p5.js Image numFrames()用法及代碼示例

function preload() { 
    example_gif = 
      loadImage("sample-gif.gif"); 
} 
  
function setup() { 
    createCanvas(500, 300); 
    textSize(18); 
  
    text("Click on the button to get " + 
         "the total number of frames", 
         20, 20); 
  
    frameBtn = 
      createButton("Get number of frames"); 
    frameBtn.position(30, 40); 
    frameBtn.mousePressed(getTotalFrames); 
} 
  
function draw() { 
  
  // Draw the GIF on screen 
  image(example_gif, 20, 60, 240, 120); 
} 
  
function getTotalFrames() 
{ 
  // Get the total number of frames 
  let numberOfFrames = 
      example_gif.numFrames(); 
  
  text("Number of frames in the GIF is:"
       + numberOfFrames, 20, 200); 
}