Implementation of the Erase Button

Question

I have created the "Erase" button. The erase button when it's clicked should delete the drawing which is drawn by the mouse. It should work similarly to the paint program. I have used the following code and it does nothing to the functionality of the Erase button. So, if I draw something when toggle is turned on and if I click "Erase" button nothing is happening. Could someone please help me with this issue.

import controlP5.*;

ControlP5 cp5;


boolean onOff = false;

boolean erase = false;

void setup(){
  size(1000, 1000);
  background(255);
  PFont font = createFont("Calibri", 15);
  
  
  cp5 = new ControlP5(this);
  
   cp5.addToggle("onOff").
  setPosition(150, 20).
  setSize(40, 15).
  setFont(font).
  
  setMode(ControlP5.SWITCH);
  
   cp5.addButton("Erase").
  setPosition(890, 20).
  setSize(100, 30).
  setFont(font);
  
}
  
  void draw(){
    
    
  fill(246, 246, 246);
  stroke(246, 246, 246);
  rect(0,0, 1000, 80);
  
  stroke(0);
 if (mousePressed == true && onOff == true) {
 line(mouseX, mouseY, pmouseX, pmouseY);
 }
 
}

 void keyPressed(){ 
   if(erase == true) {
     
     background(255);
   }
 }

Answer 1

I used the Button class and Toggle class, so that I could use the Button::isPressed function to check if the erase button is pressed. And then since you wanted it to erase when you clicked the button, you should use the mousePressed instead of keyPressed function.

import controlP5.*;

ControlP5 cp5;

Button erase;
Toggle onOff;

void setup(){
  size(1000, 1000);
  background(255);
  
  PFont font = createFont("Calibri", 15);
  cp5 = new ControlP5(this);

  onOff = new Toggle(cp5, "onOff").
  setPosition(150, 20).
  setSize(40, 15).
  setFont(font).
  
  setMode(ControlP5.SWITCH);
  
  erase = new Button(cp5, "Erase").
  setPosition(890, 20).
  setSize(100, 30).
  setFont(font);
}
  
void draw(){
  fill(246, 246, 246);
  stroke(246, 246, 246);
  rect(0,0, 1000, 80);
  
  stroke(0);
  
  if(mousePressed && onOff.getBooleanValue()) {
     line(mouseX, mouseY, pmouseX, pmouseY);
  }
}

void mousePressed(){
  if(erase.isPressed()){
     background(255);
  }
}