--- gsf-output-gzip.c.orig	2019-10-14 10:28:11.549673629 -0400
+++ gsf-output-gzip.c	2019-10-14 13:09:36.813060057 -0400
@@ -35,6 +35,7 @@
 
 	GsfOutput *sink; /* compressed data */
 	gboolean raw; /* No header and no trailer.  */
+	gint complev; /* zlib compression level */
 
 	z_stream  stream;
 	uLong     crc;     /* crc32 of uncompressed data */
@@ -51,7 +52,8 @@
 enum {
 	PROP_0,
 	PROP_RAW,
-	PROP_SINK
+	PROP_SINK,
+	PROP_COMPLEV
 };
 
 
@@ -63,7 +65,7 @@
 {
 	int ret;
 
-	ret = deflateInit2 (&gzip->stream, Z_DEFAULT_COMPRESSION,
+	ret = deflateInit2 (&gzip->stream, gzip->complev,
 			    Z_DEFLATED, -MAX_WBITS, MAX_MEM_LEVEL,
 			    Z_DEFAULT_STRATEGY);
 	if (ret != Z_OK)
@@ -105,6 +107,39 @@
 }
 
 /**
+ * gsf_output_gzip_new_full:
+ * @sink: The underlying data source.
+ * @compress_level: The zlib compression level (0 to 9).
+ * @err: optionally %NULL.
+ *
+ * Adds a reference to @sink.
+ *
+ * Returns: a new file or %NULL.
+ **/
+GsfOutput *
+gsf_output_gzip_new_full (GsfOutput *sink, gint compress_level, GError **err)
+{
+	GsfOutput *output;
+	GError const *con_err;
+
+	g_return_val_if_fail (GSF_IS_OUTPUT (sink), NULL);
+
+	output = g_object_new (GSF_OUTPUT_GZIP_TYPE, "sink", sink,
+	                       "complev", compress_level, NULL);
+
+	con_err = gsf_output_error (output);
+
+	if (con_err) {
+		if (err)
+			*err = g_error_copy (con_err);
+		g_object_unref (output);
+		return NULL;
+	}
+
+	return output;
+}
+
+/**
  * gsf_output_gzip_new:
  * @sink: The underlying data source.
  * @err: optionally %NULL.
@@ -281,6 +316,7 @@
 	gzip->isize             = 0;
 	gzip->buf		= NULL;
 	gzip->buf_size		= 0;
+	gzip->complev           = Z_DEFAULT_COMPRESSION;
 }
 
 static void
@@ -298,6 +334,9 @@
 	case PROP_SINK:
 		g_value_set_object (value, gzip->sink);
 		break;
+	case PROP_COMPLEV:
+		g_value_set_int (value, gzip->complev);
+		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 		break;
@@ -329,6 +368,9 @@
 	case PROP_SINK:
 		gsf_output_gzip_set_sink (gzip, g_value_get_object (value));
 		break;
+	case PROP_COMPLEV:
+		gzip->complev = g_value_get_int (value);
+		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 		break;
@@ -393,6 +435,16 @@
 				      GSF_PARAM_STATIC |
 				      G_PARAM_READWRITE |
 				      G_PARAM_CONSTRUCT_ONLY));
+	g_object_class_install_property
+		(gobject_class,
+		 PROP_COMPLEV,
+		 g_param_spec_int ("complev", "Complev",
+				   "zlib compression level.",
+				   -1, 9, -1,
+				   GSF_PARAM_STATIC |
+				   G_PARAM_READWRITE |
+				   G_PARAM_CONSTRUCT_ONLY));
+	
 
 	parent_class = g_type_class_peek_parent (gobject_class);
 }
--- gsf-output-gzip.h.orig	2019-10-14 10:28:11.549673629 -0400
+++ gsf-output-gzip.h	2019-10-14 10:30:49.916341194 -0400
@@ -36,6 +36,8 @@
 GType gsf_output_gzip_get_type      (void);
 /* void  gsf_output_gzip_register_type (GTypeModule *module); glib dynamic types are not thread safe */
 
+GsfOutput *gsf_output_gzip_new_full (GsfOutput *sink, gint compress_level, GError **err);
+
 GsfOutput *gsf_output_gzip_new	    (GsfOutput *sink, GError **err);
 
 G_END_DECLS