excellent idea JHarker.

You might want ppl to post patches against the latest released community version as well as against the irex standard in order to minimize the integration work.

Apart from the portrait/landscape code overlaps I feel that the ipdf renderer needs some work:

• The prerendering deleter is dumb: it routinely throws away rendered pages that are needed in a few seconds when memory is low, just because they are the oldest rendered pages.
• The prerendering routines should be made to work with multiple zoom rates; this allows ppl to switch zooms on pages much faster. We could do all kinds of stuff with this; show ppl a tiny page at the top of the screen while panning, rapidly switch zoom if needed for a wider column in column mode, etc.
• Wilder idea: the renderer/poppler could render to "Mono4", and store 2 pixels in every byte. This way prerendered bitmaps are much smaller, and we would be able to hold twice as much in memory. Display would be slower (have to test how expensive this is), unless we can find some shortcuts in the (not released) fb code.
• And even wilder: allow ppl to use a server based renderer, and allow the ipdf renderer to talk to the server via wifi. No more memory restrictions on prerendering.

Also, there is a lot of non-functional whitespace in the irex code; not important in any sense but nice to remove if we are going to clean house anyway.

[nekokami]

If you're going to be overhauling the pdf viewer, I'd like to see a thumbnail view page selector. I.e., display a 4x4 grid of page thumbnails with scribbles, and allow the user to tap one to go to that page. Page bar to view the next set of thumbs (which could probably be generated in the background while the user is scanning the first screen). This would allow quick navigation to places where we've made notes, as well as other easily recognizable pages. Often we can recognize pages by the general shape of the text, as well, so if we're looking for a page with a particular illustration or a long passage of dialog, we'd be able to get there more quickly. Page turning on the iLiad is a bit slow due in part to the e ink refresh rate -- I'm thinking this would help take the place of quickly fanning through a book or notebook to find a particular page.

[jharker]

Hi, everybody! Wow, lots and lots of great responses! Things have been really busy the past couple of days and I haven't had time to respond the way I'd like, but I wanted to let you know I'm still here!

Here's a somewhat abbreviated reply...

• If a patch has been posted elsewhere, or sent to me previously, I'd still like the author to post the patch specifically in the Community iPDF Patches thread. This will remove a lot of work for me in terms of finding, cleaning up, and documenting patches. It will also make everything available in one centralized place. Finally, it will hopefully make new authors think about the quality of their patches in the context of a larger project, hopefully leading to higher patch quality and fewer conflicts in general.
• That said, many people (rincewind, wpd, etc.) have made excellent patches that I expect to work with little or no modification. But please submit them in the patch thread so I don't have to!
• I love the idea of this project being encouraged as an iRex Community Project. I don't know if my role warrants a whole development iLiad, although I wouldn't say no! Perhaps we should wait until the first release to gauge how much interest there is, before you decide if it's worth it?
• I don't want this to become a full-fledged fork of the iPDF software, at least not for now. However, I agree that there are lots of parts of iPDF that could be substantially improved by a large rewrite. If anyone submits a (large) patch to overhaul the rendering / pre-rendering system, the landscape/portrait split, or anything else, I would certainly consider it and it would be more than welcome. I might even eventually get around to writing one myself...
• I like the idea of a "feature selector", we'll have to get someone to write a patch for that... All the other ideas that have been proposed sound great, too!
• For now, I'm asking for patches to be based off of the latest svn. But in the future, as wpd suggested, this will change to either more recent svns, or possibly with reference to the current version of community ipdf.

While we're throwing out ideas, here's one aimed at Rincewind because you've done a lot with gestures, and I don't know what you've already done that I haven't seen... If some simple, easy-to-use gesture-based UI could take the place of the erase, pan, scribble, and zoom buttons, that would clear up a lot of toolbar space. I'm thinking of something as intuitive as the iPhone gestures...?

Regarding the portrait/landscape split, the two are even more alike than you might suspect. If you compare the differing math sections, you'll see that they LOOK different because they're written differently... however, if you actually do the math you'll see that many of the calculations do the same thing, just using different variable names or a slightly different order of calculations (i.e. in portrait it's foo = bar - x; and in landscape it's foo = bar; foo -= x; ). So I suspect that once these incongruities are ironed out there will be very few places where it's actually different.

As far as I know, iRex is still working on a modular viewer base that will eventually replace iPDF. Does anyone know if that's still in the works? And whether it will be open-sourced?

Okay, that's all for now, I have to get back to work! So far so good! Let's see those patches!

[rincewind]

Very well, I'll get around to updating the patches for the svn version, and posting them. :-) Hopefully I'll have some more time to fiddle with this as I just finished my PhD the other day. :-D

As far as I know (this was the story some months ago at least), the new wunder-viewer from iRex will be closed source. So, if we do a massive clean-up of iPDF, I for one will keep using it even after the new viewer has been made...

When it comes to gestures, I have got some work to do. I'll either find some free library to recognize gestures, or create something myself. I really would like a map of gesture-to-function, making it possible for users to configure or customize them if they like. The iPhone is a multi-touch screen, meaning that for example zooming (drag two fingers away from each other) does of course not work on the iLiad. I hope to create/use something that allows me to specify gestures as right-downleft-right (for a Z) and map that to a function.

On a somewhat different note, I really would like to have a mode to let my iLiad control a presentation... I would then have the presentation (with some notes) on the iLiad, and when I press "next page", it would send a message to the computer doing the displaying... Anyone else in for something like this?

/R

[alanine]

Originally Posted by rincewind

On a somewhat different note, I really would like to have a mode to let my iLiad control a presentation... I would then have the presentation (with some notes) on the iLiad, and when I press "next page", it would send a message to the computer doing the displaying... Anyone else in for something like this?

So far only thing come to mind is to export DISPLAY to another Linux box that connects to a projector, though I've never tried it.

[good153]

Excuse me. Could you please tell me how to install and simply add the column mode (made by WPD) function to my ipdf without cancelling the functions of bookmarks and fullscreen? Could one be so kind to make an installer? I am sorry for my ignorance. Thank you very much.

[jharker]

Hi, good153! At the moment, there's no way to do that until someone makes a version that includes all the improvements. But you came to the right place, because that's exactly what this project is about! As soon as those patches are submitted, I'll be releasing a version of ipdf that includes all those features.

Which reminds me, since I'm the author of the fullscreen patch, I guess I should submit it.

[nekokami]

Theoretically one could make a content-lister runnable patch script with the ability to trigger patch application and a recompile, if there were a compiler ported to the iLiad itself... but that really seems like overkill (if doable at all).

I'd really like the multicolumn feature myself, though. I think I'd use it more than any other community-generated feature, with the possible exception of comments/bookmarks. However, from the description, I think the multicolumn feature as written would only work for text-based PDFs, not image-based (scanned) PDFs. Am I misinterpreting the patch description?

[daudi]

Originally Posted by nekokami

... from the description, I think the multicolumn feature as written would only work for text-based PDFs, not image-based (scanned) PDFs. Am I misinterpreting the patch description?

This is correct. It is based on text, so you would not benefit when reading scanned PDFs.