07-19-2019, 12:27 PM | #1 |
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Quick Question
Hi all.
I've looked in the forums and wiki but I can't seem to figure out why that when I reflow text on a PDF that the output is always in B&W. Even when I have checked "Color Rendering" in Koreader settings. I'm using an Android device, Alcatel Tetra. Any advice or help here? Thanks! |
07-19-2019, 12:29 PM | #2 |
BLAM!
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Possibly because k2pdfopt always outputs B&W pixmaps, or we always request B&W pixmaps from it, I haven't checked, but that seems plausible, given the main target device type .
EDIT: A quick glance at the examples would hint at the former, so, tough luck . Last edited by NiLuJe; 07-19-2019 at 12:34 PM. |
07-19-2019, 12:33 PM | #3 |
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Is there not a fix for that? I've used the standalone k2pdfopt before and I know for sure that you can reflow the text while still retaining the color.
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07-19-2019, 12:35 PM | #4 |
BLAM!
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Possibly, but I've lost any and all motivation to work on PDF stuff, because it's a mess that I don't use .
(i.e., patches welcome!) |
07-19-2019, 01:45 PM | #5 |
Wizard
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I like PDF but I have basically no motivation for reflow I'm afraid.
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07-19-2019, 02:45 PM | #6 |
cosiñeiro
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Color output is available since v1.15 https://www.willus.com/k2pdfopt/help/color.shtml
A quick look at our repo searching for dst_color: https://github.com/koreader/libk2pdf...ed_q=dst_color |
08-27-2019, 04:12 PM | #7 | |
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Quote:
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08-28-2019, 03:36 AM | #8 | |
Wizard
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Quote:
I suspect the main loss of color is in the main C files. In settings.c k2settings->dst_color should be set to 1 (or rather allow for a Lua interface override like the DPI property), in functions like k2pdfopt_reflow_bmp and friends I imagine a 24-bit bitmap should be used, and then there's a bunch of presumably much easier to get around stuff in koptinterface.lua and pdfdocument.lua. Unfortunately however, if I'm going to sit down for a good few hours to work on something I figure my time would be better spent migrating Android to Clang or to see if I can figure out https://github.com/koreader/koreader-base/pull/762 Especially because I know a lot more about the build system than about K2pdfopt. |
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08-28-2019, 11:34 AM | #9 | |
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Quote:
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08-28-2019, 12:16 PM | #10 |
Wizard
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This stuff was originally written in 2011 for Kindle only. Color wasn't just unnecessary, but an unnecessary strain on resources.
Anyway, it shouldn't be super complicated. But I just looked at the code and I don't quite see where the color info is lost. Setting all the mupdf.color stuff to true results in a garbled part of the image, setting color to true in k2pdfopt makes it a nice equal black but still lost. Probably some BB conversion somewhere but boy is the call chain complicated. On Android you can easily use https://gitlab.com/axet/android-k2pdfopt much like on PC. Most Android devices are also quite fast. KOReader's secret sauce here is doing only one page at a time instead of the whole document. It also has some definite disadvantages but otherwise the reflowing process might take quite a while on your average ereader — especially a 2011 Kindle. |
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