write scan-properties.xml to szi

see https://github.com/jcupitt/libvips/issues/853

ChangeLog

@@ -1,6 +1,7 @@
 23/12/17 started 8.7.0
 - add magicksave, save image with libMagick [dlemstra]
 - dzsave to szi sets suffix correctly [martinweihrauch]
+- dzsave szi writes "scan-properties.xml"
 
 5/1/18 started 8.6.2
 - vips_sink_screen() keeps a ref to the input image ... stops a rare race

libvips/foreign/dzsave.c

@@ -76,6 +76,8 @@
  * 24/11/17
  * 	- output overlap-only tiles on edges for better deepzoom spec
  * 	  compliance
+ * 6/1/18
+ * 	- add scan-properties.xml for szi output
  */
 
 /*
@@ -858,6 +860,81 @@ write_vips_meta( VipsForeignSaveDz *dz )
 	return( 0 );
 }
 
+static void
+build_scan_property( VipsDbuf *dbuf, VipsImage *image, 
+	const char *vips_name, const char *szi_name )
+{
+	const char *str;
+
+	if( vips_image_get_typeof( image, vips_name ) &&
+		!vips_image_get_string( image, vips_name, &str ) ) { 
+		vips_dbuf_writef( dbuf, "    <property>\n" );  
+		vips_dbuf_writef( dbuf, "      <name>" ); 
+		vips_dbuf_write_amp( dbuf, szi_name );
+		vips_dbuf_writef( dbuf, "</name>\n" ); 
+		vips_dbuf_writef( dbuf, "      <value type=\"str\">" ); 
+		vips_dbuf_write_amp( dbuf, str );
+		vips_dbuf_writef( dbuf, "</value>\n" ); 
+		vips_dbuf_writef( dbuf, "    </property>\n" );  
+	}
+}
+
+/* Make the xml we write to scan-properties.xml in szi write. 
+ * Free with g_free().
+ */
+char *
+build_scan_properties( VipsImage *image )
+{
+	VipsDbuf dbuf;
+	GTimeVal now;
+	char *date;
+
+	vips_dbuf_init( &dbuf ); 
+
+	g_get_current_time( &now );
+	date = g_time_val_to_iso8601( &now ); 
+	vips_dbuf_writef( &dbuf, "<?xml version=\"1.0\"?>\n" ); 
+	vips_dbuf_writef( &dbuf, "<image xmlns=\"http://www.pathozoom.com/szi\""
+		" date=\"%s\" version=\"1.0\">\n", date ); 
+	g_free( date ); 
+	vips_dbuf_writef( &dbuf, "  <properties>\n" );  
+
+	build_scan_property( &dbuf, image, 
+		"openslide.vendor", "Vendor" );
+	build_scan_property( &dbuf, image, 
+		"openslide.objective-power", "ObjectiveMagnification" );
+	build_scan_property( &dbuf, image, 
+		"openslide.mpp-x", "MicronsPerPixelX" );
+	build_scan_property( &dbuf, image, 
+		"openslide.mpp-y", "MicronsPerPixelY" );
+
+	vips_dbuf_writef( &dbuf, "  </properties>\n" );  
+	vips_dbuf_writef( &dbuf, "</image>\n" );  
+
+	return( (char *) vips_dbuf_steal( &dbuf, NULL ) ); 
+}
+
+static int
+write_scan_properties( VipsForeignSaveDz *dz )
+{
+	VipsForeignSave *save = (VipsForeignSave *) dz;
+
+	char *dump;
+	GsfOutput *out;
+
+	if( !(dump = build_scan_properties( save->ready )) )
+                return( -1 );
+
+	out = vips_gsf_path( dz->tree, "scan-properties.xml", NULL );
+	gsf_output_write( out, strlen( dump ), (guchar *) dump ); 
+	(void) gsf_output_close( out );
+	g_object_unref( out );
+
+	g_free( dump );
+
+	return( 0 );
+}
+
 /* Our state during a threaded write of a strip.
  */
 typedef struct _Strip {
@@ -1936,6 +2013,10 @@ vips_foreign_save_dz_build( VipsObject *object )
 		write_vips_meta( dz ) )
 		return( -1 );
 
+	if( dz->write_szi &&
+		write_scan_properties( dz ) )
+		return( -1 );
+
 	/* This is so ugly. In earlier versions of dzsave, we wrote x.dzi and
 	 * x_files. Now we write x/x.dzi and x/x_files to make it possible to
 	 * create zip files. 

