Round Meter

This example demonstrates the basic steps in creating a round meter.

A round meter can be created with the following steps:

Create an AngularMeter object using AngularMeter.AngularMeter. In this example, the background color is set Transparent.
Specify the geometry of the meter scale using AngularMeter.setMeter. This specifies the center, the radius, and the starting and ending angles of the meter scale.
Optionally add a background and/or a border using AngularMeter.addRing.
Set the numeric scale of the meter using BaseMeter.setScale
Optionally configures the label style using BaseMeter.setLabelStyle, the tick length using BaseMeter.setTickLength and the tick width using BaseMeter.setLineWidth.
Optionally add a color scale to the meter using BaseMeter.addColorScale. Whereas the meter scale displays the values with text labels, a color scale represents the values with different colors.
Optionally add additional labels to the meter using BaseChart.addText.
Add a "new style" pointer to the meter using AngularMeter.addPointer2. For compatibility with earlier versions of ChartDirector, classical pointers are still supported using the previous method BaseMeter.addPointer.

The following is the command line version of the code in "cppdemo/roundmeter". The MFC version of the code is in "mfcdemo/mfcdemo". The Qt Widgets version of the code is in "qtdemo/qtdemo". The QML/Qt Quick version of the code is in "qmldemo/qmldemo".

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The value to display on the meter
    double value = 72.3;

    // Create an AngularMeter object of size 250 x 250 pixels with transparent background
    AngularMeter* m = new AngularMeter(250, 250, Chart::Transparent);

    // Center at (125, 125), scale radius = 111 pixels, scale angle -145 to +145 degrees
    m->setMeter(125, 125, 111, -145, 145);

    // Add a very light grey (0xeeeeee) circle with radius 123 pixels as background
    m->addRing(0, 123, 0xeeeeee);
    // Add a grey (0xcccccc) ring between radii 116 and 123 pixels as border
    m->addRing(116, 123, 0xcccccc);

    // Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
    m->setScale(0, 100, 10, 5, 1);

    // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    // 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m->setLabelStyle("Arial Italic", 15);
    m->setTickLength(-12, -9, -6);
    m->setLineWidth(0, 2, 1, 1);

    // Add a smooth color scale to the meter
    double smoothColorScale[] = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
        0xff0000};
    const int smoothColorScale_size = (int)(sizeof(smoothColorScale)/sizeof(*smoothColorScale));
    m->addColorScale(DoubleArray(smoothColorScale, smoothColorScale_size));

    // Add a text label centered at (125, 175) with 15pt Arial Italic font
    m->addText(125, 175, "CPU", "Arial Italic", 15, Chart::TextColor, Chart::Center);

    // Add a red (0xff0000) pointer at the specified value
    m->addPointer2(value, 0xff0000);

    // Output the chart
    m->makeChart("roundmeter.png");

    //free up resources
    delete m;

    return 0;
}