Add Other Rectangular Picker

[JaydenIrwin]

Please add this style of rectangular picker.

[RastislavMirek]

Why is it needed? Reasons?

Btw. you can do add it yourself by subclassing ColorPaleteControl. No need to to change FlexColorPicker code for that. See https://github.com/RastislavMirek/FlexColorPicker#extending--overriding. You will also need Hue slider to go with that kind of palette (subclass ColorSliderControl). Hue slider is a planned feature so push request would be very welcome.

EDIT: for creating palette like that, you do not event need to subclass ColorPaletteControl. Just implement your own ColorPaletteDelegate and set is as color delegate of a ColorPaletteControl. That's much simpler.

[JaydenIrwin]

Why? I thought it would be a nice enhancement. I will see what I can do.