started base class for band ops

TODO

@@ -1,8 +1,24 @@
+- started bandary.[hc] ... move bandjoin/extract/mean on top of it
+
+- get real, get_imag can be arith unary ops
+
+- form complex can be an arith binary op
+
+
+
 - can we common-up bits of recomb and bandmean? any other ops? bandjoin must
   be rather similar?
 
   they should certainly be able to share a y pixel loop 
 
+  yes, extract_band is very similar too
+
+  make a class of Bandary ops ... n images in, one image out, number of bands
+  changes (ie. don't bandalike, but do sizealike/formatalike), then a buffer
+  processing function
+
+  base on bandjoin since that's the most general
+
 
 
 - test docs

libvips/arithmetic/arithmetic.c

@@ -268,6 +268,7 @@ vips_arithmetic_gen( VipsRegion *or,
 	VipsRegion **ir = (VipsRegion **) seq;
 	VipsArithmetic *arithmetic = VIPS_ARITHMETIC( b ); 
 	VipsArithmeticClass *class = VIPS_ARITHMETIC_GET_CLASS( arithmetic ); 
+	Rect *r = &or->valid;
 
 	PEL *p[MAX_INPUT_IMAGES], *q;
 	int i, y;
@@ -275,16 +276,15 @@ vips_arithmetic_gen( VipsRegion *or,
 	/* Prepare all input regions and make buffer pointers.
 	 */
 	for( i = 0; ir[i]; i++ ) {
-		if( vips_region_prepare( ir[i], &or->valid ) ) 
+		if( vips_region_prepare( ir[i], r ) ) 
 			return( -1 );
-		p[i] = (PEL *) VIPS_REGION_ADDR( ir[i], 
+		p[i] = (PEL *) VIPS_REGION_ADDR( ir[i], r->left, r->top );
-			or->valid.left, or->valid.top );
 	}
 	p[i] = NULL;
-	q = (PEL *) VIPS_REGION_ADDR( or, or->valid.left, or->valid.top );
+	q = (PEL *) VIPS_REGION_ADDR( or, r->left, r->top );
 
-	for( y = 0; y < or->valid.height; y++ ) {
+	for( y = 0; y < r->height; y++ ) {
-		class->process_line( arithmetic, q, p, or->valid.width );
+		class->process_line( arithmetic, q, p, r->width );
 
 		for( i = 0; ir[i]; i++ )
 			p[i] += VIPS_REGION_LSKIP( ir[i] );

