cabana: drag&drop to change chart order (#27832)

tools/cabana/chartswidget.cc

@@ -19,6 +19,7 @@
 #include <QtConcurrent>
 
 const int MAX_COLUMN_COUNT = 4;
+const QString mime_type = "application/x-cabanachartview";
 static inline bool xLessThan(const QPointF &p, float x) { return p.x() < x; }
 
 // ChartsWidget
@@ -75,14 +76,7 @@ ChartsWidget::ChartsWidget(QWidget *parent) : align_timer(this), auto_scroll_tim
   main_layout->addWidget(toolbar);
 
   // charts
-  charts_layout = new QGridLayout();
+  charts_container = new ChartsContainer(this);
-  charts_layout->setSpacing(10);
-
-  charts_container = new QWidget(this);
-  QVBoxLayout *charts_main_layout = new QVBoxLayout(charts_container);
-  charts_main_layout->setContentsMargins(0, 0, 0, 0);
-  charts_main_layout->addLayout(charts_layout);
-  charts_main_layout->addStretch(0);
 
   charts_scroll = new QScrollArea(this);
   charts_scroll->setFrameStyle(QFrame::NoFrame);
@@ -227,7 +221,7 @@ ChartView *ChartsWidget::createChart() {
   QObject::connect(chart, &ChartView::seriesAdded, this, &ChartsWidget::seriesChanged);
   QObject::connect(chart, &ChartView::axisYLabelWidthChanged, &align_timer, qOverload<>(&QTimer::start));
   QObject::connect(chart, &ChartView::hovered, this, &ChartsWidget::showValueTip);
-  charts.push_back(chart);
+  charts.push_front(chart);
   updateLayout();
   updateToolBar();
   return chart;
@@ -236,7 +230,7 @@ ChartView *ChartsWidget::createChart() {
 void ChartsWidget::showChart(const MessageId &id, const cabana::Signal *sig, bool show, bool merge) {
   ChartView *chart = findChart(id, sig);
   if (show && !chart) {
-    chart = merge && charts.size() > 0 ? charts.back() : createChart();
+    chart = merge && charts.size() > 0 ? charts.front() : createChart();
     chart->addSeries(id, sig);
   } else if (!show && chart) {
     chart->removeIf([&](auto &s) { return s.msg_id == id && s.sig == sig; });
@@ -252,7 +246,8 @@ void ChartsWidget::setColumnCount(int n) {
   }
 }
 
-void ChartsWidget::updateLayout() {
+void ChartsWidget::updateLayout(bool force) {
+  auto charts_layout = charts_container->charts_layout;
   int n = MAX_COLUMN_COUNT;
   for (; n > 1; --n) {
     if ((n * CHART_MIN_WIDTH + (n - 1) * charts_layout->spacing()) < charts_layout->geometry().width()) break;
@@ -262,13 +257,13 @@ void ChartsWidget::updateLayout() {
   columns_action->setVisible(show_column_cb);
 
   n = std::min(column_count, n);
-  if (charts.size() != charts_layout->count() || n != current_column_count) {
+  if ((charts.size() != charts_layout->count() || n != current_column_count) || force) {
     current_column_count = n;
-    charts_layout->parentWidget()->setUpdatesEnabled(false);
+    charts_container->setUpdatesEnabled(false);
     for (int i = 0; i < charts.size(); ++i) {
-      charts_layout->addWidget(charts[charts.size() - i - 1], i / n, i % n);
+      charts_layout->addWidget(charts[i], i / n, i % n);
     }
-    QTimer::singleShot(0, [this]() { charts_layout->parentWidget()->setUpdatesEnabled(true); });
+    QTimer::singleShot(0, [this]() { charts_container->setUpdatesEnabled(true); });
   }
 }
 
@@ -299,6 +294,13 @@ void ChartsWidget::doAutoScroll() {
   bool vertical_unchanged = value == scroll->value();
   if (vertical_unchanged) {
     stopAutoScroll();
+  } else {
+    // mouseMoveEvent to updates the drag-selection rectangle
+    const QPoint globalPos = charts_scroll->viewport()->mapToGlobal(pos);
+    const QPoint windowPos = charts_scroll->window()->mapFromGlobal(globalPos);
+    QMouseEvent mm(QEvent::MouseMove, pos, windowPos, globalPos,
+                   Qt::NoButton, Qt::LeftButton, Qt::NoModifier, Qt::MouseEventSynthesizedByQt);
+    QApplication::sendEvent(charts_scroll->viewport(), &mm);
   }
 }
 
