undesirable effects by change of mimetype

Description

greenshot 1.1.7 build 17 (64bit)

problem:

  • greenshot ignores EXIF-tags available at opened tif-file

  • greenshot hides change of mimetype from user -> all exif-tags are lost/deleted

Problem may be an feature ( .

what happened:

  • scanner produced tif-file (.tif) with certain file- and exif-tags (file:filetype=tif, file:mimetype=image/tif, exif:xpkeywords="key1 key2")

  • exif-tags became manually updated (changed to desired values) with "exiftool"

  • tif-file opened for manipulation with greenshot, done (text + arrows added) and saved (not saved as)

  • it turned out, that file-tags file:mimetype and file:filetype where changed by greenshot to image/png and png and that exif-tags where deleted.

Further experiments show, that to explicitly save the added text and arrows with filetype=tiff also ignores all at opened file available exif-tags AND deletes them in order to establish an new set of exif-tags (with values, greenshot "decides" on).

Requested behaviour is, that greenshot

  • does not hide change of mimetype but asks user if for example EXIF-tags shall/may be deleted/updated by greenshot (best case: displays new set of exif-tags with values)

  • does keep at opened file available exif-tags and only adds (does not delete) new ones for its own values (for example exif:software=greenshot).

Please contact me, if further explaination is requested.

To deal with files' meta-information generally greenshot may implement usage of exiftool (http://www.sno.phy.queensu.ca/~phil/exiftool/).

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Activity

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Robin Krom
July 29, 2014, 3:01 PM

Hello,

I finally had a bit of time to take a look at this.

First I want to start with the following: Greenshot was not designed to be a tool to modify non screenshots.
If we take that into consideration, I hope you understand why it doesn't support EXIF tags... screenshots don't origin from files, thus have not EXIF-tags.

That said... I really would like to make sure it does work as it is supposed to.

For me the change to the mime-type seems to be logical, it would cause many problems for tools if the file is of type "png" but has a non matching mime-type.

If tags are deleted, that is another thing... Greenshot is build with .NET 2.0, which is very old and only has a minimal implementation of EXIF, this might explain why the are lost.

"Implementing" the usage of exiftool is not really how things work, we do not add other tools as this causes many issues (licensing, distribution etc). If we need external "help" this would be in the form of a library (DLL) and only if it's written for .NET,
Maybe I will look at: https://github.com/mono/taglib-sharp

Currently I do not have a solution, and I don't know if there is one on short notice. But maybe I have more possibilities with using a newer .NET Framework, which is what I currently do for Greenshot 2.x (won't be soon).

I'll keep you informed if I find something.

Best wishes,
Robin

Assignee

Unassigned

Reporter

Harald Tichy

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