ChartDirector 7.1 (C++ Edition)

Pareto Chart




This example demonstrates the pareto chart style.

A pareto chart is a bar chart with the data sorted in descending order, together with a line chart showing the same data in accumulated form. In the current example, the data is shown as both percentages and values on the two y-axes.

The chart in this example is composed of two layers - a BarLayer created using XYChart.addBarLayer, and a LineLayer created using XYChart.addLineLayer.

This example employs the ArrayMath utility class for computing the accumulated line, obtaining the scaling factor between the two y-axes, and re-scaling the line data as percentages.

The two y-axes are synchronized using Axis.syncAxis.

Source Code Listing

The following is the command line version of the code in "cppdemo/pareto". 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 data for the chart double data[] = {40, 15, 7, 5, 2}; const int data_size = (int)(sizeof(data)/sizeof(*data)); // The labels for the chart const char* labels[] = {"Hard Disk", "PCB", "Printer", "CDROM", "Keyboard"}; const int labels_size = (int)(sizeof(labels)/sizeof(*labels)); // In the pareto chart, the line data are just the accumulation of the raw data, scaled to a // range of 0 - 100% ArrayMath lineData = ArrayMath(DoubleArray(data, data_size)); lineData.acc(); double scaleFactor = lineData.maxValue() / 100; if (scaleFactor == 0) { // Avoid division by zero error for zero data scaleFactor = 1; } lineData.div(scaleFactor); // Create a XYChart object of size 480 x 300 pixels. Set background color to brushed silver, // with a grey (bbbbbb) border and 2 pixel 3D raised effect. Use rounded corners. Enable soft // drop shadow. XYChart* c = new XYChart(400, 300, Chart::brushedSilverColor(), 0xbbbbbb, 2); c->setRoundedFrame(); c->setDropShadow(); // Add a title to the chart using 15 points Arial Italic. Set top/bottom margins to 12 pixels. TextBox* title = c->addTitle("Pareto Chart Demonstration", "Arial Italic", 15); title->setMargin(0, 0, 12, 12); // Tentatively set the plotarea at (50, 40). Set the width to 100 pixels less than the chart // width, and the height to 80 pixels less than the chart height. Use pale grey (f4f4f4) // background, transparent border, and dark grey (444444) dotted grid lines. c->setPlotArea(50, 40, c->getWidth() - 100, c->getHeight() - 80, 0xf4f4f4, -1, Chart::Transparent, c->dashLineColor(0x444444, Chart::DotLine)); // Add a line layer for the pareto line LineLayer* lineLayer = c->addLineLayer(); // Add the pareto line using deep blue (0000ff) as the color, with circle symbols lineLayer->addDataSet(lineData, 0x0000ff)->setDataSymbol(Chart::CircleShape, 9, 0x0000ff, 0x0000ff); // Set the line width to 2 pixel lineLayer->setLineWidth(2); // Bind the line layer to the secondary (right) y-axis. lineLayer->setUseYAxis2(); // Add a multi-color bar layer using the given data. BarLayer* barLayer = c->addBarLayer(DoubleArray(data, data_size), IntArray(0, 0)); // Set soft lighting for the bars with light direction from the right barLayer->setBorderColor(Chart::Transparent, Chart::softLighting(Chart::Right)); // Set the labels on the x axis. c->xAxis()->setLabels(StringArray(labels, labels_size)); // Set the secondary (right) y-axis scale as 0 - 100 with a tick every 20 units c->yAxis2()->setLinearScale(0, 100, 20); // Set the format of the secondary (right) y-axis label to include a percentage sign c->yAxis2()->setLabelFormat("{value}%"); // Set the relationship between the two y-axes, which only differ by a scaling factor c->yAxis()->syncAxis(c->yAxis2(), scaleFactor); // Set the format of the primary y-axis label foramt to show no decimal point c->yAxis()->setLabelFormat("{value|0}"); // Add a title to the primary y-axis c->yAxis()->setTitle("Frequency"); // Set all axes to transparent c->xAxis()->setColors(Chart::Transparent); c->yAxis()->setColors(Chart::Transparent); c->yAxis2()->setColors(Chart::Transparent); // Adjust the plot area size, such that the bounding box (inclusive of axes) is 10 pixels from // the left edge, just below the title, 10 pixels from the right edge, and 20 pixels from the // bottom edge. c->packPlotArea(10, title->getHeight(), c->getWidth() - 10, c->getHeight() - 20); // Output the chart c->makeChart("pareto.jpg"); //free up resources delete c; return 0; }