MobileRead Forums - View Single Post - A4 PDFs - tips, tricks, and a call to the community

alex_d · 12-11-2006, 02:49 AM

UPDATE: Readability seems further improved when you invert the colors and make it White text on Black background.

PNG example 2c

Also, I should for reference say which command I used to output to PNG:

"C:\Program Files\gs\gs8.54\bin\gswin32c.exe" -q -dBATCH -dSAFER -dNOPAUSE -sDEVICE=pnggray -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -g600x768 -r72x72 -dUseCropBox -sOutputFile=out%03d.png -fin.pdf

gswin32c.exe is a binary you get when you install Ghostscript
-f specified input files
%03d inside the output filename tells it to output one PNG per page, replacing "%03d" with 001, 002, etc.
-r72x72 specifies raster size. 72 is good for A4. If you use a different page size, change this or the output will be either cropped or won't fit the whole image (which is always 600x768). You can also use this to stretch the produced image by using differing numbers.
-dUseCropBox crops PDFs, but only if they have defined a crop box. It kinda really sucks that ghostscript can't autocrop files itself (ie, what the Reader tries to do).

now, I just have to find a commandline program to invert PNG colors.

also, there are probably utilities which'll manipulate PDFs to autocrop them or add cropboxes before they're sent to ghostscript. I'm calling it a day for now, but maybe someone already knows which ones those are? It would be extremely useful.

Now, the UBER hack would be to compile ghostscript for the Reader, load it, and use it as the rastering engine. Earlier I mentioned that fixing the Reader would probably be better than converting, and it now seems there's a [relatively] easy path to doing it. Now why the hell couldn't Sony have done it itself? Can I curse at Sony some more? This hack also presents an opportunity to do stuff like pre-rastering the next page or, for godssake, make navigating books easier with an improved UI (like one where you can, say, USE THE NUMBER PAD TO ENTER PAGE NUMBERS).

12-11-2006, 02:49 AM	#9
alex_d Addict Posts: 303 Karma: 187 Join Date: Dec 2006 Device: Sony Reader	UPDATE: Readability seems further improved when you invert the colors and make it White text on Black background. PNG example 2c Also, I should for reference say which command I used to output to PNG: "C:\Program Files\gs\gs8.54\bin\gswin32c.exe" -q -dBATCH -dSAFER -dNOPAUSE -sDEVICE=pnggray -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -g600x768 -r72x72 -dUseCropBox -sOutputFile=out%03d.png -fin.pdf gswin32c.exe is a binary you get when you install Ghostscript -f specified input files %03d inside the output filename tells it to output one PNG per page, replacing "%03d" with 001, 002, etc. -r72x72 specifies raster size. 72 is good for A4. If you use a different page size, change this or the output will be either cropped or won't fit the whole image (which is always 600x768). You can also use this to stretch the produced image by using differing numbers. -dUseCropBox crops PDFs, but only if they have defined a crop box. It kinda really sucks that ghostscript can't autocrop files itself (ie, what the Reader tries to do). now, I just have to find a commandline program to invert PNG colors. also, there are probably utilities which'll manipulate PDFs to autocrop them or add cropboxes before they're sent to ghostscript. I'm calling it a day for now, but maybe someone already knows which ones those are? It would be extremely useful. Now, the UBER hack would be to compile ghostscript for the Reader, load it, and use it as the rastering engine. Earlier I mentioned that fixing the Reader would probably be better than converting, and it now seems there's a [relatively] easy path to doing it. Now why the hell couldn't Sony have done it itself? Can I curse at Sony some more? This hack also presents an opportunity to do stuff like pre-rastering the next page or, for godssake, make navigating books easier with an improved UI (like one where you can, say, USE THE NUMBER PAD TO ENTER PAGE NUMBERS). Last edited by alex_d; 12-11-2006 at 04:51 AM.