使用角度库将图像转换为base64

Question

i have a problem to convert an image to base64 with the library base64 of angularjs.

see my function :

var img = new Image();
img.src = conf.storeUrl + '/' +$scope.fRoot.name + $scope.getFileWay() + value.name;
var base64Img = base64.encode(img);

the url of the image is good and the image has been created but the base64Img is empty... i don't understand why.... Some one have a idea ?

thank in advance

Answer 1

Try this:

/**
 * Convert image 
 * to a base64 data uri
 * @param  {String}   url         
 * @param  {Function} callback    
 * @param  {String}   [outputFormat=image/png]           
 */
function convertImageToDataURI(url, callback, outputFormat) {
    var img = new Image();
    img.crossOrigin = 'Anonymous';
    img.onload = function(){
        var canvas = document.createElement('CANVAS'),
        ctx = canvas.getContext('2d'), dataURL;
        canvas.height = this.height;
        canvas.width = this.width;
        ctx.drawImage(this, 0, 0);
        dataURL = canvas.toDataURL(outputFormat);
        callback(dataURL);
        canvas = null; 
    };
    img.src = url;
}

Usage

convertImageToDataURI('ImageLink', function(base64Decoded){
    // Base64DataURI
});

Supported input formats

image/png, image/jpeg, image/jpg, image/gif, image/bmp, image/tiff, image/x-icon, image/svg+xml, image/webp, image/xxx
Supported output formats

image/png,image/jpeg,image/webp (chrome)

Demo:

fiddle

Test: toDataUrl mime type

http://kangax.github.io/jstests/toDataUrl_mime_type_test/

Browser Support (so far I know)

• http://caniuse.com/#feat=canvas

• IE10 (IE10 just works with same origin images)

Images from the local file system

If you want to convert images from the users file system you need to take a different approach. Use the FileReader API (Check out this fiddle ).