Reports: Utilization of urls

[Geert Janssens]

On Monday 07 March 2016 07:10:07 Carsten Rinke wrote:
> Hi,
> 
> when trying to introduce line charts to all graphical reports I run
> into the effect, that warnings are thrown in the area of setting up
> urls for the charts.
> 
> I think that is to make the charts interactive, so you can click on
> lines and bars or account names in the legend to open the
> corresponding account registers.
> 
> With the introduction of jqplot these kind of url utilization is not
> supported anymore (at least, I did not find support for it in the
> jqplot pages).
> 
GnuCash used to have interactive charts stem in the 1.x era. Back then it used an guppi to plot 
the charts.

Guppi was replaced with goffice during the migration to gtk2 (which also started the 2.x series 
of gnucash). I was not part of the team back then so I don't know why this choice was made. I 
suspect guppi was never ported to gtk2.

The goffice based chart rendering however is much more primitive. In fact the only thing 
gnucash did was to render the chart as a static image, which didn't allow for any interaction at 
all. The urls for interaction were kept in place as a reminder this functionality got missing and 
for someone to eventually figure out how to restore it.

This never happened until today.

Then jqplot was introduced between 2.4.x and 2.6. jqplot uses vector graphics to plot the charts, 
which is supported by many current webbrowsers. In theory vector graphics do support 
embedding of clickable links [1]. So with jqplot we're in a much better position to potentially re-
enable links. It may not be supported by jqplot itself directly, but there may be ways to add it 
indirectly. (Note: I haven't investigated this at all...)

> Should we take out all scheme-code that comes along with it?
> 
Having said all that, I think we can just as well remove this code unless someone is willing to do 
the work to re-enable it. It just clutters the current code. If someone wants to re-enable it in the 
future, the current code is still in the git history to study and revive then.

Regards,

Geert