libvips/include/vips/dbuf.h

@@ -69,6 +69,7 @@ unsigned char *vips_dbuf_get_write( VipsDbuf *dbuf, size_t *size );
 gboolean vips_dbuf_write( VipsDbuf *dbuf, 
 	const unsigned char *data, size_t size );
 gboolean vips_dbuf_writef( VipsDbuf *dbuf, const char *fmt, ... );
+gboolean vips_dbuf_write_amp( VipsDbuf *dbuf, const char *str );
 void vips_dbuf_reset( VipsDbuf *dbuf );
 void vips_dbuf_destroy( VipsDbuf *dbuf );
 gboolean vips_dbuf_seek( VipsDbuf *dbuf, off_t offset, int whence );

libvips/iofuncs/dbuf.c

@@ -206,6 +206,52 @@ vips_dbuf_writef( VipsDbuf *dbuf, const char *fmt, ... )
 	return( TRUE ); 
 }
 
+/**
+ * vips_dbuf_write_amp: 
+ * @dbuf: the buffer
+ * @str: string to write
+ *
+ * Write @str to @dbuf, but escape <>&.
+ *
+ * Returns: %FALSE on out of memory, %TRUE otherwise.
+ */
+gboolean
+vips_dbuf_write_amp( VipsDbuf *dbuf, const char *str )
+{
+	const char *p;
+	size_t len;
+
+	for( p = str; *p; p += len ) {
+		len = strcspn( p, "&<>" );
+
+		vips_dbuf_write( dbuf, (unsigned char *) p, len );
+		switch( p[len] ) {
+		case '&': 
+			if( vips_dbuf_writef( dbuf, "&amp;" ) )
+				return( FALSE ); 
+			len += 1;
+			break;
+
+		case '<': 
+			if( vips_dbuf_writef( dbuf, "&lt;" ) )
+				return( FALSE );
+			len += 1;
+			break;
+
+		case '>': 
+			if( vips_dbuf_writef( dbuf, "&gt;" ) )
+				return( FALSE );
+			len += 1;
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	return( TRUE ); 
+}
+
 /**
  * vips_dbuf_reset:
  * @dbuf: the buffer

libvips/iofuncs/vips.c

@@ -743,40 +743,6 @@ dbuf_write_quotes( VipsDbuf *dbuf, const char *str )
 	}
 }
 
-/* Append a string to a buffer, but escape &<>.
- */
-static void
-dbuf_write_amp( VipsDbuf *dbuf, const char *str )
-{
-	const char *p;
-	size_t len;
-
-	for( p = str; *p; p += len ) {
-		len = strcspn( p, "&<>" );
-
-		vips_dbuf_write( dbuf, (unsigned char *) p, len );
-		switch( p[len] ) {
-		case '&': 
-			vips_dbuf_writef( dbuf, "&amp;" );
-			len += 1;
-			break;
-
-		case '<': 
-			vips_dbuf_writef( dbuf, "&lt;" );
-			len += 1;
-			break;
-
-		case '>': 
-			vips_dbuf_writef( dbuf, "&gt;" );
-			len += 1;
-			break;
-
-		default:
-			break;
-		}
-	}
-}
-
 static void *
 build_xml_meta( VipsMeta *meta, VipsDbuf *dbuf )
 {
@@ -808,7 +774,7 @@ build_xml_meta( VipsMeta *meta, VipsDbuf *dbuf )
 				g_type_name( type ) ); 
 			dbuf_write_quotes( dbuf, meta->name );
 			vips_dbuf_writef( dbuf, "\">" );  
-			dbuf_write_amp( dbuf, str );
+			vips_dbuf_write_amp( dbuf, str );
 			vips_dbuf_writef( dbuf, "</field>\n" );  
 		}
 
@@ -839,7 +805,7 @@ build_xml( VipsImage *image )
 		vips_dbuf_writef( &dbuf, 
 			"    <field type=\"%s\" name=\"Hist\">", 
 			g_type_name( VIPS_TYPE_REF_STRING ) );
-		dbuf_write_amp( &dbuf, str );
+		vips_dbuf_write_amp( &dbuf, str );
 		vips_dbuf_writef( &dbuf, "</field>\n" ); 
 	}
 
@@ -884,11 +850,11 @@ vips__xml_properties_meta( VipsImage *image,
 
 		vips_dbuf_writef( dbuf, "    <property>\n" );  
 		vips_dbuf_writef( dbuf, "      <name>" ); 
-		dbuf_write_amp( dbuf, field );
+		vips_dbuf_write_amp( dbuf, field );
 		vips_dbuf_writef( dbuf, "</name>\n" ); 
 		vips_dbuf_writef( dbuf, "      <value type=\"%s\">",
 			g_type_name( type ) );  
-		dbuf_write_amp( dbuf, str );
+		vips_dbuf_write_amp( dbuf, str );
 		vips_dbuf_writef( dbuf, "</value>\n" ); 
 		vips_dbuf_writef( dbuf, "    </property>\n" );