Improve performance for drag and drop

- Changing the style sheets for the selection frame dynamically considerably
  slowed down the handling of the mouse events.
  Instead two separate widgets with fixed style sheets are now used.
- Recreating the macro segments after dropping a widget took too much
  time leading to unresponsive drop operations

src/headers/advanced-scene-switcher.hpp

@@ -298,8 +298,6 @@ public slots:
 	void on_close_clicked();
 
 private:
-	void SetSelection(MacroSegmentList *, int);
-
 	MacroSegmentList *conditionsList = nullptr;
 	MacroSegmentList *actionsList = nullptr;
 

src/headers/macro-segment.hpp

@@ -62,8 +62,10 @@ signals:
 protected:
 	Section *_section;
 	QLabel *_headerInfo;
-	QFrame *_frame;
-	QVBoxLayout *_selectionFrameLayout;
+	QWidget *_frame;
+	QFrame *_noBorderframe;
+	QFrame *_borderFrame;
+	QVBoxLayout *_contentLayout;
 
 private:
 	virtual MacroSegment *Data() = 0;

src/macro-action-edit.cpp

@@ -80,14 +80,14 @@ MacroActionEdit::MacroActionEdit(QWidget *parent,
 	_section->AddHeaderWidget(_headerInfo);
 
 	QVBoxLayout *actionLayout = new QVBoxLayout;
-	actionLayout->setContentsMargins(0, 0, 0, 0);
-	actionLayout->setSpacing(0);
-	actionLayout->addWidget(_frame);
-	_selectionFrameLayout->addWidget(_section);
+	actionLayout->setContentsMargins({7, 7, 7, 7});
+	actionLayout->addWidget(_section);
+	_contentLayout->addLayout(actionLayout);
 
 	QHBoxLayout *mainLayout = new QHBoxLayout;
 	mainLayout->setContentsMargins(0, 0, 0, 0);
-	mainLayout->addLayout(actionLayout);
+	mainLayout->setSpacing(0);
+	mainLayout->addWidget(_frame);
 	setLayout(mainLayout);
 
 	_entryData = entryData;
@@ -316,8 +316,8 @@ void AdvSceneSwitcher::MacroActionSelectionChanged(int idx)
 		return;
 	}
 
-	SetSelection(actionsList, idx);
-	SetSelection(conditionsList, -1);
+	actionsList->SetSelection(idx);
+	conditionsList->SetSelection(-1);
 
 	if (idx < 0 || (unsigned)idx >= macro->Actions().size()) {
 		currentActionIdx = -1;
@@ -346,10 +346,7 @@ void AdvSceneSwitcher::MacroActionReorder(int to, int from)
 		macro->Actions().insert(macro->Actions().begin() + to, action);
 	}
 
-	int idx = to > from ? from : to;
 	macro->UpdateActionIndices();
-	actionsList->Clear(idx);
-	PopulateMacroActions(*macro, idx);
 	HighlightAction(to);
 	SetActionData(*macro);
 }

src/macro-condition-edit.cpp

@@ -125,14 +125,14 @@ MacroConditionEdit::MacroConditionEdit(
 	_section->AddHeaderWidget(_dur);
 
 	QVBoxLayout *conditionLayout = new QVBoxLayout;
-	conditionLayout->setContentsMargins(0, 0, 0, 0);
-	conditionLayout->setSpacing(0);
-	conditionLayout->addWidget(_frame);
-	_selectionFrameLayout->addWidget(_section);
+	conditionLayout->setContentsMargins({7, 7, 7, 7});
+	conditionLayout->addWidget(_section);
+	_contentLayout->addLayout(conditionLayout);
 
 	QHBoxLayout *mainLayout = new QHBoxLayout;
 	mainLayout->setContentsMargins(0, 0, 0, 0);
-	mainLayout->addLayout(conditionLayout);
+	mainLayout->setSpacing(0);
+	mainLayout->addWidget(_frame);
 	setLayout(mainLayout);
 
