Flameshot: Hide region via pixelation

[tecosaur]

Is your feature request related to a problem?
Often screenshots can contain sensitive content. The current blur tool is insufficient for hiding said information. Increasing the blur helps, and is suggested in #127 as is another approach — pixelating/mosaicing.

Performing a quick search on the two approaches I find this article describing the (lack of) effectiveness of these two methods. Of key interest are the following figures

Gaussian Blur

Mosaicing/pixelating

Of note, is that at a given mosaic/blur size, mosaicing outperforms the gaussian blur.

With a 40pt radius, reading from the graph about 3/4 of the blurred information can be recovered, but from the look of the mosaic graph, less than 1/4 from that approach with a square size of 40pt.

As a result of all this, I believe it would be beneficial to add a mosaic/pixelation option to Flameshot. While both techniques have issues, pixelation with large square sizes appears to be a safer way to go.

[borgmanJeremy]

Interesting, I really like this idea and will play with adding this on my fork and get a PR once its done.

We can pick a good default pixel size, but I suspect people will need to adjust it based on the information needing to be censored. IE 100pt font will need a larger pixel size than 10pt font. I'm not sure yet the best way to integrate that option into the UI.

[tecosaur]

Glad to see there's interest :smiley:

We can pick a good default pixel size, but I suspect people will need to adjust it based on the information needing to be censored.

@borgmanJeremy I imagine that one could just use a user-variable size as with line thinkness, text size etc.

[borgmanJeremy]

@tecosaur Yeah I think the best way to integrate it is with the scroll wheel.

Do you have any objections to replacing the current blur tool with the pixelate tool?

[borgmanJeremy]

Something like this?

[Tc-001]

I believe this could be a great change.
Maybe make it toggle-able with a checkbox (set to pixelise by default) in case anyone prefers the old method

[tecosaur]

This is quite a late reply from me, but @borgmanJeremy that demo looks great!

[borgmanJeremy]

This is merged in and will be present in the next release.