BitmapFilter::execute can be const

...after a little tweak to BitmapMosaicFilter

Change-Id: I76b8ffdbf719a9d7960e7f3dafeb3adeb2300ec5
Reviewed-on: https://gerrit.libreoffice.org/60165
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/include/vcl/BitmapMosaicFilter.hxx b/include/vcl/BitmapMosaicFilter.hxx
index 0fbf19613b5f..f38e0ac1c6d5 100644
--- a/include/vcl/BitmapMosaicFilter.hxx
+++ b/include/vcl/BitmapMosaicFilter.hxx
@@ -11,6 +11,10 @@
 #ifndef INCLUDED_VCL_BITMAPMOSAICFILTER_HXX
 #define INCLUDED_VCL_BITMAPMOSAICFILTER_HXX
 
+#include <sal/config.h>
+
+#include <algorithm>
+
 #include <vcl/BitmapFilter.hxx>
 
 class BitmapEx;
@@ -19,12 +23,12 @@ class VCL_DLLPUBLIC BitmapMosaicFilter : public BitmapFilter
 {
 public:
     BitmapMosaicFilter(sal_uLong nTileWidth, sal_uLong nTileHeight)
-        : mnTileWidth(nTileWidth)
-        , mnTileHeight(nTileHeight)
+        : mnTileWidth(std::max(nTileWidth, sal_uLong(1)))
+        , mnTileHeight(std::max(nTileHeight, sal_uLong(1)))
     {
     }
 
-    virtual BitmapEx execute(BitmapEx const& rBitmapEx) override;
+    virtual BitmapEx execute(BitmapEx const& rBitmapEx) const override;
 
 private:
     sal_uLong mnTileWidth;