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I know I need explain.
First is what I want: I want view a scanned PDF using mobi format in my Kindle paperwhite 2. The reason is I dislike kinlde display a border around the PDF content, and also kindle may be not stable for PDF file. Then I want the convert process is lossless to avoid scale image twice (kinlde will scale while display if resolution not match the best resolution, although I don't know which is but the PDF file I've tested is small than that), and do not want increase the output filesize (the test file image have 5 color and resample will have 32 color and double the filesize).
Then what I have done. After many test and adjustment, I found using trim mode and native PDF output, by using a tool to render the pages, the result image can match the source exactly pixel by pixel. But since I view it in landscape mode, I need k2pdfopt split the pages to about 40% original height and trim and merge with next page. Then I found the I can not render out page exactly as the original. Even using native PDF mode, the transform matrix of Xobj image can not always be like "1 0 0 1 -12 -405", so it will resample pixels and color number will be extended and finale mobi filesize will double.
By now I just think I almost have made it, by using such parameter (I am using GUI):
-m 74p,145p,74p,81p -idpi 72 -bp-- 0 -vb -2
-de 1.5 -wrap- -n -c -col 1 -odpi 72 -h 0.37s -w 0.8s -ws 0
but there are a few pages still have 32 color and big size, I checked then I found these are combined by two pages, I guess there are a gap between page. But even I use -bp-- 0, it's still there, 2 matrix look like "0.99643 0 0 0.99643 -71.74332 220.49945" and "0.99643 0 0 0.99643 -60.78253 -531.09894".
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