Hi, I am a newbie on JS and was trying to do alpha blending without a full success for a couple of days. The code is here:
var img1 = document.getElementById('foreground'); var img2 = document.getElementById('background'); var canvas = document.getElementById("result"); var context = canvas.getContext("2d"); var width = img1.width; var height = img1.height; canvas.width = width; canvas.height = height; var alpha = 0.5; var pixels = 4 * width * height; // get foreground image data context.drawImage(img1, 0, 0); var image1 = context.getImageData(0, 0, width, height); var imageData1 = image1.data; // get background image data context.drawImage(img2, 0, 0); var image2 = context.getImageData(0, 0, width, height); var imageData2 = image2.data; // alpha blending while (pixels--) { imageData1[pixels] = imageData1[pixels] * alpha + imageData2[pixels] * alpha; } // send the result to canvas image1.data = imageData1; context.putImageData(image1, 0, 0); I found that Safari displays blended image just fine. However in Chrome, the line on context.getImageData triggered the following error message: 58 Uncaught Error: SECURITY_ERR: DOM Exception 18 Thank you very much in advance, Jane -- To view archived discussions from the original JSMentors Mailman list: http://www.mail-archive.com/jsmentors@jsmentors.com/ To search via a non-Google archive, visit here: http://www.mail-archive.com/jsmentors@googlegroups.com/ To unsubscribe from this group, send email to jsmentors+unsubscr...@googlegroups.com