I found way to vastly improve displaying of text!

Malder1 · 10-02-2006, 05:22 PM

I found way to vastly improve displaying of text on iLiad!

I love iLiad and the display is perfect, but I think that my iLiad can more:

I noticed that letters on virtual keyboard look more sharp than letters displayed in PDF textes. After long investigation I found that as in Acrobat Reader, iRead (in xPDF) uses simple bilinear resizing of text symbols and all letters a little blurred, not enough crisp, and gritty.

After this I captured screenshot of this text in Word to BMP image and then transferred file to iLiad. Note that I don't use ClearType.

I was totally impressed how good iLiad displayed same text as BMP file image now! Very crisp, but antialiased symbols! So you see that your iLiad can more!

If you will test this moment, note that image should be a little smaller than display to prevent resizing of an image.

The question.
How to prepare book in pre-rendered images? I don't know how to create PDF file with rightly calculated size of images to prevent resizing of BMP images.

I again should say that iLiad is amazing ebook, and I think that Sony/Hanlin uses same text rendering problem because Microsoft uses special high quality antialiasing of text.

CommanderROR · 10-02-2006, 06:10 PM

This is great news indeed!!!
I had been wondering about the strangely grainy letters for a long while!
I'll try to find a way to do this for my books, but I don't know how...I use OpenOffice to create PDF files, but those are text-based and not image based, so I woul dhave to convert the PDF files I get to image-based PDFs that don't use anti-alias or something...ah...can somebody work this out for me please?

tribble · 10-02-2006, 06:15 PM

I am a lazy person, could you upload the PDF and the corresponding bmp file?
Thanks

scotty1024 · 10-02-2006, 06:26 PM

Uh folks, if you read scanned PDF's on the iLiad (or Sony Reader) they'll be scaled to fit and not look their best.

If on the other hand you OCR and create the PDF (or work from Baen/Gutenberg sources) the iLiad will use nice crisply generated glyphs.

If you can crop enough margin off to get to 1 to 1 then there will be no scaling of the image (and thus of the glyphs inside the image.)

You can also use my rotate tool to decrease the amount of scaling on scanned PDF's to have them look better as well.

Bi-linear scaling is faster than bi-cubic scaling. Using bi-linear will help improve battery life.

Moral of the story: OCR'd PDF's (e.g. text PDF's) are clearer than non-OCR'd PDF's (e.g. image per page PDF's.)

Malder1 · 10-02-2006, 06:30 PM

scotty1024,
I meant true text as fonts in PDF. And

I attached text in PDF and part of same text in PNG.

Upload to iLiad and feel the difference! PNG image looks more crisp, isn't it?

scotty1024 · 10-02-2006, 07:09 PM

Sorry, now I understand what you are pointing out.

Your document uses a media box larger than the screen of the iLiad. This then forces the iLiad to scale your text PDF's as well.

The text should look crisp even then but here your document falls into a typographic trap.

In a perfect world one would render from the outline information included in the font file to make wonderful looking glyphs for each character at whatever size is requested.

In the real world the rendering engine cheats to keep performance high. Built in fonts will have so called "pre-rendered glyphs" e.g. already rendered characters for the even type sizes: 12, 10, 8. To get the odd sizes the engine will scale the existing even glyphs.

But to make matters worse...

When you scale a letter sized document down to an iLiad screen a 12pt font will be roughly 7pt, not precisely 7pt. The rendering engine will do what it can but the resulting glyph is not going to look as sharp as it could.

In Postscript one could turn off this pre-rendering behavior, the laser printer would take more memory and more time, but your marked pieces of paper would be crisper.

I don't know if xpdf supports doing that, and even if it does, iRex would have it turned on to keep speed up and battery use lower.

What do I do?

I use a font I bought: Tiresias (http://www.myfonts.com/fonts/bitstream/tiresias/) and have it embedded into my PDF documents (automatic in most cases.)

I set the font size above 14pt (to avoid pre-rendered glyphs), use the correct media box (iLiad actual viewable area sized) and I get text so crisp and sharp I can shave with it.

Malder1 · 10-02-2006, 07:10 PM

I created 759 x 933 image (and 158 dpi) in Photoshop then choosed PDFCreator as printer and in page properties set 122 x 150 mm.
And I've got PDF with text as image which looks crystally sharp.

kusmi · 10-03-2006, 03:50 AM

@scotty2^10

it seems iLiad only does anti-aliasing on text, not on images, that's why scanned books do not look so crisp, as the scaling mechanism is a very simple one with no smoothing...

ali · 10-03-2006, 04:03 AM

Quote:

Originally Posted by scotty1024

I set the font size above 14pt (to avoid pre-rendered glyphs), use the correct media box (iLiad actual viewable area sized) and I get text so crisp and sharp I can shave with it.

I still don't get it fully. So xpdf chooses to uses bitmap fonts (with bitmap scaling) over drawing outline/vector glyphs, if the font size is below a certain threshold?

