diff --git a/ChangeLog b/ChangeLog
index 68680286..008218d7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+24/3/16 started 8.2.4
+- fix nohalo and vsqbs interpolators, thanks Rafael
+
 27/1/16 started 8.2.3
 - fix a crash with SPARC byte-order labq vips images
 - fix parsing of filenames containing brackets, thanks shilpi230
diff --git a/configure.ac b/configure.ac
index cfc15321..a810ec7e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT([vips], [8.2.3], [vipsip@jiscmail.ac.uk])
+AC_INIT([vips], [8.2.4], [vipsip@jiscmail.ac.uk])
 # required for gobject-introspection
 AC_PREREQ(2.62)
 
@@ -18,7 +18,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [8])
 m4_define([vips_minor_version], [2])
-m4_define([vips_micro_version], [3])
+m4_define([vips_micro_version], [4])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -38,7 +38,7 @@ VIPS_VERSION_STRING=$VIPS_VERSION-`date`
 #   binary interface changes not backwards compatible?: reset age to 0
 
 LIBRARY_CURRENT=45
-LIBRARY_REVISION=3
+LIBRARY_REVISION=4
 LIBRARY_AGE=3
 
 # patched into include/vips/version.h
diff --git a/libvips/resample/nohalo.cpp b/libvips/resample/nohalo.cpp
index 01e5cf51..909fbfa9 100644
--- a/libvips/resample/nohalo.cpp
+++ b/libvips/resample/nohalo.cpp
@@ -1493,8 +1493,8 @@ vips_interpolate_nohalo_interpolate( VipsInterpolate* restrict interpolate,
    *
    * It's 2 not 0 since we ask for a window_offset of 2 at the bottom.
    */
-  const int ix = (int) absolute_x;
-  const int iy = (int) absolute_y;
+  const int ix = (int) (absolute_x + 0.5);
+  const int iy = (int) (absolute_y + 0.5);
 
   /*
    * Move the pointer to (the first band of) the top/left pixel of the
@@ -1523,8 +1523,8 @@ vips_interpolate_nohalo_interpolate( VipsInterpolate* restrict interpolate,
 
   g_assert( ix - 2 >= in->valid.left );
   g_assert( iy - 2 >= in->valid.top );
-  g_assert( ix + 2 < VIPS_RECT_RIGHT( &in->valid ) );
-  g_assert( iy + 2 < VIPS_RECT_BOTTOM( &in->valid ) );
+  g_assert( ix + 2 <= VIPS_RECT_RIGHT( &in->valid ) );
+  g_assert( iy + 2 <= VIPS_RECT_BOTTOM( &in->valid ) );
 
   /* Confirm that absolute_x and absolute_y are >= 2, see above. 
    */
@@ -1586,7 +1586,7 @@ vips_interpolate_nohalo_class_init( VipsInterpolateNohaloClass *klass )
     _( "edge sharpening resampler with halo reduction" );
 
   interpolate_class->interpolate   = vips_interpolate_nohalo_interpolate;
-  interpolate_class->window_size   = 5;
+  interpolate_class->window_size   = 6;
   interpolate_class->window_offset = 2;
 }
 
diff --git a/libvips/resample/vsqbs.cpp b/libvips/resample/vsqbs.cpp
index 77e1ecb4..6595a79a 100644
--- a/libvips/resample/vsqbs.cpp
+++ b/libvips/resample/vsqbs.cpp
@@ -313,8 +313,8 @@ vips_interpolate_vsqbs_interpolate( VipsInterpolate* restrict interpolate,
    *
    * It's 1 not 0 since we ask for a window_offset of 1 at the bottom.
    */
-  const int ix = (int) absolute_x;
-  const int iy = (int) absolute_y;
+  const int ix = (int) (absolute_x + 0.5);
+  const int iy = (int) (absolute_y + 0.5);
 
   /*
    * Move the pointer to (the first band of) the top/left pixel of the
@@ -343,8 +343,8 @@ vips_interpolate_vsqbs_interpolate( VipsInterpolate* restrict interpolate,
 
   g_assert( ix - 1 >= in->valid.left );
   g_assert( iy - 1 >= in->valid.top );
-  g_assert( ix + 1 < VIPS_RECT_RIGHT( &in->valid ) );
-  g_assert( iy + 1 < VIPS_RECT_BOTTOM( &in->valid ) );
+  g_assert( ix + 1 <= VIPS_RECT_RIGHT( &in->valid ) );
+  g_assert( iy + 1 <= VIPS_RECT_BOTTOM( &in->valid ) );
 
   /* Confirm that absolute_x and absolute_y are >= 1, see above. 
    */
@@ -405,7 +405,7 @@ vips_interpolate_vsqbs_class_init( VipsInterpolateVsqbsClass *klass )
   object_class->description = _( "B-Splines with antialiasing smoothing" );
 
   interpolate_class->interpolate   = vips_interpolate_vsqbs_interpolate;
-  interpolate_class->window_size   = 3;
+  interpolate_class->window_size   = 4;
   interpolate_class->window_offset = 1;
 }