p5.js scale() Function

Last Updated : 17 Aug, 2023

The scale() function in p5.js is used to increase or decrease the size of a shape or model by expanding or contracting its vertices. The scale values are specified as decimal percentages, that is, a scale value of “2.0” would increase the dimensions of the shape by 200%. Similarly, a negative of “-2.0” would decrease the dimensions of the shape by 200%

The objects always scale from their relative origin to the coordinate system. The z parameter of this function is only available in the WebGL mode for scaling across the z-axis.

As scale() is a transformation, every transformation that happens after one call multiplies the effect. If scale() is called within the draw() loop, then the transformation is reset when the loop begins again.

Syntax:

scale( s, [y], [z] )

scale( scales )

Parameters: This function accepts four parameters as mentioned above and described below.

s: It is a p5.Vector, Number or array of Numbers which define the percent to scale the object. If multiple arguments are given, it denotes the percent to scale the object in the x direction.
y: It is a Number which denotes the percent to scale the object in the y direction. It is an optional parameter.
z: It is a Number which denotes the percent to scale the object in the z direction. It is an optional parameter.
scales: It is a p5.Vector or array of Numbers which specify per-axis percents to scale the object.

The program below illustrate the scale() function in p5.js:

Example 1:

function setup() { 
  createCanvas(500, 400); 
  textSize(16); 
  
  scaleXslider = createSlider(-3, 3, 1, 0.1); 
  scaleXslider.position(30, 30); 
  
  scaleYslider = createSlider(-3, 3, 1, 0.1); 
  scaleYslider.position(30, 50); 
} 
  
function draw() { 
  clear(); 
  text("Move the sliders to change the scale value", 20, 20); 
  fill("red"); 
  rect(150, 150, 100, 100); 
  
  // Get the scale parameters 
  let scaleXValue = scaleXslider.value(); 
  let scaleYValue = scaleYslider.value(); 
  
  text("Scale x value: " + scaleXValue, 20, 350); 
  text("Scale y value: " + scaleYValue, 20, 370); 
  
  // Set the scale according to properties 
  scale(scaleXValue, scaleYValue); 
  
  fill("green"); 
  rect(150, 150, 100, 100); 
} 

Output:

scale-2d_xy

Example 2:

function preload() { 
  ballObj = loadModel("models/ball.obj", true); 
} 
  
function setup() { 
  createCanvas(500, 300, WEBGL); 
  
  scaleXslider = createSlider(-3, 3, 0.5, 0.1); 
  scaleXslider.position(30, 30); 
  
  scaleYslider = createSlider(-3, 3, 0.5, 0.1); 
  scaleYslider.position(30, 50); 
  
  scaleZslider = createSlider(-3, 3, 0.5, 0.1); 
  scaleZslider.position(30, 70); 
  
  debugMode(); 
} 
  
function draw() { 
  clear(); 
  noStroke(); 
  lights(); 
  orbitControl(); 
  
  // Get the scale parameters 
  let scaleXValue = scaleXslider.value(); 
  let scaleYValue = scaleYslider.value(); 
  let scaleZValue = scaleZslider.value(); 
  
  // Set the scale according to properties 
  scale(scaleXValue, scaleYValue, scaleZValue); 
  
  fill("green") 
  model(ballObj); 
} 