ChartDirector Ver 3.0 (C++ Edition)

Y Zone Colors




This example demonstates using y zone colors - colors that change at certain y value thresholds.

In this example, a y zone color is used as the fill color of an area layer, so that the area fill color changes above a certain threshold.

Y zone colors are created using Layer.yZoneColor. You can use a y zone color in any ChartDirector API that expects a color. For instance, you can use a y zone color as background color, fill color of data sets, line color, etc.

A single y zone color can support one threshold value and change between two colors. The two colors can be any colors, including another y zone colors. You may create y zone colors with multiple thresholds by cascading multiple y zone colors this way.

Source Code Listing

[The following project is available in "cppdemo/yzonecolor".]
#include "chartdir.h" int main(int argc, char *argv[]) { //The data for the chart double data[] = {30, 28, 40, 55, 75, 68, 54, 60, 50, 62, 75, 65, 75, 89, 60, 55, 53, 35, 50, 66, 56, 48, 52, 65, 62}; //The labels for the chart const char *labels[] = {"0", "", "", "3", "", "", "6", "", "", "9", "", "", "12", "", "", "15", "", "", "18", "", "", "21", "", "", "24"}; //Create a XYChart object of size 500 x 300 pixels, with a pale yellow //(0xffffc0) background, a black border, and 1 pixel 3D border effect XYChart *c = new XYChart(500, 300, 0xffffc0, 0x0, 1); //Set the plotarea at (55, 50) and of size 420 x 205 pixels, with white //background. Turn on both horizontal and vertical grid lines with light //grey color (0xc0c0c0) c->setPlotArea(55, 50, 420, 205, 0xffffff)->setGridColor(0xc0c0c0, 0xc0c0c0) ; //Add a legend box at (55, 25) (top of the chart) with horizontal layout. //Use 8 pts Arial font. Set the background and border color to Transparent. LegendBox *legendBox = c->addLegend(55, 25, false, "", 8); legendBox->setBackground(Transparent); //Add keys to the legend box to explain the color zones legendBox->addKey("Normal Zone", 0x8033ff33); legendBox->addKey("Alert Zone", 0x80ff3333); //Add a title box to the chart using 13 pts Arial Bold Italic font. The //title is in CDML and includes embedded images for highlight. The text is //white (0xffffff) on a black background, with a 1 pixel 3D border. c->addTitle( "<*block,valign=absmiddle*><*img=star.png*><*img=star.png*> Y Zone " "Color Demo <*img=star.png*><*img=star.png*><*/*>", "arialbi.ttf", 13, 0xffffff)->setBackground(0x0, -1, 1); //Add a title to the y axis c->yAxis()->setTitle("Energy Concentration (KJ per liter)"); //Set the labels on the x axis c->xAxis()->setLabels(StringArray(labels, sizeof(labels)/sizeof(*labels))); //Add a title to the x axis using CDML c->xAxis()->setTitle( "<*block,valign=absmiddle*><*img=clock.png*> Elapsed Time (hour)<*/*>") ; //Set the axes width to 2 pixels c->xAxis()->setWidth(2); c->yAxis()->setWidth(2); //Add an area layer to the chart. The area is using a y zone color, where //the color is semi-transparent green below 60, and semi-transparent red //above 60. AreaLayer *layer = c->addAreaLayer(); layer->addDataSet(DoubleArray(data, sizeof(data)/sizeof(*data)), layer->yZoneColor(60, 0x8033ff33, 0x80ff3333)); //Add a custom CDML text at the bottom right of the plot area as the logo c->addText(475, 255, "<*block,valign=absmiddle*><*img=small_molecule.png*> <*block*>" "<*font=timesbi.ttf,size=10,color=804040*>Molecular\nEngineering<*/*>" )->setAlignment(BottomRight); //output the chart c->makeChart("yzonecolor.png"); //free up resources delete c; return 0; }