cabana: fix unable to scroll to the right edge of the message list. (#27947)

* fix scroll issue

* resize bytes section after model reset

tools/cabana/messageswidget.cc

@@ -62,6 +62,7 @@ MessagesWidget::MessagesWidget(QWidget *parent) : QWidget(parent) {
     if (current_msg_id) {
       selectMessage(*current_msg_id);
     }
+    view->updateBytesSectionSize();
   });
   QObject::connect(view->selectionModel(), &QItemSelectionModel::currentChanged, [=](const QModelIndex &current, const QModelIndex &previous) {
     if (current.isValid() && current.row() < model->msgs.size()) {
@@ -296,7 +297,21 @@ void MessageView::drawRow(QPainter *painter, const QStyleOptionViewItem &option,
 }
 
 void MessageView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles) {
-   // Bypass the slow call to QTreeView::dataChanged.
-   // QTreeView::dataChanged will invalidate the height cache and that's what we don't need in MessageView.
-   QAbstractItemView::dataChanged(topLeft, bottomRight, roles);
+  // Bypass the slow call to QTreeView::dataChanged.
+  // QTreeView::dataChanged will invalidate the height cache and that's what we don't need in MessageView.
+  QAbstractItemView::dataChanged(topLeft, bottomRight, roles);
+}
+
+void MessageView::updateBytesSectionSize() {
+  auto delegate = ((MessageBytesDelegate *)itemDelegate());
+  int max_bytes = 8;
+  if (!delegate->multipleLines()) {
+    for (auto it = can->last_msgs.constBegin(); it != can->last_msgs.constEnd(); ++it) {
+      max_bytes = std::max(max_bytes, it.value().dat.size());
+    }
+  }
+  int width = delegate->widthForBytes(max_bytes);
+  if (header()->sectionSize(5) != width) {
+    header()->resizeSection(5, width);
+  }
 }

tools/cabana/messageswidget.h

@@ -42,6 +42,7 @@ public:
   void drawRow(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
   void drawBranches(QPainter *painter, const QRect &rect, const QModelIndex &index) const override {}
   void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles = QVector<int>()) override;
+  void updateBytesSectionSize();
 };
 
 class MessagesWidget : public QWidget {

tools/cabana/util.cc

@@ -53,6 +53,11 @@ void MessageBytesDelegate::setMultipleLines(bool v) {
   }
 }
 
+int MessageBytesDelegate::widthForBytes(int n) const {
+  int h_margin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
+  return n * byte_size.width() + h_margin * 2;
+}
+
 QSize MessageBytesDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const {
   int v_margin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameVMargin) + 1;
   auto data = index.data(BytesRole);
@@ -64,12 +69,11 @@ QSize MessageBytesDelegate::sizeHint(const QStyleOptionViewItem &option, const Q
 
   QSize size = size_cache[n - 1];
   if (size.isEmpty()) {
-    int h_margin = QApplication::style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
     if (!multiple_lines) {
-      size.setWidth(h_margin * 2 + n * byte_size.width());
+      size.setWidth(widthForBytes(n));
       size.setHeight(byte_size.height() + 2 * v_margin);
     } else {
-      size.setWidth(h_margin * 2 + 8 * byte_size.width());
+      size.setWidth(widthForBytes(8));
       size.setHeight(byte_size.height() * std::max(1, n / 8) + 2 * v_margin);
     }
     size_cache[n - 1] = size;

tools/cabana/util.h

@@ -69,6 +69,8 @@ public:
   QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override;
   bool helpEvent(QHelpEvent *event, QAbstractItemView *view, const QStyleOptionViewItem &option, const QModelIndex &index) override;
   void setMultipleLines(bool v);
+  int widthForBytes(int n) const;
+  bool multipleLines() const { return multiple_lines; }
 
 private:
   QFont fixed_font;