Z-axis logarithmic scale tool always disabled in image panel

[PierreRaybaut]

Summary

In the image visualization panel, the toolbar action Base-10 logarithmic Z axis is permanently greyed out. It cannot be activated for any image, regardless of the selection.

Steps to reproduce

1. Open DataLab and switch to the image panel.
2. Add any image (e.g. via File > Open or Create > New image).
3. Select the image.
4. Look at the Base-10 logarithmic Z axis button in the toolbar: it stays disabled.

Expected behavior

The action should be enabled when an image is displayed and selected, and toggling it should switch the displayed image between linear and logarithmic Z scale.

Root cause

Bug in PlotPy: ZAxisLogTool only supports plain ImageItem instances, while DataLab uses MaskedXYImageItem for all image rendering. See PlotPyStack/PlotPy#XXX for the full analysis and fix.

Resolution

Fixed upstream in PlotPy. DataLab needs to require the next PlotPy release that includes the fix. No code change is required on the DataLab side.

Classification

Bug fix (depends on upstream PlotPy release):
PlotPyStack/PlotPy#59