From 33cca3ecbc5b69cf6937fd51ae77e888f412779a Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Fri, 1 Oct 2021 12:36:02 +0100
Subject: [PATCH] fix jxload restart

if the loader was restarted (eg by vipsdisp) it could fail to fetch pixels
---
 libvips/foreign/jxlload.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/libvips/foreign/jxlload.c b/libvips/foreign/jxlload.c
index db754f38..ebe3a052 100644
--- a/libvips/foreign/jxlload.c
+++ b/libvips/foreign/jxlload.c
@@ -2,6 +2,8 @@
  *
  * 18/3/20
  * 	- from heifload.c
+ * 1/10/21
+ * 	- reset read point for _load
  */
 
 /*
@@ -627,6 +629,17 @@ vips_foreign_load_jxl_load( VipsForeignLoad *load )
 	if( vips_foreign_load_jxl_set_header( jxl, t[0] ) ) 
 		return( -1 );
 
+	/* We have to reset the reader ... we can't reply onb the read point
+	 * being left just after the header.
+	 */
+	if( vips_source_rewind( jxl->source ) )
+                return( -1 );
+
+	if( vips_foreign_load_jxl_fill_input( jxl, 0 ) )
+		return( -1 );
+	JxlDecoderSetInput( jxl->decoder, 
+		jxl->input_buffer, jxl->bytes_in_buffer );
+
 	/* Read to the end of the image.
 	 */
 	do {