[#5047] - Variable height footers

I know that JasperReports has never supported variable height footers and the reason given for not implementing is that the layout algorithm is rather complex so it would imply a lot of effort, particularly to ensure that it doesn't affect existing reports.

Nonetheless, even a limited version of variable height support for footers would be extremely useful. In particular, I find it very common to have to generate reports in which a variable amount of data should be included either on each footer or on the last page footer, and due to government regulations said data simply *can't* be allowed in any other place on the page.

The thing is, these footers are variable height but only in a limited sense: the height *can* be known right from the beginning, since it doesn't depend on any report data: it only depends on data sent via parameters.

Would it be possible to implement the footer size calculation so that it takes into account parameter fields, so I can for instance remove entire sections with a simple "print when" condition? As long as all the necessary information for said calculation is available right from the start (that is, there are no data fields filled by a query or in any other way variable, they are all just report parameters), wouldn't it be possible to use it to initialize the footer height, instead of having it fixed at design time? Then all the usual layout algorithms will work as expected, since the footer will still have a "fixed" height, simply calculated once, right before starting the layout process.