Change Color If Above or Below last bar value

[garaujo]

Hello... im trying to do a simple color change on an indicator, but i was unable to do it. Seams i can't retrive data from my .getValue (-).

can anyone help me please. What i would like to do is Plot Red if indicator falling, and plot green is rising.

---- EFS ---
function preMain() {

setPriceStudy(true);
setStudyTitle("MP");
setCursorLabelName("50%", 0);
setDefaultBarStyle(PS_DOT, 0);
setDefaultBarFgColor(Color.red, 0);
setDefaultBarThickness(2, 0);
setPlotType(PLOTTYPE_LINE, 0);
//}}EFSWizard_PreMain 29264

}

function main(vBars, vOffset) {
//Create Edit Functions to Change LookBack and Offset
if (vBars == null) {
vBars = 20;

}

if (vOffset == null) {
vOffset = 2;

}
//Create New Indicator to Get Highest High and Lowest Low

var vDonchian = new DonchianStudy(vBars+2, vOffset);

var vDochUp = (vDonchian.getValue(DonchianStudy.UPPER));
var vDochDown = (vDonchian.getValue(DonchianStudy.LOWER));

//Calc MidPoint of the Range

var vDochMidpoint = (vDochUp + vDochDown)

//Change Color

// if( vDochMidpoint > vDochMidpoint.getSeries(-1)) {
// setPriceBarColor(Color.green);}
debugPrintln(vDochMidpoint/2)
return (vDochMidpoint/2);

[ACM]

garaujo
You don't actually need to calculate the midpoint of the Donchian Channel as that is already available through one of the methods of the DonchianStudy() function eg

xxx.getValue(DonchianStudy.BASIS,0)//current bar's value of the midpoint
xxx.getValue(DonchianStudy.BASIS,-1)//prior bar's value of the midpoint
xxx.getValue(DonchianStudy.BASIS,-2)//value of the midpoint two bars ago
//etc 

To accomplish what you want remove the following lines of code from your script

var vDochUp = (vDonchian.getValue(DonchianStudy.UPPER));
var vDochDown = (vDonchian.getValue(DonchianStudy.LOWER));

//Calc MidPoint of the Range

var vDochMidpoint = (vDochUp + vDochDown)

//Change Color

 //   if( vDochMidpoint > vDochMidpoint.getSeries(-1)) {
   //     setPriceBarColor(Color.green);}
debugPrintln(vDochMidpoint/2) 

and replace them with the following

var MidPointCurrent = vDonchian.getValue(DonchianStudy.BASIS,0);
var MidPointPreviousBar = vDonchian.getValue(DonchianStudy.BASIS,-1);
//then run a null check on the oldest value being retrieved
if(MidPointPreviousBar==null) return;
//then set your conditions
if(MidPointCurrent > MidPointPreviousBar){
    //your commands to be executed if current value is greater than previous value (ie rising)
}else if(MidPointCurrent < MidPointPreviousBar){
    //your commands to be executed if current value is less than previous value (ie falling)
} else {
    //your commands to be executed if neither of the above condition is true
} 

Then replace the return statement ie return (vDochMidpoint/2); with return MidPointCurrent;
Alex