Pie Chart with Legend (2)

This example demonstrates a pie chart with a legend box, together with many effects, such as gradient color background, rounded frame, soft drop shadow, custom sector colors, sector gradient shading, customized sector labels and using CDML and Parameter Substitution and Formatting to format legend text.

The gradient background is achieved by using BaseChart.linearGradientColor to define the gradient color, then use BaseChart.setBackground to set it as the chart background color.
The rounded frame is configured using BaseChart.setRoundedFrame.
The soft drop shadow is configured using BaseChart.setDropShadow.
The sector colors are set using BaseChart.setColors. The sector gradient shading is configured using PieChart.setSectorStyle.
The sector labels are configured using PieChart.setLabelFormat to show the sector number. PieChart.setLabelStyle is used to set the label style. It returns a TextBox object representing the sector label prototype. The Box.setBackground method of the label prototype is then used to add black borders around the labels.
The legend text is configured by calling the TextBox.setText method of the LegendBox object. The legend text template is specified using CDML and Parameter Substitution and Formatting as follows:

<*block,valign=top*>{={sector}+1}.<*advanceTo=22*><*block,width=120*>{label}<*/*><*block,width=40,halign=right*>{percent}<*/*>%

The starting "<*block,valign=top*>" means the different parts in the legend entry should be aligned to the top. This is necessarily because the second part of the legend entry (described below) can have multiple lines.

The first part of the legend entry is "{={sector}+1}.<*advanceTo=22*>", which means the show the sector number, then "tab" to the 22th pixel position. (In ChartDirector, the sector number starts from 0. So we add 1 to {sector} to make the displayed sector number to start from 1.)

The second part "<*block,width=120*>{label}<*/*>" which means to show the sector label in a 120 pixels block. If the label is wider than 120 pixels, it will be wrapped into multiple lines within the block.

The last part "<*block,width=40,halign=right*>{percent}<*/*>%" means to show the percentage in a 40 pixels block, with the contents right aligned.

The following is the command line version of the code in "cppdemo/legendpie2". 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 pie chart
    double data[] = {21, 18, 15, 12, 8, 24};
    const int data_size = (int)(sizeof(data)/sizeof(*data));

    // The labels for the pie chart
    const char* labels[] = {"Labor", "Licenses", "Taxes", "Legal", "Facilities", "Production"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // The colors to use for the sectors
    int colors[] = {0x66aaee, 0xeebb22, 0xbbbbbb, 0x8844ff, 0xdd2222, 0x009900};
    const int colors_size = (int)(sizeof(colors)/sizeof(*colors));

    // Create a PieChart object of size 600 x 320 pixels. Use a vertical gradient color from light
    // blue (99ccff) to white (ffffff) spanning the top 100 pixels as background. Set border to grey
    // (888888). Use rounded corners. Enable soft drop shadow.
    PieChart* c = new PieChart(600, 320);
    c->setBackground(c->linearGradientColor(0, 0, 0, 100, 0x99ccff, 0xffffff), 0x888888);
    c->setRoundedFrame();
    c->setDropShadow();

    // Add a title using 18pt Times New Roman Bold Italic font. Add 16 pixels top margin to the
    // title.
    c->addTitle("Pie Chart With Legend Demonstration", "Times New Roman Bold Italic", 18
        )->setMargin(0, 0, 16, 0);

    // Set the center of the pie at (160, 165) and the radius to 110 pixels
    c->setPieSize(160, 165, 110);

    // Draw the pie in 3D with a pie thickness of 25 pixels
    c->set3D(25);

    // Set the pie data and the pie labels
    c->setData(DoubleArray(data, data_size), StringArray(labels, labels_size));

    // Set the sector colors
    c->setColors(Chart::DataColor, IntArray(colors, colors_size));

    // Use local gradient shading for the sectors
    c->setSectorStyle(Chart::LocalGradientShading);

    // Use the side label layout method, with the labels positioned 16 pixels from the pie bounding
    // box
    c->setLabelLayout(Chart::SideLayout, 16);

    // Show only the sector number as the sector label
    c->setLabelFormat("{={sector}+1}");

    // Set the sector label style to Arial Bold 10pt, with a dark grey (444444) border
    c->setLabelStyle("Arial Bold", 10)->setBackground(Chart::Transparent, 0x444444);

    // Add a legend box, with the center of the left side anchored at (330, 175), and using 10pt
    // Arial Bold Italic font
    LegendBox* b = c->addLegend(330, 175, true, "Arial Bold Italic", 10);
    b->setAlignment(Chart::Left);

    // Set the legend box border to dark grey (444444), and with rounded conerns
    b->setBackground(Chart::Transparent, 0x444444);
    b->setRoundedCorners();

    // Set the legend box margin to 16 pixels, and the extra line spacing between the legend entries
    // as 5 pixels
    b->setMargin(16);
    b->setKeySpacing(0, 5);

    // Set the legend box icon to have no border (border color same as fill color)
    b->setKeyBorder(Chart::SameAsMainColor);

    // Set the legend text to show the sector number, followed by a 120 pixels wide block showing
    // the sector label, and a 40 pixels wide block showing the percentage
    b->setText(
        "<*block,valign=top*>{={sector}+1}.<*advanceTo=22*><*block,width=120*>{label}<*/*>"
        "<*block,width=40,halign=right*>{percent}<*/*>%");

    // Output the chart
    c->makeChart("legendpie2.png");

    //free up resources
    delete c;

    return 0;
}