12/13/2018

Ideally, we'd like heatmap bins to be squares. How do we support square bins?

When we are talking about "square" bins, I see at least two interpretations:
1. X and Y are on the same scale (same units) and we want bin size to be the same in x and y directions.
2. Given xyratio and total number of bins, the bins should appear as squares for the given axes ranges.

Currently, when creating a heatmap, we allow user to specify the number of bins `nbins.x` and `nbin.y` and axis range (xmin, xmax) and (ymin,ymax) . The default number of bins in x and y direction is 100. The default range is data range.

In Plotly chart, user can change axes ranges interactively, and we probably don't want to recalculate bins based on these changes. Plotly allows to preserve aspect ratio by linking the axes using `scaleanchor` and `scaleratio` attributes.

4/11/2016
Currently decimation process assumes aspect ratio 1. For decimated plots, the displayed area size (or user supplied value) needs to be used as an aspect ratio to approximate square bins.

• When aspect ratio changes, decimation process needs to be redone.
• To avoid server calls on resize, disallow flexible aspect ratio for decimated data.