ChartDirector Ver 4.1 (C++ Edition)

Semi-Circle Meter




This example demonstrates a simple half circle angular meter.

A basic angular meter can be created using the following steps:

In addition to the basic angular meter, this example demonstrates the following features:

Note that by default, the drawing ordering of the text box objects and meter pointer follow the order in which they are added to the chart. Thus this sample code adds the meter pointer last, to ensure it stays on top of the custom text boxes.

Source Code Listing

[The following code is available in "cppdemo/semicirclemeter". A MFC version of the code is available in "mfcdemo" (Windows edition only).]
#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The value to display on the meter
    double value = 27.48;

    // Create an AngularMeter object of size 200 x 115 pixels, with silver background
    // color, black border, 2 pixel 3D border border and rounded corners
    AngularMeter *m = new AngularMeter(200, 115, Chart::silverColor(), 0x000000, 2);
    m->setRoundedFrame();

    // Set the meter center at (100, 100), with radius 85 pixels, and span from -90
    // to +90 degress (semi-circle)
    m->setMeter(100, 100, 85, -90, 90);

    // 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 0 - 60 as green (66FF66) zone
    m->addZone(0, 60, 0, 85, 0x66ff66);

    // Set 60 - 80 as yellow (FFFF33) zone
    m->addZone(60, 80, 0, 85, 0xffff33);

    // Set 80 - 100 as red (FF6666) zone
    m->addZone(80, 100, 0, 85, 0xff6666);

    // Add a text label centered at (100, 60) with 12 pts Arial Bold font
    m->addText(100, 60, "PSI", "arialbd.ttf", 12, Chart::TextColor, Chart::Center);

    // Add a text box at the top right corner of the meter showing the value
    // formatted to 2 decimal places, using white text on a black background, and
    // with 1 pixel 3D depressed border
    m->addText(156, 8, m->formatValue(value, "2"), "arial.ttf", 8, 0xffffff
        )->setBackground(0x000000, 0, -1);

    // Add a semi-transparent blue (40666699) pointer with black border at the
    // specified value
    m->addPointer(value, 0x40666699, 0x000000);

    // output the chart
    m->makeChart("semicirclemeter.png");

    //free up resources
    delete m;
    return 0;
}