2020.4.2

Main changes

• Removed restriction VTK<9. Even so, VTK9 seems significantly slower and unexpected behaviors are still possible.

• Various minor issues have been fixed.

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addons.py:

• name change addLight() -> Light(). Improved API. Revised example basic/lights.py
  (thanks to @mit10000 and @theponpon input #249)
• added size keyword for addScalarBar() to control size in pixels (@RubendeBruin #237)

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io.py:

• added default bitrate specification Video.options="-b:v 8000k" (for ffmpeg)
  seems to produce much better quality results - tested on linux system only.

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plotter.py:

• modified plotter.addLight()
• added warning to non-existing camera keywords (@FedeClaudi #244)
• In rendering window:
  • pressing 3 cycles over predefined set of textures for clicked Mesh objects
  • pressing I picks the color under the mouse (uses colors.pickColor())

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shapes.py:

• added class Brace (see example scatter3.py)
• can sweep() a Line object to create a surface

New/Revised examples:

vedo -r rgbaImage
vedo -r cutWithMesh2
vedo -r scatter3
vedo -r lights
vedo -r plot_density4d (thanks to @edmontz)
vedo -r app_raycaster
vedo -r app_isobrowser