Can I plot a colorbar for a bokeh heatmap?

Question

Does bokeh have a simple way to plot the colorbar for a heatmap?

In this example it would be a strip illustrating how colors correspond to values.

Answer 1

Here is some code loosely based on birdsarah's response for generating a colorbar:

def generate_colorbar(palette, low=0, high=15, plot_height = 100, plot_width = 500, orientation = 'h'):

    y = np.linspace(low,high,len(palette))
    dy = y[1]-y[0]
    if orientation.lower()=='v':
        fig = bp.figure(tools="", x_range = [0, 1], y_range = [low, high], plot_width = plot_width, plot_height=plot_height)
        fig.toolbar_location=None
        fig.xaxis.visible = None
        fig.rect(x=0.5, y=y, color=palette, width=1, height = dy)
    elif orientation.lower()=='h':
        fig = bp.figure(tools="", y_range = [0, 1], x_range = [low, high],plot_width = plot_width, plot_height=plot_height)
        fig.toolbar_location=None
        fig.yaxis.visible = None
        fig.rect(x=y, y=0.5, color=palette, width=dy, height = 1)
    return fig

Also, if you are interested in emulating matplot lib colormaps, try using this:

import matplotlib as mpl
def return_bokeh_colormap(name):
    cm = mpl.cm.get_cmap(name)
    colormap = [rgb_to_hex(tuple((np.array(cm(x))*255).astype(np.int))) for x in range(0,cm.N)]
    return colormap
def rgb_to_hex(rgb):
    return '#%02x%02x%02x' % rgb[0:3]