fix im_point()

oops ... helps ruby-vips self test

ChangeLog

@@ -1,5 +1,6 @@
 4/7/14 started 7.40.4
 - fix vips_rawsave_fd(), thanks aferrero2707 
+- fix im_point()
 
 30/6/14 started 7.40.3
 - fix interlaced thumbnails in vipsthumbnail, thanks lovell

TODO

@@ -1,15 +1,3 @@
-- im_point() is broken?
-
-	$ vips im_point k2.jpg bilinear 0 0 2
-	110.926
-
-  doesn't seem right, should be 0, see deprecated/im_point_bilinear.c
-
-  part of fixing up ruby-vips self-tests
-
-  dx/dy seem broken, esp. with clipping
-
-
 
 - threadpool recyling might be useful for dzsave?
 

libvips/deprecated/arith_dispatch.c

@@ -172,7 +172,7 @@ point_vec( im_object *argv )
 	VipsInterpolate *interpolate = VIPS_INTERPOLATE( argv[1] );
 	double x = *((double *) argv[2]);
 	double y = *((double *) argv[3]);
-	int band = *((double *) argv[4]);
+	int band = *((int *) argv[4]);
 
 	return( im_point( argv[0], interpolate, x, y, band, argv[5] ) );
 }

libvips/deprecated/im_point_bilinear.c

@@ -84,7 +84,7 @@ im_point( IMAGE *im, VipsInterpolate *interpolate,
 		im_affinei( t[0], t[1], 
 			interpolate,
 			1, 0, 0, 1,
-			x - floor( x ), y - floor( y ),
+			floor( x ) - x, floor( y ) - y,
 			floor( x ), floor( y ), 1, 1 ) ||
 		im_avg( t[1], out ) ) {
 		im_close( mem );