color.c

/*
 * by DJ0ABR 
 * 
 * assign colors to each pixel of the waterfall
 * 
 * */

#include <gd.h>
#include <math.h>
#include "color.h"
#include "gdfontt.h"
#include "gdfonts.h"
#include "gdfontmb.h"
#include "gdfontl.h"
#include "gdfontg.h"
#include "config.h"

double coltab[256][3] = {
    {0.5000,0.7000,1.0000},
    {0.6000,0.9000,1.0000},
    {0.0000,0.0000,1.0000},
    {0.0157,0.0000,0.0000},
    {0.0235,0.0000,0.0000},
    {0.0314,0.0000,0.0000},
    {0.0392,0.0000,0.0000},
    {0.0471,0.0000,0.0000},
    {0.0549,0.0000,0.0000},
    {0.0627,0.0000,0.0000},
    {0.0706,0.0000,0.0000},
    {0.0784,0.0000,0.0000},
    {0.0863,0.0000,0.0000},
    {0.0941,0.0000,0.0000},
    {0.1020,0.0000,0.0000},
    {0.1098,0.0000,0.0000},
    {0.1176,0.0000,0.0000},
    {0.1255,0.0000,0.0000},
    {0.1333,0.0000,0.0000},
    {0.1412,0.0000,0.0000},
    {0.1490,0.0000,0.0000},
    {0.1569,0.0000,0.0000},
    {0.1647,0.0000,0.0000},
    {0.1725,0.0000,0.0000},
    {0.1804,0.0000,0.0000},
    {0.1882,0.0000,0.0000},
    {0.1961,0.0000,0.0000},
    {0.2039,0.0000,0.0000},
    {0.2118,0.0000,0.0000},
    {0.2196,0.0000,0.0000},
    {0.2275,0.0000,0.0000},
    {0.2353,0.0000,0.0000},
    {0.2431,0.0000,0.0000},
    {0.2510,0.0000,0.0000},
    {0.2588,0.0000,0.0000},
    {0.2667,0.0000,0.0000},
    {0.2745,0.0000,0.0000},
    {0.2824,0.0000,0.0000},
    {0.2902,0.0000,0.0000},
    {0.2980,0.0000,0.0000},
    {0.3059,0.0000,0.0000},
    {0.3137,0.0000,0.0000},
    {0.3216,0.0000,0.0000},
    {0.3294,0.0000,0.0000},
    {0.3373,0.0000,0.0000},
    {0.3451,0.0000,0.0000},
    {0.3529,0.0000,0.0000},
    {0.3608,0.0000,0.0000},
    {0.3686,0.0000,0.0000},
    {0.3765,0.0000,0.0000},
    {0.3843,0.0000,0.0000},
    {0.3922,0.0000,0.0000},
    {0.4000,0.0000,0.0000},
    {0.4078,0.0000,0.0000},
    {0.4157,0.0000,0.0000},
    {0.4235,0.0000,0.0000},
    {0.4314,0.0000,0.0000},
    {0.4392,0.0000,0.0000},
    {0.4471,0.0000,0.0000},
    {0.4549,0.0000,0.0000},
    {0.4627,0.0000,0.0000},
    {0.4706,0.0000,0.0000},
    {0.4784,0.0000,0.0000},
    {0.4863,0.0000,0.0000},
    {0.4941,0.0000,0.0000},
    {0.5020,0.0000,0.0000},
    {0.5098,0.0098,0.0000},
    {0.5176,0.0176,0.0000},
    {0.5255,0.0255,0.0000},
    {0.5333,0.0333,0.0000},
    {0.5412,0.0412,0.0000},
    {0.5490,0.0490,0.0000},
    {0.5569,0.0569,0.0000},
    {0.5647,0.0647,0.0000},
    {0.5725,0.0725,0.0000},
    {0.5804,0.0804,0.0000},
    {0.5882,0.0882,0.0000},
    {0.5961,0.0961,0.0000},
