Lib symbol editor, export SVG: fix incorrect position of the drawings.

Fixes #13249
https://gitlab.com/kicad/code/kicad/issues/13249

eeschema/symbol_editor/symbol_edit_frame.h

@@ -297,8 +297,10 @@ public:
 
     /**
      * Create the SVG print file for the current edited symbol.
+     * @param aFullFileName is the full filename
+     * @param aOffset is a plot offset, in iu
      */
-    void SVGPlotSymbol( const wxString& aFullFileName );
+    void SVGPlotSymbol( const wxString& aFullFileName, VECTOR2I aOffset );
 
     /**
      * Synchronize the library manager to the symbol library table, and then the symbol tree

eeschema/symbol_editor/symbol_editor_plotter.cpp

@@ -27,7 +27,7 @@
 #include <locale_io.h>
 #include <plotters/plotters_pslike.h>
 
-void SYMBOL_EDIT_FRAME::SVGPlotSymbol( const wxString& aFullFileName )
+void SYMBOL_EDIT_FRAME::SVGPlotSymbol( const wxString& aFullFileName, VECTOR2I aOffset )
 {
     KIGFX::SCH_RENDER_SETTINGS renderSettings;
     renderSettings.LoadColors( GetColorSettings() );
@@ -65,8 +65,8 @@ void SYMBOL_EDIT_FRAME::SVGPlotSymbol( const wxString& aFullFileName )
         TRANSFORM      temp;                 // Uses default transform
         wxPoint        plotPos;
 
-        plotPos.x = pageInfo.GetWidthIU( schIUScale.IU_PER_MILS ) / 2;
-        plotPos.y = pageInfo.GetHeightIU( schIUScale.IU_PER_MILS ) / 2;
+        plotPos.x = aOffset.x;
+        plotPos.y = aOffset.y;
 
         m_symbol->Plot( plotter, GetUnit(), GetConvert(), background, plotPos, temp, false );
 

eeschema/tools/symbol_editor_control.cpp

@@ -582,15 +582,20 @@ int SYMBOL_EDITOR_CONTROL::ExportSymbolAsSVG( const TOOL_EVENT& aEvent )
         PAGE_INFO pageSave = editFrame->GetScreen()->GetPageSettings();
         PAGE_INFO pageTemp = pageSave;
 
-        VECTOR2I symbolSize = symbol->GetUnitBoundingBox( editFrame->GetUnit(),
-                                                          editFrame->GetConvert(), false ).GetSize();
+        BOX2I symbolBBox = symbol->GetUnitBoundingBox( editFrame->GetUnit(),
+                                                       editFrame->GetConvert(), false );
 
-        // Add a small margin to the plot bounding box
-        pageTemp.SetWidthMils( schIUScale.IUToMils( symbolSize.x * 1.2 ) );
-        pageTemp.SetHeightMils( schIUScale.IUToMils( symbolSize.y * 1.2 ) );
+        // Add a small margin (10% of size)to the plot bounding box
+        symbolBBox.Inflate( symbolBBox.GetSize().x * 0.1, symbolBBox.GetSize().y * 0.1 );
+
+        pageTemp.SetWidthMils( schIUScale.IUToMils( symbolBBox.GetSize().x ) );
+        pageTemp.SetHeightMils( schIUScale.IUToMils( symbolBBox.GetSize().y ) );
+
+        // Add an offet to plot the symbol centered on the page.
+        VECTOR2I plot_offset = symbolBBox.GetOrigin();
 
         editFrame->GetScreen()->SetPageSettings( pageTemp );
-        editFrame->SVGPlotSymbol( fullFileName );
+        editFrame->SVGPlotSymbol( fullFileName, -plot_offset );
         editFrame->GetScreen()->SetPageSettings( pageSave );
     }