diff --git a/ChangeLog b/ChangeLog
index 846f3e47..6cd85103 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -36,10 +36,8 @@
   we get expat as part of glib
 - add vips_smartcrop(), based on sharp's smartcropper
 - vipsthumbnail has a --smartcrop option
-- the C functions vips_math2_const(), vips_boolean_const() and 
-  vips_relational_const() have changed argument order to match
-  Python/CLI/C++ ... sorry
 - added vips_rot90() etc. convenience functions
+- fix vips_resize() bug when hscale and vscale were very different
 
 8/12/16 started 8.4.5
 - allow libgsf-1.14.26 to help centos, thanks tdiprima
diff --git a/TODO b/TODO
index f2d03d0f..36f83c6e 100644
--- a/TODO
+++ b/TODO
@@ -17,10 +17,6 @@
 
 - try moving some more of the CLI tests to py
 
-- try SEQ_UNBUFFERED on jpg source, get out of order error?
-
-- could load pdf thumbnails?
-
 - colour needs to split _build() into preprocess / process / postprocess
   phases
 
@@ -63,32 +59,20 @@
 
 - why can't we do
 
-
-im = Vips.Image.new_from_file("/data/john/pics/k2.jpg", access = "sequential")
-
-
-
-import logging
-logging.basicConfig(level = logging.DEBUG)
-from gi.repository import Vips
-im = Vips.Image.new_from_file("/data/john/pics/k2.jpg", access = "sequential")
-
-DEBUG:gi.overrides.Vips:assigning sequential to access
-DEBUG:gi.overrides.Vips:access needs a <GType VipsAccess (20432752)>
-DEBUG:gi.overrides.Vips:assigning sequential
-
-  ValueError: invalid literal for int() with base 10: 'sequential'
+	im = Vips.Image.new_from_file("/data/john/pics/k2.jpg", access = "sequential")
 
   no idea ... this works fine:
 
   	im.embed(10, 10, 100, 100, extend = "copy")
 
-  what about 
+  test:
 
-	im = Vips.Image.jpegload(sys.argv[1], access = "sequential")
-
-  nope, fails too ... mysterious!
+	op = Vips.Operation.new("embed")
+	op.props.__setattr__("extend", "copy")
+	op = Vips.Operation.new("jpegload")
+	op.props.__setattr__("access", "sequential")
 
+  first setattr works fine, second fails with invalid literal
 
 
 
@@ -437,4 +421,3 @@ new operations
 	http://www.nature.com/srep/2015/150730/srep12096/full/srep12096.html
 
   sounds useful for BM?
-
diff --git a/cplusplus/VImage.cpp b/cplusplus/VImage.cpp
index e617b3f7..27b29fdf 100644
--- a/cplusplus/VImage.cpp
+++ b/cplusplus/VImage.cpp
@@ -982,29 +982,29 @@ operator<( VImage a, VImage b )
 VImage 
 operator<( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_MORE ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_MORE, 
+		to_vector( a ) ) ); 
 }
 
 VImage 
 operator<( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_LESS ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_LESS, 
+		to_vector( b ) ) );  
 }
 
 VImage 
 operator<( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_MORE ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_MORE, 
+		a ) );  
 }
 
 VImage 
 operator<( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_LESS ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_LESS, 
+		b ) ); 
 }
 
 VImage 
@@ -1016,29 +1016,29 @@ operator<=( VImage a, VImage b )
 VImage 
 operator<=( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_MOREEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_MOREEQ, 
+		to_vector( a ) ) );  
 }
 
 VImage 
 operator<=( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_LESSEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_LESSEQ, 
+		to_vector( b ) ) );  
 }
 
 VImage 
 operator<=( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_MOREEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_MOREEQ, 
+		a ) );
 }
 
 VImage 
 operator<=( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_LESSEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_LESSEQ,
+		b ) );
 }
 
 VImage 
@@ -1050,29 +1050,29 @@ operator>( VImage a, VImage b )
 VImage 
 operator>( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_LESS ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_LESS, 
+		to_vector( a ) ) ); 
 }
 
 VImage 
 operator>( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_MORE ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_MORE, 
+		to_vector( b ) ) );
 }
 
 VImage 
 operator>( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_LESS ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_LESS, 
+		a ) );
 }
 
 VImage 
 operator>( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_MORE ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_MORE, 
+		b ) );
 }
 
 VImage 
@@ -1084,29 +1084,29 @@ operator>=( VImage a, VImage b )
 VImage 
 operator>=( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_LESSEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_LESSEQ, 
+		to_vector( a ) ) );  
 }
 
 VImage 
 operator>=( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_MOREEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_MOREEQ, 
+		to_vector( b ) ) ); 
 }
 
 VImage 
 operator>=( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_LESSEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_LESSEQ, 
+		a ) );
 }
 
 VImage 
 operator>=( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_MOREEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_MOREEQ, 
+		b ) );
 }
 
 VImage 
@@ -1118,29 +1118,29 @@ operator==( VImage a, VImage b )
 VImage 
 operator==( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_EQUAL ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_EQUAL, 
+		to_vector( a ) ) );
 }
 
 VImage 
 operator==( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_EQUAL ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_EQUAL, 
+		to_vector( b ) ) );
 }
 
 VImage 
 operator==( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_EQUAL ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_EQUAL, 
+		a ) );
 }
 
 VImage 
 operator==( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_EQUAL ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_EQUAL, 
+		b ) );
 }
 
 VImage 
@@ -1152,29 +1152,29 @@ operator!=( VImage a, VImage b )
 VImage 
 operator!=( double a, VImage b ) 
 {
-	return( b.relational_const( to_vector( a ), 
-		VIPS_OPERATION_RELATIONAL_NOTEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_NOTEQ,
+		to_vector( a ) ) );  
 }
 
 VImage 
 operator!=( VImage a, double b ) 
 { 
-	return( a.relational_const( to_vector( b ), 
-		VIPS_OPERATION_RELATIONAL_NOTEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_NOTEQ, 
+		to_vector( b ) ) );
 }
 
 VImage 
 operator!=( std::vector<double> a, VImage b ) 
 {
-	return( b.relational_const( a, 
-		VIPS_OPERATION_RELATIONAL_NOTEQ ) );
+	return( b.relational_const( VIPS_OPERATION_RELATIONAL_NOTEQ,
+		a ) );
 }
 
