im_lineset() needs to ask for WIO of mask and ink

ChangeLog

@@ -19,6 +19,7 @@
   almostdeprecated to avoid breakage
 - im_csv2vips(): allow lines that end with EOF rather than \n
 - im_vips2tiff has a bigtiff option
+- oops, im_lineset() needs to ask for WIO of mask and ink
 
 15/1/10 started 7.21.1
 - added "written" callbacks, used to implement write to non-vips formats

libvips/inplace/line_draw.c

@@ -40,6 +40,8 @@
  *	- im_incheck() changed to im_makerw()
  * 5/12/06
  * 	- im_invalidate() after paint
+ * 1/3/10
+ * 	- oops, lineset needs to ask for WIO of mask and ink
  */
 
 /*
@@ -438,6 +440,10 @@ im_lineset( IMAGE *in, IMAGE *out, IMAGE *mask, IMAGE *ink,
 	mask_rect.width = mask->Xsize;
 	mask_rect.height = mask->Ysize;
 
+	if( im_incheck( ink ) ||
+		im_incheck( mask ) )
+		return( -1 );
+
 	for( i = 0; i < n; i++ ) {
 		if( im_fastlineuser( out, x1v[i], y1v[i], x2v[i], y2v[i], 
 			im_plotmask, ink->data, mask->data, &mask_rect ) )