Eeschema, printing: fix incorrect number of available pages to print.

The page count was incorrect because the new virtual root sheet was counted.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/22019

eeschema/printing/sch_printout.cpp

@@ -53,13 +53,13 @@ SCH_PRINTOUT::SCH_PRINTOUT( SCH_EDIT_FRAME* aParent, const wxString& aTitle ) :
 void SCH_PRINTOUT::GetPageInfo( int* minPage, int* maxPage, int* selPageFrom, int* selPageTo )
 {
     *minPage = *selPageFrom = 1;
-    *maxPage = *selPageTo   = m_parent->Schematic().Root().CountSheets();
+    *maxPage = *selPageTo   = m_parent->Schematic().Root().CountActiveSheets();
 }
 
 
 bool SCH_PRINTOUT::HasPage( int pageNum )
 {
-    return m_parent->Schematic().Root().CountSheets() >= pageNum;
+    return m_parent->Schematic().Root().CountActiveSheets() >= pageNum;
 }
 
 

eeschema/sch_sheet.cpp

@@ -850,6 +850,17 @@ int SCH_SHEET::CountSheets() const
 }
 
 
+int SCH_SHEET::CountActiveSheets() const
+{
+    int count = CountSheets();
+
+    if( IsVirtualRootSheet() )
+        count--;
+
+    return count;
+}
+
+
 void SCH_SHEET::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, std::vector<MSG_PANEL_ITEM>& aList )
 {
     // Don't use GetShownText(); we want to see the variable references here

eeschema/sch_sheet.h

@@ -316,6 +316,15 @@ public:
      */
     int CountSheets() const;
 
+    /**
+     * Count the number of sheets found in "this" sheet including all of the subsheets.
+     *
+     * @return the full count of active sheets+subsheets contained by "this"
+     * An active sheet is a "physical" sheet actually used in schematic, and not a virtual sheet only
+     * used to handle a set of sheets in a hierarchy and having no UUID
+     */
+    int CountActiveSheets() const;
+
     /**
      * Count the number of sheets that refer to a specific file
      * including all of the subsheets.