PDF invert colours.

[Nexutix]

It's really good to read PDFs or other formats on ebook readers with inverted colours. (like blackboard). ...just like we do with images.
Has anyone tried this? How will we invert colours in PDF? Any ideas?
(I converted pages to images, inverted colors and reading them is more comfortable. I was looking to invert colours in PDF format.)

[frabjous]

If you didn't mind rasterizing* the PDF, you could use imagemagick. See the two attached PDFs. I created output.pdf from input.pdf with the single command:

convert -density 300 input.pdf -negate output.pdf

(If that means nothing to you, let me know and I'll try to give full or at least fuller instructions.)

*Rasterizing the PDF means converting each page to an image inside the PDF. On a fixed-resolution device, it should look exactly the same. However, since the text has been replaced with a series of images, dictionary and search functions will no longer work. The PDF is usually much larger in file size too.

If you need a solution that preserves text as text, I'll have to think about it some more, though it's probably possible with the right software.

However, I think with an e-Ink device such as a Kindle, Nook or Sony Reader, this would drain the battery a lot faster. (On the flipside, with an LCD device such as an iPad, it might even improve batter life.)

[Jellby]

Originally Posted by frabjous

However, I think with an e-Ink device such as a Kindle, Nook or Sony Reader, this would drain the battery a lot faster.

Why? If the whole screen "flashes" at page turns, I don't see a difference. If only the parts that change from page to page are updated, I don't see a difference either.

[frabjous]

Originally Posted by Jellby

Why? If the whole screen "flashes" at page turns, I don't see a difference. If only the parts that change from page to page are updated, I don't see a difference either.

I'm not sure I really understand enough of the technology, but what I think I see is that the screen flashes, but then goes all-white, and then the parts that need to become black become black, so the more that needs to become black, the work electricity is used in the final step.

If I'm wrong about that middle step of going all white, then I guess there's nothing to worry about. (And maybe it wouldn't matter much anyway.)

[Nexutix]

Originally Posted by frabjous

If you didn't mind
...
batter life.)

Thank You! Works perfect!

[meem]

It worked perfectly with me also.
Good idea to skip black flashing with full page refresh, but it's not needed now with some new devices like "NookTouch" or Kindle with "Duokan" firmware.