add vips_similarity()

simple wrapper over vips_affine() that lets you give the matrix as scale
+ angle.

ChangeLog

@@ -28,6 +28,8 @@
   thanks Lovell 
 - im_tone_map() and im_tone_analyse() deprecated
 - new --band arg to vips_maplut() replaces im_tone_map() functionality
+- added vips_similarity(), simple wrapper for vips_affine() that lets you
+  give a scale and rotate
 
 3/7/13 started 7.34.2
 - lower priority for Matlab load to reduce segvs from Mat_Open(), thanks

libvips/convolution/conv.c

@@ -1,27 +1,7 @@
-/* histogram cumulativisation
+/* convolution
  *
- * Author: N. Dessipris
- * Written on: 02/08/1990
- * 24/5/95 JC
- *	- tidied up and ANSIfied
- * 20/7/95 JC
- *	- smartened up again
- *	- now works for hists >256 elements
- * 3/3/01 JC
- *	- broken into cum and norm ... helps im_histspec()
- *	- better behaviour for >8 bit hists
- * 31/10/05 JC
- * 	- was broken for vertical histograms, gah
- * 	- neater im_histnorm()
- * 23/7/07
- * 	- eek, off by 1 for more than 1 band hists
- * 12/5/08
- * 	- histcum works for signed hists now as well
- * 24/3/10
- * 	- gtkdoc
- * 	- small cleanups
  * 12/8/13	
- * 	- redone im_histcum() as a class, vips_conv()
+ * 	- from vips_hist_cum()
  */
 
 /*
@@ -51,6 +31,11 @@
 
  */
 
+/* This is a simple wrapper over the old vips7 functions. At some point we
+ * should rewrite this as a pure vips8 class and redo the vips7 functions as
+ * wrappers over this.
+ */
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif /*HAVE_CONFIG_H*/

libvips/include/vips/resample.h

@@ -41,6 +41,8 @@ extern "C" {
 int vips_shrink( VipsImage *in, VipsImage **out, 
 	double xshrink, double yshrink, ... )
 	__attribute__((sentinel));
+int vips_similarity( VipsImage *in, VipsImage **out, ... )
+	__attribute__((sentinel));
 int vips_affine( VipsImage *in, VipsImage **out, 
 	double a, double b, double c, double d, ... )
 	__attribute__((sentinel));

libvips/resample/Makefile.am

@@ -8,6 +8,7 @@ libresample_la_SOURCES = \
 	affine.c \
 	quadratic.c \
 	resample.c \
+	similarity.c \
 	presample.h \
 	shrink.c \
 	interpolate.c \
@@ -22,6 +23,7 @@ else
 
 libresample_la_SOURCES = \
 	resample.c \
+	similarity.c \
 	presample.h \
 	shrink.c \
 	affine.c \

libvips/resample/affine.c

@@ -398,7 +398,7 @@ vips_affine_build( VipsObject *object )
 			affine->oarea->n, 4 ) )
 		return( -1 );
 
-	if( !vips_object_argument_isset( object, "interpolate" ) )
+	if( !affine->interpolate )
 		affine->interpolate = vips_interpolate_new( "bilinear" );
 
 	in = resample->in;
@@ -443,11 +443,9 @@ vips_affine_build( VipsObject *object )
 
 	if( vips__transform_calc_inverse( &affine->trn ) )
 		return( -1 );
-	
-	/*
+
 	if( vips__transform_isidentity( &affine->trn ) )
 		return( vips_image_write( in, resample->out ) );
-	 */
 
 	/* Check for coordinate overflow ... we want to be able to hold the
 	 * output space inside INT_MAX / TRANSFORM_SCALE.

libvips/resample/resample.c

@@ -114,9 +114,11 @@ vips_resample_operation_init( void )
 	extern GType vips_shrink_get_type( void ); 
 	extern GType vips_quadratic_get_type( void ); 
 	extern GType vips_affine_get_type( void ); 
+	extern GType vips_similarity_get_type( void ); 
 
 	vips_shrink_get_type(); 
 	vips_quadratic_get_type(); 
 	vips_affine_get_type(); 
+	vips_similarity_get_type(); 
 }
 

