Feature Request: Fool-proof Cut-off in the Histograms

[shundhammer]

Received via mail from Nicolas Brisset:

While I'm writing you a mail, I'd like to add another proposal. I fell into the trap a couple of times, and I guess I'm not the only one: when using histograms, the automatic cut-off is computed only on file counts (I guess). I had some directories with few but huge files (typicall core dumps or archive files) and when I checked the histogram I first could not see them. I would suggest adding a warning overlaid on the histogram, or maybe an option in the settings to compute the cut-off based on file counts (as now) but to check whether the sum of files shown in the histogram accounts for the right percentage (99%?) of the total size.

[shundhammer]

It's already there, and really prominent, too:

Why and how that cut-off is generated is documented extensively here:

https://github.com/shundhammer/qdirstat/blob/master/doc/stats/File-Size-Histogram.md

QDirStat by default uses some heuristics to determine useful boundaries for the histogram: It uses the interquartile distance (Q3 - Q1) and adds some generous distance to the left and to the right of Q1 and Q3:

leftBoundary = Q1 - 3 * (Q3 - Q1)

rightBoundary = Q3 + 3 * (Q3 - Q1)

https://github.com/shundhammer/qdirstat/blob/master/doc/stats/Overflow-Area.md

[brisset]

Thanks for the explanations. In fact, I had failed to understand the cut-off view at first glance. May I suggest to add a short explanation on the cut-off view? Maybe something like a subtitle explaining "Some files are currently not displayed in the histogram, they amount for x % of the file count and y % of disk space. You can click on the "Options" button below to change histogram settings". You can also make it a tooltip if such a text is too invasive.
Maybe a legend would also help? (red = masked files).

To better explain why I had a problem with that view, find below a screenshot of the directory I was using it with. This is under a mate desktop with a dark theme... Not very easy to read!

[shundhammer]

Now explicitly using a white background and black text color for the complete histogram view, even for dark widget themes:

[shundhammer]

The very concept of that QGraphicsView / QGraphicsScene / QGraphicsTextItem using the application's widget theme palette is broken by design: Those classes are designed to be used as a canvas to draw custom graphics.

Of course such custom graphics use custom colors which are not dependent at all on the current widget theme. That default behaviour is completely insane and useless.