function createCanvas(w, h) {
    var canvas = document.createElement('canvas');
    canvas.setAttribute('width', w);
    canvas.setAttribute('height', h);
    return canvas;
  }
  
  // globals
  var g_ctx = document.getElementById('cnv').getContext('2d');
  var g_img = document.getElementById('img');
  var g_offscreenCanvas = createCanvas(320, 240);
  
  
  g_offscreenCanvas.getContext('2d').drawImage(g_img, 0, 0);
  var imageData = g_ctx.getImageData(0,0,g_offscreenCanvas.width, g_offscreenCanvas.height);

Teardown JS

Test cases

Test #1

Title *

Async

Code *g_ctx.drawImage(g_img, 0, 0);

Test #2

Title *

Async

Code *g_ctx.drawImage(g_offscreenCanvas, 0, 0);

Test #3

Title *

Async

Code *g_ctx.putImageData(imageData,0,0);

Test case details

Preparation Code

Test cases

Test #1

Test #2

Test #3