dont share image data between different bitmap classes (this fixes issue when you load pixmap from .xpm, then assign it to portablenetworkgraphics class and after save to .png you'll get .xpm content inside .png file)

git-svn-id: trunk@12946 -

lcl/include/bitmap.inc

@@ -57,6 +57,7 @@ begin
   if Source is TBitmap
   then begin
     // TBitmap can share image data
+    
     // -> check if already shared
     if SrcBitmap.FImage=FImage then exit;// already sharing
 
@@ -76,6 +77,15 @@ begin
     // share FImage with assigned graphic
     FImage := SrcBitmap.FImage;
     FImage.Reference;
+
+    // Paul: we can share image data only is ClassTypes are the same
+    // if ClassTypes are differ then we should create copy of data and free save stream
+    if Source.ClassType <> ClassType then
+    begin
+      UnshareImage(True);
+      FreeSaveStream;
+    end;
+
     //DebugLn(['TBitMap.Assign B ',Width,',',Height,' ',HandleAllocated,' RefCount=',FImage.RefCount]);
     Changed(Self);