Qt: Add a packet diagram view.

Add a new top-level view that shows each packet as a series of diagrams
similar to what you'd find in a networking textook or an RFC.

Add proto_item_set_bits_offset_len so that we can display some diagram
fields correctly.

Bugs / to do:
  - Make this a separate dialog instead of a main window view?
  - Handle bitfields / flags

Change-Id: Iba4897a5bf1dcd73929dde6210d5483cf07f54df
Reviewed-on: https://code.wireshark.org/review/37497
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

19 files changed, 972 insertions, 32 deletions

diff --git a/ui/qt/CMakeLists.txt b/ui/qt/CMakeLists.txt
index 2903124d10..c7751bc87b 100644
--- a/ui/qt/CMakeLists.txt
+++ b/ui/qt/CMakeLists.txt
@@ -181,6 +181,7 @@ set(WIRESHARK_QT_HEADERS
 	mtp3_summary_dialog.h
 	multicast_statistics_dialog.h
 	packet_comment_dialog.h
+	packet_diagram.h
 	packet_dialog.h
 	packet_format_group_box.h
 	packet_list.h
@@ -406,6 +407,7 @@ set(WIRESHARK_QT_SRC
 	manage_interfaces_dialog.cpp
 	module_preferences_scroll_area.cpp
 	packet_comment_dialog.cpp
+	packet_diagram.cpp
 	packet_dialog.cpp
 	packet_format_group_box.cpp
 	packet_list.cpp
diff --git a/ui/qt/io_graph_dialog.cpp b/ui/qt/io_graph_dialog.cpp
index fde5f4fdc9..e5c6c73efe 100644
--- a/ui/qt/io_graph_dialog.cpp
+++ b/ui/qt/io_graph_dialog.cpp
@@ -1462,7 +1462,7 @@ void IOGraphDialog::on_buttonBox_helpRequested()
     wsApp->helpTopicAction(HELP_STATS_IO_GRAPH_DIALOG);
 }
 
-// XXX - Copied from tcp_stream_dialog. This should be common code.
+// XXX - We have similar code in tcp_stream_dialog and packet_diagram. Should this be a common routine?
 void IOGraphDialog::on_buttonBox_accepted()
 {
     QString file_name, extension;
diff --git a/ui/qt/layout_preferences_frame.cpp b/ui/qt/layout_preferences_frame.cpp
index bef7507062..a1bf03c5b5 100644
--- a/ui/qt/layout_preferences_frame.cpp
+++ b/ui/qt/layout_preferences_frame.cpp
@@ -106,6 +106,9 @@ void LayoutPreferencesFrame::updateWidgets()
     case layout_pane_content_pbytes:
         ui->pane1PacketBytesRadioButton->setChecked(true);
         break;
+    case layout_pane_content_pdiagram:
+        ui->pane1PacketDiagramRadioButton->setChecked(true);
+        break;
     case layout_pane_content_none:
         ui->pane1NoneRadioButton->setChecked(true);
         break;
@@ -121,6 +124,9 @@ void LayoutPreferencesFrame::updateWidgets()
     case layout_pane_content_pbytes:
         ui->pane2PacketBytesRadioButton->setChecked(true);
         break;
+    case layout_pane_content_pdiagram:
+        ui->pane2PacketDiagramRadioButton->setChecked(true);
+        break;
     case layout_pane_content_none:
         ui->pane2NoneRadioButton->setChecked(true);
         break;
@@ -136,6 +142,9 @@ void LayoutPreferencesFrame::updateWidgets()
     case layout_pane_content_pbytes:
         ui->pane3PacketBytesRadioButton->setChecked(true);
         break;
+    case layout_pane_content_pdiagram:
+        ui->pane3PacketDiagramRadioButton->setChecked(true);
+        break;
     case layout_pane_content_none:
         ui->pane3NoneRadioButton->setChecked(true);
         break;
@@ -208,6 +217,16 @@ void LayoutPreferencesFrame::on_pane1PacketBytesRadioButton_toggled(bool checked
         ui->pane3NoneRadioButton->click();
 }
 
+void LayoutPreferencesFrame::on_pane1PacketDiagramRadioButton_toggled(bool checked)
+{
+    if (!checked) return;
+    prefs_set_enum_value(pref_layout_content_1_, layout_pane_content_pdiagram, pref_stashed);
+    if (ui->pane2PacketDiagramRadioButton->isChecked())
+        ui->pane2NoneRadioButton->click();
+    if (ui->pane3PacketDiagramRadioButton->isChecked())
+        ui->pane3NoneRadioButton->click();
+}
+
 void LayoutPreferencesFrame::on_pane1NoneRadioButton_toggled(bool checked)
 {
     if (!checked) return;
@@ -244,6 +263,16 @@ void LayoutPreferencesFrame::on_pane2PacketBytesRadioButton_toggled(bool checked
         ui->pane3NoneRadioButton->click();
 }
 
+void LayoutPreferencesFrame::on_pane2PacketDiagramRadioButton_toggled(bool checked)
+{
+    if (!checked) return;
+    prefs_set_enum_value(pref_layout_content_2_, layout_pane_content_pdiagram, pref_stashed);
+    if (ui->pane1PacketDiagramRadioButton->isChecked())
+        ui->pane1NoneRadioButton->click();
+    if (ui->pane3PacketDiagramRadioButton->isChecked())
+        ui->pane3NoneRadioButton->click();
+}
+
 void LayoutPreferencesFrame::on_pane2NoneRadioButton_toggled(bool checked)
 {
     if (!checked) return;
@@ -280,6 +309,16 @@ void LayoutPreferencesFrame::on_pane3PacketBytesRadioButton_toggled(bool checked
         ui->pane2NoneRadioButton->click();
 }
 
