//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;

int zoomLevel=1;
double xstart=-3;
double ystart=-2;
int  maxiteration = 200 ;


int grayRamp(int value, int range) {
   if (range == 0) range = 1;
   int distance = ( value * 255 ) / range;
   return (RGB(distance, distance, distance));
}

int colorRamp(int part, int whole)
{
    int pixelDistanceAlongPath = (part * 1792) / whole;
    int red, green, blue;
    // Which edge of the color cube are we on?
    if (pixelDistanceAlongPath < 256) {
        // Edge 1 from BLACK to BLUE
        red=0; green=0; blue=pixelDistanceAlongPath;
    }
    else if (pixelDistanceAlongPath < 512) {
        // Edge 2 from BLUE to CYAN
        red =0; green=pixelDistanceAlongPath-256; blue=255;
    }
    else if (pixelDistanceAlongPath < 768) {
        // Edge 3 from CYAN to GREEN
        red =0; green =255; blue= 255-(pixelDistanceAlongPath-512);
    }
    else if (pixelDistanceAlongPath < 1024) {
        // Edge 4 from GREEN to YELLOW
        red= (pixelDistanceAlongPath-768); green =255; blue =0;
    }
    else if (pixelDistanceAlongPath <1280) {
        // Edge 5 from YELLOW to RED
        red =255; green=255-(pixelDistanceAlongPath-1024); blue =0;
    }
    else if (pixelDistanceAlongPath < 1536) {
        // Edge 6 from RED to MAGENTA
        red =255; green=0; blue=pixelDistanceAlongPath -1280;
    }
    else {
        // Edge 7 from MAGENTA to WHITE
        red =255; green=pixelDistanceAlongPath-1536; blue =255;
    }
    return (RGB(red, green, blue));
}

void renderPix(int iX, int iY, double X, double Y, double zoom) {
double xC=(xstart)+double((double(iX)+.5)/100/zoom);
double yC=(ystart)+double((double(iY)-.5)/100/zoom);
double x0=(xstart)+double((double(iX)+.5)/100/zoom);
double y0=(ystart)+double((double(iY)-.5)/100/zoom);
double x2 = xC*xC;
double y2 = yC*yC;

int  iteration = 0;

 
  while ( (x2 + y2) < (2*2)  &&  iteration < maxiteration ) {
 
	yC = 2*xC*yC + y0;
	xC = x2 - y2 + x0;

	x2 = xC*xC;
	y2 = yC*yC;

	iteration++;
  }
 
  if ( iteration == maxiteration )
	  Form1->PaintBox1->Canvas->Pixels[iX][iY]=clBlack;
  else
	  Form1->PaintBox1->Canvas->Pixels[iX][iY]=
            static_cast<TColor>
			(colorRamp(iteration, maxiteration));
}


void Render(void) {

 for (int i=0; i < 500; i++) {
   for (int j=0; j<500; j++) {
	   renderPix(i,j,xstart,ystart,zoomLevel);
   }
 }

}



//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
	Render();
}
//---------------------------------------------------------------------------


void __fastcall TForm1::PaintBox1MouseDown(TObject *Sender, TMouseButton Button,
	  TShiftState Shift, int X, int Y)
{
   if(Button==0)
   {
	xstart=(xstart)+(double(X)/100/double(zoomLevel))-1.25/double(zoomLevel);
	ystart=(ystart)+(double(Y)/100/double(zoomLevel))-1.25/double(zoomLevel);
	zoomLevel*=2;
	}
	else
	{
	xstart=(xstart)+(double(X)/100/double(zoomLevel))-5/double(zoomLevel);
	ystart=(ystart)+(double(Y)/100/double(zoomLevel))-5/double(zoomLevel);
	zoomLevel/=2;
	}
	Render();
}
//---------------------------------------------------------------------------

void __fastcall TForm1::TrackBar1Change(TObject *Sender)
{
	maxiteration=Form1->TrackBar1->Position;
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button2Click(TObject *Sender)
{
	zoomLevel=1;
	xstart=-2;
	ystart=-2;
	Render();
}
//---------------------------------------------------------------------------