如何使用camanjs更改图像不透明度？

Question

how to change image opacity with caman js I tried with lates version also. Still issue is coming. If anything need to enable to achieve this ? //throwing not defined with caman js. In this reference - https://www.sitepoint.com/manipulating-images-web-pages-camanjs/ this.opacity(20);

Answer 1

Add these filter in camen.js

Filter.register("opacity", function (adjust) {
        adjust = Math.floor(255 * (adjust / 100)); 
        var imageData = this.imageData.data,
            length = imageData.length;
        // set every fourth value to 50
        for (var i = 3; i < length; i += 4) {
            imageData[i] = imageData[i] == 0 ? imageData[i] : adjust;
        }
        // after the manipulation, reset the data
        this.imageData.data = imageData;
        this.context.putImageData(this.imageData, 0, 0); 
    });

Now opacity filter will work.