How is this threshold defined? Height, in pixels, on screen? (Or in pt, assuming xpdf knows the screen resolution) Or pt size in document coordinates?

That is, in the latter case I could make all my documents A0 with 100pt-fonts, which would be scaled to the screen size, but prohibits use of bitmap fonts.

In the former case I would simply have to use exotic fonts for which there are no bitmaps on the Iliad, right?

ath · 10-03-2006, 04:16 AM

Quote:

Originally Posted by ali

So xpdf chooses to uses bitmap fonts (with bitmap scaling) over drawing outline/vector glyphs, if the font size is below a certain threshold?

At first sight, this seems improbable. xpdf *may* do it, in general, but then it needs to have a bitmap font file around somewhere ... and that can't really be expected for anything but the standard PDF typefaces (Times, Helvetica, etc.).

However, if there really is such a bitmap font file around, the result is very likely to look better -- the raster glyphs would typically have been hand tuned.

Malder1 · 10-03-2006, 04:21 AM

Its seems that xPDF just renders any text fonts as bitmap in 4x larger than necessary (without antialiasing at all) and then reduces it back using bilinear resizing. It gives font smoothing.

Same font smoothing at least old Acrobat Reader versions uses on PC.

Anybody can say iRex about this problem?

The GreatGonzo · 10-03-2006, 02:18 PM

Quote:

Originally Posted by scotty1024

Uh folks, if you read scanned PDF's on the iLiad (or Sony Reader) they'll be scaled to fit and not look their best.

If on the other hand you OCR and create the PDF (or work from Baen/Gutenberg sources) the iLiad will use nice crisply generated glyphs.
...
Moral of the story: OCR'd PDF's (e.g. text PDF's) are clearer than non-OCR'd PDF's (e.g. image per page PDF's.)

Which is why I'm thinking we should probably have a nice thread somewhere on scanning and OCR - what scanners are good for the average home user, what OCR software to use, reviews, recommendations, personal tales of horror and joy - anyone?

I would really like to start scanning my Winnie-the-Pooh books so I can read them to the kids wherever...

I have a scanner/printer combo monster that's really impractical for book scanning - can anyone recommend a small one that could process, say, a paperback in a reasonable amount of time? And I'm totally at a loss as to which OCR software to choose...

Malder1 · 10-03-2006, 06:10 PM

I've attached two photos of iLiad screen I did with Canon 350D camera.

iLiad PDF.jpg - text displayed in PDF file. You see that symbols has jaggies.

iLiad PNG.jpg - same .doc text opened in Word, PrintScr key and saved as PNG image. You see that symbols look clear and sharp.

scotty1024 · 10-03-2006, 06:47 PM

Quote:

Originally Posted by The GreatGonzo

Which is why I'm thinking we should probably have a nice thread somewhere on scanning and OCR

There is one. Paul has posted his process for scanning out of copy right books. He prefers to keep the books in scanned form, in order to preserve their look and some of the "feel" but you can follow his recipe and insert OCR at the end.

The GreatGonzo · 10-03-2006, 07:39 PM

Well, I was hoping for input from more than one user - for starters, the HP Scanner/Printer Paul is using is way out of my league, so if somebody has found a more economic solution, I wouldn't mind hearing about it.

Also, I'm pretty clear on how to scan and how to have a pdf file as the end result - but I would like to know more about the different OCR options.

10-02-2006, 05:22 PM	#1
Malder1 Connoisseur Posts: 52 Karma: 10 Join Date: Aug 2006	I found way to vastly improve displaying of text! I found way to vastly improve displaying of text on iLiad! I love iLiad and the display is perfect, but I think that my iLiad can more: I noticed that letters on virtual keyboard look more sharp than letters displayed in PDF textes. After long investigation I found that as in Acrobat Reader, iRead (in xPDF) uses simple bilinear resizing of text symbols and all letters a little blurred, not enough crisp, and gritty. After this I captured screenshot of this text in Word to BMP image and then transferred file to iLiad. Note that I don't use ClearType. I was totally impressed how good iLiad displayed same text as BMP file image now! Very crisp, but antialiased symbols! So you see that your iLiad can more! If you will test this moment, note that image should be a little smaller than display to prevent resizing of an image. The question. How to prepare book in pre-rendered images? I don't know how to create PDF file with rightly calculated size of images to prevent resizing of BMP images. I again should say that iLiad is amazing ebook, and I think that Sony/Hanlin uses same text rendering problem because Microsoft uses special high quality antialiasing of text.

