在Chrome瀏覽器中調整圖片大小，但不在Firefox中

Question

我的Angular 1.5應用程序中有一個函數，如果尺寸超過最大尺寸，它會調整base64編碼圖片的大小。該功能在Chrome中非常適用，但在Firefox中，它返回一個空字符串，而不是任何base64編碼的。

I've got it packaged up in an Angular app in Plunker here,但這裏的相關功能：

// Image resizing 
    $scope.resizeImage = function(base64Data, maxWidth, maxHeight) { 
    img = document.createElement('img'); 

    img.src = base64Data; 
    height = img.height; 
    width = img.width; 

    if (width > maxWidth) { 
     ratio = maxWidth/width; // get ratio for scaling image 
     height = height * ratio; // Reset height to match scaled image 
     width = width * ratio; // Reset width to match scaled image 
    } 

    // Check if current height is larger than max 
    if (height > maxHeight) { 
     ratio = maxHeight/height; // get ratio for scaling image 
     width = width * ratio; // Reset width to match scaled image 
     height = height * ratio; // Reset height to match scaled image 
    } 

    var canvas = document.createElement('canvas'); 
    var ctx = canvas.getContext('2d'); 

    // We set the dimensions at the wanted size. 
    canvas.width = width; 
    canvas.height = height; 

    // We resize the image with the canvas method drawImage(); 
    ctx.drawImage(img, 0, 0, width, height); 

    var dataURI = canvas.toDataURL(); 
    return dataURI; 
    } 

Answer 1

您可能需要等到<img>加載：

img.onload = function() { 
    // now your image is ready for use 
};