    {0.6039,0.1039,0.0000},
    {0.6118,0.1118,0.0000},
    {0.6196,0.1196,0.0000},
    {0.6275,0.1275,0.0000},
    {0.6353,0.1353,0.0000},
    {0.6431,0.1431,0.0000},
    {0.6510,0.1510,0.0000},
    {0.6588,0.1588,0.0000},
    {0.6667,0.1667,0.0000},
    {0.6745,0.1745,0.0000},
    {0.6824,0.1824,0.0000},
    {0.6902,0.1902,0.0000},
    {0.6980,0.1980,0.0000},
    {0.7059,0.2059,0.0000},
    {0.7137,0.2137,0.0000},
    {0.7216,0.2216,0.0000},
    {0.7294,0.2294,0.0000},
    {0.7373,0.2373,0.0000},
    {0.7451,0.2451,0.0000},
    {0.7529,0.2529,0.0000},
    {0.7608,0.2608,0.0000},
    {0.7686,0.2686,0.0000},
    {0.7765,0.2765,0.0000},
    {0.7843,0.2843,0.0000},
    {0.7922,0.2922,0.0000},
    {0.8000,0.3000,0.0000},
    {0.8078,0.3078,0.0000},
    {0.8157,0.3157,0.0000},
    {0.8235,0.3235,0.0000},
    {0.8314,0.3314,0.0000},
    {0.8392,0.3392,0.0000},
    {0.8471,0.3471,0.0000},
    {0.8549,0.3549,0.0000},
    {0.8627,0.3627,0.0000},
    {0.8706,0.3706,0.0000},
    {0.8784,0.3784,0.0000},
    {0.8863,0.3863,0.0000},
    {0.8941,0.3941,0.0000},
    {0.9020,0.4020,0.0000},
    {0.9098,0.4098,0.0000},
    {0.9176,0.4176,0.0000},
    {0.9255,0.4255,0.0000},
    {0.9333,0.4333,0.0000},
    {0.9412,0.4412,0.0000},
    {0.9490,0.4490,0.0000},
    {0.9569,0.4569,0.0000},
    {0.9647,0.4647,0.0000},
    {0.9725,0.4725,0.0000},
    {0.9804,0.4804,0.0000},
    {0.9882,0.4882,0.0000},
    {0.9961,0.4961,0.0000},
    {1.0000,0.5039,0.0000},
    {1.0000,0.5118,0.0118},
    {1.0000,0.5196,0.0196},
    {1.0000,0.5275,0.0275},
    {1.0000,0.5353,0.0353},
    {1.0000,0.5431,0.0431},
    {1.0000,0.5510,0.0510},
    {1.0000,0.5588,0.0588},
    {1.0000,0.5667,0.0667},
    {1.0000,0.5745,0.0745},
    {1.0000,0.5824,0.0824},
    {1.0000,0.5902,0.0902},
    {1.0000,0.5980,0.0980},
    {1.0000,0.6059,0.1059},
    {1.0000,0.6137,0.1137},
    {1.0000,0.6216,0.1216},
    {1.0000,0.6294,0.1294},
    {1.0000,0.6373,0.1373},
    {1.0000,0.6451,0.1451},
    {1.0000,0.6529,0.1529},
    {1.0000,0.6608,0.1608},
    {1.0000,0.6686,0.1686},
    {1.0000,0.6765,0.1765},
    {1.0000,0.6843,0.1843},
    {1.0000,0.6922,0.1922},
    {1.0000,0.7000,0.2000},
    {1.0000,0.7078,0.2078},
    {1.0000,0.7157,0.2157},
    {1.0000,0.7235,0.2235},
    {1.0000,0.7314,0.2314},
    {1.0000,0.7392,0.2392},
    {1.0000,0.7471,0.2471},
    {1.0000,0.7549,0.2549},
    {1.0000,0.7627,0.2627},
    {1.0000,0.7706,0.2706},
    {1.0000,0.7784,0.2784},
    {1.0000,0.7863,0.2863},
    {1.0000,0.7941,0.2941},
