Plot curve colours should carry on from the last selected colour

[Nick Draper]

From Richard Heenan:

If change the colour of the last workspace on a plot, then the next workspace added does get the next colour in the table as expected, but add any more added all get the same colour as the one before. Also, thank you for moving the invisible yellow colour further down the list.

[Nick Draper]

Moved to backlog at the code freeze for R2.6

[Russell Taylor]

This feels like it is related to #4132 (or that a solution could incorporate that).

[Martyn Gigg]

Agreed. Would you like me to take #4132 off your hands or given it's visible thing would you prefer to incorporate this one into the update from #4132?

[Nick Draper]

Poker Estimate: 4d

[Russell Taylor]

We've agreed that I'll take this and fix it as part of #4132.

[Russell Taylor]

I ran out of time for #4132 in this release, but I should be able to fix this one I think.

[Russell Taylor]

Re #6980. Fix calculation of color index.

The problem was that the ColorBox had been added, which extended the number of colours to 24, but the method contained this hard-coded so the calculation wrapped around too soon. Also if you hit white you then got 'stuck' at black - now it skips on to the next colour. I've changed to calling methods on ColorBox instead of magic numbers, and also streamlined the code in other places.

Changeset: e8a67c6b8f931441c5288a453b6b5bf3096ffa97

[Russell Taylor]

The described problem should be sorted out now, so have a go at plotting a spectrum, adding more (you can drag the workspace onto the graph) and changing colours around.

There is one case in which you will still get 'stuck' on black. This is if you have a curve with the last colour in the list (dark yellow); subsequently added curves will all be black. I don't think it's worth implementing a more complex solution for this likely rare case.

[Arturs Bekasovs]

Merge remote-tracking branch 'origin/bugfix/6980_curve_colour_choosing'

Full changeset: ​a58b3ce80276601b33842c0d6b4f31f3c099f6d8

[Arturs Bekasovs]

All works as expected. White color is skipped correctly, all the consequent curves get the color which is "lower" in the list of colors than the "lowest" one, no matter which part of the color list they are in.

Was able to reproduce the problem with color being black when we run out of colors for new curves, but I don't see any obvious solutions as well and I agree that it's quite a rare case.

[Stuart Campbell]

This ticket has been transferred to github issue ​7826