@@ -423,7 +425,7 @@ ChartView::ChartView(const std::pair<double, double> &x_range, ChartsWidget *par
 
 void ChartView::createToolButtons() {
   move_icon = new QGraphicsPixmapItem(utils::icon("grip-horizontal"), chart());
-  move_icon->setToolTip(tr("Drag and drop to combine charts"));
+  move_icon->setToolTip(tr("Drag and drop to move chart"));
 
   QToolButton *remove_btn = toolButton("x", tr("Remove Chart"));
   close_btn_proxy = new QGraphicsProxyWidget(chart());
@@ -864,32 +866,23 @@ void ChartView::hideTip() {
 }
 
 void ChartView::dragEnterEvent(QDragEnterEvent *event) {
-  can_drop = event->source() != this;
+  if (event->mimeData()->hasFormat(mime_type)) {
-  viewport()->update();
+    drawDropIndicator(event->source() != this);
-  QChartView::dragEnterEvent(event);
+    event->acceptProposedAction();
-}
+  }
-void ChartView::dragLeaveEvent(QDragLeaveEvent *event) {
-  can_drop = false;
-  viewport()->update();
-  QChartView::dragLeaveEvent(event);
 }
 
 void ChartView::dragMoveEvent(QDragMoveEvent *event) {
   if (event->mimeData()->hasFormat(mime_type)) {
     event->setDropAction(event->source() == this ? Qt::MoveAction : Qt::CopyAction);
     event->accept();
-  } else {
-    event->ignore();
   }
   charts_widget->startAutoScroll();
 }
 
 void ChartView::dropEvent(QDropEvent *event) {
   if (event->mimeData()->hasFormat(mime_type)) {
-    if (event->source() == this) {
+    if (event->source() != this) {
-      event->setDropAction(Qt::MoveAction);
-      event->accept();
-    } else {
       ChartView *source_chart = (ChartView *)event->source();
       for (auto &s : source_chart->sigs) {
         source_chart->chart()->removeSeries(s.series);
@@ -906,8 +899,6 @@ void ChartView::dropEvent(QDropEvent *event) {
       event->acceptProposedAction();
     }
     can_drop = false;
-  } else {
-    event->ignore();
   }
 }
 
@@ -1199,3 +1190,55 @@ void ValueTipLabel::paintEvent(QPaintEvent *ev) {
   p.end();
   QLabel::paintEvent(ev);
 }
+
+// ChartsContainer
+
+ChartsContainer::ChartsContainer(ChartsWidget *parent) : charts_widget(parent), QWidget(parent) {
+  setAcceptDrops(true);
+  QVBoxLayout *charts_main_layout = new QVBoxLayout(this);
+  charts_main_layout->setContentsMargins(0, 0, 0, 0);
+  charts_layout = new QGridLayout();
+  charts_layout->setSpacing(10);
+  charts_main_layout->addLayout(charts_layout);
+  charts_main_layout->addStretch(0);
+}
+
+void ChartsContainer::dragEnterEvent(QDragEnterEvent *event) {
+  if (event->mimeData()->hasFormat(mime_type)) {
+    event->acceptProposedAction();
+    drawDropIndicator(event->pos());
+  }
+}
+
+void ChartsContainer::dropEvent(QDropEvent *event) {
+  if (event->mimeData()->hasFormat(mime_type)) {
+    auto w = getDropBefore(event->pos());
+    auto chart = qobject_cast<ChartView *>(event->source());
+    if (w != chart) {
+      charts_widget->charts.removeOne(chart);
+      int to = w ? charts_widget->charts.indexOf(w) : charts_widget->charts.size();
+      charts_widget->charts.insert(to, chart);
+      charts_widget->updateLayout(true);
+      event->acceptProposedAction();
+    }
+    drawDropIndicator({});
+  }
+}
+
+void ChartsContainer::paintEvent(QPaintEvent *ev) {
+  if (!drop_indictor_pos.isNull() && !childAt(drop_indictor_pos)) {
+    if (auto insert_after = getDropBefore(drop_indictor_pos)) {
+      auto area = insert_after->geometry();
+      QRect r = QRect(area.left(), area.top() - 10, area.width(), 10);
+      QPainter(this).fillRect(r, qApp->palette().highlight());
+    }
+  }
+}
+
+ChartView *ChartsContainer::getDropBefore(const QPoint &pos) const {
+  auto it = std::find_if(charts_widget->charts.cbegin(), charts_widget->charts.cend(), [&pos](auto c) {
+    auto area = c->geometry();
+    return pos.x() >= area.left() && pos.x() <= area.right() && pos.y() < area.top();
+  });
+  return it == charts_widget->charts.cend() ? nullptr : *it;
+}

