diff --git a/common/rfb/HextileEncoder.cxx b/common/rfb/HextileEncoder.cxx
index ba71d56..73f1f57 100644
--- a/common/rfb/HextileEncoder.cxx
+++ b/common/rfb/HextileEncoder.cxx
@@ -58,7 +58,8 @@
 {
 }
 
-bool HextileEncoder::writeRect(const Rect& r, ImageGetter* ig, Rect* actual)
+bool HextileEncoder::writeRect(const Rect& r, TransImageGetter* ig,
+                               Rect* actual)
 {
   writer->startRect(r, encodingHextile);
   rdr::OutStream* os = writer->getOutStream();