Improve drag & drop behaviour of macro segments

- Depending on the drop position you can either drop before or after a
  widget
- Added a visual indicator where the macro segment will be dropped

src/headers/macro-segment-list.hpp

@@ -31,15 +31,22 @@ protected:
 	void mousePressEvent(QMouseEvent *event);
 	void mouseMoveEvent(QMouseEvent *event);
 	void mouseReleaseEvent(QMouseEvent *event);
+	void dragLeaveEvent(QDragLeaveEvent *event);
 	void dragEnterEvent(QDragEnterEvent *event);
+	void dragMoveEvent(QDragMoveEvent *event);
 	void dropEvent(QDropEvent *event);
 
 private:
-	int GetIndex(QPoint);
-	int GetDropIndex(QPoint);
+	int GetDragIndex(const QPoint &);
+	int GetDropIndex(const QPoint &);
+	int GetWidgetIdx(const QPoint &);
+	bool IsInListArea(const QPoint &);
 	QRect GetContentItemRectWithPadding(int idx);
+	void HideLastDropLine();
+	MacroSegmentEdit *WidgetAt(int idx);
 
 	int _dragPosition = -1;
+	int _dropLineIdx = -1;
 
 	QVBoxLayout *_layout;
 	QVBoxLayout *_contentLayout;

src/headers/macro-segment.hpp

@@ -63,15 +63,38 @@ protected:
 	Section *_section;
 	QLabel *_headerInfo;
 	QWidget *_frame;
-	QFrame *_noBorderframe;
-	QFrame *_borderFrame;
 	QVBoxLayout *_contentLayout;
 
 private:
+	enum class DropLineState {
+		NONE,
+		ABOVE,
+		BELOW,
+	};
+
 	virtual MacroSegment *Data() = 0;
+	void ShowDropLine(DropLineState);
+
+	// 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.
+	QFrame *_noBorderframe;
+	QFrame *_borderFrame;
+
+	// In most cases the line above the widget will be used.
+	// The lower one will only be used if the segment is the last one in
+	// the list.
+	QFrame *_dropLineAbove;
+	QFrame *_dropLineBelow;
 
 	bool _showHighlight;
 	QTimer _timer;
+
+	friend class MacroSegmentList;
 };
 
 class MouseWheelWidgetAdjustmentGuard : public QObject {

src/macro-segment-list.cpp

@@ -17,7 +17,7 @@ MacroSegmentList::MacroSegmentList(QWidget *parent)
 {
 	_helpMsg->setWordWrap(true);
 	_helpMsg->setAlignment(Qt::AlignCenter);
-
+	_contentLayout->setSpacing(0);
 	auto helperLayout = new QGridLayout();
 	helperLayout->addWidget(_helpMsg, 0, 0,
 				Qt::AlignHCenter | Qt::AlignVCenter);
@@ -33,7 +33,7 @@ MacroSegmentList::MacroSegmentList(QWidget *parent)
 	setAcceptDrops(true);
 }
 
-int MacroSegmentList::GetIndex(QPoint pos)
+int MacroSegmentList::GetDragIndex(const QPoint &pos)
 {
 	for (int idx = 0; idx < _contentLayout->count(); ++idx) {
 		auto item = _contentLayout->itemAt(idx);
@@ -49,7 +49,7 @@ int MacroSegmentList::GetIndex(QPoint pos)
 			mapToGlobal(QPoint(geo.topLeft().x(),
 					   geo.topLeft().y() - scrollOffset)),
 			geo.size());
-		if (rect.contains(pos) && idx != _dragPosition) {
+		if (rect.contains(pos)) {
 			return idx;
 		}
 	}
@@ -147,7 +147,7 @@ bool MacroSegmentList::eventFilter(QObject *object, QEvent *event)
 void MacroSegmentList::mousePressEvent(QMouseEvent *event)
 {
 	if (event->button() == Qt::LeftButton) {
-		_dragPosition = GetIndex(event->globalPos());
+		_dragPosition = GetDragIndex(event->globalPos());
 		emit SelectionChagned(_dragPosition);
 	} else {
 		_dragPosition = -1;
@@ -181,6 +181,11 @@ void MacroSegmentList::mouseReleaseEvent(QMouseEvent *)
 	_dragPosition = -1;
 }
 
+void MacroSegmentList::dragLeaveEvent(QDragLeaveEvent *)
+{
+	HideLastDropLine();
+}
+
 void MacroSegmentList::dragEnterEvent(QDragEnterEvent *event)
 {
 	if (event->mimeData() && event->mimeData()->hasImage()) {
@@ -190,6 +195,103 @@ void MacroSegmentList::dragEnterEvent(QDragEnterEvent *event)
 	}
 }
 
