Drawing PNG to a canvas element -- not showing transparency

Question

I'm trying to use drawImage to draw a semi-transparent PNG on a canvas element. However, it draws the image as completely opaque. When I look at the resource that's being loaded and load the actual PNG in the browser, it shows the transparency, but when I draw it on the canvas, it does not. Any ideas?

Here's the code:

drawing = new Image() 
drawing.src = "draw.png" 
context.drawImage(drawing,0,0);

Answer 1

Don't forget to add an event listener to the image's load event. Image loading is something that happens in the background, so when the JavaScript interpreter gets to the canvas.drawImage part it is most likely the image probably will not have loaded yet and is just an empty image object, without content.

drawing = new Image();
drawing.src = "draw.png"; // can also be a remote URL e.g. http://
drawing.onload = function() {
   context.drawImage(drawing,0,0);
};