+void LayoutPreferencesFrame::on_pane3PacketDiagramRadioButton_toggled(bool checked)
+{
+    if (!checked) return;
+    prefs_set_enum_value(pref_layout_content_3_, layout_pane_content_pdiagram, pref_stashed);
+    if (ui->pane1PacketDiagramRadioButton->isChecked())
+        ui->pane1NoneRadioButton->click();
+    if (ui->pane2PacketDiagramRadioButton->isChecked())
+        ui->pane2NoneRadioButton->click();
+}
+
 void LayoutPreferencesFrame::on_pane3NoneRadioButton_toggled(bool checked)
 {
     if (!checked) return;
diff --git a/ui/qt/layout_preferences_frame.h b/ui/qt/layout_preferences_frame.h
index 246e8c6060..342f3cf5b4 100644
--- a/ui/qt/layout_preferences_frame.h
+++ b/ui/qt/layout_preferences_frame.h
@@ -54,14 +54,17 @@ private slots:
     void on_pane1PacketListRadioButton_toggled(bool checked);
     void on_pane1PacketDetailsRadioButton_toggled(bool checked);
     void on_pane1PacketBytesRadioButton_toggled(bool checked);
+    void on_pane1PacketDiagramRadioButton_toggled(bool checked);
     void on_pane1NoneRadioButton_toggled(bool checked);
     void on_pane2PacketListRadioButton_toggled(bool checked);
     void on_pane2PacketDetailsRadioButton_toggled(bool checked);
     void on_pane2PacketBytesRadioButton_toggled(bool checked);
+    void on_pane2PacketDiagramRadioButton_toggled(bool checked);
     void on_pane2NoneRadioButton_toggled(bool checked);
     void on_pane3PacketListRadioButton_toggled(bool checked);
     void on_pane3PacketDetailsRadioButton_toggled(bool checked);
     void on_pane3PacketBytesRadioButton_toggled(bool checked);
+    void on_pane3PacketDiagramRadioButton_toggled(bool checked);
     void on_pane3NoneRadioButton_toggled(bool checked);
     void on_restoreButtonBox_clicked(QAbstractButton *button);
     void on_packetListSeparatorCheckBox_toggled(bool checked);
diff --git a/ui/qt/layout_preferences_frame.ui b/ui/qt/layout_preferences_frame.ui
index 02d03045cb..0ce09cad74 100644
--- a/ui/qt/layout_preferences_frame.ui
+++ b/ui/qt/layout_preferences_frame.ui
@@ -213,6 +213,16 @@
         </widget>
        </item>
        <item>
+        <widget class="QRadioButton" name="pane1PacketDiagramRadioButton">
+         <property name="text">
+          <string>Packet Diagram</string>
+         </property>
+         <attribute name="buttonGroup">
+          <string notr="true">pane1ButtonGroup</string>
+         </attribute>
+        </widget>
+       </item>
+       <item>
         <widget class="QRadioButton" name="pane1NoneRadioButton">
          <property name="text">
           <string>None</string>
@@ -264,6 +274,16 @@
         </widget>
        </item>
        <item>
+        <widget class="QRadioButton" name="pane2PacketDiagramRadioButton">
+         <property name="text">
+          <string>Packet Diagram</string>
+         </property>
+         <attribute name="buttonGroup">
+          <string notr="true">pane2ButtonGroup</string>
+         </attribute>
+        </widget>
+       </item>
+       <item>
         <widget class="QRadioButton" name="pane2NoneRadioButton">
          <property name="text">
           <string>None</string>
@@ -315,6 +335,16 @@
         </widget>
        </item>
        <item>
+        <widget class="QRadioButton" name="pane3PacketDiagramRadioButton">
+         <property name="text">
+          <string>Packet Diagram</string>
+         </property>
+         <attribute name="buttonGroup">
+          <string notr="true">pane3ButtonGroup</string>
+         </attribute>
+        </widget>
+       </item>
+       <item>
         <widget class="QRadioButton" name="pane3NoneRadioButton">
          <property name="text">
           <string>None</string>
diff --git a/ui/qt/main_window.cpp b/ui/qt/main_window.cpp
index 4cb3ef5cf9..4c1a7c0243 100644
--- a/ui/qt/main_window.cpp
+++ b/ui/qt/main_window.cpp
@@ -57,6 +57,7 @@ DIAG_ON(frame-larger-than=)
 #include "funnel_statistics.h"
 #include "import_text_dialog.h"
 #include "interface_toolbar.h"
+#include "packet_diagram.h"
 #include "packet_list.h"
 #include "proto_tree.h"
 #include "simple_dialog.h"
@@ -466,20 +467,23 @@ MainWindow::MainWindow(QWidget *parent) :
     packet_list_->setProtoTree(proto_tree_);
     packet_list_->installEventFilter(this);
 
+    packet_diagram_ = new PacketDiagram(&master_split_);
+
     welcome_page_ = main_ui_->welcomePage;
 
-    connect(proto_tree_, SIGNAL(fieldSelected(FieldInformation *)),
-            this, SIGNAL(fieldSelected(FieldInformation *)));
-    connect(packet_list_, SIGNAL(fieldSelected(FieldInformation *)),
-            this, SIGNAL(fieldSelected(FieldInformation *)));
-    connect(this, SIGNAL(fieldSelected(FieldInformation *)),
-            this, SLOT(setMenusForSelectedTreeRow(FieldInformation *)));
-    connect(this, SIGNAL(fieldSelected(FieldInformation *)),
-            main_ui_->statusBar, SLOT(selectedFieldChanged(FieldInformation *)));
+    connect(proto_tree_, &ProtoTree::fieldSelected,
+            this, &MainWindow::fieldSelected);
+    connect(packet_list_, &PacketList::fieldSelected,
+            this, &MainWindow::fieldSelected);
+    connect(this, &MainWindow::fieldSelected,
+            this, &MainWindow::setMenusForSelectedTreeRow);
+    connect(this, &MainWindow::fieldSelected,
+            main_ui_->statusBar, &MainStatusBar::selectedFieldChanged);
 
-    connect(this, SIGNAL(fieldHighlight(FieldInformation *)),
-            main_ui_->statusBar, SLOT(highlightedFieldChanged(FieldInformation *)));
-    connect(wsApp, SIGNAL(captureActive(int)), this, SIGNAL(captureActive(int)));
+    connect(this, &MainWindow::fieldHighlight,
+            main_ui_->statusBar, &MainStatusBar::highlightedFieldChanged);
+    connect(wsApp, &WiresharkApplication::captureActive,
+            this, &MainWindow::captureActive);
 
     byte_view_tab_ = new ByteViewTab(&master_split_);
 
@@ -543,14 +547,14 @@ MainWindow::MainWindow(QWidget *parent) :
             filter_expression_toolbar_, &FilterExpressionToolBar::filterExpressionsChanged);
 
     /* Connect change of capture file */
-    connect(this, SIGNAL(setCaptureFile(capture_file*)),
-            main_ui_->searchFrame, SLOT(setCaptureFile(capture_file*)));
-    connect(this, SIGNAL(setCaptureFile(capture_file*)),
-            main_ui_->statusBar, SLOT(setCaptureFile(capture_file*)));
-    connect(this, SIGNAL(setCaptureFile(capture_file*)),
-            packet_list_, SLOT(setCaptureFile(capture_file*)));
-    connect(this, SIGNAL(setCaptureFile(capture_file*)),
-            proto_tree_, SLOT(setCaptureFile(capture_file*)));
+    connect(this, &MainWindow::setCaptureFile,
+            main_ui_->searchFrame, &SearchFrame::setCaptureFile);
+    connect(this, &MainWindow::setCaptureFile,
+            main_ui_->statusBar, &MainStatusBar::setCaptureFile);
+    connect(this, &MainWindow::setCaptureFile,
+            packet_list_, &PacketList::setCaptureFile);
+    connect(this, &MainWindow::setCaptureFile,
+            proto_tree_, &ProtoTree::setCaptureFile);
 
     connect(wsApp, SIGNAL(zoomMonospaceFont(QFont)),
             packet_list_, SLOT(setMonospaceFont(QFont)));
@@ -701,6 +705,7 @@ QMenu *MainWindow::createPopupMenu()
     menu->addAction(main_ui_->actionViewPacketList);
     menu->addAction(main_ui_->actionViewPacketDetails);
     menu->addAction(main_ui_->actionViewPacketBytes);
+    menu->addAction(main_ui_->actionViewPacketDiagram);
     return menu;
 }
 
