Hey!
Could it be, that the widget VisitsSummary (getEvolutionGraph) doesn’t work with token_auth? When using the following code, I get only a “Keine Daten für dieses Diagramm”-messsage (No data for this chart). If I’m logged in, it works. Other widgets I’ve tested are working with token_auth.
<div id="widgetIframe"><iframe width="100%" height="170" src="http://piwik.xyz.de/index.php?module=Widgetize&action=iframe&columns[]=nb_visits&moduleToWidgetize=VisitsSummary&actionToWidgetize=getEvolutionGraph&idSite=1&period=day&disableLink=1&token_auth=473a5af9c096e329f25cac9392c51095" scrolling="no" frameborder="0" marginheight="0" marginwidth="0"></iframe></div>
By the way: Unfortunately, I didn’t find a solution, to create this chart on my own by using the API-data.