    {1.0000,0.8020,0.3020},
    {1.0000,0.8098,0.3098},
    {1.0000,0.8176,0.3176},
    {1.0000,0.8255,0.3255},
    {1.0000,0.8333,0.3333},
    {1.0000,0.8412,0.3412},
    {1.0000,0.8490,0.3490},
    {1.0000,0.8569,0.3569},
    {1.0000,0.8647,0.3647},
    {1.0000,0.8725,0.3725},
    {1.0000,0.8804,0.3804},
    {1.0000,0.8882,0.3882},
    {1.0000,0.8961,0.3961},
    {1.0000,0.9039,0.4039},
    {1.0000,0.9118,0.4118},
    {1.0000,0.9196,0.4196},
    {1.0000,0.9275,0.4275},
    {1.0000,0.9353,0.4353},
    {1.0000,0.9431,0.4431},
    {1.0000,0.9510,0.4510},
    {1.0000,0.9588,0.4588},
    {1.0000,0.9667,0.4667},
    {1.0000,0.9745,0.4745},
    {1.0000,0.9824,0.4824},
    {1.0000,0.9902,0.4902},
    {1.0000,0.9980,0.4980},
    {1.0000,1.0000,0.5059},
    {1.0000,1.0000,0.5137},
    {1.0000,1.0000,0.5216},
    {1.0000,1.0000,0.5294},
    {1.0000,1.0000,0.5373},
    {1.0000,1.0000,0.5451},
    {1.0000,1.0000,0.5529},
    {1.0000,1.0000,0.5608},
    {1.0000,1.0000,0.5686},
    {1.0000,1.0000,0.5765},
    {1.0000,1.0000,0.5843},
    {1.0000,1.0000,0.5922},
    {1.0000,1.0000,0.6000},
    {1.0000,1.0000,0.6078},
    {1.0000,1.0000,0.6157},
    {1.0000,1.0000,0.6235},
    {1.0000,1.0000,0.6314},
    {1.0000,1.0000,0.6392},
    {1.0000,1.0000,0.6471},
    {1.0000,1.0000,0.6549},
    {1.0000,1.0000,0.6627},
    {1.0000,1.0000,0.6706},
    {1.0000,1.0000,0.6784},
    {1.0000,1.0000,0.6863},
    {1.0000,1.0000,0.6941},
    {1.0000,1.0000,0.7020},
    {1.0000,1.0000,0.7098},
    {1.0000,1.0000,0.7176},
    {1.0000,1.0000,0.7255},
    {1.0000,1.0000,0.7333},
    {1.0000,1.0000,0.7412},
    {1.0000,1.0000,0.7490},
    {1.0000,1.0000,0.7569},
    {1.0000,1.0000,0.7647},
    {1.0000,1.0000,0.7725},
    {1.0000,1.0000,0.7804},
    {1.0000,1.0000,0.7882},
    {1.0000,1.0000,0.7961},
    {1.0000,1.0000,0.8039},
    {1.0000,1.0000,0.8118},
    {1.0000,1.0000,0.8196},
    {1.0000,1.0000,0.8275},
    {1.0000,1.0000,0.8353},
    {1.0000,1.0000,0.8431},
    {1.0000,1.0000,0.8510},
    {1.0000,1.0000,0.8588},
    {1.0000,1.0000,0.8667},
    {1.0000,1.0000,0.8745},
    {1.0000,1.0000,0.8824},
    {1.0000,1.0000,0.8902},
    {1.0000,1.0000,0.8980},
    {1.0000,1.0000,0.9059},
    {1.0000,1.0000,0.9137},
    {1.0000,1.0000,0.9216},
    {1.0000,1.0000,0.9294},
    {1.0000,1.0000,0.9373},
    {1.0000,1.0000,0.9451},
    {1.0000,1.0000,0.9529},
    {1.0000,1.0000,0.9608},
    {1.0000,1.0000,0.9686},
    {1.0000,1.0000,0.9765},
    { 1.0,0.0,0.0},
    { 1.0,0.0,0.0}
};

