p5.js mousePressed() Function

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The mousePressed() function in p5.js works when mouse clicked on the document. The mouseButton variable is used to specify which button is pressed. The touchStarted() function is used instead of mousePressed() function if mousePressed() function is not defined.

Syntax:

mousePressed(Event)

Below programs illustrate the mousePressed() function in p5.js:

Example 1: This example uses mousePressed() function.

function setup() { 
      
    // Create Canvas 
    createCanvas(500, 500); 
} 
   
let value = 0; 
  
function draw() { 
      
    // Set background color 
    background(200); 
      
    // Fill the color 
    fill(value, value-50, value-100); 
      
    // Create rectangle 
    rect(25, 25, 460, 440); 
      
    // Set the color of text 
    fill('lightgreen'); 
      
    // Set font size 
    textSize(15); 
      
    // Display content 
    text('Keep on Clicking the Mouse Across'
        + 'the page \nto change Canvas Color.', 
            windowHeight/10, windowWidth/4); 
} 
  
function mousePressed() { 
      
    value = value + 5; 
      
    if (value > 255) { 
        value = 0; 
    } 
} 

Output:

Example 2:

let valueX; 
let valueY; 
  
function setup() { 
    
    // Create Canvas 
    createCanvas(500, 500); 
} 
   
function draw() { 
      
    // Set background color 
    background(200);  
      
    // Set the text color 
    fill('green'); 
      
    // Set text size 
    textSize(25); 
      
    text('Drag mouse to change color', 30, 30); 
      
    // Fill color according to mouseMoved()  
    fill(valueX, 255-valueY, 255-valueX); 
      
    // Draw ellipse   
    ellipse(mouseX, mouseY, 115, 115); 
} 
  
function mousePressed() { 
    valueX = mouseX%255; 
    valueY = mouseY%255; 
} 