@@ -2058,6 +2063,7 @@ void MainWindow::initShowHideMainWidgets()
     shmw_actions[main_ui_->actionViewPacketList] = packet_list_;
     shmw_actions[main_ui_->actionViewPacketDetails] = proto_tree_;
     shmw_actions[main_ui_->actionViewPacketBytes] = byte_view_tab_;
+    shmw_actions[main_ui_->actionViewPacketDiagram] = packet_diagram_;
 
     foreach(QAction *shmwa, shmw_actions.keys()) {
         shmwa->setData(QVariant::fromValue(shmw_actions[shmwa]));
diff --git a/ui/qt/main_window.h b/ui/qt/main_window.h
index e1125c816b..74f4a68068 100644
--- a/ui/qt/main_window.h
+++ b/ui/qt/main_window.h
@@ -85,6 +85,7 @@ class FilterDialog;
 class FunnelStatistics;
 class WelcomePage;
 class PacketCommentDialog;
+class PacketDiagram;
 class PacketList;
 class ProtoTree;
 #if defined(HAVE_LIBNL) && defined(HAVE_NL80211)
@@ -191,7 +192,8 @@ private:
     // probably be full-on values instead of pointers.
     PacketList *packet_list_;
     ProtoTree *proto_tree_;
-    ByteViewTab * byte_view_tab_;
+    ByteViewTab *byte_view_tab_;
+    PacketDiagram *packet_diagram_;
     QWidget *previous_focus_;
     FileSetDialog *file_set_dialog_;
     QWidget empty_pane_;
diff --git a/ui/qt/main_window.ui b/ui/qt/main_window.ui
index 024e3eebc5..79b6ffc08c 100644
--- a/ui/qt/main_window.ui
+++ b/ui/qt/main_window.ui
@@ -362,6 +362,7 @@
     <addaction name="actionViewPacketList"/>
     <addaction name="actionViewPacketDetails"/>
     <addaction name="actionViewPacketBytes"/>
+    <addaction name="actionViewPacketDiagram"/>
     <addaction name="separator"/>
     <addaction name="menuTime_Display_Format"/>
     <addaction name="menuName_Resolution"/>
@@ -2473,6 +2474,20 @@
     <string>Show or hide the packet bytes</string>
    </property>
   </action>
+  <action name="actionViewPacketDiagram">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="checked">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>Packet &amp;Diagram</string>
+   </property>
+   <property name="toolTip">
+    <string>Show or hide the packet diagram</string>
+   </property>
+  </action>
   <action name="actionViewInternalsConversationHashTables">
    <property name="text">
     <string>&amp;Conversation Hash Tables</string>
diff --git a/ui/qt/main_window_layout.cpp b/ui/qt/main_window_layout.cpp
index 741a563301..f201784f37 100644
--- a/ui/qt/main_window_layout.cpp
+++ b/ui/qt/main_window_layout.cpp
@@ -24,9 +24,10 @@
 #include <QAction>
 #include <QToolBar>
 
+#include <ui/qt/byte_view_tab.h>
 #include <ui/qt/packet_list.h>
+#include <ui/qt/packet_diagram.h>
 #include <ui/qt/proto_tree.h>
-#include <ui/qt/byte_view_tab.h>
 
 /*
  * The generated Ui_MainWindow::setupUi() can grow larger than our configured limit,
@@ -56,6 +57,8 @@ QWidget* MainWindow::getLayoutWidget(layout_pane_content_e type) {
             return proto_tree_;
         case layout_pane_content_pbytes:
             return byte_view_tab_;
+        case layout_pane_content_pdiagram:
+            return packet_diagram_;
         default:
             g_assert_not_reached();
             return NULL;
@@ -76,7 +79,8 @@ void MainWindow::layoutPanes()
                                                        << prefs.gui_layout_content_3
                                                        << recent.packet_list_show
                                                        << recent.tree_view_show
-                                                       << recent.byte_view_show;
+                                                       << recent.byte_view_show
+                                                       << recent.packet_diagram_show;
 
     if (cur_layout_ == new_layout) return;
 
@@ -84,10 +88,11 @@ void MainWindow::layoutPanes()
 
     // Reparent all widgets and add them back in the proper order below.
     // This hides each widget as well.
-    packet_list_->freeze(); // Clears tree and byte view tabs.
+    packet_list_->freeze(); // Clears tree, byte view tabs, and diagram.
     packet_list_->setParent(main_ui_->mainStack);
     proto_tree_->setParent(main_ui_->mainStack);
     byte_view_tab_->setParent(main_ui_->mainStack);
+    packet_diagram_->setParent(main_ui_->mainStack);
     empty_pane_.setParent(main_ui_->mainStack);
     extra_split_.setParent(main_ui_->mainStack);
 
@@ -156,6 +161,7 @@ void MainWindow::layoutPanes()
     packet_list_->setVisible(ms_children.contains(packet_list_) && recent.packet_list_show);
     proto_tree_->setVisible(ms_children.contains(proto_tree_) && recent.tree_view_show);
     byte_view_tab_->setVisible(ms_children.contains(byte_view_tab_) && recent.byte_view_show);
+    packet_diagram_->setVisible(ms_children.contains(packet_diagram_) && recent.packet_diagram_show);
 
     // Show the packet list here to prevent pending resize events changing columns
     // when the packet list is set as current widget for the first time.
diff --git a/ui/qt/main_window_slots.cpp b/ui/qt/main_window_slots.cpp
index 6ae4238e36..a0d3250cf3 100644
--- a/ui/qt/main_window_slots.cpp
+++ b/ui/qt/main_window_slots.cpp
@@ -127,6 +127,7 @@ DIAG_ON(frame-larger-than=)
 #include "mtp3_summary_dialog.h"
 #include "multicast_statistics_dialog.h"
 #include "packet_comment_dialog.h"
+#include "packet_diagram.h"
 #include "packet_dialog.h"
 #include "packet_list.h"
 #include "credentials_dialog.h"
@@ -360,6 +361,7 @@ void MainWindow::updatePreferenceActions()
     main_ui_->actionViewPacketList->setEnabled(prefs_has_layout_pane_content(layout_pane_content_plist));
     main_ui_->actionViewPacketDetails->setEnabled(prefs_has_layout_pane_content(layout_pane_content_pdetails));
     main_ui_->actionViewPacketBytes->setEnabled(prefs_has_layout_pane_content(layout_pane_content_pbytes));
+    main_ui_->actionViewPacketDiagram->setEnabled(prefs_has_layout_pane_content(layout_pane_content_pdiagram));
 
     main_ui_->actionViewNameResolutionPhysical->setChecked(gbl_resolv_flags.mac_name);
     main_ui_->actionViewNameResolutionNetwork->setChecked(gbl_resolv_flags.network_name);
@@ -378,6 +380,7 @@ void MainWindow::updateRecentActions()
     main_ui_->actionViewPacketList->setChecked(recent.packet_list_show && prefs_has_layout_pane_content(layout_pane_content_plist));
     main_ui_->actionViewPacketDetails->setChecked(recent.tree_view_show && prefs_has_layout_pane_content(layout_pane_content_pdetails));
     main_ui_->actionViewPacketBytes->setChecked(recent.byte_view_show && prefs_has_layout_pane_content(layout_pane_content_pbytes));
+    main_ui_->actionViewPacketDiagram->setChecked(recent.packet_diagram_show && prefs_has_layout_pane_content(layout_pane_content_pdiagram));
 
