[MU4 Issue] Apply current palette element command not implemented

[MarcSabatella]

Describe the bug
MuseScore 3 had a command "apply current palette element" to easily reapply the most recently-used palette element. This was a great usability feature and especially valuable for blind users even though it had no default shortcut. This command is missing in MU4.

To Reproduce
Steps to reproduce the behavior:

1. Go to Edit / Preferences / Shortcuts
2. Search for "palette"
3. See error: no "Apply current palette element" command available

Expected behavior
The "apply current palette element" should be available, and ideally, should have a default shortcut assigned even though there was none in MU3. FWIW, I normally used "\".

Platform information

• OS: Linux

Additional context
I know there is some new functionality coming for shortcuts via the GSoC project, but on the assumption that none of the pending work for that is being targeted for 4.0, re-implementing this one command would be a big help for now.

There are a handful of other commands that were dropped from MU3, some consciously, some perhaps less so. This to me is the one most worth adding back for 4.0.

[wizofaus]

You normally used ""?
There is still "applyCurrentPaletteElement" in PalettesPanel.qml but nothing calling it...hard to judge whether it will actually work.

[MarcSabatella]

Sorry, I typed a backslash but GitHub ate it. Fixed now.

[MarcSabatella]

@Tantacrul - also not beta-critical at all, but, for me personally, I think I miss the command more than any other single MU3 feature. An unbelievably useful productivity tool.

[MarcSabatella]

I can make an attempt, if I can get a little help. I knew how things worked in MU3 but it still is a lot of trial and error for me in MU4.

@wizofaus - I assume you're talking about the code here:

https://github.com/musescore/MuseScore/blob/master/src/palette/qml/MuseScore/Palette/PalettesPanel.qml#L46-L47

It looks like the actual work then is done here:

https://github.com/musescore/MuseScore/blob/master/src/palette/qml/MuseScore/Palette/internal/PaletteTree.qml#L111-L120

which looks about right to me (not that I know my way QML at all). So, it seems promising.

In theory, then, all we'd need to do is make sure the command exists and calls the applyCurrentPaletteElement function. The place where the command would be to be defined, I assume, is here:

https://github.com/MarcSabatella/MuseScore/blob/apply-current-palette-element/src/palette/internal/paletteuiactions.cpp#L33-L71

And then after defining the command itself there, I'd need to register it here:

https://github.com/musescore/MuseScore/blob/master/src/notation/internal/notationactioncontroller.cpp

That last part is the mystery to me - I have no idea what magic it would take to actually reference the applyCurrentPaletteElement function here.

[cbjeukendrup]

@MarcSabatella You could use the "palette-search" action as an example.

The class PaletteRootModel is instantiated in QML, and registers itself as a handler for this action. When the action is called, the model emits a signal, namely paletteSearchRequested().

MuseScore/src/palette/view/paletterootmodel.cpp

Lines 26 to 32 in 644cc12

	PaletteRootModel::PaletteRootModel(QObject* parent)
	: QObject(parent)
	{
	dispatcher()->reg(this, "palette-search", [this]() {
	emit paletteSearchRequested();
	});
	}

In QML, there is a handler for this signal; in this handler, the relevant function in QML is called.

MuseScore/src/palette/qml/MuseScore/Palette/PalettesPanel.qml

Lines 62 to 68 in 644cc12

	PaletteRootModel {
	id: paletteRootModel
	onPaletteSearchRequested: {
	palettesPanelHeader.startSearch()
	}
	}

So, you can basically just copy & paste the handler registrations and fill in the correct names, action code and QML function.

[MarcSabatella]

Great, that gets me started! Signals, yeah, makes sense. I'll give it a shot.

BTW, the palette search command is actually defined in the palette code but I had been thinking it made sense for the apply current palette element command to be defined in notation, since that's where the focus would be on executing it and where action would actually take effect. But maybe I'll try it all here in the palette code first.

[wizofaus]

I'd expect it to be in the Palette code - I wouldn't think the Notation code should depend on/ know about the Palette generally.