 	UpdateEntryData(id);
@@ -460,8 +460,8 @@ void AdvSceneSwitcher::MacroConditionSelectionChanged(int idx)
 		return;
 	}
 
-	SetSelection(conditionsList, idx);
-	SetSelection(actionsList, -1);
+	conditionsList->SetSelection(idx);
+	actionsList->SetSelection(-1);
 
 	if (idx < 0 || (unsigned)idx >= macro->Conditions().size()) {
 		currentConditionIdx = -1;
@@ -500,10 +500,7 @@ void AdvSceneSwitcher::MacroConditionReorder(int to, int from)
 					   condition);
 	}
 
-	int idx = to > from ? from : to;
 	macro->UpdateConditionIndices();
-	conditionsList->Clear(idx);
-	PopulateMacroConditions(*macro, idx);
 	HighlightCondition(to);
 	SetConditionData(*macro);
 }

src/macro-segment-list.cpp

@@ -157,11 +157,11 @@ void MacroSegmentList::mousePressEvent(QMouseEvent *event)
 void MacroSegmentList::mouseMoveEvent(QMouseEvent *event)
 {
 	if (event->buttons() & Qt::LeftButton && _dragPosition != -1) {
-		QWidget *widget = nullptr;
-		if (_contentLayout->itemAt(_dragPosition)) {
-			widget =
-				_contentLayout->itemAt(_dragPosition)->widget();
+		auto item = _contentLayout->itemAt(_dragPosition);
+		if (!item) {
+			return;
 		}
+		auto widget = item->widget();
 		if (!widget) {
 			return;
 		}
@@ -256,6 +256,8 @@ void MacroSegmentList::dropEvent(QDropEvent *event)
 		if (dropPosition == -1) {
 			return;
 		}
+		_contentLayout->insertItem(
+			dropPosition, _contentLayout->takeAt(_dragPosition));
 		emit Reorder(dropPosition, _dragPosition);
 	}
 	_dragPosition = -1;

src/macro-segment.cpp

@@ -56,17 +56,47 @@ bool MouseWheelWidgetAdjustmentGuard::eventFilter(QObject *o, QEvent *e)
 }
 
 MacroSegmentEdit::MacroSegmentEdit(bool highlight, QWidget *parent)
-	: QWidget(parent), _showHighlight(highlight)
+	: QWidget(parent),
+	  _showHighlight(highlight),
+	  _section(new Section(300)),
+	  _headerInfo(new QLabel()),
+	  _contentLayout(new QVBoxLayout),
+	  _frame(new QWidget),
+	  _borderFrame(new QFrame),
+	  _noBorderframe(new QFrame)
 {
-	_section = new Section(300);
-	_headerInfo = new QLabel();
+	// The reason for using two separate frame widget each with their own
+	// stylesheet and changing their visibility vs. using a single frame
+	// and changing the stylesheet at runtime is that the operation of
+	// adjusting the stylesheet is very expensive and can take multiple
+	// hundred milliseconds per widget.
+	// This performance impact would hurt in areas like drag and drop or
+	// emitting the "SelectionChanged" signal.
+	_borderFrame->setObjectName("border");
+	_borderFrame->setStyleSheet("#border {"
+				    "border-color: rgba(0, 0, 0, 255);"
+				    "border-width: 2px;"
+				    "border-style: dashed;"
+				    "border-radius: 4px;"
+				    "background-color: rgba(0,0,0,100);"
+				    "}");
+	_noBorderframe->setObjectName("noBorder");
+	_noBorderframe->setStyleSheet("#noBorder {"
+				      "border-color: rgba(0, 0, 0, 0);"
+				      "border-width: 2px;"
+				      "border-style: dashed;"
+				      "border-radius: 4px;"
+				      "background-color: rgba(0,0,0,50);"
+				      "}");
+	_frame->setObjectName("frameWrapper");
+	_frame->setStyleSheet("#frameWrapper {"
+			      "border-width: 2px;"
+			      "border-radius: 4px;"
+			      "background-color: rgba(0,0,0,0);"
+			      "}");
 
