Fix blur and sharpen performance for images with alpha channel

CHANGELOG.md

@@ -10,6 +10,7 @@
 - (pro) Use PNG quantization for very low-complexity images when the `best` format is used.
 
 ### Fixed
+- Fix blur and sharpen performance for images with alpha channel.
 - (pro) Fix object detecttion accuracy.
 
 ## [3.27.0] - 2024-12-18

vips/vips.c

@@ -609,7 +609,7 @@ vips_apply_filters(VipsImage *in, VipsImage **out, double blur_sigma,
       return 1;
     }
 
-    in = t[0];
+    in = t[1];
     premultiplied = TRUE;
   }