     foreach(QAction *action, main_ui_->menuInterfaceToolbars->actions()) {
         if (g_list_find_custom(recent.interface_toolbars, action->text().toUtf8(), (GCompareFunc)strcmp)) {
@@ -2299,6 +2302,9 @@ void MainWindow::showHideMainWidgets(QAction *action)
     } else if (widget == byte_view_tab_) {
         recent.byte_view_show = show;
         main_ui_->actionViewPacketBytes->setChecked(show);
+    } else if (widget == packet_diagram_) {
+        recent.packet_diagram_show = show;
+        main_ui_->actionViewPacketDiagram->setChecked(show);
     } else {
         foreach(QAction *action, main_ui_->menuInterfaceToolbars->actions()) {
             QToolBar *toolbar = action->data().value<QToolBar *>();
diff --git a/ui/qt/packet_diagram.cpp b/ui/qt/packet_diagram.cpp
new file mode 100644
index 0000000000..f83f782ec1
--- /dev/null
+++ b/ui/qt/packet_diagram.cpp
@@ -0,0 +1,736 @@
+/* packet_diagram.cpp
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "packet_diagram.h"
+
+#include "math.h"
+
+#include "epan/epan.h"
+#include "epan/epan_dissect.h"
+
+#include "wsutil/utf8_entities.h"
+
+#include "wireshark_application.h"
+
+#include "ui/qt/main_window.h"
+#include "ui/qt/utils/proto_node.h"
+#include "ui/qt/utils/variant_pointer.h"
+
+
+#include <QContextMenuEvent>
+#include <QGraphicsItem>
+#include <QMenu>
+
+#if defined(QT_SVG_LIB) && 0
+#include <QBuffer>
+#include <QMimeData>
+#include <QSvgGenerator>
+#endif
+
+#include <QDebug>
+
+// "rems" are root em widths, aka the regular font height, similar to rems in CSS.
+class DiagramLayout {
+public:
+    DiagramLayout() :
+        bits_per_row_(32),
+        small_font_rems_(0.75),
+        bit_width_rems_(1.0),
+        padding_rems_(0.5),
+        span_mark_offset_rems_(0.2),
+        show_fields_(false)
+    {
+        setFont(wsApp->font());
+    }
+
+    void setFont(QFont font) {
+        regular_font_ = font;
+        small_font_ = font;
+        small_font_.setPointSize(regular_font_.pointSize() * small_font_rems_);
+
+        QFontMetrics fm(regular_font_);
+        root_em_ = fm.height();
+    }
+    void setShowFields(bool show_fields = false) { show_fields_ = show_fields; }
+
+    int bitsPerRow() const { return bits_per_row_; }
+    const QFont regularFont() const { return regular_font_; }
+    const QFont smallFont() const { return small_font_; }
+    int bitWidth() const { return root_em_ * bit_width_rems_; }
+    int lineHeight() const { return root_em_; }
+    int hPadding() const { return root_em_ * padding_rems_; }
+    int vPadding() const { return root_em_ * padding_rems_; }
+    int spanMarkOffset() const { return root_em_ * span_mark_offset_rems_; }
+    int rowHeight() const {
+        int rows = show_fields_ ? 2 : 1;
+        return ((lineHeight() * rows) + (vPadding() * 2));
+    }
+    bool showFields() const { return show_fields_; }
+private:
+    int bits_per_row_;
+    double small_font_rems_;
+    double bit_width_rems_;
+    double padding_rems_;
+    double span_mark_offset_rems_; // XXX Make this padding_rems_ / 2 instead?
+    bool show_fields_;
+    QFont regular_font_;
+    QFont small_font_;
+    int root_em_;
+};
+
+class FieldInformationGraphicsItem : public QGraphicsPolygonItem
+{
+public:
+    FieldInformationGraphicsItem(field_info *fi, int start_bit, int fi_length, const DiagramLayout *layout, QGraphicsItem *parent = nullptr) :
+        QGraphicsPolygonItem(QPolygonF(), parent),
+        finfo_(new FieldInformation(fi)),
+        start_bit_(start_bit),
+        layout_(layout),
+        collapsed_len_(fi_length),
+        collapsed_row_(-1)
+    {
+        Q_ASSERT(layout_);
+
+        for (int idx = 0; idx < NumSpanMarks; idx++) {
+            span_marks_[idx] = new QGraphicsLineItem(this);
+            span_marks_[idx]->hide();
+        }
+
+        int bits_per_row = layout_->bitsPerRow();
+        int row1_start = start_bit_ % bits_per_row;
+        int bits_remain = fi_length;
+
+        int row1_bits = bits_remain;
+        if (bits_remain + row1_start > bits_per_row) {
+            row1_bits = bits_per_row - row1_start;
+            bits_remain -= row1_bits;
+            if (row1_start == 0 && bits_remain > bits_per_row) {
+                // Collapse first row
+                bits_remain %= bits_per_row;
+                collapsed_row_ = 0;
+            }
+        } else {
+            bits_remain = 0;
+        }
+
+        int row2_bits = bits_remain;
+        if (bits_remain > bits_per_row) {
+            row2_bits = bits_per_row;
+            bits_remain -= bits_per_row;
+            if (bits_remain > bits_per_row) {
+                // Collapse second row
+                bits_remain %= bits_per_row;
+                collapsed_row_ = 1;
+            }
+        } else {
+            bits_remain = 0;
+        }
+        int row3_bits = bits_remain;
+
+        collapsed_len_ = row1_bits + row2_bits + row3_bits;
+
+        QRectF rr1, rr2, rr3;
+        QRectF row_rect = QRectF(row1_start, 0, row1_bits, 1);
+        unit_shape_ = QPolygonF(row_rect);
+        rr1 = row_rect;
+        unit_tr_ = row_rect;
+
+        if (row2_bits > 0) {
+            row_rect = QRectF(0, 1, row2_bits, 1);
+            unit_shape_ = unit_shape_.united(QPolygonF(row_rect));
+            rr2 = row_rect;
+            if (row2_bits > row1_bits) {
+                unit_tr_ = row_rect;
+            }
+
+            if (row3_bits > 0) {
+                row_rect = QRectF(0, 2, row3_bits, 1);
+                unit_shape_ = unit_shape_.united(QPolygonF(row_rect));
+                rr3 = row_rect;
+            }
+            QPainterPath pp;
+            pp.addPolygon(unit_shape_);
+            unit_shape_ = pp.simplified().toFillPolygon();
+        }
+
+        updateLayout();
+
+        if (finfo_->isValid()) {
+            setToolTip(QString("%1 (%2) = %3")
+                       .arg(finfo_->headerInfo().name)
+                       .arg(finfo_->headerInfo().abbreviation)
+                       .arg(finfo_->toString()));
+            setData(Qt::UserRole, VariantPointer<field_info>::asQVariant(finfo_->fieldInfo()));
+        } else {
+            setToolTip(QObject::tr("Gap in dissection"));
+        }
+    }
+
+    int collapsedLength() { return collapsed_len_; }
+
+    void setPos(qreal x, qreal y) {
+        QGraphicsPolygonItem::setPos(x, y);
+        updateLayout();
+    }
+
+    int maxLeftY() {
+        qreal rel_len = (start_bit_ % layout_->bitsPerRow()) + collapsed_len_;
+        QPointF pt = mapToParent(QPointF(0, ceil(rel_len / layout_->bitsPerRow()) * layout_->rowHeight()));
+        return pt.y();
+    }
+
+    int maxRightY() {
+        qreal rel_len = (start_bit_ % layout_->bitsPerRow()) + collapsed_len_;
+        QPointF pt = mapToParent(QPointF(0, floor(rel_len / layout_->bitsPerRow()) * layout_->rowHeight()));
+        return pt.y();
+    }
+
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *) {
+
+        painter->setPen(Qt::NoPen);
+        painter->save();
+        if (!finfo_->isValid()) {
+            QBrush brush = QBrush(option->palette.text().color(), Qt::BDiagPattern);
+            painter->setBrush(brush);
+        } else if (isSelected()) {
+            painter->setBrush(option->palette.highlight().color());
+        }
+        painter->drawPolygon(polygon());
+        painter->restore();
+
+        // Lower and inner right borders
+        painter->setPen(option->palette.text().color());
+        QPolygonF shape = polygon();
+        for (int idx = 1; idx < unit_shape_.size(); idx++) {
+            QPointF u_start = unit_shape_[idx - 1];
+            QPointF u_end = unit_shape_[idx];
+            QPointF start, end;
+            bool draw_line = false;
+
+            if (u_start.y() > 0 && u_start.y() == u_end.y()) {
+                draw_line = true;
+            } else if (u_start.x() > 0 && u_start.x() < layout_->bitsPerRow() && u_start.x() == u_end.x()) {
+                draw_line = true;
+            }
+            if (draw_line) {
+                start = shape[idx - 1];
+                end = shape[idx];
+                painter->drawLine(start, end);
+            }
+        }
+
+        if (!finfo_->isValid()) {
+            return;
+        }
+
+        // Field label(s)
+        QString label = finfo_->headerInfo().name;
+        paintLabel(painter, label, scaled_tr_);
+
+        if (layout_->showFields()) {
+            label = finfo_->toString();
+            paintLabel(painter, label, scaled_tr_.adjusted(0, scaled_tr_.height(), 0, scaled_tr_.height()));
+        }
+    }
+
+private:
+    enum SpanMark {
+        TopLeft,
+        BottomLeft,
+        TopRight,
+        BottomRight,
+        NumSpanMarks
+    };
+    FieldInformation *finfo_;
+    int start_bit_;
+    const DiagramLayout *layout_;
+    int collapsed_len_;
+    int collapsed_row_;
+    QPolygonF unit_shape_;
+    QRectF unit_tr_;
+    QRectF scaled_tr_;
+    QGraphicsLineItem *span_marks_[NumSpanMarks];
+
+    void updateLayout() {
+        QTransform xform;
+
+        xform.scale(layout_->bitWidth(), layout_->rowHeight());
+        setPolygon(xform.map(unit_shape_));
+        scaled_tr_ = xform.mapRect(unit_tr_);
+        scaled_tr_.adjust(layout_->hPadding(), layout_->vPadding(), -layout_->hPadding(), -layout_->vPadding());
+        scaled_tr_.setHeight(layout_->lineHeight());
+
+        // Collapsed / span marks
