Sonic Visualiser 5.0.0

What's new in this version:

- Port to Qt6. The code now builds only with Qt6, and Qt5 is no longer supported
- Add mechanism to ignore plugins on subsequent runs if they fail to load, and to review ignored plugins from the preferences dialog
- Add Mel scale to the options for vertical spectrogram scale
- Add an opaque toggle to the spectrogram; switching it off gives spectrograms some transparency, so they can be overlaid over other layers, including other spectrograms
- Update opaque toggle in colour 3d layers so that it works like the new one in the spectrogram. Previously colour 3d plot layers could be translucent at low resolutions but not at higher ones; now the setting affects all resolutions. Correspondingly make it default to off, as in the spectrogram
- Add smoothing toggle directly to spectrogram parameters, like the one already found in colour 3d plot layers. Previously spectrogram smoothing could be toggled only from the preferences
- Stop snapping spectrogram frequency range to bin frequencies. This already-confusing feature caused problems with the new support for translucent spectrograms, which permits overlaying spectrograms of
differing bin counts that would be too hard to line up properly if the frequency extents were always snapped to the nearest bin
- Clarify keyboard and mouse shortcut descriptions in the Key And Mouse Reference window, especially for the platform-specific descriptions used on the Mac, and add a few more alternative
shortcuts including more standard zoom in/out shortcuts
- Fix disappearing peaks in peak-bin display mode in the spectrogram, caused by overzealous smoothing
- Fix jumps in spectrogram when changing zoom level between certain values in hi-dpi pixel-doubled situations, caused by a failure of cache invalidation
- Fix some very slow spectrogram painting
- Fix disappearance of right-button Transforms menu after file load
- Fix inconsistent default vs set threshold values in spectrogram

Fix crash on painting very low-resolution dense 3d plots Changes in Sonic Visualiser v4.5.2 (3 May 2023) since the previous release 4.5.1:
- Support multi-line text labels on time instants
- Improve refresh and rendering of text labels in various layers
- Improve abbreviation of layer names in the key at bottom-right of a pane
- Fix repeated writes to settings file when rendering time-ruler layers at close zoom levels
- Use system Vamp host SDK if provided