-	_frame = new QFrame;
-	_frame->setObjectName("segmentFrame");
-	_selectionFrameLayout = new QVBoxLayout;
-	SetSelected(false);
-	_frame->setLayout(_selectionFrameLayout);
-	// Set background transparent to avoid blocking highlight frame
+	// Set background of these widget types to be transparent to avoid
+	// blocking highlight frame background
 	setStyleSheet("QCheckBox { background-color: rgba(0,0,0,0); }"
 		      "QLabel { background-color: rgba(0,0,0,0); }"
 		      "QSlider { background-color: rgba(0,0,0,0); }");
@@ -75,9 +105,9 @@ MacroSegmentEdit::MacroSegmentEdit(bool highlight, QWidget *parent)
 	// the edit areas
 	setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
 
+	// Signal handling
 	QWidget::connect(_section, &Section::Collapsed, this,
 			 &MacroSegmentEdit::Collapsed);
-
 	// Macro signals
 	QWidget::connect(parent, SIGNAL(MacroAdded(const QString &)), this,
 			 SIGNAL(MacroAdded(const QString &)));
@@ -87,7 +117,6 @@ MacroSegmentEdit::MacroSegmentEdit(bool highlight, QWidget *parent)
 			 SIGNAL(MacroRenamed(const QString &, const QString)),
 			 this,
 			 SIGNAL(MacroRenamed(const QString &, const QString)));
-
 	// Scene group signals
 	QWidget::connect(parent, SIGNAL(SceneGroupAdded(const QString &)), this,
 			 SIGNAL(SceneGroupAdded(const QString &)));
@@ -98,6 +127,15 @@ MacroSegmentEdit::MacroSegmentEdit(bool highlight, QWidget *parent)
 		SIGNAL(SceneGroupRenamed(const QString &, const QString)), this,
 		SIGNAL(SceneGroupRenamed(const QString &, const QString)));
 
+	// Frame layout
+	auto layout = new QGridLayout;
+	layout->setContentsMargins(0, 0, 0, 0);
+	layout->addLayout(_contentLayout, 0, 0);
+	layout->addWidget(_noBorderframe, 0, 0);
+	layout->addWidget(_borderFrame, 0, 0);
+	_frame->setLayout(layout);
+	SetSelected(false);
+
 	_timer.setInterval(1500);
 	connect(&_timer, SIGNAL(timeout()), this, SLOT(Highlight()));
 	_timer.start();
@@ -153,21 +191,6 @@ void MacroSegmentEdit::SetCollapsed(bool collapsed)
 
 void MacroSegmentEdit::SetSelected(bool selected)
 {
-	if (selected) {
-		_frame->setStyleSheet("#segmentFrame {"
-				      "border-color: rgba(0, 0, 0, 255);"
-				      "border-width: 2px;"
-				      "border-style: dashed;"
-				      "border-radius: 4px;"
-				      "background-color: rgba(0,0,0,100);"
-				      "}");
-	} else {
-		_frame->setStyleSheet("#segmentFrame {"
-				      "border-color: rgba(0, 0, 0, 0);"
-				      "border-width: 2px;"
-				      "border-style: dashed;"
-				      "border-radius: 4px;"
-				      "background-color: rgba(0,0,0,50);"
-				      "}");
-	}
+	_borderFrame->setVisible(selected);
+	_noBorderframe->setVisible(!selected);
 }

src/macro-tab.cpp

@@ -601,11 +601,6 @@ void AdvSceneSwitcher::MinimizeConditions()
 	ui->macroSplitter->setSizes(sizes);
 }
 
-void AdvSceneSwitcher::SetSelection(MacroSegmentList *list, int idx)
-{
-	list->SetSelection(idx);
-}
-
 void AdvSceneSwitcher::DeleteMacroSegementHotkey()
 {
 	if (currentActionIdx != -1) {