PDF Viewer 0.3.0 pre-release

[pruss]

I didn't find the Android free PDF viewers I tried completely satisfactory, though I found Maciej's PDF Viewer to be pretty good. And it was open source, so I made a bunch of enhancements, with a view to ebook reading, and joined the project.

Anyway, I now need people to test and offer suggestions. The 0.3.0 pre-release versions are here.

New features since the official 0.2.9 release:
- speed optimizations (optimize a couple of things, render ahead)
- page number display
- full screen option
- color reverse option
- page with volume keys
- zoom to width
- finer zoom adjustment
- better font rendering
- monochrome mode (use if running out of memory; also nice with color reverse option so you don't get weird colors)
- remember zoom setting for each file (and the last page viewed, but I think that was already in 0.2.9)
- overhauled file selection: added icons for directories, added home
directory option.

[pruss]

I posted 0.3.0 pre 3:

- fix inverse grayscale mode
- add more color modes (yellowish background, green on black, red on black)

Anybody try it? I am happy to add features to make it better, as long as they're not too hard. :-)

[rhari79]

Hi,

True. Android did not seem to have real good pdf readers. I had tried the pdfviewer before and found it to be really basic.

So I had to buy the ezpdfreader. It was ok. Goodreader for ipad still beat it hands-down.

Saw your post and tried this on my Adam(ver 0.3).

The best feature in this is the Reverse Color. Most of pdfs are white. so this allows me to read without glare. I have only seen this on the Stanza for ipad.
Great feature.

My comments:
1. Recent books seem to be shown at the top of the file system(sdcard). This looks like the file has been copied there, but actually isnt.

2. Would it be possible to lock the panning? Once i set the zoom, scrolling usually took the pdf offscreen. But again most readers i used dont seem to have this.

3. The app did crash a couple of times, but recovered. Maybe it was the pdf.

4. I also like the 2% zoom increment. In the absence of a goodreader like or pinch zoom this allowed me to do finer adjustment. This is now my default level.

5. Touch zones for next/prev pages and a slider for scrolling pages would be good to have.

Its a simple pdf reader. So feature wise this is good; Only improvements maybe, make it faster(dont really need it cos its faster than my reading speed); stabler(helps esp if it crashes regularly for some pdfs).

Keep up your good work!!

[pruss]

Thanks for the report!

Originally Posted by rhari79

1. Recent books seem to be shown at the top of the file system(sdcard). This looks like the file has been copied there, but actually isnt.

Any suggestions on how to fix this visually? Maybe show their names in italics, so it looks like a shortcut? Maybe change the order, putting the HOME button between the recent entries and the other files?

(By the way, I only show the recent items when you're viewing the home directory.)

2. Would it be possible to lock the panning? Once i set the zoom, scrolling usually took the pdf offscreen. But again most readers i used dont seem to have this.

Scrolling with the volume keys helps with this issue. How do you think the interface for locking the panning would work?

I've been thinking of doing something like what the Android browser does, though I don't know exactly the algorithm it uses. When you scroll approximately downward, it locks it into straight up and down movement, and you need to move seriously side to side to unlock it.

3. The app did crash a couple of times, but recovered. Maybe it was the pdf.

It could also be a memory usage issue. Could you switch it to "black and white" (normal or inverted) mode and see if it still happens? And could you send me the pdf that crashes it?

5. Touch zones for next/prev pages and a slider for scrolling pages would be good to have.

I personally hate the way touch zones often get implemented: I touch and instead it scrolls; I scroll and instead it flips. Maybe there is a good way to do it, though. But I still think using the volume buttons for scrolling is much saner. I'll think about it.

The priority is the crashing--so please send me the problematic pdf (arpruss@gmail.com).

Its a simple pdf reader. So feature wise this is good; Only improvements maybe, make it faster(dont really need it cos its faster than my reading speed)

My guess is that it may be close to as fast as other pdf readers, but other pdf readers have better ways of hiding the slowness, e.g., by not showing progressive screen updates or doing more rendering forward or back from the current position. I could be wrong.

[sherbs]

Hi,

Just had a try with ver 0.3.0 on my Eee Pad with a retail magazine but I'm sorry to say it was just too slow to be usable.

After the cover finished loading in portait mode I could see the top portion of the next page underneath but had to wait a while before I could scroll down to it. Only the left half of the next page had rendered by this time and once it had loaded, I had to wait some more before I could scroll further.

The pages look good once they're rendered fully but it's taking too long to get there at the moment.

Cheers.

[pruss]

Originally Posted by sherbs

Just had a try with ver 0.3.0 on my Eee Pad with a retail magazine but I'm sorry to say it was just too slow to be usable.

After the cover finished loading in portait mode I could see the top portion of the next page underneath but had to wait a while before I could scroll down to it. Only the left half of the next page had rendered by this time and once it had loaded, I had to wait some more before I could scroll further.

Tell me your screen resolution.

I think APV is particularly slow in rendering images. I wish I had some good test files to try this out on. The files I read are mainly text. The first page renders somewhat slowly at 480x800, but the succeeding pages seem fine.

