add im_wrap

include/vips/proto.h

@@ -506,6 +506,7 @@ int im_replicate( IMAGE *in, IMAGE *out, int across, int down );
 int im_grid( IMAGE *in, IMAGE *out, int tile_height, int across, int down );
 int im_msb ( IMAGE * in, IMAGE * out );
 int im_msb_band ( IMAGE * in, IMAGE * out, int band );
+int im_wrap( IMAGE *in, IMAGE *out, int x, int y );
 
 /* colour
  */

libsrc/conversion/Makefile.am

@@ -55,6 +55,7 @@ libconversion_la_SOURCES = \
 	im_vips2jpeg.c \
 	im_vips2ppm.c \
 	im_vips2png.c \
+	im_wrap.c \
 	im_zoom.c
 
 INCLUDES = -I${top_srcdir}/include @VIPS_CFLAGS@ @VIPS_INCLUDES@

libsrc/conversion/conver_dispatch.c

@@ -1878,6 +1878,35 @@ static im_function rightshift_size_desc = {
   rightshift_size_args		/* Arg list */
 };
 
+/* Args to im_wrap.
+ */
+static im_arg_desc wrap_args[] = {
+	IM_INPUT_IMAGE( "in" ),
+	IM_OUTPUT_IMAGE( "out" ),
+	IM_INPUT_INT( "x" ),
+	IM_INPUT_INT( "y" )
+};
+
+/* Call im_wrap via arg vector.
+ */
+static int
+wrap_vec (im_object * argv)
+{
+  return im_wrap( (IMAGE*)argv[0], (IMAGE*)argv[1], *(int*)argv[2], *(int*)argv[3] );
+}
+
+/* Description of im_wrap.
+ */
+static im_function wrap_desc = {
+  "im_wrap",		/* Name */
+  "shift image origin, wrapping at sides",
+  IM_FN_PIO | IM_FN_TRANSFORM,	/* Flags */
+  wrap_vec,		/* Dispatch function */
+  IM_NUMBER (wrap_args),	/* Size of arg list */
+  wrap_args		/* Arg list */
+};
+
+
 /* Package up all these functions.
  */
 static im_function *conv_list[] = {
@@ -1952,6 +1981,7 @@ static im_function *conv_list[] = {
 	&vips2png_desc,
 	&vips2ppm_desc,
 	&vips2tiff_desc,
+	&wrap_desc,
 	&zoom_desc
 };
 

libsrc/conversion/im_wrap.c

@@ -0,0 +1,127 @@
+/* Wrap an image so that what was the origin is at (x,y).
+ *
+ * int im_wrap( IMAGE *in, IMAGE *out, int x, int y );
+ *
+ * All functions return 0 on success and -1 on error
+ *
+ * Copyright: 2008, Nottingham Trent University
+ * Author: Tom Vajzovic
+ * Written on: 2008-01-15
+ */
+
+/*
+
+    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
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <vips/intl.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <vips/vips.h>
+
+#ifdef WITH_DMALLOC
+#include <dmalloc.h>
+#endif /*WITH_DMALLOC*/
+
+static int wrap( REGION *out, void *seq, void *a, void *b ){
+#define IM ((IMAGE*)a)
+#define X (((int*)b)[0])
+#define Y (((int*)b)[1])
+  int left= out-> valid. left - X;
+  int top= out-> valid. top - Y;
+  int right= left + out-> valid. width;
+  int bot= top + out-> valid. height;
+  Rect source_a= {
+    left: IM-> Xsize + left,
+    top: IM-> Ysize + top,
+    width: 0 < right ? -left : out-> valid. width,
+    height: 0 < bot ? -top : out-> valid. height
+  };
+  Rect source_b= {
+    left: source_a. left,
+    top: 0 > top ? 0 : top,
+    width: source_a. width,
+    height: 0 > top ? bot : out-> valid. height
+  };
+  Rect source_c= {
+    left: 0 > left ? 0 : left,
+    top: source_a. top,
+    width: 0 > left ? right : out-> valid. width,
+    height: source_a. height
+  };
+  Rect source_d= {
+    left: source_c. left,
+    top: source_b. top,
+    width: source_c. width,
+    height: source_b. height
+  };
+  if( 0 > left ){
+    if( 0 > top && im_prepare_to( (REGION*)seq, out, & source_a, 
+          out-> valid. left, out-> valid. top ))
+      return -1;
+    
+    if( 0 < bot && im_prepare_to( (REGION*)seq, out, & source_b, 
+          out-> valid. left, 0 > top ? Y : out-> valid. top ))
+      return -1;
+  }
+  if( 0 < right ){
+    if( 0 > top && im_prepare_to( (REGION*)seq, out, & source_c, 
+          0 > left ? X : out-> valid. left, out-> valid. top ))
+      return -1;
+    
+    if( 0 < bot && im_prepare_to( (REGION*)seq, out, & source_d, 
+          0 > left ? X : out-> valid. left, 0 > top ? Y : out-> valid. top ))
+      return -1;    
+  }
+  return 0;
+#undef IM
+#undef X
+#undef Y 
+}
+
+int im_wrap( IMAGE *in, IMAGE *out, int x, int y ){
+  if( im_piocheck( in, out ))
+    return -1;
+  {
+    int *params= IM_ARRAY( out, 2, int );
+    if( ! params )
+      return -1;
+
+    params[ 0 ]= x % in-> Xsize;
+    params[ 1 ]= y % in-> Ysize;
+    if( 0 > x )
+      params[ 0 ]+= in-> Xsize;
+    if( 0 > y )
+      params[ 1 ]+= in-> Ysize;
+    
+    return im_cp_desc( out, in )
+      || im_demand_hint( out, IM_THINSTRIP, in, NULL )
+      || im_generate( out, im_start_one, wrap, im_stop_one, (void*)in, (void*)params );
+  }
+}