Better error message.

diff --git a/src/lib/image.cc b/src/lib/image.cc
index 8718223ae83cf96eeb144695472319ee7d3057c1..d1f1fb9d14702873db816e8ef0ef45b8bd8b710e 100644 (file)
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -542,7 +542,7 @@ Image::alpha_blend (shared_ptr<const Image> other, Position<int> position)
                break;
        }
        default:
-               DCPOMATIC_ASSERT (false);
+               throw PixelFormatError ("alpha_blend()", _pixel_format);
        }
 }