Hi!
So you are saying that using "xlsx" recipe only we can prepare charts right?
both the html-to-xlsx and the xlsx recipe can prepare charts, both approaches even are similar, in both, you put the chart already in the .xlsx using the MS Excel, and in another sheet you put the data, in the MS Excel you do some steps to define the chart to be updated based on the data of the other sheet, in both cases you can use the steps described in the pivot table tutorial to bind the chart with the other sheet.
the only difference between the html-to-xlsx vs xlsx recipe, in this case, is that using the xlsx recipe you are able to "Hide" the "Data" sheet, if that is something you don't want to show.
I think the steps to produce the same example with a pie chart are straightforward, if we take one of the examples and try to modify, for example, I have downloaded the pivot-template .xlsx there and did the following:
right-click the existing chart, selected "change chart type", selected pie > 2-D pie, then the chart is updated, i can even see the chart updated with the old sample data, (even if the "Data" worksheet is empty). you can hide the sheet with the data if you don't want to show that sheet in the output (just right-click "Data" sheet and select "Hide")
finally i save the xlsx file and uploaded again in the playground, replacing the previous pivot-template, i've also updated the data on the playground with some different names, run the example and it works. the live example is
here
so i think you can do it the same, and any modification you need to do to the chart can be done just fine.
It will be great If we can connect for 5-10 minutes on Skype or in hangout to clear the things as we have to make the application live asap
we prefer to keep the conversation of these kinds of general common questions on the forum. so just continue here if you get more problems.