Adding a way for plugin config widgets to resize

- Adding an event plugins can emit to indicate their geometry has changed
- Modifying the PCL2 plugin to use it as an example

Fixes swri-robotics#393

mapviz/include/mapviz/mapviz_plugin.h

@@ -256,6 +256,7 @@ namespace mapviz
 
   Q_SIGNALS:
     void DrawOrderChanged(int draw_order);
+    void SizeChanged();
     void TargetFrameChanged(const std::string& target_frame);
     void UseLatestTransformsChanged(bool use_latest_transforms);
     void VisibleChanged(bool visible);

mapviz/src/mapviz.cpp

@@ -56,12 +56,14 @@
 #include <QMessageBox>
 #include <QProcessEnvironment>
 #include <QFileInfo>
+#include <QListWidgetItem>
 
 #include <swri_math_util/constants.h>
 #include <swri_transform_util/frames.h>
 #include <swri_yaml_util/yaml_util.h>
 
 #include <mapviz/config_item.h>
+#include <QtGui/QtGui>
 
 namespace mapviz
 {
@@ -1058,6 +1060,7 @@ MapvizPluginPtr Mapviz::CreateNewDisplay(
   connect(config_item, SIGNAL(UpdateSizeHint()), this, SLOT(UpdateSizeHints()));
   connect(config_item, SIGNAL(ToggledDraw(QListWidgetItem*, bool)), this, SLOT(ToggleShowPlugin(QListWidgetItem*, bool)));
   connect(plugin.get(), SIGNAL(VisibleChanged(bool)), config_item, SLOT(ToggleDraw(bool)));
+  connect(plugin.get(), SIGNAL(SizeChanged()), this, SLOT(UpdateSizeHints()));
 
   if (draw_order == 0)
   {
@@ -1295,10 +1298,16 @@ void Mapviz::Screenshot()
 
 void Mapviz::UpdateSizeHints()
 {
-  ROS_INFO("Updating size hints");
   for (int i = 0; i < ui_.configs->count(); i++)
   {
-    ui_.configs->item(i)->setSizeHint(ui_.configs->itemWidget(ui_.configs->item(i))->sizeHint());
+    QListWidgetItem* item = ui_.configs->item(i);
+    ConfigItem* widget = static_cast<ConfigItem*>(ui_.configs->itemWidget(item));
+    if (widget) {
+      // Make sure the ConfigItem in the QListWidgetItem we're getting really
+      // exists; if this method is called before it's been initialized, it would
+      // cause a crash.
+      item->setSizeHint(widget->sizeHint());
+    }
   }
 }
 

mapviz_plugins/include/mapviz_plugins/pointcloud2_plugin.h

@@ -123,6 +123,7 @@ namespace mapviz_plugins
       double PointFeature(const uint8_t*, const Field_info&);
       void PointCloud2Callback(const sensor_msgs::PointCloud2ConstPtr& scan);
       QColor CalculateColor(const StampedPoint& point);
+      void UpdateMinMaxWidgets();
 
       Ui::PointCloud2_config ui_;
       QWidget* config_widget_;