Add the ability to add a title to the legend

[etimberg]

Resolves #4466

• Legend title can be specified
• Font & color options added
• Padding option added
• Positioning option added
• Legend title sample file added

[kurkle]

Just one question

[benmccann]

I'm not sure all the positions end up quite where I'd expect. The orange one I agree. The others they're all very far from the legend. I'd expect it to be within the bounds of the legend, but potentially left, center, or right aligned. See below

[etimberg]

I see what you mean about the vertical positioned title (a separate setting would need to be added to move the entire legend up and down). For the horizontal legend, it's because by default the legend takes the entire width of the chart.

[etimberg]

Looking into this some more ... I don't know what I was thinking when I first wrote the legend. Lots of updating happens in draw() and I have no idea why. If everything happened in fit this would be relatively easy since I'd know the height/width of the largest column/row which is what I really need.

[etimberg]

Ok, figured out why it was needed ... the final width isn't know until the layout process is done. I've got it working with the align setting. I've updated the sample to be more thorough

[benmccann]

In the last image it looks like the title position affects the entire legend and not just the title. Perhaps instead of calling them position and title.position it should be align and verticalAlign?

[etimberg]

@benmccann sorry for the confusion, it’s actually a mix of settings. align moves the legend up and down. Title align just moves the title. I added align into the sample so I could be sure it worked in all cases

[benmccann]

@etimberg this one will need to be rebased

[kurkle]

Build failing!