Import GFX: temporary disable SVG import until V6.0.

SVG import need some refinements to be efficient, so it is disable for v 5.x.
Will be re-enabled later.
Enabling SVG import is *only* for developers, not for users.

pcbnew/import_gfx/dialog_import_gfx.cpp

@@ -49,6 +49,14 @@
 #define IMPORT_GFX_LINEWIDTH_UNITS_KEY          "GfxImportLineWidthUnits"
 #define IMPORT_GFX_LINEWIDTH_KEY                "GfxImportLineWidth"
 
+// Currently (Version 5.1) SVG import is disabled by default, to avoid issues
+// SVG needs some enhancements.
+// Especially, all SVG shapes are imported as curves and converted to a lot of segments.
+// A better approach is to convert to polylines (not yet existing in Pcbnew) and keep
+// arcs and circles as primitives (not yet possible with tinysvg library.
+// So, until these issues are solved, disable SVG import option.
+// Warning: enable svg import is currently only for developers.
+#define DISABLE_SVG_IMPORT
 
 // Static members of DIALOG_IMPORT_GFX, to remember
 // the user's choices during the session
@@ -234,10 +242,16 @@ void DIALOG_IMPORT_GFX::onBrowseFiles( wxCommandEvent& event )
 
     // Generate the list of handled file formats
     wxString wildcardsDesc;
+
+#ifdef DISABLE_SVG_IMPORT
+    wildcardsDesc = DxfFileWildcard();
+#else
     wxString allWildcards;
 
     for( auto pluginType : GRAPHICS_IMPORT_MGR::GFX_FILE_TYPES )
     {
+        if( !pluginType == GRAPHICS_IMPORT_MGR::GFX_FILE_T::DXF )
+            continue;
         auto plugin = GRAPHICS_IMPORT_MGR::GetPlugin( pluginType );
         const auto wildcards = plugin->GetWildcards();
 
@@ -246,6 +260,7 @@ void DIALOG_IMPORT_GFX::onBrowseFiles( wxCommandEvent& event )
     }
 
     wildcardsDesc = "All supported formats|" + allWildcards + wildcardsDesc;
+#endif
 
     wxFileDialog dlg( m_parent, _( "Open File" ), path, filename,
                        wildcardsDesc, wxFD_OPEN|wxFD_FILE_MUST_EXIST );
@@ -286,7 +301,11 @@ void DIALOG_IMPORT_GFX::onOKClick( wxCommandEvent& event )
     m_default_lineWidth = getPCBdefaultLineWidthMM();
 
     m_importer->SetLayer( PCB_LAYER_ID( m_layer ) );
+#ifdef DISABLE_SVG_IMPORT
+    auto plugin = GRAPHICS_IMPORT_MGR::GetPluginByExt( "dxf" );
+#else
     auto plugin = GRAPHICS_IMPORT_MGR::GetPluginByExt( wxFileName( m_filename ).GetExt() );
+#endif
 
     if( plugin )
     {