#335 ddjvu: incorrect output in pdf and tiff formats

[Janusz]

Enclose please find the files created with the commands:

ddjvu -verbose -format=tiff -page=19 -segment=112x42+431+965 Zaborowski_MBC.djvu tiff_test.tiff
ddjvu -verbose -format=pdf -page=19 -segment=112x42+431+965 Zaborowski_MBC.djvu pdf_test.pdf

You can reproduce them themselves as the document Zaborowski_MBC.djvu
is available at https://github.com/jsbien/Zaborowski-index4djview.

The PDF file is evidently distorted. The TIFF by most tools is displayed correctly, but it is also incorrect. In the thread
https://tug.org/pipermail/xetex/2021-June/027952.html
the following faults has been described of the file obtained by converting the TIFF output:

• The image has different resolutions in the x- and y-directions (Heiko Oberdiek and others)
• Resolution Unit: inches . Surely not! unless it needs ~100 units for the inch. Further down there are Pixel units of meters. (Ross Moore)

Fortunately the ppm output seems OK.

Best regards

Janusz

[Leon Bottou]

Would that change do the trick?

diff --git a/tools/ddjvu.cpp b/tools/ddjvu.cpp
index e7b489b7..a7465a28 100644
--- a/tools/ddjvu.cpp
+++ b/tools/ddjvu.cpp
@@ -486,9 +486,9 @@ render(ddjvu_page_t page, int pageno)
         TIFFSetField(tiff, TIFFTAG_IMAGEWIDTH, (uint32)rrect.w);
         TIFFSetField(tiff, TIFFTAG_IMAGELENGTH, (uint32)rrect.h);
         TIFFSetField(tiff, TIFFTAG_XRESOLUTION,
-             (float)((dpirrect.w+iw/2)/iw));
+             (float)((dpiprect.w+iw/2)/iw));
         TIFFSetField(tiff, TIFFTAG_YRESOLUTION,
-             (float)((dpirrect.h+ih/2)/ih));
+             (float)((dpi*prect.h+ih/2)/ih));
         TIFFSetField(tiff, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
         TIFFSetField(tiff, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
 # ifdef CCITT_SUPPORT

On 6/11/21 12:47 AM, Janusz wrote:

---

[bugs:#335] https://sourceforge.net/p/djvu/bugs/335/ ddjvu:
incorrect output in pdf and tiff formats

Status: open
Group: djvulibre
Created: Fri Jun 11, 2021 04:47 AM UTC by Janusz
Last Updated: Fri Jun 11, 2021 04:47 AM UTC
Owner: nobody
Attachments:

• tests.zip
  https://sourceforge.net/p/djvu/bugs/335/attachment/tests.zip
  (25.8 kB; application/zip)

Enclose please find the files created with the commands:

|ddjvu -verbose -format=tiff -page=19 -segment=112x42+431+965
Zaborowski_MBC.djvu tiff_test.tiff|
|ddjvu -verbose -format=pdf -page=19 -segment=112x42+431+965
Zaborowski_MBC.djvu pdf_test.pdf|

You can reproduce them themselves as the document Zaborowski_MBC.djvu
is available at https://github.com/jsbien/Zaborowski-index4djview.
https://github.com/jsbien/Zaborowski-index4djview.

The PDF file is evidently distorted. The TIFF by most tools is
displayed correctly, but it is also incorrect. In the thread
https://tug.org/pipermail/xetex/2021-June/027952.html
https://tug.org/pipermail/xetex/2021-June/027952.html
the following faults has been described of the file obtained by
converting the TIFF output:

• The image has different resolutions in the x- and y-directions
  (Heiko Oberdiek and others)
• Resolution Unit: inches . Surely not! unless it needs ~100 units
  for the inch. Further down there are Pixel units of meters. (Ross
  Moore)

Fortunately the ppm output seems OK.

Best regards

Janusz

---

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[Janusz]

Unfortunately after converting TIFFs to PNGs and using them in XeLaTeX I see the same (or very similar) problem. I haven't applied the patch myself but just pulled the code from the repository.

[Leon Bottou]

Here the fix works on file Zaborowski_MBC.djvu.
You mustn't have obtained the patch for some reason....