From numerical values to continuous colors

The ptvis.color.ContinuousColorConversion class defines a conversion from numerical values to continuous colors.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = list(range(len(elements)))

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(),
)

plotly.io.show(fig)

Defining a conversion with colors for evenly spaced levels

The colors argument determines colors at evenly spaced levels of a color scale.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = list(range(len(elements)))

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(
        colors=["blue", "green", "red"],
    ),
)

plotly.io.show(fig)

Defining a conversion with colors at arbitrary levels

The levels of the colors argument can be changed by the levels argument. The arugment must be given in ascending order.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = list(range(len(elements)))

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(
        colors=["blue", "green", "red"],
        levels=[-1, -0.5, 1],
    ),
)

plotly.io.show(fig)

Clipping

By default, the minimum and maximum values correspond with the lowest and highest levels. Values corresponding with the lowest and highest levels can be changed by the value_min and value_max arguments. Values out of range are converted into colors of the lowest and highest levels.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = list(range(len(elements)))

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(
        colors=["blue", "green", "red"],
        value_min=30,
        value_max=60,
    ),
)

plotly.io.show(fig)

Colors for out-of-range values can be changed by the lower_color and higher_color argument.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = list(range(len(elements)))

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(
        colors=["blue", "green", "red"],
        value_min=30,
        value_max=60,
        lower_color="black",
        higher_color="white",
    ),
)

plotly.io.show(fig)

Color for NaN

A color for NaN can be changed by the na_color argument.

import plotly
import ptvis.color


elements = list(ptvis.Element)
values = [i if i % 10 else float("nan") for i in range(len(elements))]

fig = plotly.graph_objects.Figure()
ptvis.attach_plain_cells(
    fig,
    elements,
    colors=values,
    color_conversion=ptvis.color.ContinuousColorConversion(
        colors=["blue", "green", "red"],
        na_color="white",
    ),
)

plotly.io.show(fig)