+        for (int idx = 0; idx < NumSpanMarks; idx++) {
+            span_marks_[idx]->hide();
+        }
+        if (collapsed_row_ >= 0) {
+            QRectF bounding_rect = polygon().boundingRect();
+            qreal center_y = bounding_rect.top() + (layout_->rowHeight() * collapsed_row_) + (layout_->rowHeight() / 2);
+            qreal mark_w = layout_->bitWidth() / 3; // Each mark side to center
+            QLineF span_l = QLineF(-mark_w, mark_w / 2, mark_w, -mark_w / 2);
+            for (int idx = 0; idx < NumSpanMarks; idx++) {
+                QPointF center;
+                switch (idx) {
+                case TopLeft:
+                    center = QPointF(bounding_rect.left(), center_y - layout_->spanMarkOffset());
+                    break;
+                case BottomLeft:
+                    center = QPointF(bounding_rect.left(), center_y + layout_->spanMarkOffset());
+                    break;
+                case TopRight:
+                    center = QPointF(bounding_rect.right(), center_y - layout_->spanMarkOffset());
+                    break;
+                case BottomRight:
+                    center = QPointF(bounding_rect.right(), center_y + layout_->spanMarkOffset());
+                    break;
+                }
+
+                span_marks_[idx]->setLine(span_l.translated(center));
+                span_marks_[idx]->setZValue(zValue() - 0.1);
+                span_marks_[idx]->show();
+            }
+        }
+    }
+
+    void paintLabel(QPainter *painter, QString label, QRectF label_rect) {
+        QFontMetrics fm = QFontMetrics(layout_->regularFont());
+
+        painter->setFont(layout_->regularFont());
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 11, 0))
+        int label_w = fm.horizontalAdvance(label);
+#else
+        int label_w = fm.width(label);
+#endif
+        if (label_w > label_rect.width()) {
+            painter->setFont(layout_->smallFont());
+            fm = QFontMetrics(layout_->smallFont());
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 11, 0))
+            label_w = fm.horizontalAdvance(label);
+#else
+            label_w = fm.width(label);
+#endif
+            if (label_w > label_rect.width()) {
+                // XXX Use parent+ItemClipsChildrenToShape or setScale instead?
+                label = fm.elidedText(label, Qt::ElideRight, label_rect.width());
+            }
+        }
+        painter->drawText(label_rect, Qt::AlignCenter, label);
+    }
+};
+
+PacketDiagram::PacketDiagram(QWidget *parent) :
+    QGraphicsView(new QGraphicsScene(), parent),
+    layout_(new DiagramLayout),
+    cap_file_(nullptr),
+    root_node_(nullptr),
+    selected_field_(nullptr),
+    y_pos_(0)
+{
+    setAccessibleName(tr("Packet diagram"));
+
+    setRenderHint(QPainter::Antialiasing);
+
+    // XXX Move to setMonospaceFont similar to ProtoTree
+    layout_->setFont(font());
+
+    connect(wsApp, &WiresharkApplication::appInitialized, this, &PacketDiagram::connectToMainWindow);
+    QGraphicsScene *this_scene = scene();
+    connect(this_scene, &QGraphicsScene::selectionChanged, this, &PacketDiagram::sceneSelectionChanged);
+
+    connect(wsApp, &WiresharkApplication::zoomRegularFont, this, &PacketDiagram::setFont);
+}
+
+PacketDiagram::~PacketDiagram()
+{
+    delete layout_;
+}
+
+void PacketDiagram::setRootNode(proto_node *root_node)
+{
+    scene()->clear();
+    root_node_ = root_node;
+    selected_field_ = nullptr;
+    y_pos_ = 0;
+
+    ProtoNode parent_node(root_node_);
+    if (!parent_node.isValid()) {
+        return;
+    }
+
+    ProtoNode::ChildIterator kids = parent_node.children();
+    while (kids.element().isValid())
+    {
+        proto_node *tl_node = kids.element().protoNode();
+        kids.next();
+
+        // Exclude all ("Frame") and nothing
+        if (tl_node->finfo->start == 0 && tl_node->finfo->length == (int) tvb_captured_length(cap_file_->edt->tvb)) {
+            continue;
+        }
+        if (tl_node->finfo->length < 1) {
+            continue;
+        }
+        addDiagram(tl_node);
+    }
+}
+
+void PacketDiagram::clear()
+{
+    setRootNode(nullptr);
+}
+
+void PacketDiagram::setCaptureFile(capture_file *cf)
+{
+    // For use by the main view, set the capture file which will later have a
+    // dissection (EDT) ready.
+    // The packet dialog sets a fixed EDT context and MUST NOT use this.
+    cap_file_ = cf;
+}
+
+void PacketDiagram::setFont(const QFont &font)
+{
+    layout_->setFont(font);
+    setRootNode(root_node_);
+}
+
+void PacketDiagram::selectedFieldChanged(FieldInformation *finfo)
+{
+    setSelectedField(finfo ? finfo->fieldInfo() : nullptr);
+}
+
+void PacketDiagram::selectedFrameChanged(QList<int> frames)
+{
+    if (frames.count() == 1 && cap_file_ && cap_file_->edt && cap_file_->edt->tree) {
+        setRootNode(cap_file_->edt->tree);
+    } else {
+        // Clear the proto tree contents as they have become invalid.
+        setRootNode(nullptr);
+    }
+}
+
+void PacketDiagram::contextMenuEvent(QContextMenuEvent *event)
+{
+    if (!event) {
+        return;
+    }
+
+    QAction *action;
+    QMenu ctx_menu(this);
+
+    action = ctx_menu.addAction(tr("Show Field Values"));
+    action->setCheckable(true);
+    action->setChecked(layout_->showFields());
+    connect(action, &QAction::toggled, this, &PacketDiagram::showFieldsToggled);
+
+    ctx_menu.addSeparator();
+
+    action = ctx_menu.addAction(tr("Save Diagram As" UTF8_HORIZONTAL_ELLIPSIS));
+    connect(action, &QAction::triggered, this, &PacketDiagram::saveAsTriggered);
+
+    action = ctx_menu.addAction(tr("Copy as Raster Image"));
+    connect(action, &QAction::triggered, this, &PacketDiagram::copyAsRasterTriggered);
+
+#if defined(QT_SVG_LIB) && !defined(Q_OS_MAC)
+    action = ctx_menu.addAction(tr(UTF8_HORIZONTAL_ELLIPSIS "as SVG"));
+    connect(action, &QAction::triggered, this, &PacketDiagram::copyAsSvgTriggered);
+#endif
+
+    ctx_menu.exec(event->globalPos());
+}
+
+void PacketDiagram::connectToMainWindow()
+{
+    MainWindow *main_window = qobject_cast<MainWindow *>(wsApp->mainWindow());
+    if (!main_window) {
+        return;
+    }
+    connect(main_window, &MainWindow::setCaptureFile, this, &PacketDiagram::setCaptureFile);
+    connect(main_window, &MainWindow::fieldSelected, this, &PacketDiagram::selectedFieldChanged);
+    connect(main_window, &MainWindow::framesSelected, this, &PacketDiagram::selectedFrameChanged);
+
+    connect(this, &PacketDiagram::fieldSelected, main_window, &MainWindow::fieldSelected);
+}
+
+void PacketDiagram::sceneSelectionChanged()
+{
+    field_info *sel_fi = nullptr;
+    if (! scene()->selectedItems().isEmpty()) {
+        sel_fi = VariantPointer<field_info>::asPtr(scene()->selectedItems().first()->data(Qt::UserRole));
+    }
+
+    if (sel_fi) {
+        FieldInformation finfo(sel_fi, this);
+        emit fieldSelected(&finfo);
+    } else {
+        emit fieldSelected(nullptr);
+    }
+}
+
+struct WireItem {
+    proto_item *item;
+    int start_bit;
+    int length;
+};
+
+void PacketDiagram::addDiagram(proto_node *tl_node)
+{
+    QGraphicsItem *item;
+    QGraphicsSimpleTextItem *t_item;
+    int bits_per_row = layout_->bitsPerRow();
+    int bit_width = layout_->bitWidth();
+    int diag_w = bit_width * layout_->bitsPerRow();
+    qreal x = layout_->hPadding();
+
+    // Title
+    t_item = scene()->addSimpleText(tl_node->finfo->hfinfo->name);
+    t_item->setFont(layout_->regularFont());
+    t_item->setPos(0, y_pos_);
+    y_pos_ += layout_->lineHeight() + (bit_width / 4);
+
+    int border_top = y_pos_;
+
+    // Bit scale + tick marks
+    QList<int> tick_nums;
+    for (int tn = 0 ; tn < layout_->bitsPerRow(); tn += 16) {
+        tick_nums << tn << tn + 15;
+    }
+    qreal y_bottom = y_pos_ + bit_width;
+    QGraphicsItem *tl_item = scene()->addLine(x, y_bottom, x + diag_w, y_bottom);
+    for (int tick_n = 0; tick_n < bits_per_row; tick_n++) {
+        x = layout_->hPadding() + (tick_n * bit_width);
+        qreal y_top = y_pos_ + (tick_n % 8 == 0 ? 0 : bit_width / 2);
+        if (tick_n > 0) {
+            scene()->addLine(x, y_top, x, y_bottom);
+        }
+
+        if (tick_nums.contains(tick_n)) {
+            t_item = scene()->addSimpleText(QString::number(tick_n));
+            t_item->setFont(layout_->smallFont());
+            t_item->setPos(x + ((bit_width - t_item->boundingRect().width()) / 2.0) + 2, y_pos_);
+        }
+    }
+    y_pos_ = y_bottom;
+    x = layout_->hPadding();
+
+    // Top-level fields
+    int last_start_bit = -1;
+    int max_l_y = y_bottom;
+    QList<WireItem>wire_items;
+    for (proto_item *cur_item = tl_node->first_child; cur_item; cur_item = cur_item->next) {
+        if (proto_item_is_generated(cur_item) || proto_item_is_hidden(cur_item)) {
+            continue;
+        }
+
+        field_info *fi = cur_item->finfo;
+        int start_bit = ((fi->start - tl_node->finfo->start) * 8) + FI_GET_BITS_OFFSET(fi);
+        int length = FI_GET_BITS_SIZE(fi) ? FI_GET_BITS_SIZE(fi) : fi->length * 8;
+
+        if (start_bit <= last_start_bit || length <= 0) {
+            qDebug() << "Skipping pass 1" << fi->hfinfo->abbrev << start_bit << last_start_bit << length;
+            continue;
+        }
+        last_start_bit = start_bit;
+
+        WireItem wire_item = { cur_item, start_bit, length };
+        wire_items << wire_item;
+    }
