Heat Map Cell Labels

This example demonstrates adding labels to the cells, adding gaps between cells and using a custom color scale.

This example is similar to Discrete Heat Map, with the following additions:

Some cells are set to NoValue to hide them.
Layer.setDataLabelFormat is used to set the cell labels to "{z|0}", which means to display the cell value with no decimal place. Please refer to Parameter Substitution and Formatting for available formatting options.
DiscreteHeatMapLayer.setCellGap is used to configured the gaps between cells.
ColorAxis.setColorScale is used to configured a custom color scale.

pythondemo\heatmapcelllabels.py

#!/usr/bin/python

# The ChartDirector for Python module is assumed to be in "../lib"
import sys, os
sys.path.insert(0, os.path.join(os.path.abspath(sys.path[0]), "..", "lib"))

from pychartdir import *

# The x-axis and y-axis labels
xLabels = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J"]
yLabels = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]

# Random data for the 10 x 10 cells
rand = RanSeries(2)
zData = rand.get2DSeries(len(xLabels), len(yLabels), 0, 100)

# We set the middle 5 x 5 cells to NoValue to remove them from the chart
for x in range(3, 7) :
    for y in range(3, 7) :
        zData[y * len(xLabels) + x] = NoValue

# Create an XYChart object of size 480 x 540 pixels.
c = XYChart(480, 540)

# Set the plotarea at (50, 40) and of size 400 x 400 pixels. Set the background, border, and grid
# lines to transparent.
p = c.setPlotArea(50, 40, 400, 400, -1, -1, Transparent, Transparent)

# Create a discrete heat map with 10 x 10 cells
layer = c.addDiscreteHeatMapLayer(zData, len(xLabels))

# Set the x-axis labels. Use 8pt Arial Bold font. Set axis stem to transparent, so only the labels
# are visible. Set 0.5 offset to position the labels in between the grid lines. Position the x-axis
# at the top of the chart.
c.xAxis().setLabels(xLabels)
c.xAxis().setLabelStyle("Arial Bold", 8)
c.xAxis().setColors(Transparent, TextColor)
c.xAxis().setLabelOffset(0.5)
c.xAxis().setTitle("X axis title placeholder", "Arial Bold", 12)
c.setXAxisOnTop()

# Set the y-axis labels. Use 8pt Arial Bold font. Set axis stem to transparent, so only the labels
# are visible. Set 0.5 offset to position the labels in between the grid lines. Reverse the y-axis
# so that the labels are flowing top-down instead of bottom-up.
c.yAxis().setLabels(yLabels)
c.yAxis().setLabelStyle("Arial Bold", 8)
c.yAxis().setColors(Transparent, TextColor)
c.yAxis().setLabelOffset(0.5)
c.yAxis().setTitle("Y axis title placeholder", "Arial Bold", 12)
c.yAxis().setReverse()

# Set a 3-pixel gap between cells
layer.setCellGap(3)

# Use the z value as the cell label
layer.setDataLabelFormat("{z|0}")

# Position the color axis 20 pixels below the plot area and of the width as the plot area. Put the
# labels at the bottom side of the color axis. Use 8pt Arial Bold font for the labels.
cAxis = layer.setColorAxis(p.getLeftX(), p.getBottomY() + 20, TopLeft, p.getWidth(), Bottom)
cAxis.setLabelStyle("Arial Bold", 8)
cAxis.setTitle("Color legend title placeholder", "Arial Bold", 12)

# Set the color stops and scale of the color axis
colorScale = [0, 0x00ff00, 50, 0xffff00, 80, 0xff6600, 100, 0xff0000]
cAxis.setColorScale(colorScale)
cAxis.setLinearScale(0, 100, 10)

# Output the chart
c.makeChart("heatmapcelllabels.png")