[FEATURE] SVG export for gridplot

[birdsarah]

Currently export of a gridplot works for export png but not for svg.

With svg you get a series of plots back and have to manually compile.

User jcacbelos on discourse seems to have a start at something that works: https://discourse.bokeh.org/t/generate-svg-images-from-bokeh-plots-and-include-them-in-a-pdf-report-with-using-svglib-and-reportlab/3889

[chesucr]

I am "jcacabelos"

Actually I export the plots as SVG files individually, with the export_svgs function. Then I create a PDF file including all of them, not a SVG file.

But what you want is to export an unique SVG file with all the plots in a gridplot right? Or you just want to export them one by one (the same you do with the PNG files)? I think having both options would be a nice feature

[mattpap]

Currently export of a gridplot works for export png but not for svg.

The "export" part should be emphasized, because otherwise bokeh can't save a gridplot as a PNG, only as a sequence of PNGs. This is because gridplot's implementation doesn't live up to its name and produces a composite layout. We can export such layout as a single PNG, because export utility captures a screenshot of an entire page where a gridplot was rendered.

When issue #3821 is fixed, which is currently work in progress scheduled for bokeh 1.4, it will be possible to put multiple plots on a single canvas, which in turn will allow to save multiple plots a single file (PNG or SVG). At bokeh 2.0, gridplot() will produce an instance of a single canvas GridPlot model. The old behavior will still be possible with an existing GridBox layout.

[bryevdv]

At bokeh 2.0, gridplot() will produce an instance of a single canvas GridPlot model.

We will have to conduct some experiments to validate that single-canvas performance is acceptable, first.

[birdsarah]

At bokeh 2.0, gridplot() will produce an instance of a single canvas GridPlot model.
We will have to conduct some experiments to validate that single-canvas performance is acceptable, first.

This is very exciting.

Regarding performance I would be happy to accept poor performance in the case where I was trying to do an svg export.

Happy to help test / chip in on that!

Thanks for the clarification @chesucr. the pdf arrangement is useful to me while other solutions are coming along but it sounds like @mattpap is working up a proper solution.