Improve color guessing when first loading a data matrix

[Anastasia Baryshnikova]

The flow of checks should be: 1) Is it a binary matrix? (only 0, 1 and Empty in the data) If yes, set 0 to black and 1 to red. If not, check next.

2) Is it a matrix where with positive and negative values? (at least 1% positive data and 1% negative) If yes, set 0 to black, negatives to red and positives to green. If not, fall back to default strategy.

[Robert Leach]

I think that if we do this, we should consider additionally implementing this guessing in 2 ways: behind the scenes when new data is first loaded, as is suggested here, and as a button in the slider edit dialog, as is proposed in issue #49. The buttons would be something akin to move selected to "median", "mean", "center", "0.0", etc:

[Anastasia Baryshnikova]

I think this may be overkill.. In my (biased) experience, I always knew where I wanted the color bars to be. And I wouldn't be able to 100% trust the buttons because it's not clear to me what is included in the calculation of the median/mean or center.. What if my matrix has many zeros? Do they get to contribute? I know this is probably an easy thing to implement, so we can leave it on the table, but I'm a little skeptical whether it will be practically useful or not..

[Anastasia Baryshnikova]

You know what could be a nice compromise?

Set color: [ Color picker ]

Set value: [ Input box ]

Suggested values:

• Median = 0.523
• Mean = 0.54
• Center = 0.55

So, the values are just suggestions and you'd see them before you enter them into the box.

[Robert Leach]

I like that better.

[Robert Leach]

Perhaps, as an abstraction of "binary matrices", we could support "discreet matrices" (i.e. all values are integers). The default could be (if there are 2 values in the population) RedGreen with the values set as the boundaries or (if there are >2 values), the median gets black and the median-1 gets red and the median+1 gets green. They can add colors as desired.

If the median happens to be a min or max, we'd have to have a special case where the median value gets incremented/decremented or something.

[Anastasia Baryshnikova]

Sounds reasonable

[Robert Leach]

Removing milestone: Import/export data (automated comment)