[Scilab-users] Simple Date & Time Plotting

[Samuel Gougeon]

Le 20/07/2018 à 12:20, David Chèze a écrit :
> Hi Pat and all,
>
> I was looking for similar simple feature for plotting time series with
> readable date time format and I can share an intermediate approach to update
> the x-ticks with a call to function labxdtv(), cf linked file  labxdtv.sci
> <http://mailinglists.scilab.org/file/t375348/labxdtv.sci>
> There's no callback function, the function is called after the plot action
> and after every changes in windows size or zoom level : initial plot is like
> plot2(dtnm,Donnees), with dtnm a vector of datenum values and Donnees a
> matrix of related data to plot. After the figure is plot at first time or
> after every changes in windows size or level of zoom, call again labxdtv, it
> regraduates automatically the x-axis according to the datanum span and
> convert the datenum in readable date time vector format (auto_ticks are set
> to on in the function).
>
> Would be great to have in scilab a more powerful/flexible builtin
> function... :)

Sure, but it's a rather complex function. The need was reported 10 years 
ago @ http://bugzilla.scilab.org/6228
labxdtv() gives a rather raw idea of the task. On it's showcase example, 
ticks are every 3 months over one year:

But they are not nice:

  * At this scale, major ticks should rather be on the 1st of months.
  * there should not be any shift 17 => 18 => 19. This means that
    subticking must be completely customized, with a polyline
    superimposed to the axis, since it is irregular.
  * here there is only one subtick instead of rather two (for an
    automatic handling)
  * etc..

So yes, a powerful function formating dates would be nice. But 
implementing a really nice and useful one is definitely not trivial.

Cheers
Samuel

PS : there is presently no event triggered by zooming or panning an axes.

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