Bug report

Bug summary

Savefig does not generate legends with a single marker when scatterpoints=1 and the output file format is PDF/EPS/SVG. (A similar problem also happens when scatterpoints=2).

Code for reproduction

from matplotlib import pyplot as plt
plt.scatter([1,2,3], [2,4,7], [10,20,70], facecolor="none", edgecolor="y", label="Foobar")
plt.legend(scatterpoints=1)
plt.savefig("output.png")  # this works perfectly
plt.savefig("output.pdf")  # this does not
plt.savefig("output.eps")  # this does not
plt.savefig("output.svg")  # this does not

Expected outcome

The output images should all be be similar, with a legend that only shows a single marker (since scatterpoints=1).

Actual outcome

The output PNG file looks perfect, just like with plt.show(). The PDF/EPS/SVG files have 3 superimposed markers inside the legend.

Matplotlib version

• Operating System: Ubuntu 16.04
• Matplotlib Version: 1.5.1
• Python Version: 3.5.2
• Jupyter Version (if applicable): None.
• Other Libraries: None.