Faster Screenshot

[akaszynski]

Overview

Simple fix to speedup screenshots (at least on Linux). Discovered this while working on potentially automating tests using screenshots.

Details

Here's the screenshot speed on Linux and Windows

import pyvista as pv

plotter = pv.Plotter(off_screen=True)
plotter.add_mesh(pv.Sphere(), smooth_shading=True)
timeit plotter.screenshot('/tmp/tmp.png')

feat/faster_screenshot (this branch)

# LINUX:   70.9 ms ± 212 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
# WINDOWS: 70 ms ± 145 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)

master

# LINUX:   324 ms ± 564 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)
# WINDOWS: 312 ms ± 462 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)

MISC

I've also made a minor change in the tests to make sure we test all file types.

[codecov]

Codecov Report

Merging #957 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #957      +/-   ##
==========================================
+ Coverage   86.97%   86.98%   +0.01%     
==========================================
  Files          36       36              
  Lines        9060     9062       +2     
==========================================
+ Hits         7880     7883       +3     
+ Misses       1180     1179       -1     

[akaszynski]

@pyvista/developers, ready for review.