 VImage 
 operator!=( VImage a, std::vector<double> b ) 
 { 
-	return( a.relational_const( b, 
-		VIPS_OPERATION_RELATIONAL_NOTEQ ) );
+	return( a.relational_const( VIPS_OPERATION_RELATIONAL_NOTEQ,
+		b ) );
 }
 
 VImage 
@@ -1186,27 +1186,27 @@ operator&( VImage a, VImage b )
 VImage 
 operator&( double a, VImage b ) 
 {
-	return( b.boolean_const( to_vector( a ), 
-		VIPS_OPERATION_BOOLEAN_AND ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_AND, 
+		to_vector( a ) ) );  
 }
 
 VImage 
 operator&( VImage a, double b ) 
 { 
-	return( a.boolean_const( to_vector( b ), 
-		VIPS_OPERATION_BOOLEAN_AND ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_AND, 
+		to_vector( b ) ) );
 }
 
 VImage 
 operator&( std::vector<double> a, VImage b ) 
 {
-	return( b.boolean_const( a, VIPS_OPERATION_BOOLEAN_AND ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_AND, a ) );
 }
 
 VImage 
 operator&( VImage a, std::vector<double> b ) 
 { 
-	return( a.boolean_const( b, VIPS_OPERATION_BOOLEAN_AND ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_AND, b ) );
 }
 
 VImage & 
@@ -1236,27 +1236,29 @@ operator|( VImage a, VImage b )
 VImage 
 operator|( double a, VImage b ) 
 {
-	return( b.boolean_const( to_vector( a ), 
-		VIPS_OPERATION_BOOLEAN_OR ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_OR, 
+		to_vector( a ) ) ); 
 }
 
 VImage 
 operator|( VImage a, double b ) 
 { 
-	return( a.boolean_const( to_vector( b ), 
-		VIPS_OPERATION_BOOLEAN_OR ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_OR, 
+		to_vector( b ) ) );
 }
 
 VImage 
 operator|( std::vector<double> a, VImage b ) 
 {
-	return( b.boolean_const( a, VIPS_OPERATION_BOOLEAN_OR ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_OR, 
+		a ) );
 }
 
 VImage 
 operator|( VImage a, std::vector<double> b ) 
 { 
-	return( a.boolean_const( b, VIPS_OPERATION_BOOLEAN_OR ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_OR, 
+		b ) );
 }
 
 VImage & 
@@ -1286,27 +1288,29 @@ operator^( VImage a, VImage b )
 VImage 
 operator^( double a, VImage b ) 
 {
-	return( b.boolean_const( to_vector( a ), 
-		VIPS_OPERATION_BOOLEAN_EOR ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_EOR, 
+		to_vector( a ) ) ); 
 }
 
 VImage 
 operator^( VImage a, double b ) 
 { 
-	return( a.boolean_const( to_vector( b ), 
-		VIPS_OPERATION_BOOLEAN_EOR ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_EOR, 
+		to_vector( b ) ) ); 
 }
 
 VImage 
 operator^( std::vector<double> a, VImage b ) 
 {
-	return( b.boolean_const( a, VIPS_OPERATION_BOOLEAN_EOR ) );
+	return( b.boolean_const( VIPS_OPERATION_BOOLEAN_EOR,
+		a ) );
 }
 
 VImage 
 operator^( VImage a, std::vector<double> b ) 
 { 
-	return( a.boolean_const( b, VIPS_OPERATION_BOOLEAN_EOR ) );
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_EOR,
+		b ) );
 }
 
 VImage & 
@@ -1336,14 +1340,15 @@ operator<<( VImage a, VImage b )
 VImage 
 operator<<( VImage a, double b ) 
 { 
-	return( a.boolean_const( to_vector( b ), 
-		VIPS_OPERATION_BOOLEAN_LSHIFT ) ); 
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_LSHIFT, 
+		to_vector( b ) ) ); 
 }
 
 VImage 
 operator<<( VImage a, std::vector<double> b ) 
 { 
-	return( a.boolean_const( b, VIPS_OPERATION_BOOLEAN_LSHIFT ) ); 
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_LSHIFT, 
+		b ) ); 
 }
 
 VImage & 
@@ -1373,14 +1378,15 @@ operator>>( VImage a, VImage b )
 VImage 
 operator>>( VImage a, double b ) 
 { 
-	return( a.boolean_const( to_vector( b ), 
-		VIPS_OPERATION_BOOLEAN_RSHIFT ) ); 
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_RSHIFT, 
+		to_vector( b ) ) );  
 }
 
 VImage 
 operator>>( VImage a, std::vector<double> b ) 
 { 
-	return( a.boolean_const( b, VIPS_OPERATION_BOOLEAN_RSHIFT ) ); 
+	return( a.boolean_const( VIPS_OPERATION_BOOLEAN_RSHIFT,
+		b ) ); 
 }
 
 VImage & 
diff --git a/cplusplus/include/vips/VImage8.h b/cplusplus/include/vips/VImage8.h
index 00d05896..b23a76d8 100644
--- a/cplusplus/include/vips/VImage8.h
+++ b/cplusplus/include/vips/VImage8.h
@@ -699,15 +699,15 @@ public:
 	VImage 
 	pow( double other, VOption *options = 0 )
 	{
-		return( math2_const( to_vector( other ), 
-			VIPS_OPERATION_MATH2_POW, options ) );
+		return( math2_const( VIPS_OPERATION_MATH2_POW, 
+			to_vector( other ), options ) );
 	}
 
 	VImage 
 	pow( std::vector<double> other, VOption *options = 0 )
 	{
-		return( math2_const( other, 
-			VIPS_OPERATION_MATH2_POW, options ) );
+		return( math2_const( VIPS_OPERATION_MATH2_POW, 
+			other, options ) );
 	}
 
 	VImage 
@@ -719,15 +719,15 @@ public:
 	VImage 
 	wop( double other, VOption *options = 0 )
 	{
-		return( math2_const( to_vector( other ), 
-			VIPS_OPERATION_MATH2_WOP, options ) );
+		return( math2_const( VIPS_OPERATION_MATH2_WOP, 
+			to_vector( other ), options ) );
 	}
 
