Created attachment 152160 [details]
two charts abou the idea: left: what already is available, right, the are plot i'd like to use

I'd like to have a new type of plot available.
i'm attaching pictures to illustrate my ideas.

The basic idea is: have support for integrating histograms, of integrating area plots (the later looks better imho).

This way, one could have a plot for expenses, that is summing up all expenses in the period, and could see when, and for what did he/she spend money for. On the other hand, seeing how much money would be a bit more difficult.

Based on this, one could have a Migthy-all-in-one plot, giving a good overview in a report. In my opinion, this should be implemented this way:

draw an "integrating" area plot, that is summing up expenses, showing the type of expenses also. this looks like a monotonously increasing function.
Over this plot, 2 other plots would be plotted, but with lines instead of area plots. These would be income (only the sum of all sources, as this plot would basically detail expenses), and balance. These lines would use some different, well distingiushable colour, not used in the the expense plots.

With this plot, and could track the rate he/she is spending money, and getting money, and the balance would show ih he/she is overspending himself (or herself).

The most obvious problem is the problem of scales: if someone has greater amount of money, and is not spending much, this would make the scales bad, as expenses might not be distinguishable. But the ability to manually set up the accounts, like to exclude the savings, could solve this also.

I'm illustration: a picture, made in oocalc, on the left, the current expenses barchart, and on the right, the area plot i'd like to use.

The line plot overlay is not implemented on the illustration, but hopefully i could describe my idea clearly.