ChartDirector Ver 3.0 (Python 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

[File: pythondemo/yzonecolor.py] (The CGI version is available as "pythondemo_cgi/yzonecolor.py".)
#!/usr/bin/python from pychartdir import * #The data for the chart 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 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 c = 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 = c.addLegend(55, 25, 0, "", 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(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. layer = c.addAreaLayer2() layer.addDataSet(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")