You can add shading to a function following drawFunction ( ), or to a step function, following a drawStep ( ). All you have to do is indicate the range that you want shaded:
var wGraph = new mathyma.Graph(400,200);
wGraph.setXrange(-3,3);
wGraph.drawFunction("sin(Math.PI*x)");
wGraph.addShade(-0.5,1.5);
wGraph.printInWindow();
The following slightly more complicated example demonstrates a number of features including how to draw shade under a step function. Notice how you can draw graphs of your own functions. Note also how the first step graph is named "wDraw1", this is a cDrawing object. This allows us to add shade and a label to it even after we have drawn the next two step functions.
function binom(iVal, iNum, iProb) {
var wRes = Math.pow(1 - iProb, iNum);
for (var ix = 1; ix <= iVal; ix++) {
wRes *= ((iNum - (ix - 1))/ix)*(iProb/(1 - iProb));
}
return wRes;
}
var wGraph = new mathymaGraph(380,300);
wGraph.setYstretch(40);
wGraph.setXrange(-0.5,20.5);
wGraph.setXgrid(5);
wDraw1 = wGraph.drawStep("binom(x+0.5,20,0.1)",1);
wGraph.drawStep("binom(x+0.5,20,0.5)",1);
wGraph.addShade(-0.5,20.5);
wGraph.addLabel("b (x,20,0.5)",9,0.2);
wGraph.drawStep("binom(x+0.5,20,0.9)",1);
wGraph.addShade(-0.5,20.5);
wGraph.addLabel("b (x,20,0.8)",15.5,0.3);
wDraw1.addLabel("b (x,20,0.2)",0.5,0.3);
wDraw1.addShade(-0.5,20.5);
wGraph.printInWindow();