ChartDirector 6.0 (Python Edition)

Continuous Contour Coloring




This example demonstrates continuous coloring of the ContourLayer.

By default, a contour layer will be discretely colored, which means the color will change in discrete steps according to the z level. In continuous coloring, the color will change continuously according to the z level. Continuous coloring can be enabled using ColorAxis.setColorGradient or ColorAxis.setColorScale.

Source Code Listing

[Standalone Version] pythondemo\smoothcontour.py
#!/usr/bin/python
from pychartdir import *
import math

# The x and y coordinates of the grid
dataX = [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
dataY = [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

# The values at the grid points. In this example, we will compute the values using the formula z =
# Sin(x / 2) * Sin(y / 2).
dataZ = [0] * (len(dataX) * len(dataY))
for yIndex in range(0, len(dataY)) :
    y = dataY[yIndex]
    for xIndex in range(0, len(dataX)) :
        x = dataX[xIndex]
        dataZ[yIndex * len(dataX) + xIndex] = math.sin(x / 2.0) * math.sin(y / 2.0)

# Create a XYChart object of size 600 x 500 pixels
c = XYChart(600, 500)

# Add a title to the chart using 18 points Times New Roman Bold Italic font
c.addTitle("Nano Lattice Twister Field Intensity        ", "timesbi.ttf", 18)

# Set the plotarea at (75, 40) and of size 400 x 400 pixels. Use semi-transparent black (80000000)
# dotted lines for both horizontal and vertical grid lines
c.setPlotArea(75, 40, 400, 400, -1, -1, -1, c.dashLineColor(0x80000000, DotLine), -1)

# Set x-axis and y-axis title using 12 points Arial Bold Italic font
c.xAxis().setTitle("Lattice X Direction (nm)", "arialbi.ttf", 12)
c.yAxis().setTitle("Lattice Y Direction (nm)", "arialbi.ttf", 12)

# Set x-axis and y-axis labels to use Arial Bold font
c.xAxis().setLabelStyle("arialbd.ttf")
c.yAxis().setLabelStyle("arialbd.ttf")

# When auto-scaling, use tick spacing of 40 pixels as a guideline
c.yAxis().setTickDensity(40)
c.xAxis().setTickDensity(40)

# Add a contour layer using the given data
layer = c.addContourLayer(dataX, dataY, dataZ)

# Set the contour color to transparent
layer.setContourColor(Transparent)

# Move the grid lines in front of the contour layer
c.getPlotArea().moveGridBefore(layer)

# Add a color axis (the legend) in which the left center point is anchored at (495, 240). Set the
# length to 370 pixels and the labels on the right side.
cAxis = layer.setColorAxis(495, 240, Left, 370, Right)

# Add a bounding box to the color axis using light grey (eeeeee) as the background and dark grey
# (444444) as the border.
cAxis.setBoundingBox(0xeeeeee, 0x444444)

# Add a title to the color axis using 12 points Arial Bold Italic font
cAxis.setTitle("Twist Pressure (Twist-Volt)", "arialbi.ttf", 12)

# Set color axis labels to use Arial Bold font
cAxis.setLabelStyle("arialbd.ttf")

# Use smooth gradient coloring
cAxis.setColorGradient(1)

# Output the chart
c.makeChart("smoothcontour.jpg")

[CGI Version] pythondemo_cgi\smoothcontour.py
#!/usr/bin/python
from pychartdir import *
import math

# The x and y coordinates of the grid
dataX = [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
dataY = [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

# The values at the grid points. In this example, we will compute the values using the formula z =
# Sin(x / 2) * Sin(y / 2).
dataZ = [0] * (len(dataX) * len(dataY))
for yIndex in range(0, len(dataY)) :
    y = dataY[yIndex]
    for xIndex in range(0, len(dataX)) :
        x = dataX[xIndex]
        dataZ[yIndex * len(dataX) + xIndex] = math.sin(x / 2.0) * math.sin(y / 2.0)

# Create a XYChart object of size 600 x 500 pixels
c = XYChart(600, 500)

# Add a title to the chart using 18 points Times New Roman Bold Italic font
c.addTitle("Nano Lattice Twister Field Intensity        ", "timesbi.ttf", 18)

# Set the plotarea at (75, 40) and of size 400 x 400 pixels. Use semi-transparent black (80000000)
# dotted lines for both horizontal and vertical grid lines
c.setPlotArea(75, 40, 400, 400, -1, -1, -1, c.dashLineColor(0x80000000, DotLine), -1)

# Set x-axis and y-axis title using 12 points Arial Bold Italic font
c.xAxis().setTitle("Lattice X Direction (nm)", "arialbi.ttf", 12)
c.yAxis().setTitle("Lattice Y Direction (nm)", "arialbi.ttf", 12)

# Set x-axis and y-axis labels to use Arial Bold font
c.xAxis().setLabelStyle("arialbd.ttf")
c.yAxis().setLabelStyle("arialbd.ttf")

# When auto-scaling, use tick spacing of 40 pixels as a guideline
c.yAxis().setTickDensity(40)
c.xAxis().setTickDensity(40)

# Add a contour layer using the given data
layer = c.addContourLayer(dataX, dataY, dataZ)

# Set the contour color to transparent
layer.setContourColor(Transparent)

# Move the grid lines in front of the contour layer
c.getPlotArea().moveGridBefore(layer)

# Add a color axis (the legend) in which the left center point is anchored at (495, 240). Set the
# length to 370 pixels and the labels on the right side.
cAxis = layer.setColorAxis(495, 240, Left, 370, Right)

# Add a bounding box to the color axis using light grey (eeeeee) as the background and dark grey
# (444444) as the border.
cAxis.setBoundingBox(0xeeeeee, 0x444444)

# Add a title to the color axis using 12 points Arial Bold Italic font
cAxis.setTitle("Twist Pressure (Twist-Volt)", "arialbi.ttf", 12)

# Set color axis labels to use Arial Bold font
cAxis.setLabelStyle("arialbd.ttf")

# Use smooth gradient coloring
cAxis.setColorGradient(1)

# Output the chart
print("Content-type: image/jpeg\n")
binaryPrint(c.makeChart2(JPG))