nonselection_glyph seems to be drawn after selection_glyph

[birdsarah]

Using patches to draw a map and want to do selection as it works on the map here: http://africawatermap.aptivate.org/

This doesn't seem to be possible as the non-selected glyphs are being drawn over the selected glyph. Couple of screenshots to highlight this.

---

selected and non-selected elements are full alpha, but selected has thick line

non-selected element keeps line alpha but has full alpha set to 0

non-selected element has line_alpha of 0 and fill_alpha of 0.2

non-selected element has line_alpha of 0 and fill_alpha of 1

[bryevdv]

@birdsarah is it possible you are drawing the patches twice somehow? I don't understand this because the main render method splits all the indices into two groups, the selected and non-selected, and calls individual glyph render functions separately for each (disjoint) set of indices here:

https://github.com/bokeh/bokeh/blob/master/bokehjs/src/coffee/renderer/glyph/glyph_renderer.coffee#L117

It's certainly possible there is a real problem in BokehJS I would just be surprised not to see if affect every glyph in the same way.

[birdsarah]

Hi @bryevdv I'm not understanding your question, but you have hit on the problem

My understanding of the code you linked to:

do_render(ctx, selected, @selection_glyph)
do_render(ctx, nonselected, @nonselection_glyph)

is that:

• It's rendering the non-selected elements second.
• This means that in the case where they overlap, the non-selected ones are "on top"

Having tried changing that order locally. That is indeed the source of my error:

With the current code:

With the order of do_render switched:

In case it's useful, here's the relevant piece of code:

    borders = Patches(
        xs='xs', ys='ys',
        fill_color='color_for_active_year', fill_alpha=1,
        line_color="#FFFFFF", line_width=1,
    )
    selected_borders = Patches(
        xs='xs', ys='ys',
        fill_color='color_for_active_year', fill_alpha=1,
        line_color=ORANGE, line_width=5,
    )

    plot.add_glyph(source, borders, selection_glyph=selected_borders, nonselection_glyph=borders)

[bryevdv]

Oh, I see. I misunderstood to mean that an entire non selected glyph was obscuring a selected one, not just the borders. That is a simple fix, but it should go in after our big BokehJS build PR which will hopefully be merged tomorrow.

[bryevdv]

This was changed.

[damianavila]

This was changed.

Can you link where was changed? Thanks.

[bryevdv]

fixed in #2143