Reduce the number of built-up calls to DisplayFootprint

When updating the libtree, we modify the tree multiple times to avoid
crashes on Linux.  These generated events that buffered while the widget
was frozen and resulted in redrawing the same footprint 4-10x.

This reduces the buffering by discarding events that are generated
during the freeze and only redrawing when there is a new footprint to
draw

common/widgets/footprint_preview_widget.cpp

@@ -19,6 +19,7 @@
  */
 
 #include <widgets/footprint_preview_widget.h>
+#include <lib_id.h>
 #include <wx/stattext.h>
 #include <wx/sizer.h>
 #include <kiway.h>
@@ -87,15 +88,21 @@ void FOOTPRINT_PREVIEW_WIDGET::ClearStatus()
 
 void FOOTPRINT_PREVIEW_WIDGET::DisplayFootprint( const LIB_ID& aFPID )
 {
-    if( !m_prev_panel )
+    if( !m_prev_panel || m_libid == aFPID )
         return;
 
     wxBusyCursor busy;
 
     if( m_prev_panel->DisplayFootprint( aFPID ) )
+    {
         ClearStatus();
+        m_libid = aFPID;
+    }
     else
+    {
         SetStatusText( _( "Footprint not found." ) );
+        m_libid.clear();
+    }
 }
 
 

common/widgets/lib_tree.cpp

@@ -117,9 +117,12 @@ LIB_TREE::LIB_TREE( wxWindow* aParent, LIB_TABLE* aLibTable,
         // Force an update of the adapter with the empty text to ensure preselect is done
         Regenerate( false );
     }
-
-    // There may be a part preselected in the model. Make sure it is displayed.
-    postPreselectEvent();
+    else
+    {
+        // There may be a part preselected in the model. Make sure it is displayed.
+        // Regenerate does this in the other branch
+        postPreselectEvent();
+    }
 
     Layout();
     sizer->Fit( this );
@@ -374,7 +377,8 @@ void LIB_TREE::onQueryCharHook( wxKeyEvent& aKeyStroke )
 
 void LIB_TREE::onTreeSelect( wxDataViewEvent& aEvent )
 {
-    postPreselectEvent();
+    if( !m_tree_ctrl->IsFrozen() )
+        postPreselectEvent();
 }
 
 

include/widgets/footprint_preview_widget.h

@@ -24,12 +24,12 @@
 #include <wx/panel.h>
 #include <functional>
 #include <import_export.h>
+#include <lib_id.h>
 
 #include <gal/color4d.h>
 
 class FOOTPRINT_LOAD_EVENT;
 class FOOTPRINT_PREVIEW_PANEL_BASE;
-class LIB_ID;
 class KIWAY;
 class wxStaticText;
 class wxSizer;
@@ -77,6 +77,7 @@ private:
     wxPanel*      m_statusPanel;
     wxSizer*      m_statusSizer;
     wxSizer*      m_outerSizer;
+    LIB_ID        m_libid;
 
 };
 

include/widgets/lib_tree.h

@@ -174,6 +174,8 @@ protected:
     wxTextCtrl*      m_query_ctrl;
     wxDataViewCtrl*  m_tree_ctrl;
     wxHtmlWindow*    m_details_ctrl;
+
+    LIB_ID           m_last_libid;
 };
 
 ///< Custom event sent when a new component is preselected