#!/usr/bin/python
from pychartdir import *
import cgi, sys, math

# Get HTTP query parameters
query = cgi.FieldStorage()

# This script can draw different charts depending on the chartIndex
chartIndex = int(query["img"].value)

# The x and y coordinates of the grid
dataX = [-4, -3, -2, -1, 0, 1, 2, 3, 4]
dataY = [-4, -3, -2, -1, 0, 1, 2, 3, 4]

# The values at the grid points. In this example, we will compute the values using the formula z =
# Sin(x * pi / 3) * Sin(y * pi / 3).
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 * 3.1416 / 3) * math.sin(y * 3.1416 / 3)

# Create a XYChart object of size 360 x 360 pixels
c = XYChart(360, 360)

# Set the plotarea at (30, 25) and of size 300 x 300 pixels. Use semi-transparent black (c0000000)
# for both horizontal and vertical grid lines
c.setPlotArea(30, 25, 300, 300, -1, -1, -1, 0xc0000000, -1)

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

# Set the x-axis and y-axis scale
c.xAxis().setLinearScale(-4, 4, 1)
c.yAxis().setLinearScale(-4, 4, 1)

if chartIndex == 0 :
    # Discrete coloring, spline surface interpolation
    c.addTitle("Spline Surface - Discrete Coloring", "arialbi.ttf", 12)
elif chartIndex == 1 :
    # Discrete coloring, linear surface interpolation
    c.addTitle("Linear Surface - Discrete Coloring", "arialbi.ttf", 12)
    layer.setSmoothInterpolation(0)
elif chartIndex == 2 :
    # Smooth coloring, spline surface interpolation
    c.addTitle("Spline Surface - Continuous Coloring", "arialbi.ttf", 12)
    layer.setContourColor(Transparent)
    layer.colorAxis().setColorGradient(1)
else :
    # Discrete coloring, linear surface interpolation
    c.addTitle("Linear Surface - Continuous Coloring", "arialbi.ttf", 12)
    layer.setSmoothInterpolation(0)
    layer.setContourColor(Transparent)
    layer.colorAxis().setColorGradient(1)

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