 	VImage 
 	wop( std::vector<double> other, VOption *options = 0 )
 	{
-		return( math2_const( other, 
-			VIPS_OPERATION_MATH2_WOP, options ) );
+		return( math2_const( VIPS_OPERATION_MATH2_WOP, 
+			other, options ) );
 	}
 
 	VImage 
diff --git a/cplusplus/include/vips/vips-operators.h b/cplusplus/include/vips/vips-operators.h
index 889f7440..68df252a 100644
--- a/cplusplus/include/vips/vips-operators.h
+++ b/cplusplus/include/vips/vips-operators.h
@@ -1,5 +1,5 @@
 // headers for vips operations
-// Wed  1 Mar 15:40:22 GMT 2017
+// Mon 13 Mar 13:22:09 GMT 2017
 // this file is generated automatically, do not edit!
 
 static void system( char * cmd_format , VOption *options = 0 );
@@ -20,10 +20,10 @@ VImage math( VipsOperationMath math , VOption *options = 0 );
 VImage abs( VOption *options = 0 );
 VImage sign( VOption *options = 0 );
 VImage round( VipsOperationRound round , VOption *options = 0 );
-VImage relational_const( std::vector<double> c , VipsOperationRelational relational , VOption *options = 0 );
+VImage relational_const( VipsOperationRelational relational , std::vector<double> c , VOption *options = 0 );
 VImage remainder_const( std::vector<double> c , VOption *options = 0 );
-VImage boolean_const( std::vector<double> c , VipsOperationBoolean boolean , VOption *options = 0 );
-VImage math2_const( std::vector<double> c , VipsOperationMath2 math2 , VOption *options = 0 );
+VImage boolean_const( VipsOperationBoolean boolean , std::vector<double> c , VOption *options = 0 );
+VImage math2_const( VipsOperationMath2 math2 , std::vector<double> c , VOption *options = 0 );
 VImage complex( VipsOperationComplex cmplx , VOption *options = 0 );
 VImage complexget( VipsOperationComplexget get , VOption *options = 0 );
 double avg( VOption *options = 0 );
diff --git a/cplusplus/vips-operators.cpp b/cplusplus/vips-operators.cpp
index a063cb09..bff2a745 100644
--- a/cplusplus/vips-operators.cpp
+++ b/cplusplus/vips-operators.cpp
@@ -1,5 +1,5 @@
 // bodies for vips operations
-// Wed  1 Mar 15:40:06 GMT 2017
+// Mon 13 Mar 13:22:17 GMT 2017
 // this file is generated automatically, do not edit!
 
 void VImage::system( char * cmd_format , VOption *options )
@@ -231,7 +231,7 @@ VImage VImage::round( VipsOperationRound round , VOption *options )
     return( out );
 }
 
-VImage VImage::relational_const( std::vector<double> c , VipsOperationRelational relational , VOption *options )
+VImage VImage::relational_const( VipsOperationRelational relational , std::vector<double> c , VOption *options )
 {
     VImage out;
 
@@ -239,8 +239,8 @@ VImage VImage::relational_const( std::vector<double> c , VipsOperationRelational
         (options ? options : VImage::option()) ->
             set( "in", *this ) ->
             set( "out", &out ) ->
-            set( "c", c ) ->
-            set( "relational", relational ) );
+            set( "relational", relational ) ->
+            set( "c", c ) );
 
     return( out );
 }
@@ -258,7 +258,7 @@ VImage VImage::remainder_const( std::vector<double> c , VOption *options )
     return( out );
 }
 
-VImage VImage::boolean_const( std::vector<double> c , VipsOperationBoolean boolean , VOption *options )
+VImage VImage::boolean_const( VipsOperationBoolean boolean , std::vector<double> c , VOption *options )
 {
     VImage out;
 
@@ -266,13 +266,13 @@ VImage VImage::boolean_const( std::vector<double> c , VipsOperationBoolean boole
         (options ? options : VImage::option()) ->
             set( "in", *this ) ->
             set( "out", &out ) ->
-            set( "c", c ) ->
-            set( "boolean", boolean ) );
+            set( "boolean", boolean ) ->
+            set( "c", c ) );
 
     return( out );
 }
 
-VImage VImage::math2_const( std::vector<double> c , VipsOperationMath2 math2 , VOption *options )
+VImage VImage::math2_const( VipsOperationMath2 math2 , std::vector<double> c , VOption *options )
 {
     VImage out;
 
@@ -280,8 +280,8 @@ VImage VImage::math2_const( std::vector<double> c , VipsOperationMath2 math2 , V
         (options ? options : VImage::option()) ->
             set( "in", *this ) ->
             set( "out", &out ) ->
-            set( "c", c ) ->
-            set( "math2", math2 ) );
+            set( "math2", math2 ) ->
+            set( "c", c ) );
 
     return( out );
 }
@@ -493,8 +493,8 @@ VImage VImage::copy( VOption *options )
 
     call( "copy" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -505,8 +505,8 @@ VImage VImage::tilecache( VOption *options )
 
     call( "tilecache" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -517,8 +517,8 @@ VImage VImage::linecache( VOption *options )
 
     call( "linecache" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -529,8 +529,8 @@ VImage VImage::sequential( VOption *options )
 
     call( "sequential" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -541,8 +541,8 @@ VImage VImage::cache( VOption *options )
 
     call( "cache" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -569,8 +569,8 @@ VImage VImage::flip( VipsDirection direction , VOption *options )
 
     call( "flip" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
             set( "in", *this ) ->
+            set( "out", &out ) ->
             set( "direction", direction ) );
 
     return( out );
@@ -742,8 +742,8 @@ VImage VImage::cast( VipsBandFormat format , VOption *options )
 
     call( "cast" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
             set( "in", *this ) ->
+            set( "out", &out ) ->
             set( "format", format ) );
 
     return( out );
@@ -755,8 +755,8 @@ VImage VImage::rot( VipsAngle angle , VOption *options )
 
     call( "rot" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
             set( "in", *this ) ->
+            set( "out", &out ) ->
             set( "angle", angle ) );
 
     return( out );
@@ -768,8 +768,8 @@ VImage VImage::rot45( VOption *options )
 
