loadImageViaBlob(url, request)Promise.<Image>|undefined

Asynchronously loads the given image URL by first downloading it as a blob using XMLHttpRequest and then loading the image from the buffer via a blob URL. This allows access to more information that is not accessible via normal Image-based downloading, such as the size of the response. This function returns a promise that will resolve to an Image once loaded, or reject if the image failed to load. The returned image will have a "blob" property with the Blob itself. If the browser does not support an XMLHttpRequests with a responseType of 'blob', or if the provided URI is a data URI, this function is equivalent to calling loadImage, and the extra blob property will not be present.
Name Type Description
url String The source URL of the image.
request Request optional The request object. Intended for internal use only.
a promise that will resolve to the requested data when loaded. Returns undefined if request.throttle is true and the request does not have high enough priority.
// load a single image asynchronously
SuperMap3D.loadImageViaBlob('some/image/url.png').then(function(image) {
    var blob = image.blob;
    // use the loaded image or XHR
}).otherwise(function(error) {
    // an error occurred

// load several images in parallel
when.all([loadImageViaBlob('image1.png'), loadImageViaBlob('image2.png')]).then(function(images) {
    // images is an array containing all the loaded images