Add Info TextFloat for Piano Roll Knife Tool (and make cut notes auto selected) (#7953)

* Adds an informative "TextFloat::displayMessage" when the knife tool is enabled.
* Automatically selects short ends if shift is not held down.

src/gui/editors/PianoRoll.cpp

@@ -2218,6 +2218,10 @@ void PianoRoll::setKnifeAction()
 		m_knifeDown = false;
 		setCursor(Qt::ArrowCursor);
 		update();
+
+		TextFloat::displayMessage(tr("Knife Tool"),
+			tr("Click and drag over notes to cut along a line\nHold Shift to automatically remove short ends"),
+			embed::getIconPixmap("edit_knife"), 4000);
 	}
 }
 

src/tracks/MidiClip.cpp

@@ -385,6 +385,10 @@ void MidiClip::splitNotesAlongLine(const NoteVector notes, TimePos pos1, int key
 			newNote2.setPos(keyIntercept);
 			newNote2.setLength(note->endPos() - keyIntercept);
 
+			// Select the short ends
+			if (newNote1.length() < newNote2.length()) { newNote1.setSelected(true); }
+			else { newNote2.setSelected(true); }
+
 			if (deleteShortEnds)
 			{
 				addNote(newNote1.length() >= newNote2.length() ? newNote1 : newNote2, false);