diff --git a/common/rfb/ScaledPixelBuffer.cxx b/common/rfb/ScaledPixelBuffer.cxx
index 568b26b..bc59fb5 100644
--- a/common/rfb/ScaledPixelBuffer.cxx
+++ b/common/rfb/ScaledPixelBuffer.cxx
@@ -119,11 +119,11 @@
 
 Rect ScaledPixelBuffer::calculateScaleBoundary(const Rect& r) {
   static int x_start, y_start, x_end, y_end;
-  x_start = r.tl.x == 0 ? 0 : ceil((r.tl.x-1) * scale_ratio);
-  y_start = r.tl.y == 0 ? 0 : ceil((r.tl.y-1) * scale_ratio);
-  x_end = ceil(r.br.x * scale_ratio - 1); 
+  x_start = r.tl.x == 0 ? 0 : int(ceil((r.tl.x-1) * scale_ratio));
+  y_start = r.tl.y == 0 ? 0 : int(ceil((r.tl.y-1) * scale_ratio));
+  x_end = int(ceil(r.br.x * scale_ratio - 1));
   x_end = x_end < scaled_width ? x_end + 1 : scaled_width;
-  y_end = ceil(r.br.y * scale_ratio - 1);
+  y_end = int(ceil(r.br.y * scale_ratio - 1));
   y_end = y_end < scaled_height ? y_end + 1 : scaled_height;
   return Rect(x_start, y_start, x_end, y_end);
 }