I am encountering a problem with the legend entries for scatter plots when setting a figure DPI different from the default of 72. When the DPI is higher than 72, the markers in the legend become disproportionately large and get scrunched together. It looks like what is happening is the marker size is being transformed twice, and the offsets are not being transformed at all.
I have tried to debug it, and it looks like the problem is the way that the DrawingArea that contains the legend interacts with the Collection object. To fix the spacing, the _transOffset property of the Collection needs to be set, but the transform being applied by the DrawingArea ends up scaling the marker size instead.
I have attached a sample script which shows the problem. I am using the current development version of matplotlib checked out from git, with Python 2.6.2. The issue also exists in version 0.99.1.
scatterdbg.py (255 Bytes)