+    qreal z_value = tl_item->zValue();
+    for (int idx = 0; idx < wire_items.size(); idx++) {
+        WireItem *wire_item = &wire_items[idx];
+        field_info *fi = wire_item->item->finfo;
+
+        if (idx < wire_items.size() - 1) {
+            WireItem *next_item = &wire_items[idx + 1];
+            if (wire_item->start_bit + wire_item->length > next_item->start_bit) {
+                wire_item->length = next_item->start_bit - wire_item->start_bit;
+                qDebug() << "Resized pass 2" << fi->hfinfo->abbrev << wire_item->start_bit << wire_item->length << next_item->start_bit;
+                if (wire_item->length <= 0) {
+                    qDebug() << "Skipping pass 2" << fi->hfinfo->abbrev << wire_item->start_bit << wire_item->length;
+                    continue;
+                }
+            }
+
+            if (next_item->start_bit > wire_item->start_bit + wire_item->length) {
+                int gap_start_bit = wire_item->start_bit + wire_item->length;
+                int gap_len = next_item->start_bit - gap_start_bit;
+                int y_off = (gap_start_bit / bits_per_row) * layout_->rowHeight();
+                // Stack each item behind the previous one.
+                z_value -= .01;
+                FieldInformationGraphicsItem *gap_item = new FieldInformationGraphicsItem(nullptr, gap_start_bit, gap_len, layout_);
+                gap_item->setPos(x, y_bottom + y_off);
+                gap_item->setZValue(z_value);
+                scene()->addItem(gap_item);
+            }
+        }
+
+        int y_off = (wire_item->start_bit / bits_per_row) * layout_->rowHeight();
+        // Stack each item behind the previous one.
+        z_value -= .01;
+        FieldInformationGraphicsItem *fi_item = new FieldInformationGraphicsItem(fi, wire_item->start_bit, wire_item->length, layout_);
+        fi_item->setPos(x, y_bottom + y_off);
+        fi_item->setFlag(QGraphicsItem::ItemIsSelectable);
+        fi_item->setAcceptedMouseButtons(Qt::LeftButton);
+        fi_item->setZValue(z_value);
+        scene()->addItem(fi_item);
+
+        y_pos_ = fi_item->maxRightY();
+        max_l_y = fi_item->maxLeftY();
+    }
+
+    // Left & right borders
+    scene()->addLine(x, border_top, x, max_l_y);
+    scene()->addLine(x + diag_w, border_top, x + diag_w, y_pos_);
+
+    // Inter-diagram margin
+    y_pos_ = max_l_y + bit_width;
+
+    // Set the proper color. Needed for dark mode on macOS + Qt 5.15.0 at least, possibly other cases.
+    foreach (item, scene()->items()) {
+        QGraphicsSimpleTextItem *t_item = qgraphicsitem_cast<QGraphicsSimpleTextItem *>(item);
+        if (t_item) {
+            t_item->setBrush(palette().text().color());
+        }
+        QGraphicsLineItem *l_item = qgraphicsitem_cast<QGraphicsLineItem *>(item);
+        if (l_item) {
+            l_item->setPen(palette().text().color());
+        }
+    }
+}
+
+void PacketDiagram::setSelectedField(field_info *fi)
+{
+    QSignalBlocker blocker(this);
+    FieldInformationGraphicsItem *fi_item;
+
+    foreach (QGraphicsItem *item, scene()->items()) {
+        if (item->isSelected()) {
+            item->setSelected(false);
+            fi_item = qgraphicsitem_cast<FieldInformationGraphicsItem *>(item);
+        }
+        if (fi && VariantPointer<field_info>::asPtr(item->data(Qt::UserRole)) == fi) {
+            fi_item = qgraphicsitem_cast<FieldInformationGraphicsItem *>(item);
+            if (fi_item) {
+                fi_item->setSelected(true);
+            }
+        }
+    }
+}
+
+QImage PacketDiagram::exportToImage()
+{
+    // Create a hi-res 2x scaled image.
+    int scale = 2;
+    QRect rr = QRect(0, 0, sceneRect().size().width() * scale, sceneRect().size().height() * scale);
+    QImage raster_diagram = QImage(rr.size(), QImage::Format_ARGB32);
+    QPainter raster_painter(&raster_diagram);
+
+    raster_painter.setRenderHint(QPainter::Antialiasing);
+    raster_painter.fillRect(rr, palette().base().color());
+    scene()->render(&raster_painter);
+
+    raster_painter.end();
+
+    return raster_diagram;
+}
+
+#if defined(QT_SVG_LIB) && 0
+QByteArray PacketDiagram::exportToSvg()
+{
+    QRect sr = QRect(0, 0, sceneRect().size().width(), sceneRect().size().height());
+    QBuffer svg_buf;
+    QSvgGenerator svg_diagram;
+    svg_diagram.setSize(sr.size());
+    svg_diagram.setViewBox(sr);
+    svg_diagram.setOutputDevice(&svg_buf);
+
+    QPainter svg_painter(&svg_diagram);
+    svg_painter.fillRect(sr, palette().base().color());
+    scene()->render(&svg_painter);
+
+    svg_painter.end();
+
+    return svg_buf.buffer();
+}
+#endif
+
+void PacketDiagram::showFieldsToggled(bool checked)
+{
+    layout_->setShowFields(checked);
+    setRootNode(root_node_);
+}
+
+// XXX - We have similar code in tcp_stream_dialog and io_graph_dialog. Should this be a common routine?
+void PacketDiagram::saveAsTriggered()
+{
+    QString file_name, extension;
+    QDir path(wsApp->lastOpenDir());
+    QString png_filter = tr("Portable Network Graphics (*.png)");
+    QString bmp_filter = tr("Windows Bitmap (*.bmp)");
+    // Gaze upon my beautiful graph with lossy artifacts!
+    QString jpeg_filter = tr("JPEG File Interchange Format (*.jpeg *.jpg)");
+    QStringList fl = QStringList() << png_filter << bmp_filter << jpeg_filter;
+#if defined(QT_SVG_LIB) && 0
+    QString svg_filter = tr("Scalable Vector Graphics (*.svg)");
+    fl << svg_filter;
+#endif
+    QString filter = fl.join(";;");
+
+    file_name = WiresharkFileDialog::getSaveFileName(this, wsApp->windowTitleString(tr("Save Graph As" UTF8_HORIZONTAL_ELLIPSIS)),
+                                             path.canonicalPath(), filter, &extension);
+
+    if (file_name.length() > 0) {
+        bool save_ok = false;
+        if (extension.compare(png_filter) == 0) {
+            QImage raster_diagram = exportToImage();
+            save_ok = raster_diagram.save(file_name, "PNG");
+        } else if (extension.compare(bmp_filter) == 0) {
+            QImage raster_diagram = exportToImage();
+            save_ok = raster_diagram.save(file_name, "BMP");
+        } else if (extension.compare(jpeg_filter) == 0) {
+            QImage raster_diagram = exportToImage();
+            save_ok = raster_diagram.save(file_name, "JPG");
+        }
+#if defined(QT_SVG_LIB) && 0
+        else if (extension.compare(svg_filter) == 0) {
+            QByteArray svg_diagram = exportToSvg();
+            QFile file(file_name);
+            if (file.open(QIODevice::WriteOnly)) {
+                save_ok = file.write(svg_diagram) > 0;
+                file.close();
+            }
+        }
+#endif
+        // else error dialog?
+        if (save_ok) {
+            path = QDir(file_name);
+            wsApp->setLastOpenDir(path.canonicalPath().toUtf8().constData());
+        }
+    }
+}
+
+void PacketDiagram::copyAsRasterTriggered()
+{
+    QImage raster_diagram = exportToImage();
+    wsApp->clipboard()->setImage(raster_diagram);
+}
+
+#if defined(QT_SVG_LIB) && !defined(Q_OS_MAC) && 0
+void PacketDiagram::copyAsSvgTriggered()
+{
+    QByteArray svg_ba = exportToSvg();
+
+    // XXX It looks like we have to use/subclass QMacPasteboardMime in
+    // order for this to work on macOS.
+    // It might be easier to just do "Save As" instead.
+    QMimeData *md = new QMimeData();
+    md->setData("image/svg+xml", svg_buf);
+    wsApp->clipboard()->setMimeData(md);
+}
+#endif
diff --git a/ui/qt/packet_diagram.h b/ui/qt/packet_diagram.h
new file mode 100644
index 0000000000..328b67111f
--- /dev/null
+++ b/ui/qt/packet_diagram.h
@@ -0,0 +1,72 @@
+/* packet_diagram.h
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef PACKET_DIAGRAM_H
+#define PACKET_DIAGRAM_H
+
+#include <config.h>
+
+#include <epan/proto.h>
+
+#include "cfile.h"
+
+#include <ui/qt/utils/field_information.h>
+
+#include <QGraphicsView>
+
+class DiagramLayout;
+
+class PacketDiagram : public QGraphicsView
+{
+    Q_OBJECT
+public:
+    PacketDiagram(QWidget *parent = nullptr);
+    ~PacketDiagram();
+    void setRootNode(proto_node *root_node);
+    void clear();
+
+signals:
+    void fieldSelected(FieldInformation *);
+
+public slots:
+    void setCaptureFile(capture_file *cf);
+    void setFont(const QFont &font);
+    void selectedFieldChanged(FieldInformation *finfo);
+    void selectedFrameChanged(QList<int> frames);
+
+protected:
+    virtual void contextMenuEvent(QContextMenuEvent *event) override;
+
+private slots:
+    void connectToMainWindow();
+    void sceneSelectionChanged();
+
+private:
+    void addDiagram(proto_node *tl_node);
+    void setSelectedField(field_info *fi);
+    QImage exportToImage();
+#if defined(QT_SVG_LIB) && 0
+    QByteArray exportToSvg();
+#endif
+
+    void showFieldsToggled(bool checked);
+    void saveAsTriggered();
+    void copyAsRasterTriggered();
+#if defined(QT_SVG_LIB) && !defined(Q_OS_MAC) && 0
+    void copyAsSvgTriggered();
+#endif
+
+    DiagramLayout *layout_;
+    capture_file *cap_file_;
+    proto_node *root_node_;
+    field_info *selected_field_;
+    int y_pos_;
+};
+
+#endif // PACKET_DIAGRAM_H
diff --git a/ui/qt/tcp_stream_dialog.cpp b/ui/qt/tcp_stream_dialog.cpp
index b0b0f9c9ad..a19e3cd434 100644
--- a/ui/qt/tcp_stream_dialog.cpp
+++ b/ui/qt/tcp_stream_dialog.cpp
@@ -1823,6 +1823,7 @@ void TCPStreamDialog::transformYRange(const QCPRange &y_range1)
     sp->yAxis2->setRangeLower(yp2.y1());
 }
 