// allocate the color table
void allocatePalette(gdImagePtr img)
{
    // low values blue only
    for(int i=0; i<256; i++)
    {
        gdImageColorAllocate(img, (int)(coltab[i][0] * 255), (int)(coltab[i][1] * 255),(int)(coltab[i][2] * 255));
    }
}


#define ARRMIDLEN   20
struct {
    double cmaxvalarr[ARRMIDLEN];
    double cminvalarr[ARRMIDLEN];
    double cmaxval;
    double cminval;

    double hWFrefval;     // shifts the black value (higher=darker)
    double hWFgain;       // contrast (must be > 0, low=high contrast)

    double minlog;
    double factor;
} colordef[10];

// find min/max the values of one pixel line
void calcColorParms(int id, int fstart, int fend, double *d)
{
    double max = -9999;
    double min = 9999;
    static int f[10] = {1,1,1,1,1,1,1,1,1,1};
    
    colordef[id].hWFrefval = hWFrefval; //150;     // shifts the black value (higher=darker)
    colordef[id].hWFgain = (double)hWFgain/100.0; //0.00001;
    if(hWFgain == 0) colordef[id].hWFgain = 0.00001;
    
    for(int i=fstart; i<fend; i++)
    {
        // d[i] is the dBm value at the antenna input (if calibrated and AGC off)
        // it is a negative value, max range: -180 ... 0
        double da = d[i];
        if(da < min) min = da;
        if(da > max) max = da;
    }
    
    if(f[id])
    {
        // init array
        f[id]=0;
        for(int i=0; i<ARRMIDLEN; i++)
        {
            colordef[id].cminvalarr[i] = min;
            colordef[id].cmaxvalarr[i] = max;
        }
    }
    
    // insert into mid array
    for(int i=(ARRMIDLEN-1); i>=1; i--)
    {
        colordef[id].cminvalarr[i] = colordef[id].cminvalarr[i-1];
        colordef[id].cmaxvalarr[i] = colordef[id].cmaxvalarr[i-1];
    }
    colordef[id].cminvalarr[0] = min;
    colordef[id].cmaxvalarr[0] = max;
    
    colordef[id].cminval  = 0;
    colordef[id].cmaxval = 0;
    for(int i=0; i<ARRMIDLEN; i++)
    {
        colordef[id].cminval += colordef[id].cminvalarr[i];
        colordef[id].cmaxval += colordef[id].cmaxvalarr[i];
    }
    colordef[id].cminval /= ARRMIDLEN;
    colordef[id].cmaxval /= ARRMIDLEN;
    
    //printf("min:%.1f max:%.1f\r\n",colordef[id].cminval,colordef[id].cmaxval);
    
    // prepare values used my getPixelColor
    colordef[id].factor = colordef[id].hWFgain/10;
    colordef[id].minlog = log(colordef[id].factor + 1) / 255;
}

int getPixelColor(int id, double val)
{
    //printf("%.1f:",val);
    if(hWFauto)
    {
        // === black value, no signal, background noise ===
        // shift the value up, so that cminval is color=0
        val -= colordef[id].cminval;
        val -= (colordef[id].hWFrefval/10);
        
        // === max level, strongest signal ===
        // make the loudest signal to 255
        // shift cmaxval the same factor as the signal value, so both start at 0
        double cmax = (colordef[id].cmaxval - colordef[id].cminval);
        // expand the signal value so that the maxval is 255
        // do this with a log formular, high values are more effected
        double lin = val * colordef[id].factor / cmax;
        double revlin = colordef[id].factor - lin + 1;
        double mylog = log(revlin);
        double logTo255 = mylog/ colordef[id].minlog;
        double val1 = 255 - logTo255;
        
        int v = (int)val1;
        //printf("%d ",v);

        // low colors reserver for other purposes
        if (v <= 2) v = 3;
        if (v > 250) v = 255;
        return v;
    }
    
    // schiebe den Nullpunkt auf den gewünschten Zero
    double val1 = val - hWFrefval;

    // mache den Gain, zeige die max. dBm bei 255 an
    int v = (int)(val1 * hWFgain / 10.0);

    // colors < 3 are for other purposes (spectrum)
    if (v <= 2) v = 3;
    if (v > 255) v = 255;

    return v;
}