can now displace affine input space

so hopefully that means you can change corner vs. centre convention
easily

ChangeLog

@@ -33,6 +33,7 @@
 - all interpolators use corner convention ... we had round-to-nearest in
   several of them before, causing a range of annoying problems
 - redone im_affine*() as a class
+- added input space displacement to affine
 
 14/11/12 started 7.30.6
 - capture tiff warnings earlier

TODO

@@ -1,14 +1,5 @@
 - test affine labq processing
 
-- now we've removed round-to-nearest from NN, we need something extra in the
-  affine transform to displace the input cods
-
-  dx/dy displace output
-
-- make affinei into a class
-
-
-
 
 - quadratic doesn't work for order 3
 

libvips/mosaicing/global_balance.c

@@ -499,8 +499,10 @@ make_join( SymbolTable *st, JoinType type,
 	out->thistrn.b = -b;
 	out->thistrn.c = b;
 	out->thistrn.d = a;
-	out->thistrn.dx = dx;
-	out->thistrn.dy = dy;
+	out->thistrn.idx = 0;
+	out->thistrn.idy = 0;
+	out->thistrn.odx = dx;
+	out->thistrn.ody = dy;
 
 	/* Clean the table and propogate the transform down the RHS of the
 	 * graph.
@@ -519,8 +521,10 @@ make_join( SymbolTable *st, JoinType type,
 	trn.b = 0.0;
 	trn.c = 0.0;
 	trn.d = 1.0;
-	trn.dx = -out->cumtrn.oarea.left;
-	trn.dy = -out->cumtrn.oarea.top;
+	trn.idx = 0;
+	trn.idy = 0;
+	trn.odx = -out->cumtrn.oarea.left;
+	trn.ody = -out->cumtrn.oarea.top;
 	clean_table( st );
 	if( propogate_transform( out, &trn ) )
 		return( -1 );

libvips/mosaicing/mosaic1.c

@@ -80,8 +80,10 @@ apply_similarity( VipsTransformation *trn, IMAGE *in, IMAGE *out,
 	trn->b = -b;
 	trn->c = b;
 	trn->d = a;
-	trn->dx = dx;
-	trn->dy = dy;
+	trn->idx = 0;
+	trn->idy = 0;
+	trn->odx = dx;
+	trn->ody = dy;
 	vips__transform_set_area( trn );
 	if( vips__transform_calc_inverse( trn ) )
 		return( -1 );

libvips/resample/affine.c

@@ -78,6 +78,7 @@
  * 	- gtk-doc
  * 14/12/12
  * 	- redone as a class
+ * 	- added input space translation
  */
 
 /*
@@ -334,6 +335,11 @@ vips_affine_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
 		ix += iarea->left;
 		iy += iarea->top;
 
+		/* And the input offset.
+		 */
+		ix -= affine->trn.idx;
+		iy -= affine->trn.idy;
+
 		q = VIPS_REGION_ADDR( or, le, y );
 
 		for( x = le; x < ri; x++ ) {
@@ -429,6 +435,11 @@ vips_affine_build( VipsObject *object )
 	if( vips_object_argument_isset( object, "ody" ) )
 		affine->trn.ody = affine->ody;
 
+	if( vips_object_argument_isset( object, "idx" ) )
+		affine->trn.idx = affine->idx;
+	if( vips_object_argument_isset( object, "idy" ) )
+		affine->trn.idy = affine->idy;
+
 	if( vips__transform_calc_inverse( &affine->trn ) )
 		return( -1 );
 	
@@ -541,28 +552,28 @@ vips_affine_class_init( VipsAffineClass *class )
 		_( "Horizontal output displacement" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsAffine, odx ),
-		0, 10000000, 0 );
+		-10000000, 10000000, 0 );
 
 	VIPS_ARG_DOUBLE( class, "ody", 113, 
 		_( "Output offset" ), 
 		_( "Vertical output displacement" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsAffine, ody ),
-		0, 10000000, 0 );
+		-10000000, 10000000, 0 );
 
-	VIPS_ARG_DOUBLE( class, "idx", 112, 
+	VIPS_ARG_DOUBLE( class, "idx", 114, 
 		_( "Input offset" ), 
 		_( "Horizontal input displacement" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsAffine, idx ),
-		0, 10000000, 0 );
+		-10000000, 10000000, 0 );
 
-	VIPS_ARG_DOUBLE( class, "idy", 113, 
+	VIPS_ARG_DOUBLE( class, "idy", 115, 
 		_( "Input offset" ), 
 		_( "Vertical input displacement" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsAffine, idy ),
-		0, 10000000, 0 );
+		-10000000, 10000000, 0 );
 }
 
 static void