reset dcm window before magick read

ChangeLog

@@ -2,6 +2,7 @@
 - revised nohalo
 - remove fading stuff from im_render() -- cleaner and simpler
 - configure spots support for "restrict"
+- reset dcm:display-range on magick read to help DICOM
 
 3/3/09 started 7.17.2
 - im_magick2vips.c: allow funky bit depths, like 14 (thanks Mikkel)

TODO

@@ -1,3 +1,18 @@
+- need to set 
+
+	-define dcm:display-range=reset 
+
+  to stop window_width/_height screwing up our data in magick read
+
+
+  use
+
+  	SetImageOption (image_info, "dcm:display-range", "reset");
+
+  somewhere
+
+
+
 
 - move im_shrink & friends to resample?
 

libsrc/format/im_magick2vips.c

@@ -22,6 +22,8 @@
  * 	- use image->attributes if GetNextImageAttribute() is missing
  * 3/3/09
  * 	- allow funky bit depths, like 14 (thanks Mikkel)
+ * 17/3/09
+ * 	- reset dcm:display-range to help DICOM read
  */
 
 /*
@@ -585,6 +587,15 @@ im_magick2vips( const char *filename, IMAGE *im )
 	if( !(read = read_new( filename, im )) )
 		return( -1 );
 
+	/* When reading DICOM images, we want to ignore any
+	 * window_center/_width setting, since it may put pixels outside the
+	 * 0-65535 range and lose data. 
+	 *
+	 * These window settings are attached as vips metadata, so our caller
+	 * can interpret them if it wants.
+	 */
+  	SetImageOption( read->image_info, "dcm:display-range", "reset" );
+
 	read->image = ReadImage( read->image_info, &read->exception );
 	if( !read->image ) {
 		im_error( "im_magick2vips", _( "unable to read file \"%s\"\n"