var x = 118;
var y = 0;
var r = 16;
var a = 0;
var h = getHeight();
var w = getWidth();
var s = getTitle();
var clicked = 0;
leftButton = 16;
run("FFT Options...", "fft complex do");
selectWindow("FFT of "+s);
print("left click on desired aperture location...");
while (clicked==0 && isOpen("Log")) {
  getCursorLoc(xx,yy,zz,flags);
  if (flags&leftButton!=0) clicked=1;
}
x = xx - w/2;
y = yy -h/2;
// x = getNumber("horizontal offset in fpixels=", x);
// y = getNumber("vertical offset in fpixels=",y);
r = getNumber("window radius in fpixels=",r);
print("sample: x="+x+" y="+y+" r="+r);
selectWindow("Complex of "+s);
run("offsetXYmask ", "horizontal="+x+" vertical="+y+" window="+r);
run("Inverse FFT");
var s2=getTitle();
run("PhaseFromRI ");
var s3=getTitle();
run("Spectrum");
selectWindow(s2);
run("AmplitudeFromRI ");
run("Fire");
selectWindow(s2);
run("RGBfromRIS ");
selectWindow(s3);
run("GradXYfromFloat ");
a=(180./3.14159)*atan2(y,x);
print("g-vector: a="+a);
run("xyColorFromXY ", "apang="+a);
run("Tile");