ChartDirector 6.0 (Python Edition)

Black Semicircle Meters


          

This example demonstrates semicircle meters with black background, silver border and glare effect.

The silver border effect is achieved by using AngularMeter.relativeLinearGradient to create a gradient consisting of varying levels of grey.

Glare effect is added to some of the meters using AngularMeter.addGlare. Glare effect works best in a dark background.

Source Code Listing

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

def createChart(chartIndex) :

    # The value to display on the meter
    value = 72.55

    # Create an AngularMeter object of size 300 x 180 pixels with transparent background
    m = AngularMeter(300, 180, Transparent)

    # Set the default text and line colors to white (0xffffff)
    m.setColor(TextColor, 0xffffff)
    m.setColor(LineColor, 0xffffff)

    # Center at (150, 150), scale radius = 128 pixels, scale angle -90 to +90 degrees
    m.setMeter(150, 150, 128, -90, 90)

    # Gradient color for the border to make it silver-like
    ringGradient = [1, 0x909090, 0.5, 0xd6d6d6, 0, 0xeeeeee, -0.5, 0xd6d6d6, -1, 0x909090]

    # Add a black (0x000000) scale background of 148 pixels radius with a 10 pixel thick silver
    # border
    m.addScaleBackground(148, 0, 10, m.relativeLinearGradient(ringGradient, 45, 148))

    # Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units, and micro
    # tick every 5 units
    m.setScale(0, 100, 20, 10, 5)

    # Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    # 16/16/10 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m.setLabelStyle("ariali.ttf", 16)
    m.setTickLength(-16, -16, -10)
    m.setLineWidth(0, 2, 1, 1)

    # Demostrate different types of color scales and putting them at different positions
    smoothColorScale = [0, 0x0000ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
    stepColorScale = [0, 0x00aa00, 60, 0xddaa00, 80, 0xcc0000, 100]
    highLowColorScale = [0, 0x00ff00, 70, Transparent, 100, 0xff0000]

    if chartIndex == 0 :
        # Add the smooth color scale at the default position
        m.addColorScale(smoothColorScale)
    elif chartIndex == 1 :
        # Add the smooth color scale starting at radius 128 with zero width and ending at radius 128
        # with 16 pixels inner width
        m.addColorScale(smoothColorScale, 128, 0, 128, -16)
    elif chartIndex == 2 :
        # Add the smooth color scale starting at radius 70 with zero width and ending at radius 60
        # with 20 pixels outer width
        m.addColorScale(smoothColorScale, 70, 0, 60, 20)
    elif chartIndex == 3 :
        # Add the high/low color scale at the default position
        m.addColorScale(highLowColorScale)
    elif chartIndex == 4 :
        # Add the step color scale at the default position
        m.addColorScale(stepColorScale)
    else :
        # Add the smooth color scale at radius 60 with 15 pixels outer width
        m.addColorScale(smoothColorScale, 60, 15)

    # Add a text label centered at (150, 125) with 15pt Arial Italic font
    m.addText(150, 125, "CPU", "ariali.ttf", 15, TextColor, BottomCenter)

    # Add a red (0xff0000) pointer at the specified value
    m.addPointer2(value, 0xff0000)

    # Add glare up to radius 138 (= region inside border)
    if chartIndex % 2 == 0 :
        m.addGlare(138)

    # Output the chart
    m.makeChart("blacksemicirclemeter%s.png" % chartIndex)


createChart(0)
createChart(1)
createChart(2)
createChart(3)
createChart(4)
createChart(5)

[CGI Version] pythondemo_cgi\blacksemicirclemeter.py
#!/usr/bin/python
from pychartdir import *
import cgi, sys

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

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

# The value to display on the meter
value = 72.55

# Create an AngularMeter object of size 300 x 180 pixels with transparent background
m = AngularMeter(300, 180, Transparent)

# Set the default text and line colors to white (0xffffff)
m.setColor(TextColor, 0xffffff)
m.setColor(LineColor, 0xffffff)

# Center at (150, 150), scale radius = 128 pixels, scale angle -90 to +90 degrees
m.setMeter(150, 150, 128, -90, 90)

# Gradient color for the border to make it silver-like
ringGradient = [1, 0x909090, 0.5, 0xd6d6d6, 0, 0xeeeeee, -0.5, 0xd6d6d6, -1, 0x909090]

# Add a black (0x000000) scale background of 148 pixels radius with a 10 pixel thick silver border
m.addScaleBackground(148, 0, 10, m.relativeLinearGradient(ringGradient, 45, 148))

# Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units, and micro tick
# every 5 units
m.setScale(0, 100, 20, 10, 5)

# Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to 16/16/10
# pixels pointing inwards, and their widths to 2/1/1 pixels.
m.setLabelStyle("ariali.ttf", 16)
m.setTickLength(-16, -16, -10)
m.setLineWidth(0, 2, 1, 1)

# Demostrate different types of color scales and putting them at different positions
smoothColorScale = [0, 0x0000ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
stepColorScale = [0, 0x00aa00, 60, 0xddaa00, 80, 0xcc0000, 100]
highLowColorScale = [0, 0x00ff00, 70, Transparent, 100, 0xff0000]

if chartIndex == 0 :
    # Add the smooth color scale at the default position
    m.addColorScale(smoothColorScale)
elif chartIndex == 1 :
    # Add the smooth color scale starting at radius 128 with zero width and ending at radius 128
    # with 16 pixels inner width
    m.addColorScale(smoothColorScale, 128, 0, 128, -16)
elif chartIndex == 2 :
    # Add the smooth color scale starting at radius 70 with zero width and ending at radius 60 with
    # 20 pixels outer width
    m.addColorScale(smoothColorScale, 70, 0, 60, 20)
elif chartIndex == 3 :
    # Add the high/low color scale at the default position
    m.addColorScale(highLowColorScale)
elif chartIndex == 4 :
    # Add the step color scale at the default position
    m.addColorScale(stepColorScale)
else :
    # Add the smooth color scale at radius 60 with 15 pixels outer width
    m.addColorScale(smoothColorScale, 60, 15)

# Add a text label centered at (150, 125) with 15pt Arial Italic font
m.addText(150, 125, "CPU", "ariali.ttf", 15, TextColor, BottomCenter)

# Add a red (0xff0000) pointer at the specified value
m.addPointer2(value, 0xff0000)

# Add glare up to radius 138 (= region inside border)
if chartIndex % 2 == 0 :
    m.addGlare(138)

# Output the chart
print("Content-type: image/png\n")
binaryPrint(m.makeChart2(PNG))