06-08-2021, 11:55 AM
There used to be a "deskew" plugin for this. AFAIK it does it by computing a 2D Fourier transform of the document. The resulting image has "spikes" at privileged angles that correspond to the general slant of the text, from which you can deduce a corrective rotation.
If you use any program (free or not) that has a sufficient number of users, paying or not, open source or not, it can be reasonably considered safe (or at least that the holes are either well know or benign). Nasties don't remain unspotted form long in such programs.
Open Source doesn't always mean safety. Quite the contrary, since it is very easy to make something that looks like the regular app, but with nasty additions to the code. FOSS is safe if you build it from the published source(*), or if you get it from a trusted builder (for instance, your distro's repositories if you use Linux). Gimp is safe if you download it from gimp.org. If you get it from somewhere else you don't really know what is inside. Of course there are alternative builders (such as Partha) that have acquired the community's trust over the years.
(*) And even then, there have been cases of hackers poisoning the source code of apps and libraries(**). But they ar usually quite quickly spotted.
(**) Not mentioning the NSA slightly skewing the random generators in Linux to make encryption a bit weaker;
If you use any program (free or not) that has a sufficient number of users, paying or not, open source or not, it can be reasonably considered safe (or at least that the holes are either well know or benign). Nasties don't remain unspotted form long in such programs.
Open Source doesn't always mean safety. Quite the contrary, since it is very easy to make something that looks like the regular app, but with nasty additions to the code. FOSS is safe if you build it from the published source(*), or if you get it from a trusted builder (for instance, your distro's repositories if you use Linux). Gimp is safe if you download it from gimp.org. If you get it from somewhere else you don't really know what is inside. Of course there are alternative builders (such as Partha) that have acquired the community's trust over the years.
(*) And even then, there have been cases of hackers poisoning the source code of apps and libraries(**). But they ar usually quite quickly spotted.
(**) Not mentioning the NSA slightly skewing the random generators in Linux to make encryption a bit weaker;