make note when to use JSDatasource vs MemoryDatasource

mapnik · Apr 13, 2011 · f1c3f3b · f1c3f3b
1 parent 20942ce
commit f1c3f3b
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Showing 3 changed files with 27 additions and 5 deletions.
diff --git a/examples/js_datasource/osm_xapi.js b/examples/js_datasource/osm_xapi.js
@@ -10,8 +10,14 @@
 // * node-mapnik
 // * node-get
 
-// WARNING - mapnik.JSDatasource cannot be used with the async mapnik.render() (will hang)
-// and only will work with mapnik.render_to_string() or mapnik.render_to_file()
+/*
+NOTE - maps using mapnik.JSDatasource can only be rendered with
+mapnik.render_to_string() or mapnik.render_to_file() as the javascript
+callback only works if the rendering happens in the main thread.
+
+If you want async rendering using mapnik.render() then use the
+mapnik.MemoryDatasource instead of mapnik.JSDatasource.
+*/
 
 var mapnik = require('mapnik');
 var sys = require('fs');

diff --git a/examples/js_datasource/simple.js b/examples/js_datasource/simple.js
@@ -6,7 +6,17 @@ javascript callback that leverages experimental javascript
 datasource support
 */
 
-// WARNING - mapnik.JSDatasource cannot be used with the async mapnik.render() (will hang)
+/*
+NOTE - maps using mapnik.JSDatasource can only be rendered with
+mapnik.render_to_string() or mapnik.render_to_file() as the javascript
+callback only works if the rendering happens in the main thread.
+
+If you want async rendering using mapnik.render() then use the
+mapnik.MemoryDatasource instead of mapnik.JSDatasource.
+*/
+
+
+cannot be used with the async mapnik.render() (will hang)
 // and only will work with mapnik.render_to_string() or mapnik.render_to_file()
 
 var mapnik = require('mapnik');

diff --git a/examples/js_datasource/usgs_quakes.js b/examples/js_datasource/usgs_quakes.js
@@ -8,8 +8,14 @@
 // * node-mapnik
 // * node-get
 
-// WARNING - mapnik.JSDatasource cannot be used with the async mapnik.render() (will hang)
-// and only will work with mapnik.render_to_string() or mapnik.render_to_file()
+/*
+NOTE - maps using mapnik.JSDatasource can only be rendered with
+mapnik.render_to_string() or mapnik.render_to_file() as the javascript
+callback only works if the rendering happens in the main thread.
+
+If you want async rendering using mapnik.render() then use the
+mapnik.MemoryDatasource instead of mapnik.JSDatasource.
+*/
 
 var mapnik = require('mapnik');
 var sys = require('fs');