     call( "rot45" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -780,8 +780,8 @@ VImage VImage::autorot( VOption *options )
 
     call( "autorot" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -819,8 +819,8 @@ VImage VImage::bandfold( VOption *options )
 
     call( "bandfold" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -831,8 +831,8 @@ VImage VImage::bandunfold( VOption *options )
 
     call( "bandunfold" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -843,8 +843,8 @@ VImage VImage::flatten( VOption *options )
 
     call( "flatten" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -855,8 +855,8 @@ VImage VImage::premultiply( VOption *options )
 
     call( "premultiply" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -867,8 +867,8 @@ VImage VImage::unpremultiply( VOption *options )
 
     call( "unpremultiply" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -879,8 +879,8 @@ VImage VImage::grid( int tile_height , int across , int down , VOption *options
 
     call( "grid" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
             set( "in", *this ) ->
+            set( "out", &out ) ->
             set( "tile-height", tile_height ) ->
             set( "across", across ) ->
             set( "down", down ) );
@@ -894,8 +894,8 @@ VImage VImage::scale( VOption *options )
 
     call( "scale" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -906,8 +906,8 @@ VImage VImage::wrap( VOption *options )
 
     call( "wrap" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
@@ -958,8 +958,8 @@ VImage VImage::byteswap( VOption *options )
 
     call( "byteswap" ,
         (options ? options : VImage::option()) ->
-            set( "out", &out ) ->
-            set( "in", *this ) );
+            set( "in", *this ) ->
+            set( "out", &out ) );
 
     return( out );
 }
diff --git a/libvips/arithmetic/boolean.c b/libvips/arithmetic/boolean.c
index 80e2272c..2ed8594e 100644
--- a/libvips/arithmetic/boolean.c
+++ b/libvips/arithmetic/boolean.c
@@ -533,7 +533,7 @@ vips_boolean_const_init( VipsBooleanConst *boolean_const )
 
 static int
 vips_boolean_constv( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationBoolean operation, va_list ap )
+	VipsOperationBoolean operation, double *c, int n, va_list ap )
 {
 	VipsArea *area_c;
 	double *array; 
@@ -546,7 +546,7 @@ vips_boolean_constv( VipsImage *in, VipsImage **out,
 		array[i] = c[i];
 
 	result = vips_call_split( "boolean_const", ap, 
-		in, out, area_c, operation );
+		in, out, operation, area_c );
 
 	vips_area_unref( area_c );
 
@@ -557,9 +557,9 @@ vips_boolean_constv( VipsImage *in, VipsImage **out,
  * vips_boolean_const:
  * @in: input image
  * @out: output image
+ * @boolean: boolean operation to perform
  * @c: array of constants 
  * @n: number of constants in @c
- * @boolean: boolean operation to perform
  * @...: %NULL-terminated list of optional named arguments
  *
  * Perform various boolean operations on an image against an array of
@@ -580,13 +580,13 @@ vips_boolean_constv( VipsImage *in, VipsImage **out,
  */
 int
 vips_boolean_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationBoolean boolean, ... )
+	VipsOperationBoolean boolean, double *c, int n, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, boolean );
-	result = vips_boolean_constv( in, out, c, n, boolean, ap );
+	va_start( ap, n );
+	result = vips_boolean_constv( in, out, boolean, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -615,7 +615,7 @@ vips_andimage_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_boolean_constv( in, out, 
-		c, n, VIPS_OPERATION_BOOLEAN_AND, ap );
+		VIPS_OPERATION_BOOLEAN_AND, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -644,7 +644,7 @@ vips_orimage_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_boolean_constv( in, out, 
-		c, n, VIPS_OPERATION_BOOLEAN_OR, ap );
+		VIPS_OPERATION_BOOLEAN_OR, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -673,7 +673,7 @@ vips_eorimage_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_boolean_constv( in, out, 
-		c, n, VIPS_OPERATION_BOOLEAN_EOR, ap );
+		VIPS_OPERATION_BOOLEAN_EOR, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -702,7 +702,7 @@ vips_lshift_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_boolean_constv( in, out, 
-		c, n, VIPS_OPERATION_BOOLEAN_LSHIFT, ap );
+		VIPS_OPERATION_BOOLEAN_LSHIFT, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -731,7 +731,7 @@ vips_rshift_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_boolean_constv( in, out, 
-		c, n, VIPS_OPERATION_BOOLEAN_RSHIFT, ap );
+		VIPS_OPERATION_BOOLEAN_RSHIFT, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -754,13 +754,13 @@ vips_rshift_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
  */
 int
 vips_boolean_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationBoolean boolean, ... )
+	VipsOperationBoolean boolean, double c, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, boolean );
-	result = vips_boolean_constv( in, out, &c, 1, boolean, ap );
+	va_start( ap, c );
+	result = vips_boolean_constv( in, out, boolean, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -788,7 +788,7 @@ vips_andimage_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_boolean_constv( in, out, 
-		&c, 1, VIPS_OPERATION_BOOLEAN_AND, ap );
+		VIPS_OPERATION_BOOLEAN_AND, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -816,7 +816,7 @@ vips_orimage_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_boolean_constv( in, out, 
-		&c, 1, VIPS_OPERATION_BOOLEAN_OR, ap );
+		VIPS_OPERATION_BOOLEAN_OR, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -844,7 +844,7 @@ vips_eorimage_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_boolean_constv( in, out, 
-		&c, 1, VIPS_OPERATION_BOOLEAN_EOR, ap );
+		VIPS_OPERATION_BOOLEAN_EOR, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -872,7 +872,7 @@ vips_lshift_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_boolean_constv( in, out, 
-		&c, 1, VIPS_OPERATION_BOOLEAN_LSHIFT, ap );
+		VIPS_OPERATION_BOOLEAN_LSHIFT, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -900,7 +900,7 @@ vips_rshift_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_boolean_constv( in, out, 
-		&c, 1, VIPS_OPERATION_BOOLEAN_RSHIFT, ap );
+		VIPS_OPERATION_BOOLEAN_RSHIFT, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
diff --git a/libvips/arithmetic/math2.c b/libvips/arithmetic/math2.c
index 651e5829..90adecaf 100644
--- a/libvips/arithmetic/math2.c
+++ b/libvips/arithmetic/math2.c
@@ -421,7 +421,7 @@ vips_math2_const_init( VipsMath2Const *math2_const )
 
 static int
 vips_math2_constv( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationMath2 math2, va_list ap )
+	VipsOperationMath2 math2, double *c, int n, va_list ap )
 {
 	VipsArea *area_c;
 	double *array; 
@@ -433,7 +433,7 @@ vips_math2_constv( VipsImage *in, VipsImage **out,
 	for( i = 0; i < n; i++ ) 
 		array[i] = c[i];
 
