我可以从Assets中的图片创建WriteableBitmap.
Uri imageUri1 = new Uri("ms-appx:///Assets/sample1.jpg");
WriteableBitmap writeableBmp = await new WriteableBitmap(1,1).FromContent(imageUri1);
但是,我无法从图片目录创建WriteableBitmap,(我正在使用WinRT XAML Toolkit)
//open image
StorageFolder picturesFolder = KnownFolders.PicturesLibrary;
StorageFile file = await picturesFolder.GetFileAsync("sample2.jpg");
var stream = await file.OpenReadAsync();
//create bitmap
BitmapImage bitmap2 = new BitmapImage();
bitmap2.SetSource();
bitmap2.SetSource(stream);
//create WriteableBitmap,but cannot
WriteableBitmap writeableBmp3 =
await WriteableBitmapFromBitmapImageExtension.FromBitmapImage(bitmap2);
它是否正确 ？
解决方法
这是一个完全的设计,但似乎确实有效……
// load a jpeg,be sure to have the Pictures Library capability in your manifest
var folder = KnownFolders.PicturesLibrary;
var file = await folder.GetFileAsync("test.jpg");
var data = await FileIO.ReadBufferAsync(file);
// create a stream from the file
var ms = new InMemoryRandomAccessStream();
var dw = new Windows.Storage.Streams.DataWriter(ms);
dw.WriteBuffer(data);
await dw.StoreAsync();
ms.Seek(0);
// find out how big the image is,don't need this if you already know
var bm = new BitmapImage();
await bm.SetSourceAsync(ms);
// create a writable bitmap of the right size
var wb = new WriteableBitmap(bm.PixelWidth,bm.PixelHeight);
ms.Seek(0);
// load the writable bitpamp from the stream
await wb.SetSourceAsync(ms);
