Add Strum Tool to Piano Roll (#7725)

Adds a complex strum tool to the Piano Roll, allowing the user to take a selection of chords, and drag around the notes to shape the strum exactly how they want it.

---------

Co-authored-by: szeli1 <143485814+szeli1@users.noreply.github.com>
Co-authored-by: Sotonye Atemie <satemiej@gmail.com>

include/PianoRoll.h

@@ -112,7 +112,8 @@ public:
 		Erase,
 		Select,
 		Detuning,
-		Knife
+		Knife,
+		Strum
 	};
 
 	/*! \brief Resets settings to default when e.g. creating a new project */
@@ -268,7 +269,8 @@ private:
 		SelectNotes,
 		ChangeNoteProperty,
 		ResizeNoteEditArea,
-		Knife
+		Knife,
+		Strum
 	};
 
 	enum class NoteEditMode
@@ -324,6 +326,9 @@ private:
 	void setKnifeAction();
 	void cancelKnifeAction();
 
+	void setStrumAction();
+	void cancelStrumAction();
+
 	void updateScrollbars();
 	void updatePositionLineHeight();
 
@@ -347,6 +352,7 @@ private:
 	QPixmap m_toolMove = embed::getIconPixmap("edit_move");
 	QPixmap m_toolOpen = embed::getIconPixmap("automation");
 	QPixmap m_toolKnife = embed::getIconPixmap("edit_knife");
+	QPixmap m_toolStrum = embed::getIconPixmap("arp_free");
 
 	static std::array<KeyType, 12> prKeyOrder;
 
@@ -437,6 +443,7 @@ private:
 	EditMode m_editMode;
 	EditMode m_ctrlMode; // mode they were in before they hit ctrl
 	EditMode m_knifeMode; // mode they where in before entering knife mode
+	EditMode m_strumMode; //< mode they where in before entering strum mode
 
 	bool m_mouseDownRight; //true if right click is being held down
 
@@ -465,6 +472,21 @@ private:
 
 	void updateKnifePos(QMouseEvent* me, bool initial);
 
+	//! Stores the chords for the strum tool
+	std::vector<NoteVector> m_selectedChords;
+	//! Computes which notes belong to which chords from the selection
+	void setupSelectedChords();
+
+	TimePos m_strumStartTime;
+	TimePos m_strumCurrentTime;
+	int m_strumStartVertical = 0;
+	int m_strumCurrentVertical = 0;
+	float m_strumHeightRatio = 0.0f;
+	bool m_strumEnabled = false;
+	//! Handles updating all of the note positions when performing a strum
+	void updateStrumPos(QMouseEvent* me, bool initial, bool warp);
+
+
 	friend class PianoRollWindow;
 
 	StepRecorderWidget m_stepRecorderWidget;