How to reset the boolean drawing in this program?

ProsExplorer

I'm trying to implement pan, zoom, and start and stop settings into this program but the boolean drawing won't go away with any function. I don't know how to reset the drawn image, despite looking all through the references for processing and numerous code examples. How do I reset the boolean drawing in this code thus clearing the screen on keypressed?

// main setup settings
int dimy = 800;            // screen width 1681
int dimx = 850;            //screen height 1019
int bailout = 2000;         // number of iterations before bail
int plots = 171294;        // number of plots to execute per frame (x30 = plots per second) 171294
//zoom/magnification
float magx = 4.0; // default 3.0, smaller means more zoom
float magy = magx*(dimy/float(dimx));
//pan
float panx = 0.3; //default is 0.5
float pany = 0.0; //default is 0.0
//brightness multiplier
float brt = 1.0; // brightness factor

// 2D array to hold exposure values
int[] exposure = new int[dimx*dimy];
int maxexposure;           // maximum exposure value
int time = 0;
int exposures = 0;

 float x, y;
 float x0, y0;

boolean drawing; 

int sgn(float value) {            //if signus is needed sgn(x)=x/abs(x) = 1, 0 or -1
 if (value < 0) {return -1;}
 if (value > 0) {return 1;}
 return 0;
}

float cosh(float value1) {
 return 0.5*(exp(value1)+exp(-value1));
}

float sinh(float value2) {
 return 0.5*(exp(value2)-exp(-value2));
}

float arg(float axis1, float axis2) {
 if (axis2==0) {return PI;}
 else {return -atan(axis1/axis2)+PI*sgn(axis2)*0.5;}
}

float spharg(float axisa, float axisb, float axisc) {
 return acos(axisc/sqrt(sq(axisa)+sq(axisb)+sq(axisc)));
}

void setup() {
 // set up drawing area
 size(800,850,P3D);
}

void draw() {
 plotPlots();
 time++;
 if (time%1==0) { //every second
   findMaxExposure();
   renderBrot();

     // USE FOR TIFF IMAGE CAPTURE, EVERY 3 SECONDS
  //  if ( millis() >= timeFlag + 3000 ) {
  //  timeFlag = millis();
  //  saveFrame();
  //}
         if (keyPressed) {
    if (key == 'x') {
      magx=0.5+magx;
    } else if (key == 'X') {
      magx=0.5-magx;
    }}
 }

 // stop plotting = s
 // start plotting = S
           if (keyPressed) {
    if (key == 's') {
      plots=0;
      //reset();
      //bailout=0;
    } else if (key == 'S') {
      plots=171294;
      //bailout=2000;
    }
 }
}

/* void reset(){
     // clear();
     // Allows for commands outside of keypress loop

    }
*/

void plotPlots() {

 // iterate through some plots
 for (int n=0;n<plots;n++) {
   // Choose a random point in same range
   x = random(-2.0,2.0);
   y = random(-2.0,2.0);
   x0 = random(-2.0,2.0);
   y0 = random(-2.0,2.0);
   if (iterate(x,y,false)) {
     iterate(x,y,true);
     exposures++;
   }
 }
}

void renderBrot() {
 colorMode(RGB,1.0);
 // draw to screen
 for (int i=0;i<dimx;i++) {
   for (int j=0;j<dimy;j++) {
     float ramp = brt * exposure[i*dimy+j] / maxexposure;
     // blow out ultra bright regions
     if (ramp > 1)  {
       ramp = 1;
     }
     //different shading formulae
     //color c = color(pow(ramp,0.45454545454545454545),pow(ramp,0.45454545454545454545),pow(ramp,0.45454545454545454545)); //default greyscale
     //color c = color(pow(ramp,0.413223140495867768595041322314049586776859504132231404958677685950413223140495867769),pow(ramp,0.45454545454545454545),pow(ramp,0.378787878787878787878787878787878787878787878787878787878787878787878787878787878788)); //purple touch
     color c = color(pow(sin(ramp*1.570796326794896619231321691639751442098584699687552910487472296153908203143104499314),0.4),pow(ramp,0.75),pow(ramp,2.5)); // sunset
     //color c = color(pow(sin(ramp*1.570796326794896619231321691639751442098584699687552910487472296153908203143104499314),0.45454545455),pow(ramp,17/11.0),pow(ramp,109/55.0));
// "love"

     set(j,i,c);
   }
 }
} 

//   Iterate the Mandelbrot and return TRUE if the point exits
//   Also handle the drawing of the exit points
boolean iterate(float x0, float y0, boolean drawIt) {
  float x = 0.0;
  float y = 0.0;
  //float t = random(0,1);
  //float r = random(0,1);  

  //x0 = 0.0;
  //y0 = 0.0;

  float xnew, ynew;
  int ix,iy;

  for (int i=0;i<bailout;i++) {

    //set your costum formula here...
    //example:
    //default Mandelbrot
    xnew = x * x - y * y + x0;
    ynew = 2 * x * y + y0;

    if (drawIt && (i > 3)) {
      ix = int(dimx*(panx+xnew+magx/2.0)/magx);
      iy = int(dimy*(pany+ynew+magy/2.0)/magy);

      if (ix >= 0 && iy >= 0 && ix < dimx && iy < dimy) {
        // rotate and expose point
        exposure[ix*dimy+iy]++;
      }
    }
    if ((xnew*xnew + ynew*ynew) > 4) {
      // escapes
      return true;
    }
    x = xnew;
    y = ynew;
  }
  // does not escape
  return false;
}

void findMaxExposure() {
  // assume no exposure
  maxexposure=0;
  // find the largest density value
  for (int i=0;i<dimy;i++) {
    for (int j=0;j<dimx;j++) {
      maxexposure = max(maxexposure,exposure[i*dimx+j]);
    }
  }
} 

theliquu69

I think the problem is that you're not initializing the boolean and the value is null by default. Try initializing it like

boolean drawing = true; // or false, depending on what you want

GoToLoop

not initializing the boolean and the value is null by default.

@theliquu69, boolean is 1 of the 8 Java primitive datatypes:
https://Docs.Oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

Therefore, it can't have value null. It's either true or false. And false is its default value.

ProsExplorer

Could one of you provide an example in how this boolean method would be utilized?

kfrajer

Next code clears the sketch every time you clicked. I hope this helps.

Kf

boolean tgrClear=false;

void setup(){
  size(600,400);
  fill(255);
  background(0);
}

void draw(){

  //NEXT: Clears the sketch when trigger by user
  if(tgrClear){         
    tgrClear=false;
    background(0);
  }

  //NEXT: Add ellipses randomly every 30 frames aka. every sec
  if(frameCount%30==0) {
    ellipse(random(width),random(height), 25,25);
  }

}

void mousePressed(){
  tgrClear=true;
}