10-03-2006, 06:10 PM	#13
Malder1 Connoisseur Posts: 52 Karma: 10 Join Date: Aug 2006	I've attached two photos of iLiad screen I did with Canon 350D camera. iLiad PDF.jpg - text displayed in PDF file. You see that symbols has jaggies. iLiad PNG.jpg - same .doc text opened in Word, PrintScr key and saved as PNG image. You see that symbols look clear and sharp. Attached Thumbnails

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10-02-2006, 06:10 PM	#2
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	This is great news indeed!!! I had been wondering about the strangely grainy letters for a long while! I'll try to find a way to do this for my books, but I don't know how...I use OpenOffice to create PDF files, but those are text-based and not image based, so I woul dhave to convert the PDF files I get to image-based PDFs that don't use anti-alias or something...ah...can somebody work this out for me please?

10-02-2006, 06:15 PM	#3
tribble iLiad Maniac Posts: 1,382 Karma: 2369 Join Date: Apr 2006 Location: Germany Device: Bookeen Opus (i love that thing) and iPad (what an irony)	I am a lazy person, could you upload the PDF and the corresponding bmp file? Thanks

10-02-2006, 06:26 PM	#4
scotty1024 Banned Posts: 1,300 Karma: 1479 Join Date: Jul 2006 Location: Peoples Republic of Washington Device: Reader / iPhone / Librie / Kindle	Uh folks, if you read scanned PDF's on the iLiad (or Sony Reader) they'll be scaled to fit and not look their best. If on the other hand you OCR and create the PDF (or work from Baen/Gutenberg sources) the iLiad will use nice crisply generated glyphs. If you can crop enough margin off to get to 1 to 1 then there will be no scaling of the image (and thus of the glyphs inside the image.) You can also use my rotate tool to decrease the amount of scaling on scanned PDF's to have them look better as well. Bi-linear scaling is faster than bi-cubic scaling. Using bi-linear will help improve battery life. Moral of the story: OCR'd PDF's (e.g. text PDF's) are clearer than non-OCR'd PDF's (e.g. image per page PDF's.)

10-02-2006, 07:09 PM	#6
scotty1024 Banned Posts: 1,300 Karma: 1479 Join Date: Jul 2006 Location: Peoples Republic of Washington Device: Reader / iPhone / Librie / Kindle	Sorry, now I understand what you are pointing out. Your document uses a media box larger than the screen of the iLiad. This then forces the iLiad to scale your text PDF's as well. The text should look crisp even then but here your document falls into a typographic trap. In a perfect world one would render from the outline information included in the font file to make wonderful looking glyphs for each character at whatever size is requested. In the real world the rendering engine cheats to keep performance high. Built in fonts will have so called "pre-rendered glyphs" e.g. already rendered characters for the even type sizes: 12, 10, 8. To get the odd sizes the engine will scale the existing even glyphs. But to make matters worse... When you scale a letter sized document down to an iLiad screen a 12pt font will be roughly 7pt, not precisely 7pt. The rendering engine will do what it can but the resulting glyph is not going to look as sharp as it could. In Postscript one could turn off this pre-rendering behavior, the laser printer would take more memory and more time, but your marked pieces of paper would be crisper. I don't know if xpdf supports doing that, and even if it does, iRex would have it turned on to keep speed up and battery use lower. What do I do? I use a font I bought: Tiresias (http://www.myfonts.com/fonts/bitstream/tiresias/) and have it embedded into my PDF documents (automatic in most cases.) I set the font size above 14pt (to avoid pre-rendered glyphs), use the correct media box (iLiad actual viewable area sized) and I get text so crisp and sharp I can shave with it.

10-02-2006, 07:10 PM	#7
Malder1 Connoisseur Posts: 52 Karma: 10 Join Date: Aug 2006	I created 759 x 933 image (and 158 dpi) in Photoshop then choosed PDFCreator as printer and in page properties set 122 x 150 mm. And I've got PDF with text as image which looks crystally sharp.

10-03-2006, 03:50 AM	#8
kusmi Connoisseur Posts: 73 Karma: 16 Join Date: Jul 2006 Location: Zurich, Switzerland	@scotty2^10 it seems iLiad only does anti-aliasing on text, not on images, that's why scanned books do not look so crisp, as the scaling mechanism is a very simple one with no smoothing...

10-03-2006, 04:21 AM	#11
Malder1 Connoisseur Posts: 52 Karma: 10 Join Date: Aug 2006	Its seems that xPDF just renders any text fonts as bitmap in 4x larger than necessary (without antialiasing at all) and then reduces it back using bilinear resizing. It gives font smoothing. Same font smoothing at least old Acrobat Reader versions uses on PC. Anybody can say iRex about this problem?

10-03-2006, 07:39 PM	#15
The GreatGonzo Old Yeller Posts: 180 Karma: 67 Join Date: May 2006 Device: Iliad & Kindle - The Best of Both Worlds	Well, I was hoping for input from more than one user - for starters, the HP Scanner/Printer Paul is using is way out of my league, so if somebody has found a more economic solution, I wouldn't mind hearing about it. Also, I'm pretty clear on how to scan and how to have a pdf file as the end result - but I would like to know more about the different OCR options.

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