[Tool] Multi-column PDF files on 6 inch display.

[ProDigit]

Originally Posted by nrapallo

I thought the max dimensions on the Sony ebook readers were 584 width x 754 height.

I got this from page 4 of the Sony recommended pdf size.

Those could be the recommended screensize for readable text, with a small border of 2x8 pix horizontal and a 2x23pix vertical border.

Though I prefer text without border, since it takes up screen space, and you already have a border around the screen. (I mean it's not like we can make annotations on these devices or so).

when I load a pdf,with this info, and zoom on text width, I notice that the left,top and right border are the same size.
So let's assume you have a border of 8pix left,up and right of the text.
This leaves a border of 38 on the bottom.
take 13 pix of the bottom border since it seems a little larger than the others, and you'll have a bar on the bottom of about 25 pix.

in other words it could be that images with a size of 775x600 are displayed exactly the same as 800x600.
In order to figure that out I can try to see if I see any difference between the quality of 800x600 and 775x600.
Obviously 775x600 will be more stretched looking.

However I had preferred if someone knew by playing around with the internal software what the exact resolutions are.

[soilwork]

As TaeSoo and nrapallo mentioned, you can change the output resolution by modifying two lines of 'config.lua'. You can change the first two lines to these.

device_width=584
device_height=754

Better yet, you can convert set of image files into LRF using comic2lrf of Calibre. First, make one zip file from the pictures then use a simple script such as

comic2lrf -c 8 -r 'file.name.here.zip'

I think it will be easier to manage one LRF file instead of hundreds of images.

[nrapallo]

Originally Posted by ProDigit

In order to figure that out I can try to see if I see any difference between the quality of 800x600 and 775x600.
Obviously 775x600 will be more stretched looking.

It shouldn't look stretched if the original image's aspect ratio is maintained, just a bit more white margin space in lieu.

Now if PaperCrop does in fact stretch it to fit, then you would have to override this behaviour to get non-stretch/squished resulting images.

In the end, there is no right/wrong way to do this; it's a matter of personal taste/preference i.e what you like to use!

However I had preferred if someone knew by playing around with the internal software what the exact resolutions are.

Trial and error and a bit of sweat equity is always needed when charting unknown territory...

[ProDigit]

Originally Posted by soilwork

As TaeSoo and nrapallo mentioned, you can change the output resolution by modifying two lines of 'config.lua'. You can change the first two lines to these.

device_width=584
device_height=754

Better yet, you can convert set of image files into LRF using comic2lrf of Calibre. First, make one zip file from the pictures then use a simple script such as

comic2lrf -c 8 -r 'file.name.here.zip'

I think it will be easier to manage one LRF file instead of hundreds of images.

I think the problem is that we don't know what the best size is.
548x754 will be the best format for text margins in pdf.
jpg's need to use the full screen.
Making them smaller than the viewable area will result in loss of quality.
Making them larger results in loss of battery life, and display time.
Some pages I could format perfectly in 320x240 and they still will be viewable, but the quality of the page will suffer...

[nrapallo]

Oh, another bug after editing the config.lua, the resulting .png images are of size of 473 x 595 even though I set 472 x 595 as the max. dimensions my reader expects. This is probably a rounding-off problem...

[JSWolf]

Originally Posted by nrapallo

I thought the max dimensions on the Sony ebook readers were 584 width x 754 height.

I got this from page 4 of the Sony recommended pdf size.

Actually, i think the dimensions are 600x775.

[soilwork]

Originally Posted by ProDigit

I think the problem is that we don't know what the best size is.
548x754 will be the best format for text margins in pdf.
jpg's need to use the full screen.
Making them smaller than the viewable area will result in loss of quality.
Making them larger results in loss of battery life, and display time.
Some pages I could format perfectly in 320x240 and they still will be viewable, but the quality of the page will suffer...

That is why I suggested the second option of converting into LRF. First, you can make the images with arbitrarily large resolution and then use PDFLRF or Comic2lrf. Then we don't need to worry about the correct resolution at all.

Of course, if you would like to read PDF using 1000's of splitted jpg/png/gifs, then you have to figure out the correct resolution. However, since LRF is much faster and easier to manage, I cannot think of any good reason to use image files instead of LRF.

[soilwork]

Originally Posted by ProDigit

Those could be the recommended screensize for readable text, with a small border of 2x8 pix horizontal and a 2x23pix vertical border.

PDFLRF makes LRF based on images and it also uses 584 width x 754 height as the final output. So I don't think the resolution is only for text file. Of course, I am assuming that image based LRFs are displayed in the same resolution as image files.

[ProDigit]

So far I did the test of the picture Sony provided on the PRS-505 of the baby.
Resizing it would give you either 800x625 or 768x600pix.
On the baby picture I could not see any difference between the two.

I will test it out with a high quality picture (with lots of detail, and probably a resolution of higher than 1MPix, of eg: grass trees and leafs) to compare each picture's size to the quality displayed.

[ProDigit]

here are a few pictures resized all with the same settings.
I hope they work, as I'll be testing them as soon as I post this post.

Try out for yourself to see where on the reader quality decreases.
The picture is a regular picture found on google images.

Nature2 is the original.
The other formats are 8bit greyscale (256 color) versions that have lower than the original resolution.

[ProDigit]

OK,I'm back with some results.
To see the pictures full screen without zoom it is hard to distinguish between files having a resolution of 754x566 pixels or greater.
When you zoom in to the max of the zoom factor, you can see that certain artifacts (pixels) are not visible on the lower qualities, but they are at 800x600 resolution.

Upon review I'll have to recode the images,seeing that the 779x548 pix. image is way blurrier than the 800x600 image.
This can have to do with the encoding being set to retain 84% of the original quality.
Tomorrow I'll re-post everything on 100% quality.

[nrapallo]

Originally Posted by ProDigit

Nature2 is the original.

Just for comparison, this is what that image looks like using 584 x 754 as the max dimensions using PDFRead (default settings) and outputing to .lrf format in portrait and landscape modes.

BTW, this .lrf was prepared using the Sony bug-fixed pdfread.exe command line program (v1.8.2.1).

[Ulysses]

Very good idea but it crashes all the time, maybe an option to start from a certain page would be good "work around" so we can continue where we stopped..

[ProDigit]

Originally Posted by nrapallo

Just for comparison, this is what that image looks like using 584 x 754 as the max dimensions using PDFRead (default settings) and outputing to .lrf format in portrait and landscape modes.

BTW, this .lrf was prepared using the Sony bug-fixed pdfread.exe command line program (v1.8.2.1).

I apologise for not earlier replying, but I'm a bit busy lately.
I'll give those documents a look, and will let you know.
Obviously reducing the resolution will reduce the quality.
But perhaps in the document you post the quality loss is unnoticable.

So far on full screen (non-zoomed out) I could not detect any difference between jpegs with a greater than 754x566 pixels .
But probably it also has to do with filesize. A 754x566 pixels 128kB jpeg fil might look exactly the same as a 800x600pix 128kB file...

I'm a newbie here, and know very little of all of this, but perhaps I can help to figure out the 'best' pixel width and length for comic books.
For pure B&W (non graytint) comic books,gif is the best format. But the Sony reader does not support that format.

I'll do further testing later on.

[Taesoo Kwon]

Originally Posted by Ulysses

Very good idea but it crashes all the time, maybe an option to start from a certain page would be good "work around" so we can continue where we stopped..

I hope the problem will disappear after downloading the version 0.3.
If it continues to crash, please send me the PDF file to me by e-mail.