+MacroSegmentEdit *MacroSegmentList::WidgetAt(int idx)
+{
+	if (idx < 0 || idx >= _contentLayout->count()) {
+		return nullptr;
+	}
+	auto item = _contentLayout->itemAt(idx);
+	if (!item) {
+		return nullptr;
+	}
+	return static_cast<MacroSegmentEdit *>(item->widget());
+}
+
+void MacroSegmentList::HideLastDropLine()
+{
+	if (_dropLineIdx >= 0 && _dropLineIdx < _contentLayout->count()) {
+		auto widget = WidgetAt(_dropLineIdx);
+		if (widget) {
+			widget->ShowDropLine(
+				MacroSegmentEdit::DropLineState::NONE);
+		}
+	}
+	_dropLineIdx = -1;
+}
+
+bool isInUpperHalfOf(const QPoint &pos, const QRect &rect)
+{
+	return QRect(rect.topLeft(),
+		     QSize(rect.size().width(), rect.size().height() / 2))
+		.contains(pos);
+}
+
+bool widgetIsInLayout(QWidget *w, QLayout *l)
+{
+	if (w == nullptr) {
+		return false;
+	}
+	for (int i = 0; i < l->count(); ++i) {
+		auto item = l->itemAt(i);
+		if (!item) {
+			continue;
+		}
+		if (item->widget() == w) {
+			return true;
+		}
+	}
+	return false;
+}
+
+void MacroSegmentList::dragMoveEvent(QDragMoveEvent *event)
+{
+	auto widget = qobject_cast<QWidget *>(event->source());
+	if (!widgetIsInLayout(widget, _contentLayout)) {
+		return;
+	}
+	const QPoint pos(mapToGlobal(event->pos()));
+	int idx = GetWidgetIdx(pos);
+	if (idx == _dragPosition) {
+		return;
+	}
+	auto action = MacroSegmentEdit::DropLineState::ABOVE;
+	if (idx == -1) {
+		if (IsInListArea(pos)) {
+			idx = _contentLayout->count() - 1;
+			action = MacroSegmentEdit::DropLineState::BELOW;
+		} else {
+			HideLastDropLine();
+			return;
+		}
+	} else {
+		auto rect = GetContentItemRectWithPadding(idx);
+		if (idx == _contentLayout->count() - 1 &&
+		    !isInUpperHalfOf(pos, rect)) {
+			action = MacroSegmentEdit::DropLineState::BELOW;
+		} else {
+			if (!isInUpperHalfOf(pos, rect)) {
+				idx++;
+			}
+		}
+	}
+	if (idx == _dragPosition ||
+	    (idx - 1 == _dragPosition &&
+	     action != MacroSegmentEdit::DropLineState::BELOW)) {
+		HideLastDropLine();
+		return;
+	}
+	auto widget = WidgetAt(idx);
+	if (!widget) {
+		HideLastDropLine();
+		return;
+	}
+	widget->ShowDropLine(action);
+	if (_dropLineIdx != idx) {
+		HideLastDropLine();
+		_dropLineIdx = idx;
+	}
+}
+
 QRect MacroSegmentList::GetContentItemRectWithPadding(int idx)
 {
 	auto item = _contentLayout->itemAt(idx);
@@ -202,21 +304,18 @@ QRect MacroSegmentList::GetContentItemRectWithPadding(int idx)
 	}
 	const QRect itemRect = item->geometry().marginsAdded(
 		_contentLayout->contentsMargins());
-	const QRect rect(mapToGlobal(QPoint(itemRect.topLeft().x(),
-					    itemRect.topLeft().y() -
-						    _contentLayout->spacing() -
-						    scrollOffset)),
-			 itemRect.size());
+	const QRect rect(
+		mapToGlobal(QPoint(itemRect.topLeft().x(),
+				   itemRect.topLeft().y() -
+					   _contentLayout->spacing() -
+					   scrollOffset)),
+		QSize(itemRect.size().width(),
+		      itemRect.size().height() + _contentLayout->spacing()));
 	return rect;
 }
 
-int MacroSegmentList::GetDropIndex(QPoint pos)
+int MacroSegmentList::GetWidgetIdx(const QPoint &pos)
 {
-	const QRect layoutRect(mapToGlobal(_layout->contentsRect().topLeft()),
-			       _layout->contentsRect().size());
-	if (!layoutRect.contains(pos)) {
-		return -1;
-	}
 	int idx = -1;
 	for (int i = 0; i < _contentLayout->count(); ++i) {
 		if (GetContentItemRectWithPadding(i).contains(pos)) {
@@ -224,31 +323,46 @@ int MacroSegmentList::GetDropIndex(QPoint pos)
 			break;
 		}
 	}
-	if (idx == -1) {
-		idx = _contentLayout->count() - 1;
-	}
-	if (idx != _dragPosition) {
-		return idx;
-	}
-	return -1;
+	return idx;
 }
 
