I would like to generate a png chart image using ImageGraph (as explained here: http://piwik.org/docs/analytics-api/reference/#ImageGraph) showing the nb_conversions (number of goal conversions) on a monthly basis or so over the last year or so.
The problem is: I have 4 goals in total and would either (preferably) have all the nb_conversions of these goals in one evolution chart (4 lines and maybe a legend) or have a separate chart for all of these goals (i.e. 4 distinct charts in total then).
What I do not know is how to pass idGoal=[1…4] to the ImageGraph method. What I have is
&method=ImageGraph.get&apiModule=Goals&apiAction=get
but I do not want to have the nb_conversions of all goals summed up but would like to choose the specific goal by using idGoal parameter of Goals.get (see http://piwik.org/docs/analytics-api/reference/#Goals)
Is this somewhat possible?