I have a problem with trying to plot a frequency response of some filter coefficients on a logarithmic frequency axis.  How do you go about implementing that?  

I am doing the following:

void drawTransferFunction()
{
 // background(0,0,255);
 freqResponse.forward(Hb);
 for(int j=0; j< fftSize/2; j++)
 {
   H[j] = freqResponse.getBand(j);
 }
 freqResponse.forward(Ha);
 for(int j=0; j< fftSize/2; j++)
 {
   H[j] = H[j]/freqResponse.getBand(j);
 }
 for(int i=0; i < fftSize/2; i++)
 {
   float temp = 20.0*log10(abs(H[i]));
   float x = ((float)(width) - pow(1250,(fftSize*0.5-i)/(fftSize*0.5)));
   stroke(50,24,88);
   point(x, (-1*temp+20)/40*(float)(height));
 }
}


This seems to be working, but I'm not sure if it is accurate?  I wanted to plot text to say what frequency it was at as well on the axis.  Any ideas on how to go about doing that?  Basically its just a real time version of freqz in matlab, where you can drag around some biquad filters.