Question

I want to create a new ImageData object in code. If I have a Uint8ClampedArray out of which I want to make an image object, what is the best way to do it?

I guess I could make a new canvas element, extract its ImageData and overwrite its data attribute, but that seems like a wrong approach.

It would be great if I could use the ImageData constructor directly, but I can’t figure out how to.

Answer 1

This is interesting problem… You can’t just create ImageData object:

var test = new ImageData(); // TypeError: Illegal constructor

I have also tried:

var imageData= context.createImageData(width, height);
imageData.data = mydata; // TypeError: Cannot assign to read only property 'data' of #<ImageData> 

but as described in MDN data property is readonly.

So I think the only way is to create object and set data property with iteration:

var canvas = document.createElement('canvas');
var imageData = canvas.getContext('2d').createImageData(width, height);
for(var i = 0; i < myData.length; i++){
    imageData.data[i] = myData[i];
}

Update:
I have discovered the set method in data property of ImageData, so solution is very simple:

var canvas = document.createElement('canvas');
var imageData = canvas.getContext('2d').createImageData(width, height);
imageData.data.set(myData);