-	result = vips_call_split( "math2_const", ap, in, out, area_c, math2 );
+	result = vips_call_split( "math2_const", ap, in, out, math2, area_c );
 
 	vips_area_unref( area_c );
 
@@ -444,9 +444,9 @@ vips_math2_constv( VipsImage *in, VipsImage **out,
  * vips_math2_const:
  * @in: input image
  * @out: output image
+ * @math2: math operation to perform
  * @c: array of constants 
  * @n: number of constants in @c
- * @math2: math operation to perform
  * @...: %NULL-terminated list of optional named arguments
  *
  * This operation calculates various 2-ary maths operations on an image and 
@@ -471,13 +471,13 @@ vips_math2_constv( VipsImage *in, VipsImage **out,
  */
 int
 vips_math2_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationMath2 math2, ... )
+	VipsOperationMath2 math2, double *c, int n, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, math2 );
-	result = vips_math2_constv( in, out, c, n, math2, ap ); 
+	va_start( ap, n );
+	result = vips_math2_constv( in, out, math2, c, n, ap ); 
 	va_end( ap );
 
 	return( result );
@@ -504,7 +504,7 @@ vips_pow_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_math2_constv( in, out, 
-		c, n, VIPS_OPERATION_MATH2_POW, ap );
+		VIPS_OPERATION_MATH2_POW, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -531,7 +531,7 @@ vips_wop_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_math2_constv( in, out, 
-		c, n, VIPS_OPERATION_MATH2_WOP, ap );
+		VIPS_OPERATION_MATH2_WOP, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -552,13 +552,13 @@ vips_wop_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
  */
 int
 vips_math2_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationMath2 math2, ... )
+	VipsOperationMath2 math2, double c, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, math2 );
-	result = vips_math2_constv( in, out, &c, 1, math2, ap ); 
+	va_start( ap, c );
+	result = vips_math2_constv( in, out, math2, &c, 1, ap ); 
 	va_end( ap );
 
 	return( result );
@@ -584,7 +584,7 @@ vips_pow_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_math2_constv( in, out, 
-		&c, 1, VIPS_OPERATION_MATH2_POW, ap );
+		VIPS_OPERATION_MATH2_POW, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -610,7 +610,7 @@ vips_wop_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_math2_constv( in, out, 
-		&c, 1, VIPS_OPERATION_MATH2_WOP, ap );
+		VIPS_OPERATION_MATH2_WOP, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
diff --git a/libvips/arithmetic/relational.c b/libvips/arithmetic/relational.c
index 1898c8e1..96dda30d 100644
--- a/libvips/arithmetic/relational.c
+++ b/libvips/arithmetic/relational.c
@@ -574,7 +574,7 @@ vips_relational_const_init( VipsRelationalConst *relational_const )
 
 static int
 vips_relational_constv( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationRelational relational, va_list ap )
+	VipsOperationRelational relational, double *c, int n, va_list ap )
 {
 	VipsArea *area_c;
 	double *array; 
@@ -587,7 +587,7 @@ vips_relational_constv( VipsImage *in, VipsImage **out,
 		array[i] = c[i];
 
 	result = vips_call_split( "relational_const", ap, 
-		in, out, area_c, relational );
+		in, out, relational, area_c );
 
 	vips_area_unref( area_c );
 
@@ -598,9 +598,9 @@ vips_relational_constv( VipsImage *in, VipsImage **out,
  * vips_relational_const:
  * @in: input image
  * @out: output image
+ * @relational: relational operation to perform
  * @c: array of constants 
  * @n: number of constants in @c
- * @relational: relational operation to perform
  * @...: %NULL-terminated list of optional named arguments
  *
  * Perform various relational operations on an image and an array of
@@ -621,13 +621,13 @@ vips_relational_constv( VipsImage *in, VipsImage **out,
  */
 int
 vips_relational_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationRelational relational, ... )
+	VipsOperationRelational relational, double *c, int n, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, relational );
-	result = vips_relational_constv( in, out, c, n, relational, ap );
+	va_start( ap, n );
+	result = vips_relational_constv( in, out, relational, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -654,7 +654,7 @@ vips_equal_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_EQUAL, ap );
+		VIPS_OPERATION_RELATIONAL_EQUAL, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -681,7 +681,7 @@ vips_notequal_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_NOTEQ, ap );
+		VIPS_OPERATION_RELATIONAL_NOTEQ, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -708,7 +708,7 @@ vips_less_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_LESS, ap );
+		VIPS_OPERATION_RELATIONAL_LESS, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -735,7 +735,7 @@ vips_lesseq_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_LESSEQ, ap );
+		VIPS_OPERATION_RELATIONAL_LESSEQ, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -762,7 +762,7 @@ vips_more_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_MORE, ap );
+		VIPS_OPERATION_RELATIONAL_MORE, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -789,7 +789,7 @@ vips_moreeq_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 
 	va_start( ap, n );
 	result = vips_relational_constv( in, out, 
-		c, n, VIPS_OPERATION_RELATIONAL_MOREEQ, ap );
+		VIPS_OPERATION_RELATIONAL_MOREEQ, c, n, ap );
 	va_end( ap );
 
 	return( result );
@@ -799,8 +799,8 @@ vips_moreeq_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
  * vips_relational_const1:
  * @in: input image
  * @out: output image
- * @c: constant 
  * @relational: relational operation to perform
+ * @c: constant 
  * @...: %NULL-terminated list of optional named arguments
  *
  * Perform various relational operations on an image and a constant. See
@@ -812,13 +812,13 @@ vips_moreeq_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
  */
 int
 vips_relational_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationRelational relational, ... )
+	VipsOperationRelational relational, double c, ... )
 {
 	va_list ap;
 	int result;
 
