From e8c4188936a840a181d0b5fd95bf1de7be2c3b2c Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Tue, 10 Dec 2013 14:56:14 +0000
Subject: [PATCH] be more forgiving about x values

buildlut() would fail if rounding moved some of your x values away from
ints
---
 libvips/create/buildlut.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/libvips/create/buildlut.c b/libvips/create/buildlut.c
index a8a4d56b..da2b1000 100644
--- a/libvips/create/buildlut.c
+++ b/libvips/create/buildlut.c
@@ -14,6 +14,8 @@
  * 	- gtkdoc
  * 2/7/13
  * 	- convert to a class
+ * 10/12/13
+ * 	- be more forgiving about x vales not quite integers
  */
 
 /*
@@ -125,12 +127,16 @@ vips_buildlut_build_init( VipsBuildlut *lut )
 	for( y = 0; y < lut->mat->Ysize; y++ ) {
 		double v = *VIPS_MATRIX( lut->mat, 0, y ); 
 			
-		if( floor( v ) != v ) {
+		/* Allow for being a bit off.
+		 */
+		if( abs( v - VIPS_RINT( v ) ) > 0.001 ) {
 			vips_error( class->nickname,
-				"%s", _( "x value not an int" ) );
+				_( "x value row %d not an int" ), y );
 			return( -1 );
 		}
 
+		v = VIPS_RINT( v ); 
+
 		if( v < xlow )
 			xlow = v;
 		if( v > xhigh )
@@ -189,8 +195,8 @@ vips_buildlut_build_create( VipsBuildlut *lut )
 	 */
 	for( b = 0; b < bands; b++ ) {
 		for( i = 0; i < ysize - 1; i++ ) {
-			const int x1 = lut->data[i][0];
-			const int x2 = lut->data[i + 1][0];
+			const int x1 = VIPS_RINT( lut->data[i][0] );
+			const int x2 = VIPS_RINT( lut->data[i + 1][0] );
 			const int dx = x2 - x1;
 			const double y1 = lut->data[i][b + 1];
 			const double y2 = lut->data[i + 1][b + 1];