tools/cabana/chartswidget.h

@@ -84,7 +84,7 @@ private:
   void mouseReleaseEvent(QMouseEvent *event) override;
   void mouseMoveEvent(QMouseEvent *ev) override;
   void dragEnterEvent(QDragEnterEvent *event) override;
-  void dragLeaveEvent(QDragLeaveEvent *event) override;
+  void dragLeaveEvent(QDragLeaveEvent *event) override { drawDropIndicator(false); }
   void dragMoveEvent(QDragMoveEvent *event) override;
   void dropEvent(QDropEvent *event) override;
   void leaveEvent(QEvent *event) override;
@@ -96,6 +96,7 @@ private:
   void paintEvent(QPaintEvent *event) override;
   void drawForeground(QPainter *painter, const QRectF &rect) override;
   void drawBackground(QPainter *painter, const QRectF &rect) override;
+  void drawDropIndicator(bool draw) { can_drop = draw; viewport()->update(); }
   std::tuple<double, double, int> getNiceAxisNumbers(qreal min, qreal max, int tick_count);
   qreal niceNumber(qreal x, bool ceiling);
   QXYSeries *createSeries(SeriesType type, QColor color);
@@ -113,7 +114,6 @@ private:
   ValueTipLabel tip_label;
   QList<SigItem> sigs;
   double cur_sec = 0;
-  const QString mime_type = "application/x-cabanachartview";
   SeriesType series_type = SeriesType::Line;
   bool is_scrubbing = false;
   bool resume_after_scrub = false;
@@ -122,7 +122,22 @@ private:
   double tooltip_x = -1;
   ChartsWidget *charts_widget;
   friend class ChartsWidget;
- };
+};
+
+class ChartsContainer : public QWidget {
+public:
+  ChartsContainer(ChartsWidget *parent);
+  void dragEnterEvent(QDragEnterEvent *event) override;
+  void dropEvent(QDropEvent *event) override;
+  void dragLeaveEvent(QDragLeaveEvent *event) override { drawDropIndicator({}); }
+  void drawDropIndicator(const QPoint &pt) { drop_indictor_pos = pt; update(); }
+  void paintEvent(QPaintEvent *ev) override;
+  ChartView *getDropBefore(const QPoint &pos) const;
+
+  QGridLayout *charts_layout;
+  ChartsWidget *charts_widget;
+  QPoint drop_indictor_pos;
+};
 
 class ChartsWidget : public QFrame {
   Q_OBJECT
@@ -158,7 +173,7 @@ private:
   void doAutoScroll();
   void updateToolBar();
   void setMaxChartRange(int value);
-  void updateLayout();
+  void updateLayout(bool force = false);
   void settingChanged();
   void showValueTip(double sec);
   bool eventFilter(QObject *obj, QEvent *event) override;
@@ -178,9 +193,8 @@ private:
   QUndoStack *zoom_undo_stack;
 
   QAction *remove_all_btn;
-  QGridLayout *charts_layout;
   QList<ChartView *> charts;
-  QWidget *charts_container;
+  ChartsContainer *charts_container;
   QScrollArea *charts_scroll;
   uint32_t max_chart_range = 0;
   bool is_zoomed = false;
@@ -194,6 +208,7 @@ private:
   QTimer align_timer;
   friend class ZoomCommand;
   friend class ChartView;
+  friend class ChartsContainer;
 };
 
 class ZoomCommand : public QUndoCommand {