libvips/resample/similarity.c

@@ -0,0 +1,201 @@
+/* simple wrapper over vips_similarity() to make scale / rotate easy from the
+ * command-line
+ *
+ * 3/10/13
+ * 	- from similarity.c
+ */
+
+/*
+
+    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., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+/*
+#define DEBUG
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <math.h>
+
+#include <vips/vips.h>
+
+#include "presample.h"
+
+typedef struct _VipsSimilarity {
+	VipsResample parent_instance;
+
+	double scale;
+	double angle;
+	VipsInterpolate *interpolate;
+	double odx;
+	double ody;
+	double idx;
+	double idy;
+
+} VipsSimilarity;
+
+typedef VipsResampleClass VipsSimilarityClass;
+
+G_DEFINE_TYPE( VipsSimilarity, vips_similarity, VIPS_TYPE_RESAMPLE );
+
+static int
+vips_similarity_build( VipsObject *object )
+{
+	VipsResample *resample = VIPS_RESAMPLE( object );
+	VipsSimilarity *similarity = (VipsSimilarity *) object;
+
+	VipsImage **t = (VipsImage **) 
+		vips_object_local_array( object, 4 );
+
+	double a, b, c, d; 
+
+	if( VIPS_OBJECT_CLASS( vips_similarity_parent_class )->build( object ) )
+		return( -1 );
+
+	a = similarity->scale * cos( VIPS_RAD( similarity->angle ) ); 
+	b = sin( VIPS_RAD( similarity->angle ) );
+	c = -b;
+	d = a;
+
+	if( vips_affine( resample->in, &t[0], a, b, c, d, 
+		"interpolate", similarity->interpolate,
+		"odx", similarity->odx,
+		"ody", similarity->ody,
+		"idx", similarity->idx,
+		"idy", similarity->idy,
+		NULL ) ||
+		vips_image_write( t[0], resample->out ) )
+		return( -1 ); 
+
+	return( 0 );
+}
+
+static void
+vips_similarity_class_init( VipsSimilarityClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	vobject_class->nickname = "similarity";
+	vobject_class->description = _( "similarity transform of an image" );
+	vobject_class->build = vips_similarity_build;
+
+	VIPS_ARG_DOUBLE( class, "scale", 3, 
+		_( "Scale" ), 
+		_( "Scale by this factor" ), 
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, scale ),
+		0, 10000000, 1 );
+
+	VIPS_ARG_DOUBLE( class, "angle", 4, 
+		_( "Angle" ), 
+		_( "Rotate anticlockwise by this many degrees" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, angle ),
+		-10000000, 10000000, 0 );
+
+	VIPS_ARG_INTERPOLATE( class, "interpolate", 2, 
+		_( "Interpolate" ), 
+		_( "Interpolate pixels with this" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT, 
+		G_STRUCT_OFFSET( VipsSimilarity, interpolate ) );
+
+	VIPS_ARG_DOUBLE( class, "odx", 112, 
+		_( "Output offset" ), 
+		_( "Horizontal output displacement" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, odx ),
+		-10000000, 10000000, 0 );
+
+	VIPS_ARG_DOUBLE( class, "ody", 113, 
+		_( "Output offset" ), 
+		_( "Vertical output displacement" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, ody ),
+		-10000000, 10000000, 0 );
+
+	VIPS_ARG_DOUBLE( class, "idx", 114, 
+		_( "Input offset" ), 
+		_( "Horizontal input displacement" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, idx ),
+		-10000000, 10000000, 0 );
+
+	VIPS_ARG_DOUBLE( class, "idy", 115, 
+		_( "Input offset" ), 
+		_( "Vertical input displacement" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsSimilarity, idy ),
+		-10000000, 10000000, 0 );
+}
+
+static void
+vips_similarity_init( VipsSimilarity *similarity )
+{
+	similarity->scale = 1; 
+}
+
+/**
+ * vips_similarity:
+ * @in: input image
+ * @out: output image
+ *
+ * Optional arguments:
+ *
+ * @scale: scale by this factor
+ * @angle: rotate by this many degrees anticlockwise
+ * @interpolate: interpolate pixels with this
+ * @idx: input horizontal offset
+ * @idy: input vertical offset
+ * @odx: output horizontal offset
+ * @ody: output vertical offset
+ *
+ * This operator calls vips_affine() for you, calculating the matrix for the
+ * affine transform from @scale and @angle. Other parameters are passed on to
+ * vips_affine() unaltered. 
+ *
+ * See also: vips_affine(), #VipsInterpolate.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_similarity( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "similarity", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}