Transparent geometries are not visible in screenshots generated from pvbatch/pvpython
When screenshots are generated with the 'SaveScreenshot' function using pvbatch/pvpython, transparent (opacity < 1) geometries are not visible when the newest paraview versions are used (tested for 5.4.1). However, when the screenshots are directly saved from the paraview gui, the transparent geometries are displayed properly.
This behavior is illustrated in Figs. 1 and 2 for a simple example consisting of a sphere inside a cylinder, where the cylinder has an opacity of 0.5. Figure 1 is generated with pvbatch using the attached python script Test.py, Fig. 2 is directly saved from the paraview gui. However, when a slightly older version of paraview is used (tested for 5.4.0), also pvbatch/pvpython produce the correct result, as shown in Fig. 3. This behavior might be related with the fix of the wrong colorbar scaling as described in issue #17938 (closed) .