[PierreRaybaut]

Closes #453.

Depends on PlotPyStack/PlotPy#81 (cosmetic pen, merged into PlotPy develop) and DataLab-Platform/SigimaX#29 (palette, grid, automatic styles), which close PlotPyStack/PlotPy#80 and DataLab-Platform/SigimaX#28.

Changes

Style assignment by position

• SignalPlotHandler.update_automatic_styles() runs at the end of each plot refresh.
• It gives the visible curves the automatic style of their position, in the order of the signals in the panel.
• Curves whose color or line style was chosen by the user are left unchanged, but still count as a position.

Global style cycle

• Creating a plot item for the panel no longer uses the global style cycle (CURVESTYLES.suspend()).
• Thanks to SigimaX, the ROI editor and View in a new window no longer shift it either.

Reset curve styles

• View > Reset curve styles now removes the colors and line styles stored for the selected signals and gives their curves automatic styles again.
• The action is enabled when at least one signal or group is selected.

Exports

• datalab.adapters_plotpy now exports CurveStyles and LINE_STYLE_KEYS.

Documentation and translations

• Updated View menu documentation (Reset curve styles) and settings documentation (line width on high-DPI screens).
• Release notes for 1.4.0.
• French translations (UI and documentation).

Before / after

With 15 noisy signals, light and dark themes:

• the first 10 curves are drawn with solid lines and the next 5 with dashed lines;
• no curve uses dotted styles anymore;
• the grid is discreet.

Tests

• New datalab/tests/features/signal/curve_styles_unit_test.py, covering:
  • styles following curve positions;
  • the style cycle not used by the panel and dialogs;
  • user-defined styles kept across a workspace round trip;
  • styles of earlier versions handled as automatic;
  • Reset curve styles.
• Local runs:
  • datalab/tests/features/signal, features/common, features/hdf5 and backbone: 890 passed, 1 skipped;
  • features/image, features/plugins and features/control: 186 passed, 2 skipped.