-	va_start( ap, relational );
-	result = vips_relational_constv( in, out, &c, 1, relational, ap );
+	va_start( ap, c );
+	result = vips_relational_constv( in, out, relational, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -844,7 +844,7 @@ vips_equal_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_EQUAL, ap );
+		VIPS_OPERATION_RELATIONAL_EQUAL, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -870,7 +870,7 @@ vips_notequal_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_NOTEQ, ap );
+		VIPS_OPERATION_RELATIONAL_NOTEQ, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -896,7 +896,7 @@ vips_less_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_LESS, ap );
+		VIPS_OPERATION_RELATIONAL_LESS, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -922,7 +922,7 @@ vips_lesseq_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_LESSEQ, ap );
+		VIPS_OPERATION_RELATIONAL_LESSEQ, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -948,7 +948,7 @@ vips_more_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_MORE, ap );
+		VIPS_OPERATION_RELATIONAL_MORE, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
@@ -974,7 +974,7 @@ vips_moreeq_const1( VipsImage *in, VipsImage **out, double c, ... )
 
 	va_start( ap, c );
 	result = vips_relational_constv( in, out, 
-		&c, 1, VIPS_OPERATION_RELATIONAL_MOREEQ, ap );
+		VIPS_OPERATION_RELATIONAL_MOREEQ, &c, 1, ap );
 	va_end( ap );
 
 	return( result );
diff --git a/libvips/arithmetic/unaryconst.c b/libvips/arithmetic/unaryconst.c
index a3eacad7..b5cbf797 100644
--- a/libvips/arithmetic/unaryconst.c
+++ b/libvips/arithmetic/unaryconst.c
@@ -203,7 +203,7 @@ vips_unary_const_class_init( VipsUnaryConstClass *class )
 	object_class->description = _( "unary operations with a constant" );
 	object_class->build = vips_unary_const_build;
 
-	VIPS_ARG_BOXED( class, "c", 199, 
+	VIPS_ARG_BOXED( class, "c", 201, 
 		_( "c" ), 
 		_( "Array of constants" ),
 		VIPS_ARGUMENT_REQUIRED_INPUT,
diff --git a/libvips/deprecated/vips7compat.c b/libvips/deprecated/vips7compat.c
index 29de1e09..db23ec21 100644
--- a/libvips/deprecated/vips7compat.c
+++ b/libvips/deprecated/vips7compat.c
@@ -2749,7 +2749,7 @@ vips__relational_vec( IMAGE *in, IMAGE *out,
 {
 	VipsImage *t;
 
-	if( vips_relational_const( in, &t, c, n, relational, 
+	if( vips_relational_const( in, &t, relational, c, n, 
 		NULL ) )
 		return( -1 );
 	if( vips_image_write( t, out ) ) {
@@ -2921,7 +2921,7 @@ vips__boolean_vec( IMAGE *in, IMAGE *out,
 {
 	VipsImage *t;
 
-	if( vips_boolean_const( in, &t, c, n, boolean,
+	if( vips_boolean_const( in, &t, boolean, c, n, 
 		NULL ) )
 		return( -1 );
 	if( vips_image_write( t, out ) ) {
@@ -3008,7 +3008,7 @@ vips__math2_vec( IMAGE *in, IMAGE *out,
 {
 	VipsImage *t;
 
-	if( vips_math2_const( in, &t, c, n, math2, 
+	if( vips_math2_const( in, &t, math2, c, n, 
 		NULL ) )
 		return( -1 );
 	if( vips_image_write( t, out ) ) {
diff --git a/libvips/foreign/gifload.c b/libvips/foreign/gifload.c
index 5b347ac6..c97a047c 100644
--- a/libvips/foreign/gifload.c
+++ b/libvips/foreign/gifload.c
@@ -805,7 +805,7 @@ vips_foreign_load_gif_class_init( VipsForeignLoadGifClass *class )
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
 
-	object_class->nickname = "gifload";
+	object_class->nickname = "gifload_base";
 	object_class->description = _( "load GIF with giflib" );
 
 	load_class->get_flags_filename = 
diff --git a/libvips/foreign/pdfload.c b/libvips/foreign/pdfload.c
index a32591c2..7a621125 100644
--- a/libvips/foreign/pdfload.c
+++ b/libvips/foreign/pdfload.c
@@ -455,7 +455,7 @@ vips_foreign_load_pdf_class_init( VipsForeignLoadPdfClass *class )
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
 
-	object_class->nickname = "pdfload";
+	object_class->nickname = "pdfload_base";
 	object_class->description = _( "load PDF with libpoppler" );
 	object_class->build = vips_foreign_load_pdf_build;
 
diff --git a/libvips/include/vips/arithmetic.h b/libvips/include/vips/arithmetic.h
index ccee62f4..7c42e2d3 100644
--- a/libvips/include/vips/arithmetic.h
+++ b/libvips/include/vips/arithmetic.h
@@ -279,7 +279,7 @@ int vips_more( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 int vips_moreeq( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_relational_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationRelational relational, ... )
+	VipsOperationRelational relational, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_equal_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
@@ -294,7 +294,7 @@ int vips_more_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 int vips_moreeq_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_relational_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationRelational relational, ... )
+	VipsOperationRelational relational, double c, ... )
 	__attribute__((sentinel));
 int vips_equal_const1( VipsImage *in, VipsImage **out, double c, ... )
 	__attribute__((sentinel));
@@ -324,7 +324,7 @@ int vips_rshift( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 	__attribute__((sentinel));
 
