[Enhancement] Default custom colors

[l3td33r]

Set the default 16 colors in the color picker to some predefined values (right now they're all white), to make the workflow easier.

We can use colors from one of the popular palettes:
https://lospec.com/palette-list/island-joy-16 (I like this one, the colors are not too intense)
or https://lospec.com/palette-list/sweetie-16

Related: https://doc.qt.io/qt-5/qcolordialog.html#setCustomColor

[cantalisa]

I agree! I think it's a good idea.

Even an option (a toolbar or a button with an ink-bottle icon or something) with default set of colors would be great (or create another one). So in one click you choose if you want it with white nodes and gray background, x-color nodes or y-color background, or so on.

Currently the toolbar is functional but something tedious if you try several colors, mainly because the selection of colors are somewhat confusing (as for custom colors) and the basic colors are somewhat strong.

[juzzlin]

Ok, as seems to be doable with QColorDialog.

[juzzlin]

Seems that for example Ubuntu 20.04 shows a different and more simple color dialog than other systems. The system color dialog can be disabled, but not sure if that's an improvement.

[juzzlin]

This is the color picker Heimer shows on Ubuntu 20.04 by default:

[juzzlin]

This is the Qt (I think!) color picker with custom palette:

[juzzlin]

Fixed in 6eb4ca2. This can be now more easily further improved. Thanks!

[l3td33r]

Wow, looks cool, thanks!