From 4306b402eeb579ea6b2f32621590a5e5312ad1be Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Wed, 24 Mar 2010 16:20:09 +0000
Subject: [PATCH] hist hacking

---
 ChangeLog                            |  3 ++-
 libvips/histograms_lut/im_histeq.c   |  4 +--
 libvips/histograms_lut/im_histspec.c |  2 +-
 libvips/histograms_lut/im_hsp.c      | 40 +++++++++++++++-------------
 4 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9e429f3f..21a8dacf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,7 +2,8 @@
 - added progress feedback to threadpool
 - --vips-wbuffer2 switch does all wbuffer use now
 - im_wbuffer2() renamed as vips_discsink(), some cleanups
-- im_gammacorrect() can do 16-bit iamges too
+- im_gammacorrect() can do 16-bit images too
+- im_histplot() could fail for signed int histograms
 
 16/1/10 started 7.21.2
 - "invalidate" is careful to keep images alive, so invalidate callbacks can do
diff --git a/libvips/histograms_lut/im_histeq.c b/libvips/histograms_lut/im_histeq.c
index 2b03a424..deff9828 100644
--- a/libvips/histograms_lut/im_histeq.c
+++ b/libvips/histograms_lut/im_histeq.c
@@ -219,11 +219,11 @@ im_histnorm( IMAGE *in, IMAGE *out )
 int 
 im_histeq( IMAGE *in, IMAGE *out )
 {
-	IMAGE *t1 = im_open_local( out, "im_histeq:1", "p" );
+	IMAGE *t1;
 
 	/* Normalised cumulative.
 	 */
-	if( !(t1 = im_open_local( out, "im_histeq:1", "p" )) ||
+	if( !(t1 = im_open_local( out, "im_histeq", "p" )) ||
 		im_histcum( in, t1 ) || 
 		im_histnorm( t1, out ) )
 		return( -1 );
diff --git a/libvips/histograms_lut/im_histspec.c b/libvips/histograms_lut/im_histspec.c
index d8b98835..5ba9cfb9 100644
--- a/libvips/histograms_lut/im_histspec.c
+++ b/libvips/histograms_lut/im_histspec.c
@@ -169,7 +169,7 @@ match( IMAGE *in, IMAGE *ref, IMAGE *out )
  * formed, will produce an image whose PDF matches that of the image from 
  * which @ref was formed.
  *
- * See also: im_histgr(), im_maplut().
+ * See also: im_hsp(), im_histgr(), im_maplut().
  *
  * Returns: 0 on success, -1 on error
  */
diff --git a/libvips/histograms_lut/im_hsp.c b/libvips/histograms_lut/im_hsp.c
index 79af9c2b..0db4fbd0 100644
--- a/libvips/histograms_lut/im_hsp.c
+++ b/libvips/histograms_lut/im_hsp.c
@@ -1,13 +1,4 @@
-/* @(#)  Maps imagein to imageout with histogram specified by imageref
- * @(#) Both images should have the same number of bands
- * @(#) Each band of the output image is specified according to the distribution
- * @(#) of grey levels of the reference image
- * @(#)
- * @(#)  Usage:
- * @(#)  int im_hsp(in, ref, out)
- * @(#)  IMAGE *in, *ref, *out;
- * @(#)  
- * @(#)  Return 0 on success and -1 on error
+/* match histograms
  *
  * Copyright: 1990, N. Dessipris.
  *
@@ -18,6 +9,8 @@
  *	- im_ioflag() call changed to im_iocheck()
  * 25/5/95 JC
  *	- revised
+ * 24/3/10
+ * 	- gtkdoc
  */
 
 /*
@@ -59,18 +52,29 @@
 #include <dmalloc.h>
 #endif /*WITH_DMALLOC*/
 
+/**
+ * im_hsp:
+ * @in: input image
+ * @ref: reference histogram 
+ * @out: output image
+ *
+ * Maps image @in to image @out, adjusting the histogram to match image @ref.
+ * Both images should have the same number of bands.
+ *
+ * See also: im_histspec(), im_histgr().
+ *
+ * Returns: 0 on success, -1 on error
+ */
 int 
 im_hsp( IMAGE *in, IMAGE *ref, IMAGE *out )
 {
-	IMAGE *histin = im_open_local( out, "im_hsp:#1", "p" );
-	IMAGE *histref = im_open_local( out, "im_hsp:#2", "p" );
-	IMAGE *lut = im_open_local( out, "im_hsp:#3", "p" );
+	IMAGE *t[3];
 
-	if( !histin || !histref || !lut ||
-		im_histgr( in, histin, -1 ) || 
-		im_histgr( ref, histref, -1 ) ||
-		im_histspec( histin, histref, lut ) ||
-		im_maplut( in, out, lut ) )
+	if( im_open_local_array( out, t, 3, "im_hsp", "p" ) ||
+		im_histgr( in, t[0], -1 ) || 
+		im_histgr( ref, t[1], -1 ) ||
+		im_histspec( t[0], t[1], t[2] ) ||
+		im_maplut( in, out, t[2] ) )
 		return( -1 );
 
 	return( 0 );