From 150cabd6c0aadb163b37da56dac877aae19a533b Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Wed, 18 Mar 2009 16:47:17 +0000
Subject: [PATCH] stuff

---
 ChangeLog                           |  1 +
 libsrc/histograms_lut/im_buildlut.c | 22 ++++++++++------------
 libsrc/resample/snohalo1.cpp        |  2 --
 man/im_buildlut.3                   | 19 ++++++++++---------
 4 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6c8fbcbf..083c278b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,7 @@
 - remove fading stuff from im_render() -- cleaner and simpler
 - configure spots support for "restrict"
 - reset dcm:display-range on magick read to help DICOM
+- saner im_buildlut() behaviour
 
 3/3/09 started 7.17.2
 - im_magick2vips.c: allow funky bit depths, like 14 (thanks Mikkel)
diff --git a/libsrc/histograms_lut/im_buildlut.c b/libsrc/histograms_lut/im_buildlut.c
index 7654d5c9..cae08991 100644
--- a/libsrc/histograms_lut/im_buildlut.c
+++ b/libsrc/histograms_lut/im_buildlut.c
@@ -1,18 +1,14 @@
 /* @(#) Build a LUT from a set of x/y points. Eg. if input is
  * @(#) 
- * @(#)   12  100
- * @(#)   14  110
- * @(#)   18  120
+ * @(#)   0   0
+ * @(#)   255 100
  * @(#) 
  * @(#) we generate
  * @(#) 
- * @(#)   100	(12)
- * @(#)   105
- * @(#)   110
- * @(#)   112.5
- * @(#)   115
- * @(#)   117.5
- * @(#)   120	(18)
+ * @(#)   0   0
+ * @(#)   1   0.4
+ * @(#)   .. etc. linear interpolation
+ * @(#)   255 100
  * @(#)
  * @(#) The x/y points don't need to be sorted: we do that. You can have 
  * @(#) several Ys ... each becomes a band in the output LUT. 
@@ -21,6 +17,8 @@
  * 	- from im_invertlut()
  * 9/10/06
  * 	- don't output x values
+ * 18/3/09
+ * 	- saner limit and rounding behaviour
  */
 
 /*
@@ -141,7 +139,7 @@ build_state( State *state, DOUBLEMASK *input )
 		if( v > xhigh )
 			xhigh = v;
 	}
-	state->lut_size = xhigh - xlow;
+	state->lut_size = xhigh - xlow + 1;
 
 	if( state->lut_size < 1 ) {
 		im_error( "im_buildlut", "%s", _( "x range too small" ) );
@@ -202,7 +200,7 @@ buildlut( State *state, IMAGE *output )
 			const int dx = x2 - x1;
 			const double dy = y2 - y1;
 			
-			for( i = 0; i < dx; i++, x += xsize - 1 )
+			for( i = 0; i <= dx; i++, x += xsize - 1 )
 				odata[x] = y1 + i * dy / dx;
 		}
 
diff --git a/libsrc/resample/snohalo1.cpp b/libsrc/resample/snohalo1.cpp
index 3670b9ce..34432b45 100644
--- a/libsrc/resample/snohalo1.cpp
+++ b/libsrc/resample/snohalo1.cpp
@@ -501,8 +501,6 @@ vips_interpolate_snohalo1_interpolate( VipsInterpolate* restrict interpolate,
                                        double                    absolute_x,
                                        double                    absolute_y )
 {
-  VipsInterpolateSnohalo1Class *snohalo1_class = 
-    VIPS_INTERPOLATE_SNOHALO1_GET_CLASS( interpolate );
   VipsInterpolateSnohalo1 *snohalo1 = 
     VIPS_INTERPOLATE_SNOHALO1( interpolate );
   /*
diff --git a/man/im_buildlut.3 b/man/im_buildlut.3
index 22809486..86cddc3d 100644
--- a/man/im_buildlut.3
+++ b/man/im_buildlut.3
@@ -13,18 +13,19 @@ im_buildlut( DOUBLEMASK *input, IMAGE *output )
 constructs a LUT, interpolating a set of x/y points. Interpolation is strictly
 piecewise linear. For example, if the input is:
 
-  12  100
-  14  110
-  18  120
+  0 	0
+  128	20
+  255 	100
 
 we generate
 
-  100   (12)
-  105
-  110
-  112.5
-  115
-  117.5 (17)
+  0	0
+  1	0.01
+  .. etc. linear interpolation
+  128	20
+  129	20.5
+  .. etc. linear interpolation
+  255	100
 
 the x axis (12 .. 17) is implied. The x/y points don't need to be
 sorted: we do that. You can have several Ys ... each becomes a band in the