 int vips_boolean_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationBoolean boolean, ... )
+	VipsOperationBoolean boolean, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_andimage_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
@@ -337,7 +337,7 @@ int vips_lshift_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 int vips_rshift_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_boolean_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationBoolean boolean, ... )
+	VipsOperationBoolean boolean, double c, ... )
 	__attribute__((sentinel));
 int vips_andimage_const1( VipsImage *in, VipsImage **out, double c, ... )
 	__attribute__((sentinel));
@@ -358,14 +358,14 @@ int vips_pow( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 int vips_wop( VipsImage *left, VipsImage *right, VipsImage **out, ... )
 	__attribute__((sentinel));
 int vips_math2_const( VipsImage *in, VipsImage **out, 
-	double *c, int n, VipsOperationMath2 math2, ... )
+	VipsOperationMath2 math2, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_pow_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_wop_const( VipsImage *in, VipsImage **out, double *c, int n, ... )
 	__attribute__((sentinel));
 int vips_math2_const1( VipsImage *in, VipsImage **out, 
-	double c, VipsOperationMath2 math2, ... )
+	VipsOperationMath2 math2, double c, ... )
 	__attribute__((sentinel));
 int vips_pow_const1( VipsImage *in, VipsImage **out, double c, ... )
 	__attribute__((sentinel));
diff --git a/libvips/iofuncs/image.c b/libvips/iofuncs/image.c
index 79475600..8cd35a80 100644
--- a/libvips/iofuncs/image.c
+++ b/libvips/iofuncs/image.c
@@ -1622,12 +1622,12 @@ vips_image_set_progress( VipsImage *image, gboolean progress )
  * vips_image_iskilled:
  * @image: image to test
  *
- * If @image has been killed (see vips_image_kill()), set an error message,
+ * If @image has been killed (see vips_image_set_kill()), set an error message,
  * clear the #VipsImage.kill flag and return %FALSE. Otherwise return %TRUE.
  *
  * Handy for loops which need to run sets of threads which can fail. 
  *
- * See also: vips_image_kill().
+ * See also: vips_image_set_kill().
  *
  * Returns: %FALSE if @image has been killed. 
  */
diff --git a/libvips/resample/reducev.cpp b/libvips/resample/reducev.cpp
index 3cf3d7f7..8dab1ad5 100644
--- a/libvips/resample/reducev.cpp
+++ b/libvips/resample/reducev.cpp
@@ -832,6 +832,8 @@ vips_reducev_build( VipsObject *object )
 	if( VIPS_OBJECT_CLASS( vips_reducev_parent_class )->build( object ) )
 		return( -1 );
 
+	g_info( "reducev by factor %g", reducev->vshrink );
+
 	in = resample->in; 
 
 	if( reducev->vshrink < 1 ) { 
diff --git a/libvips/resample/resize.c b/libvips/resample/resize.c
index 419717e5..52c88af8 100644
--- a/libvips/resample/resize.c
+++ b/libvips/resample/resize.c
@@ -127,7 +127,7 @@ vips_resize_int_shrink( VipsResize *resize, double scale )
 
 	case VIPS_KERNEL_LANCZOS2:
 	case VIPS_KERNEL_LANCZOS3:
-		return( VIPS_MAX( 1, VIPS_FLOOR( 1.0 / (resize->scale * 2) ) ) );
+		return( VIPS_MAX( 1, VIPS_FLOOR( 1.0 / (scale * 2) ) ) );
 	}
 }
 
diff --git a/python/packages/gi/overrides/Vips.py b/python/packages/gi/overrides/Vips.py
index f4440c6e..55043ae2 100644
--- a/python/packages/gi/overrides/Vips.py
+++ b/python/packages/gi/overrides/Vips.py
@@ -60,6 +60,11 @@ vips_type_image = GObject.GType.from_name("VipsImage")
 vips_type_operation = GObject.GType.from_name("VipsOperation")
 vips_type_ref_string = GObject.GType.from_name("VipsRefString")
 
+# 8.4 and earlier had a bug which swapped the order of const args to enum
+# operations
+swap_const_args = Vips.version(0) < 8 or (Vips.version(0) == 8 and 
+                                          Vips.version(1) <= 4)
+
 def is_2D(value):
     if not isinstance(value, list):
         return False
@@ -415,6 +420,27 @@ def _call_base(name, required, optional, self = None, option_string = None):
 
     return out
 
+# handy for expanding enums
+def _call_enum(self, name, enum, other):
+    if isinstance(other, Vips.Image):
+        return _call_base(name, [other, enum], {}, self)
+    elif swap_const_args:
+        return _call_base(name + "_const", [other, enum], {}, self)
+    else:
+        return _call_base(name + "_const", [enum, other], {}, self)
+
+# for equality style operations, we need to allow comparison with None
+def _call_enum_eq(self, name, enum, other):
+    if isinstance(other, Vips.Image):
+        return _call_base(name, [other, enum], {}, self)
+    elif isinstance(other, list) or isinstance(other, numbers.Number):
+        if swap_const_args:
+            return _call_base(name + "_const", [other, enum], {}, self)
+        else:
+            return _call_base(name + "_const", [enum, other], {}, self)
+    else:
+        return False
+
 # general user entrypoint 
 def call(name, *args, **kwargs):
     return _call_base(name, args, kwargs)
@@ -712,52 +738,34 @@ class Image(Vips.Image):
             return self.remainder_const(other)
 
     def __pow__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.math2(other, Vips.OperationMath2.POW)
-        else:
-            return self.math2_const(other, Vips.OperationMath2.POW)
+        return _call_enum(self, "math2", Vips.OperationMath2.POW, other)
 
     def __rpow__(self, other):
-        return self.math2_const(other, Vips.OperationMath2.WOP)
+        return _call_enum(self, "math2", Vips.OperationMath2.WOP, other)
 
     def __abs__(self):
         return self.abs()
 
     def __lshift__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.boolean(other, Vips.OperationBoolean.LSHIFT)
-        else:
-            return self.boolean_const(other, Vips.OperationBoolean.LSHIFT)
+        return _call_enum(self, "boolean", Vips.OperationBoolean.LSHIFT, other)
 
     def __rshift__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.boolean(other, Vips.OperationBoolean.RSHIFT)
-        else:
-            return self.boolean_const(other, Vips.OperationBoolean.RSHIFT)
+        return _call_enum(self, "boolean", Vips.OperationBoolean.RSHIFT, other)
 
     def __and__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.boolean(other, Vips.OperationBoolean.AND)
-        else:
-            return self.boolean_const(other, Vips.OperationBoolean.AND)
+        return _call_enum(self, "boolean", Vips.OperationBoolean.AND, other)
 
     def __rand__(self, other):
         return self.__and__(other)
 
     def __or__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.boolean(other, Vips.OperationBoolean.OR)
-        else:
-            return self.boolean_const(other, Vips.OperationBoolean.OR)
+        return _call_enum(self, "boolean", Vips.OperationBoolean.OR, other)
 