[pruss]

0.3.0 pre 4:
- option to skip images
- home screen improvements
- fix zoom-to-width
- better position restore
- better scrolling constraints
- ARM7 optimizations

The ARM7 optimizations will make a difference to the rendering speed on a lot of devices, though not a radical one. Setting the skip-images option makes a big speed difference, but obviously at a cost (namely, no images :-) ).

https://code.google.com/p/force2sd/downloads/list

[sherbs]

Screen resolution of the Eee Pad Transfomer is 1280x800.

For text I generally use epub but pdf is the only way to read a magazine in its original form. I actually don't think there are any apps around at the moment to do the pdf justice. Apps that render well do so at the expense of speed, while the faster apps don't look good.

Cheers.

[pruss]

I found a bug in the multithreading which made the same tiles get multiply rendered. I think this was responsible for a severe slowdown under some conditions. This bug is fixed in pre6. Let me know if you can tell the difference.

[sherbs]

Had a go with pre6. Seemed a little faster but then I hit some problems. I got about four pages down and the next page stayed white with black, quarter page sized rectangles flashing randomly. Also, scrolling back over already loaded pages seemed to cause them to reload, sometimes with the black rectangles.

I must say that the pages do look good and before the problems, speed was not far off what I get with ezPDF, although their app is obviously more polished and shows a loading icon while you wait.

These magazines are heavily image laden though, the one I'm using to test is 113MB. Maybe we're at the limit of what a portable device can do with them. My PC handles them in two-page spreads without a blink.

Cheers.

As an afterthought, I loaded a simple, plain text pdf, size 79KB. Loading was obviously a lot quicker but scrolling wasn't smooth and stopped the moment I took my finger off the screen. Also there were still black rectangles showing on pages as they were scrolled into view.

[pruss]

Originally Posted by sherbs

Had a go with pre6. Seemed a little faster but then I hit some problems. I got about four pages down and the next page stayed white with black, quarter page sized rectangles flashing randomly.

Interesting. I think the document has overflowed the cache memory. As an experiment, could you put APV into black and white mode? (Menu | Options | Normal black and white.)

These magazines are heavily image laden though, the one I'm using to test is 113MB. Maybe we're at the limit of what a portable device can do with them. My PC handles them in two-page spreads without a blink.

It should work, but there is currently a memory leak.

As an afterthought, I loaded a simple, plain text pdf, size 79KB. Loading was obviously a lot quicker but scrolling wasn't smooth and stopped the moment I took my finger off the screen. Also there were still black rectangles showing on pages as they were scrolled into view.

We don't support fling scrolling at present. In any case, at the present rendering speed, this wouldn't be very good.

Do the rectangles disappear?

[pruss]

I nailed a giant memory leak (memory usage on one scanned book where each page was an image was growing by about 7mb per page). This might help with your problems. Fix is in pre7.

Pre8 builds on pre7 to optimize performance.

I just paged through a 79mb (over 200 page) photography magazine on my A43. Worked fine. Used a peak of about 80mb RAM. There may have been some leakage, but not enough to cause serious problems.

I tried the same pdf in Vudroid. The speed may have been a touch higher than in APV, but the images were blurry--I've previously noted that fonts aren't so crisp. I just deleted Vudroid.

I then tried it in Adobe's reader. Speed was higher and quality about the same as in APV. But the fact that Adobe reader doesn't keep your place in the file makes it not usable. I don't have ezPDF.

Fling scrolling is nice. I wish I knew how to implement that.

[pruss]

Version 0.3.0pre9:

- fling scrolling
- double tap to zoom
- long hold on zoom up/down to zoom up/down by large amount
- long hold on zoom-to-fit-width to zoom-to-fit-page

[sherbs]

The last two builds have been big improvements. Scrolling is a lot smoother but not enough to test the fling scrolling. On my screen I have full page and the top/bottom sections of pages either side. I can generally scroll back and forth about half a page length before it has to re-render.
The black rectangles have stopped flashing, they are just how the pages render - top left, top right, bottom left, bottom right. Already loaded pages can go black in any of the quadrants as you scroll over them again and they try to re-render. That's how it seems anyway.

Getting there.

[pruss]

Originally Posted by sherbs

The last two builds have been big improvements. Scrolling is a lot smoother but not enough to test the fling scrolling. On my screen I have full page and the top/bottom sections of pages either side. I can generally scroll back and forth about half a page length before it has to re-render.

I've generally optimized it for scrolling vertically downward, not horizontally side-to-side or vertically upward. On limited-memory devices, there are some real trade-offs, and not to waste memory the app needs to guess the direction of the next scroll. And so I have it guess that you're going to go down. This works well if you're reading a book and all the pages are vertically arranged, one after the next. You just scroll down and each successive page is waiting for you.

I think in your usage situation we would see a benefit from increasing the tile cache size (the tiles are the areas which you see getting rendered), and maybe pre-rendering tiles to the left and right. If you email me, I can send you some test versions with different tweaks. Or if any of the magazines you are viewing have a free sample copy online, you can point me to a pdf.