-bool widgetIsInLayout(QWidget *w, QLayout *l)
+bool MacroSegmentList::IsInListArea(const QPoint &pos)
 {
-	for (int i = 0; i < l->count(); ++i) {
-		auto item = l->itemAt(i);
-		if (!item) {
-			continue;
-		}
-		if (item->widget() == w) {
-			return true;
-		}
+	const QRect layoutRect(mapToGlobal(_layout->contentsRect().topLeft()),
+			       _layout->contentsRect().size());
+	return layoutRect.contains(pos);
+}
+
+int MacroSegmentList::GetDropIndex(const QPoint &pos)
+{
+	int idx = GetWidgetIdx(pos);
+	if (idx == _dragPosition) {
+		return -1;
 	}
-	return false;
+	if (idx == -1) {
+		if (IsInListArea(pos)) {
+			return _contentLayout->count() - 1;
+		}
+		return -1;
+	}
+	auto rect = GetContentItemRectWithPadding(idx);
+	if (idx == _contentLayout->count() - 1 && !isInUpperHalfOf(pos, rect)) {
+		return idx;
+	} else if (!isInUpperHalfOf(pos, rect)) {
+		idx++;
+	}
+	if (_dragPosition < idx) {
+		idx--;
+	}
+	if (idx == _dragPosition) {
+		return -1;
+	}
+	return idx;
 }
 
 void MacroSegmentList::dropEvent(QDropEvent *event)
 {
+	HideLastDropLine();
 	auto widget = qobject_cast<QWidget *>(event->source());
 	if (widget && !widget->geometry().contains(event->pos()) &&
 	    widgetIsInLayout(widget, _contentLayout)) {

src/macro-segment.cpp

@@ -63,15 +63,15 @@ MacroSegmentEdit::MacroSegmentEdit(bool highlight, QWidget *parent)
 	  _contentLayout(new QVBoxLayout),
 	  _frame(new QWidget),
 	  _borderFrame(new QFrame),
-	  _noBorderframe(new QFrame)
+	  _noBorderframe(new QFrame),
+	  _dropLineAbove(new QFrame),
+	  _dropLineBelow(new QFrame)
 {
-	// 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.
+	_dropLineAbove->setLineWidth(3);
+	_dropLineAbove->setFixedHeight(11);
+	_dropLineBelow->setLineWidth(3);
+	_dropLineBelow->setFixedHeight(11);
+
 	_borderFrame->setObjectName("border");
 	_borderFrame->setStyleSheet("#border {"
 				    "border-color: rgba(0, 0, 0, 255);"
@@ -105,7 +105,6 @@ 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
@@ -127,14 +126,21 @@ 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;
+	auto frameLayout = new QGridLayout;
+	frameLayout->setContentsMargins(0, 0, 0, 0);
+	frameLayout->addLayout(_contentLayout, 0, 0);
+	frameLayout->addWidget(_noBorderframe, 0, 0);
+	frameLayout->addWidget(_borderFrame, 0, 0);
+	auto layout = new QVBoxLayout;
 	layout->setContentsMargins(0, 0, 0, 0);
-	layout->addLayout(_contentLayout, 0, 0);
-	layout->addWidget(_noBorderframe, 0, 0);
-	layout->addWidget(_borderFrame, 0, 0);
+	layout->setSpacing(0);
+	layout->addWidget(_dropLineAbove);
+	layout->addLayout(frameLayout);
+	layout->addWidget(_dropLineBelow);
 	_frame->setLayout(layout);
+
 	SetSelected(false);
+	ShowDropLine(DropLineState::NONE);
 
 	_timer.setInterval(1500);
 	connect(&_timer, SIGNAL(timeout()), this, SLOT(Highlight()));
@@ -194,3 +200,28 @@ void MacroSegmentEdit::SetSelected(bool selected)
 	_borderFrame->setVisible(selected);
 	_noBorderframe->setVisible(!selected);
 }
+
+void MacroSegmentEdit::ShowDropLine(DropLineState state)
+{
+	switch (state) {
+	case MacroSegmentEdit::DropLineState::NONE:
+		_dropLineAbove->setFrameShadow(QFrame::Plain);
+		_dropLineAbove->setFrameShape(QFrame::NoFrame);
+		_dropLineBelow->hide();
+		break;
+	case MacroSegmentEdit::DropLineState::ABOVE:
+		_dropLineAbove->setFrameShadow(QFrame::Sunken);
+		_dropLineAbove->setFrameShape(QFrame::Panel);
+		_dropLineBelow->hide();
+		break;
+	case MacroSegmentEdit::DropLineState::BELOW:
+		_dropLineAbove->setFrameShadow(QFrame::Plain);
+		_dropLineAbove->setFrameShape(QFrame::NoFrame);
+		_dropLineBelow->setFrameShadow(QFrame::Sunken);
+		_dropLineBelow->setFrameShape(QFrame::Panel);
+		_dropLineBelow->show();
+		break;
+	default:
+		break;
+	}
+}