     def __ror__(self, other):
         return self.__or__(other)
 
     def __xor__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.boolean(other, Vips.OperationBoolean.EOR)
-        else:
-            return self.boolean_const(other, Vips.OperationBoolean.EOR)
+        return _call_enum(self, "boolean", Vips.OperationBoolean.EOR, other)
 
     def __rxor__(self, other):
         return self.__xor__(other)
@@ -772,49 +780,30 @@ class Image(Vips.Image):
         return self ^ -1
 
     def __gt__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.MORE)
-        else:
-            return self.relational_const(other, Vips.OperationRelational.MORE)
+        return _call_enum(self, 
+                          "relational", Vips.OperationRelational.MORE, other)
 
     def __ge__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.MOREEQ)
-        else:
-            return self.relational_const(other, Vips.OperationRelational.MOREEQ)
+        return _call_enum(self, 
+                          "relational", Vips.OperationRelational.MOREEQ, other)
 
     def __lt__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.LESS)
-        else:
-            return self.relational_const(other, Vips.OperationRelational.LESS)
+        return _call_enum(self, 
+                          "relational", Vips.OperationRelational.LESS, other)
 
     def __le__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.LESSEQ)
-        else:
-            return self.relational_const(other, Vips.OperationRelational.LESSEQ)
+        return _call_enum(self, 
+                          "relational", Vips.OperationRelational.LESSEQ, other)
 
     def __eq__(self, other):
-        # for == and != we need to allow comparison to None
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.EQUAL)
-        elif isinstance(other, list):
-            return self.relational_const(other, Vips.OperationRelational.EQUAL)
-        elif isinstance(other, numbers.Number):
-            return self.relational_const(other, Vips.OperationRelational.EQUAL)
-        else:
-            return False
+        # _eq version allows comparison to None
+        return _call_enum_eq(self, 
+                             "relational", Vips.OperationRelational.EQUAL, other)
 
     def __ne__(self, other):
-        if isinstance(other, Vips.Image):
-            return self.relational(other, Vips.OperationRelational.NOTEQ)
-        elif isinstance(other, list):
-            return self.relational_const(other, Vips.OperationRelational.NOTEQ)
-        elif isinstance(other, numbers.Number):
-            return self.relational_const(other, Vips.OperationRelational.NOTEQ)
-        else:
-            return False
+        # _eq version allows comparison to None
+        return _call_enum_eq(self, 
+                             "relational", Vips.OperationRelational.NOTEQ, other)
 
     def __getitem__(self, arg):
         if isinstance(arg, slice):
diff --git a/whatsnew-8.5.md b/whatsnew-8.5.md
new file mode 100644
index 00000000..79bdbbc0
--- /dev/null
+++ b/whatsnew-8.5.md
@@ -0,0 +1,97 @@
+This branch has a new implementation of sequential mode:
+
+https://github.com/jcupitt/libvips/tree/remove-seq-stalling
+
+It'd be great to get this merged to master for 8.5, but it needs some testing.
+
+How seq used to work:
+
+* The vips sink functions create a set of N threads and scan images
+top-to-bottom in tiles, allocating tiles to workers as they finish.
+
+* They have extra logic to keep workers together. They track the position
+of the most-delayed worker and if the lead thread gets more than M scanlines
+ahead, it stalls until the stragglers catch up.
+
+* There is more logic in the loaders: they keep track of the current
+Y position, and if the lead request thread gets ahead of the current
+read point, it stalls with a 60s timeout until the intermediate tiles are
+requested. This logic is implemented in the `vips_sequential()` operation.
+
+The point of trying to keep thread locality and ordering is that we want
+to limit the number of scanlines that loaders have to keep behind the read
+point. We want to stream images through memory, not be forced into a load /
+process / save model.
+
+This works reasonably well for simple cases, like thumbnailing single images,
+but can fail in more complex cases, such as repeated `vips_insert()`. Consider
+this Python program:
+
+```python 
+#!/usr/bin/python
+
+import sys import random
+
+import gi gi.require_version('Vips', '8.0') from gi.repository import Vips
+
+composite = Vips.Image.black(100000, 100000)
+
+for filename in sys.argv[2:]:
+    tile = Vips.Image.new_from_file(filename, access = Vips.Access.SEQUENTIAL)
+    x = random.randint(0, composite.width - tile.width) y = random.randint(0,
+    composite.height - tile.height) composite = composite.insert(tile, x, y)
+
+composite.write_to_file(sys.argv[1]) 
+```
+
+This makes a 100,000 x 100,000 pixel black image, then inserts a lot of
+other files into it and writes the result.
+
+With vips8.4, this could very easily fail. Imagine this situation:
+
+* image1 is very tall and thin
+
+* image2 is short and fat, and by chance covers the centre of image1
+
+* we'll write the top part of image1, then write the body of image2
+
+* after image2 has been written, we need to write the bottom of image1,
+so a thread will ask for a set of pixels near the end of image1
+
+* image1 knows that the previous request was for some scanlines near the top,
+so it thinks this request must be from a thread that has run way ahead of
+the pack and stalls it
+
+And we have a deadlock. In fact, vips wouldn't deadlock, it would just
+pause on a 60s timeout on each thread. Sad!
+
+Here's how the new seq works:
+
+* Sinks work as before.
+
+* Loaders use a revised `vips_sequential()` with the stalling logic
+removed. All it does now is track the read position, cache a few 100 lines
+behind the read point, and makes sure that lines are evaluated in order
+with no missing areas.
+
+* Operations like `vips_shrinkv()` which can cause large non-local references
+have an extra bit of code which, if the input comes from a sequential source,
+adds a an extra `vips_sequential()` operator on the output. This forces
+`vips_shrinkv()` input to be sequential.
+
+The old one constrained thread location on output, and on input as well. The
+new idea is to get rid of input constraints, and instead add extra code
+to the operations which could trigger large non-local references. Rather
+than tying threads down to stop them drifting apart, it makes sure they
+can never get too far apart in the first place.
+
+Running the test program with git master gives this result:
+
+``` 
+real    1m2.317s 
+user    2m58.472s 
+sys     0m7.568s 
+peak mem: 10gb 
+```
+
+Not bad!