Make line_width or any other numerical property of hex_tile change depending on datapoint

[robind]

Is it possible to change the line_width of a hex_tile depending on the value of a field, for example line_width=3 if field “counts” > 100, else line_width=0. For the fill_color property I can use linear_cmap. Is there something for numerical properties aswell? Best would be without adding another column to my CDS.

figure.hex_tile(q=“q”, r=“r”, line_width=3, alpha=0.4, fill_color=linear_cmap(‘counts’, ‘Viridis256’, 0, 300))

[gmerritt123]

Something like this, leveraging the amazingness of CustomJSTransform:

from bokeh.plotting import figure, show
from bokeh.transform import transform
from bokeh.models import ColumnDataSource, HexTile, CustomJSTransform

source = ColumnDataSource(dict(
        q=[0,  0, -1, -1,  1, 1, 0],
        r=[0, -1,  0,  1, -1, 0, 1],
        counts=[199,205,301,500,150]
    )
)

plot = figure(width=300, height=300)
#create a customjstransform that goes through the array of counts and populates an array of widths
width_transform = CustomJSTransform(v_func='''
                                    var widths = []
                                    //variable xs corresponds to the array corresponding to the assigned field_name in the transform
                                    //so in this case xs will be the array of counts
                                    for (var i=0;i<xs.length;i++){
                                            if (xs[i] > 300){
                                                    widths.push(8)
                                                    }
                                            else {widths.push(0)}
                                            }
                                    
                                    return widths
                                    ''')
r = plot.hex_tile(q="q", r="r", size=1, fill_color="#fb9a99", line_color="black"
                  ,line_width=transform(field_name='counts',transform=width_transform) #assign the transform to the line_widths property
                  ,source=source)


show(plot)

[robind]

Thank you very much. This is exactly what I needed. CustomJSTransform does indeed look amazing and powerful.