+// XXX - We have similar code in io_graph_dialog and packet_diagram. Should this be a common routine?
 void TCPStreamDialog::on_buttonBox_accepted()
 {
     QString file_name, extension;
diff --git a/ui/qt/utils/field_information.cpp b/ui/qt/utils/field_information.cpp
index 2648930c83..7dd1221084 100644
--- a/ui/qt/utils/field_information.cpp
+++ b/ui/qt/utils/field_information.cpp
@@ -136,16 +136,23 @@ const QString FieldInformation::moduleName()
     return module_name;
 }
 
+QString FieldInformation::toString()
+{
+    QString repr;
+    gchar *repr_str;
+    repr_str = fvalue_to_string_repr(NULL, &fi_->value, FTREPR_DISPLAY, fi_->hfinfo->display);
+    if (repr_str) {
+        repr = repr_str;
+    }
+    wmem_free(NULL, repr_str);
+    return repr;
+}
+
 QString FieldInformation::url()
 {
     QString url;
     if (flag(FI_URL) && headerInfo().isValid && IS_FT_STRING(fi_->hfinfo->type)) {
-        gchar *url_str;
-        url_str = fvalue_to_string_repr(NULL, &fi_->value, FTREPR_DISPLAY, fi_->hfinfo->display);
-        if (url_str) {
-            url = url_str;
-        }
-        wmem_free(NULL, url_str);
+        url = toString();
     }
     return url;
 }
diff --git a/ui/qt/utils/field_information.h b/ui/qt/utils/field_information.h
index e021b4ad1b..19df83e552 100644
--- a/ui/qt/utils/field_information.h
+++ b/ui/qt/utils/field_information.h
@@ -60,6 +60,7 @@ public:
     bool tvbContains(FieldInformation *);
     unsigned flag(unsigned mask);
     const QString moduleName();
+    QString toString();
     QString url();
 
