move orientation tag from vipsthumbnail output

TODO

@@ -1,7 +1,11 @@
-- we vips_image_remove() orientation, but it gets put back from the exif block
-  on jpegsave
+- vipsthumbnail needs to know about more exif orientation tags
 
-  jpegsave needs to remove again after reconstituting the exif
+- vipsthumbnail --rotate breaks for embedded thumbnail sources
+
+  embedded thumbnails seems to have had the orientation applied already
+
+  need to not copy orientation tag from main to thumb? is this right for all
+  images?
 
 
 - think of a better way to support skipahead

libvips/foreign/vips2jpeg.c

@@ -569,6 +569,7 @@ vips_exif_from_s( ExifData *ed, ExifEntry *entry, const char *value )
 typedef struct _VipsExif {
 	VipsImage *image;
 	ExifData *ed;
+	ExifContent *content;
 } VipsExif;
 
 static void
@@ -584,11 +585,14 @@ vips_exif_update_entry( ExifEntry *entry, VipsExif *ve )
 		(void) vips_image_get_string( ve->image, name, &value );
 		vips_exif_from_s( ve->ed, entry, value ); 
 	}
+	else
+		exif_content_remove_entry( ve->content, entry );
 }
 
 static void
 vips_exif_update_content( ExifContent *content, VipsExif *ve )
 {
+	ve->content = content;
         exif_content_foreach_entry( content, 
 		(ExifContentForeachEntryFunc) vips_exif_update_entry, ve );
 }

tools/vipsthumbnail.c

@@ -139,11 +139,10 @@ get_angle( VipsImage *im )
 
 	angle = VIPS_ANGLE_0;
 
-	if( vips_image_get_typeof( im, ORIENTATION ) ) {
-		if( vips_image_get_string( im, ORIENTATION, &orientation ) ) {
-			if( vips_isprefix( "6", orientation ) )
-				angle = VIPS_ANGLE_90;
-		}
+	if( vips_image_get_typeof( im, ORIENTATION ) && 
+		!vips_image_get_string( im, ORIENTATION, &orientation ) ) {
+		if( vips_isprefix( "6", orientation ) )
+			angle = VIPS_ANGLE_90;
 	}
 
 	return( angle );
@@ -636,8 +635,7 @@ thumbnail_rotate( VipsObject *process, VipsImage *im )
 			return( NULL ); 
 		im = t[0];
 
-		if( !vips_image_remove( im, ORIENTATION ) )
-			return( NULL ); 
+		(void) vips_image_remove( im, ORIENTATION );
 	}
 
 	return( im );