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Re: Issue loading TIFF images with plugin/TIF [message #59606 is a reply to message #59605]

Tue, 14 February 2023 09:02

Tom1
Messages: 1212
Registered: March 2007

Senior Contributor

Hi Mirek,

Thanks, jpeg-tiff works now. Smile

As for your question of merging my latest posted tifupp.cpp, I mostly think you could, but please consider the following:

1. The issue with:

https://www.marinha.mil.br/chm/sites/www.marinha.mil.br.chm/ files/geotiff/1511geotiff.zip

is simply solved by entirely disabling the tmpfile in FetchPage(). I bet you would come up with a more advanced solution yourself.

2. The crash with some of the GeoTIFF_Samples_from_zi_imaging, e.g. image1.tif, due to image flipping remains unsolved:

https://www.ultimatepp.org/forums/index.php?t=getfile&id =6753&

These orientation related issues need to be solved in one way or another. When going with libtiff directly, I ended up requesting the image in its stored orientation stated by TIFFTAG_ORIENTATION. This way I could avoid the internal flipping code which caused crashes. (Then I flipped it afterwards to a natural U++ Image orientation and corrected the georeferencing for the new orientation.) It is important to note that even if the image would be flipped inside the plugin to U++ Image orientation, the original orientation is still important to know in order to fix the georeferencing information. In my opinion, optimally the plugin/TIF could return the images readily flipped to U++ Image orientation and maybe also with a georeferencing solution corrected accordingly.

Best regards,

Tom

EDIT: I looked at our earlier work on plugin/JPG EXIF orientation and flipping: Yes, the image is pre-flipped and returned in its U++ orientation. So it would seem logical to do the same in plugin/TIF.

EDIT2: I came up with an idea to avoid the flipping crash. This involves further changes to tifupp.cpp, so please stand-by until I finish with this one.

EDIT3: OK, now I have prevented libtiff flipping crash and enabled correct Raster flipping, i.e. the same code that flips JPEG images. Just need to adjust the geomatrix to reflect this change... I will return.

[Updated on: Tue, 14 February 2023 11:51]

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