     const QByteArray printableData();
diff --git a/ui/qt/wireshark_application.cpp b/ui/qt/wireshark_application.cpp
index 35daf14f69..9bf6ad931d 100644
--- a/ui/qt/wireshark_application.cpp
+++ b/ui/qt/wireshark_application.cpp
@@ -1188,13 +1188,17 @@ void WiresharkApplication::zoomTextFont(int zoomLevel)
 {
     // Scale by 10%, rounding to nearest half point, minimum 1 point.
     // XXX Small sizes repeat. It might just be easier to create a map of multipliers.
-    zoomed_font_ = mono_font_;
     qreal zoom_size = mono_font_.pointSize() * 2 * qPow(qreal(1.1), zoomLevel);
     zoom_size = qRound(zoom_size) / qreal(2.0);
     zoom_size = qMax(zoom_size, qreal(1.0));
-    zoomed_font_.setPointSizeF(zoom_size);
 
+    zoomed_font_ = mono_font_;
+    zoomed_font_.setPointSizeF(zoom_size);
     emit zoomMonospaceFont(zoomed_font_);
+
+    QFont zoomed_application_font = font();
+    zoomed_application_font.setPointSizeF(zoom_size);
+    emit zoomRegularFont(zoomed_application_font);
 }
 
 #if defined(HAVE_SOFTWARE_UPDATE) && defined(Q_OS_WIN)
diff --git a/ui/qt/wireshark_application.h b/ui/qt/wireshark_application.h
index 70d61c2f95..7b0af2098b 100644
--- a/ui/qt/wireshark_application.h
+++ b/ui/qt/wireshark_application.h
@@ -205,6 +205,7 @@ signals:
     /* Signals activation and stop of a capture. The value provides the number of active captures */
     void captureActive(int);
 
+    void zoomRegularFont(const QFont & font);
     void zoomMonospaceFont(const QFont & font);
 
 public slots:
diff --git a/ui/recent.c b/ui/recent.c
index 4905666423..c36dbcad7b 100644
--- a/ui/recent.c
+++ b/ui/recent.c
@@ -35,6 +35,7 @@
 #define RECENT_KEY_PACKET_LIST_SHOW           "gui.packet_list_show"
 #define RECENT_KEY_TREE_VIEW_SHOW             "gui.tree_view_show"
 #define RECENT_KEY_BYTE_VIEW_SHOW             "gui.byte_view_show"
+#define RECENT_KEY_PACKET_DIAGRAM_SHOW        "gui.packet_diagram_show"
 #define RECENT_KEY_STATUSBAR_SHOW             "gui.statusbar_show"
 #define RECENT_KEY_PACKET_LIST_COLORIZE       "gui.packet_list_colorize"
 #define RECENT_GUI_TIME_FORMAT                "gui.time_format"
@@ -844,6 +845,10 @@ write_profile_recent(void)
             RECENT_KEY_BYTE_VIEW_SHOW,
             recent.byte_view_show);
 
+    write_recent_boolean(rf, "Packet diagram show (hide)",
+            RECENT_KEY_PACKET_DIAGRAM_SHOW,
+            recent.packet_diagram_show);
+
     write_recent_boolean(rf, "Statusbar show (hide)",
             RECENT_KEY_STATUSBAR_SHOW,
             recent.statusbar_show);
@@ -1054,6 +1059,8 @@ read_set_recent_pair_static(gchar *key, const gchar *value,
         parse_recent_boolean(value, &recent.tree_view_show);
     } else if (strcmp(key, RECENT_KEY_BYTE_VIEW_SHOW) == 0) {
         parse_recent_boolean(value, &recent.byte_view_show);
+    } else if (strcmp(key, RECENT_KEY_PACKET_DIAGRAM_SHOW) == 0) {
+        parse_recent_boolean(value, &recent.packet_diagram_show);
     } else if (strcmp(key, RECENT_KEY_STATUSBAR_SHOW) == 0) {
         parse_recent_boolean(value, &recent.statusbar_show);
     } else if (strcmp(key, RECENT_KEY_PACKET_LIST_COLORIZE) == 0) {
@@ -1323,6 +1330,7 @@ recent_read_profile_static(char **rf_path_return, int *rf_errno_return)
     recent.packet_list_show          = TRUE;
     recent.tree_view_show            = TRUE;
     recent.byte_view_show            = TRUE;
+    recent.packet_diagram_show       = TRUE;
     recent.statusbar_show            = TRUE;
     recent.packet_list_colorize      = TRUE;
     recent.gui_time_format           = TS_RELATIVE;
diff --git a/ui/recent.h b/ui/recent.h
index 2ba7110108..b154a57741 100644
--- a/ui/recent.h
+++ b/ui/recent.h
@@ -89,6 +89,7 @@ typedef struct recent_settings_tag {
     gboolean    packet_list_show;
     gboolean    tree_view_show;
     gboolean    byte_view_show;
+    gboolean    packet_diagram_show;
     gboolean    statusbar_show;
     gboolean    packet_list_colorize;
     ts_type     gui_time_format;