ChartDirector 5.1 (C++ Edition)

Wide Angular Meters


          

This example demonstrates angular meters of which the width is large compared to the height. It also demonstrates various background effects.

The meters in this example are created by using large meter radii, but small angular spans. The center (pivot for the pointer) can then be put outside the meter region and the meters can be reduced in height.

This example also demonstrates metallic background effects and background patterns. The backgrounds are configured using BaseChart.setBackground. The metallic colors are created using Chart::goldColor, Chart::silverColor and Chart::metalColor. The background patterns are created by loading image files as pattern colors using BaseChart.patternColor2.

This example also shows the effect of the semi-transparent pointers, which can avoid blocking the labels on the meter.

Source Code Listing

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

void createChart(int img, const char *filename)
{
    // The value to display on the meter
    double value = 6.5;

    // Create an AugularMeter object of size 200 x 100 pixels with rounded corners
    AngularMeter *m = new AngularMeter(200, 100);
    m->setRoundedFrame();

    // Set meter background according to a parameter
    if (img == 0) {
        // Use gold background color
        m->setBackground(Chart::goldColor(), 0x000000, -2);
    } else if (img == 1) {
        // Use silver background color
        m->setBackground(Chart::silverColor(), 0x000000, -2);
    } else if (img == 2) {
        // Use metallic blue (9898E0) background color
        m->setBackground(Chart::metalColor(0x9898e0), 0x000000, -2);
    } else if (img == 3) {
        // Use a wood pattern as background color
        m->setBackground(m->patternColor("wood.png"), 0x000000, -2);
    } else if (img == 4) {
        // Use a marble pattern as background color
        m->setBackground(m->patternColor("marble.png"), 0x000000, -2);
    } else {
        // Use a solid light purple (EEBBEE) background color
        m->setBackground(0xeebbee, 0x000000, -2);
    }

    // Set the meter center at (100, 235), with radius 210 pixels, and span from -24
    // to +24 degress
    m->setMeter(100, 235, 210, -24, 24);

    // Meter scale is 0 - 100, with a tick every 1 unit
    m->setScale(0, 10, 1);

    // Set 0 - 6 as green (99ff99) zone, 6 - 8 as yellow (ffff00) zone, and 8 - 10 as
    // red (ff3333) zone
    m->addZone(0, 6, 0x99ff99, 0x808080);
    m->addZone(6, 8, 0xffff00, 0x808080);
    m->addZone(8, 10, 0xff3333, 0x808080);

    // Add a title at the bottom of the meter using 10 pts Arial Bold font
    m->addTitle(Chart::Bottom, "OUTPUT POWER LEVEL\n", "arialbd.ttf", 10);

    // Add a semi-transparent black (80000000) pointer at the specified value
    m->addPointer(value, 0x80000000);

    // Output the chart
    m->makeChart(filename);

    //free up resources
    delete m;
}

int main(int argc, char *argv[])
{
    createChart(0, "wideameter0.png");
    createChart(1, "wideameter1.png");
    createChart(2, "wideameter2.png");
    createChart(3, "wideameter3.png");
    createChart(4, "wideameter4.png");
    createChart(5, "wideameter5.png");
    return 0;
}