filter export graphics chart JPEG GraphicExportFilter Olivier Samyn Sven Jacobi Michael Hoennig Tom Schindl How can I export a chart to a JPEG file with approproate dimensions?

I'm developping a little application, trying to generate jpeg files from OpenOffice.org charts (I will maybe use it some day to generate stats reports displayed on a webpage...). To do this, nothing more simple to connect to a OOo instance, open the calc document, select the chart and use a GraphicExportFilter to save the shape to a jpeg image. It works well. But the remaining problem is to set the size of the exported image. All dimensions in OOO are expressed in mm. The JPEG export filter seems to convert those dimensions to the pixel unit using a "black box" formula. I noticed that using a factor around 37.88 tends to give me a way to convert from the pixel to mm units. But it seems it's not exactly this factor and in some case there is a limit size (2048x2048 ?). So my question is: what's this formula ? Is there some paper explaining this or some source file I can check out to know more about this ?

There exist a possibility to set the resolution, I am sorry it doesn't made it into the developers guide. The feature is available up from OOo 1.1. Each graphic filter is supporting a property sequence which is called "FilterData" therein you can set the size in pixel with the properties "PixelWidth" and "PixelHeight", the logical size (in 1/100mm) can be set with "LogicalWidth" and "LogicalHeight". The following basic macro is demonstrating this:

Sub Export( xObject, sFileUrl As String, aFilterData ) xExporter = createUnoService( "com.sun.star.drawing.GraphicExportFilter" ) xExporter.SetSourceDocument( xObject ) Dim aArgs (2) as new com.sun.star.beans.PropertyValue Dim aURL as new com.sun.star.util.URL aURL.complete = sFileUrl aArgs(0).Name = "MediaType" aArgs(0).Value = "image/jpeg" aArgs(1).Name = "URL" aArgs(1).Value = aURL aArgs(2).Name = "FilterData" aArgs(2).Value = aFilterData xExporter.filter( aArgs() ) End Sub

And here an example of how to use this macro:

Sub ExportCurrentPageOrSelection 'creating filter dependent filter properties Dim aFilterData (4) as new com.sun.star.beans.PropertyValue aFilterData(0).Name = "PixelWidth" ' aFilterData(0).Value = 1000 aFilterData(1).Name = "PixelHeight" aFilterData(1).Value = 1000 aFilterData(2).Name ="LogicalWidth" aFilterData(2).Value = 1000 aFilterData(3).Name ="LogicalHeight" aFilterData(3).Value = 1000 aFilterData(4).Name ="Quality" aFilterData(4).Value = 60 Dim sFileUrl As String sFileUrl = "file:///d:/test2.jpg" xDoc = thiscomponent xView = xDoc.currentController xSelection = xView.selection If isEmpty( xSelection ) then xObj = xView.currentPage else xObj = xSelection End If Export( xObj, sFileUrl, aFilterData() ) End Sub Modified to match new snippet-DTD Initial version