libvips/conversion/bandary.c

@@ -0,0 +1,182 @@
+/* base class for various operations on bands
+ *
+ * Copyright: 1991, N. Dessipris, modification of im_bandary()
+ *
+ * Author: N. Dessipris
+ * Written on: 17/04/1991
+ * Modified on : 
+ * 16/3/94 JC
+ *	- rewritten for partials
+ *	- now in ANSI C
+ *	- now works for any number of input images, except zero
+ * 7/10/94 JC
+ *	- new IM_NEW()
+ * 16/4/07
+ * 	- fall back to im_copy() for 1 input image
+ * 17/1/09
+ * 	- cleanups
+ * 	- gtk-doc
+ * 	- im_bandary() just calls this
+ * 	- works for RAD coding too
+ * 27/1/10
+ * 	- formatalike inputs
+ * 17/5/11
+ * 	- sizealike inputs
+ * 27/10/11
+ * 	- rewrite as a class
+ * 20/11/11
+ * 	- from bandary
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+/*
+#define VIPS_DEBUG
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include <vips/vips.h>
+#include <vips/internal.h>
+#include <vips/debug.h>
+
+#include "bandary.h"
+
+G_DEFINE_ABSTRACT_TYPE( VipsBandary, vips_bandary, VIPS_TYPE_CONVERSION );
+
+/* Maximum number of input images -- why not?
+ */
+#define MAX_INPUT_IMAGES (64)
+
+static int
+vips_bandary_gen( VipsRegion *or, void *seq, void *a, void *b, gboolean *stop )
+{
+	VipsRegion **ir = (VipsRegion **) seq;
+	VipsBandary *bandary = (VipsBandary *) b;
+	VipsBandaryClass *class = VIPS_BANDARY_GET_CLASS( bandary ); 
+	Rect *r = &or->valid;
+
+	PEL *p[MAX_INPUT_IMAGES], *q;
+	int y, i;
+
+	for( i = 0; i < bandary->n; i++ ) {
+		if( vips_region_prepare( ir[i], r ) )
+			return( -1 );
+		p[i] = (PEL *) VIPS_REGION_ADDR( ir[i], r->left, r->top );
+	}
+	p[i] = NULL;
+	q = (PEL *) VIPS_REGION_ADDR( or, r->left, r->top );
+
+	for( y = 0; y < r->height; y++ ) {
+		class->process_line( bandary, q, p, r->width );
+
+		for( i = 0; ir[i]; i++ )
+			p[i] += VIPS_REGION_LSKIP( ir[i] );
+		q += VIPS_REGION_LSKIP( or );
+	}
+
+	return( 0 );
+}
+
+static int
+vips_bandary_build( VipsObject *object )
+{
+	VipsConversion *conversion = VIPS_CONVERSION( object );
+	VipsBandary *bandary = (VipsBandary *) object;
+
+	int i;
+	VipsImage **format;
+	VipsImage **size;
+
+	if( VIPS_OBJECT_CLASS( vips_bandary_parent_class )->build( object ) )
+		return( -1 );
+
+	if( bandary->n > MAX_INPUT_IMAGES ) {
+		vips_error( "VipsBandary", "%s", _( "too many input images" ) );
+		return( -1 );
+	}
+
+	if( vips_image_pio_output( conversion->out ) )
+		return( -1 );
+	for( i = 0; i < bandary->n; i++ )
+		if( vips_image_pio_input( bandary->in[i] ) || 
+			vips_check_uncoded( "VipsBandary", bandary->in[i] ) )
+			return( -1 );
+
+	format = (VipsImage **) vips_object_local_array( object, n );
+	size = (VipsImage **) vips_object_local_array( object, n );
+	if( vips__formatalike_vec( bandary->in, format, bandary->n ) ||
+		vips__sizealike_vec( format, size, bandary->n ) )
+		return( -1 );
+	bandary->ready = size;
+
+	if( vips_image_copy_fields_array( conversion->out, bandary->ready ) )
+		return( -1 );
+        vips_demand_hint_array( conversion->out, 
+		VIPS_DEMAND_STYLE_THINSTRIP, bandary->ready );
+
+	conversion->out->Bands = bandary->out_bands;
+
+	if( vips_image_generate( conversion->out,
+		vips_start_many, vips_bandary_gen, vips_stop_many, 
+		bandary->ready, bandary ) )
+		return( -1 );
+
+	return( 0 );
+}
+
+static void
+vips_bandary_class_init( VipsBandaryClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+
+	VIPS_DEBUG_MSG( "vips_bandary_class_init\n" );
+
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	vobject_class->nickname = "bandary";
+	vobject_class->description = _( "operations on image bands" );
+	vobject_class->build = vips_bandary_build;
+
+}
+
+static void
+vips_bandary_init( VipsBandary *bandjoin )
+{
+	/* Init our instance fields.
+	 */
+}

libvips/conversion/bandary.h

@@ -0,0 +1,93 @@
+/* base class for various operations on bands
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifndef VIPS__BANDARY_H
+#define VIPS__BANDARY_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /*__cplusplus*/
+
+#include "conversion.h"
+
+#define VIPS_TYPE_BANDARY (vips_bandary_get_type())
+#define VIPS_BANDARY( obj ) \
+	(G_TYPE_CHECK_INSTANCE_CAST( (obj), \
+		VIPS_TYPE_BANDARY, VipsBandary ))
+#define VIPS_BANDARY_CLASS( klass ) \
+	(G_TYPE_CHECK_CLASS_CAST( (klass), \
+		VIPS_TYPE_BANDARY, VipsBandaryClass))
+#define VIPS_IS_BANDARY( obj ) \
+	(G_TYPE_CHECK_INSTANCE_TYPE( (obj), VIPS_TYPE_BANDARY ))
+#define VIPS_IS_BANDARY_CLASS( klass ) \
+	(G_TYPE_CHECK_CLASS_TYPE( (klass), VIPS_TYPE_BANDARY ))
+#define VIPS_BANDARY_GET_CLASS( obj ) \
+	(G_TYPE_INSTANCE_GET_CLASS( (obj), \
+		VIPS_TYPE_BANDARY, VipsBandaryClass ))
+
+struct _VipsBandary;
+typedef void (*VipsBandaryProcessFn)( struct _VipsBandary *bandary, 
+	PEL *out, PEL **in, int width );
+
+typedef struct _VipsBandary {
+	VipsConversion parent_instance;
+
+	/* Array of input arguments, set these from a subclass.
+	 */
+	VipsImage **in;
+	int n;
+
+	/* The number of output bands. For example, VipsBandjoin sets the sum
+	 * of the bands in the input images.
+	 */
+	int out_bands;
+
+	/* The input images, ready for the operation.
+	 */
+	VipsImage **ready;
+
+} VipsBandary;
+
+typedef struct _VipsBandaryClass {
+	VipsConversionClass parent_class;
+
+	/* The buffer processor.
+	 */
+	VipsBandaryProcessFn process_line;
+
+} VipsBandjoinClass;
+
+GType vips_bandary_get_type( void );
+
+#ifdef __cplusplus
+}
+#endif /*__cplusplus*/
+
+#endif /*VIPS__BANDARY_H*/
+