//设置源图ImageSource为WriteableBitmap类型
BitmapImage himage = this.imageTarget2.Source as BitmapImage;
RandomAccessStreamReference random = RandomAccessStreamReference.CreateFromUri(himage.UriSource);
using (IRandomAccessStream stream = await random.OpenReadAsync())
{
stream.Seek(0);
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(stream);
BitmapFrame bitmapFrame = await decoder.GetFrameAsync(0);
// Get the pixels
var transform = new BitmapTransform { ScaledWidth = decoder.PixelWidth, ScaledHeight = decoder.PixelHeight };
PixelDataProvider dataProvider =
await bitmapFrame.GetPixelDataAsync(BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Straight,
transform,
ExifOrientationMode.RespectExifOrientation,
ColorManagementMode.ColorManageToSRgb);
var image_array = dataProvider.DetachPixelData();
var image_array_width = (int)decoder.PixelWidth;
var image_array_height = (int)decoder.PixelHeight;
var writeableBitmap = new WriteableBitmap(image_array_width, image_array_height);
stream.Seek(0);
await writeableBitmap.SetSourceAsync(stream);
this.imageSource1.Source = writeableBitmap;//WriteableBitmap 类型很重要
}
//裁切方法
public async static Task<SoftwareBitmap> GetCroppedBitmapAsync(SoftwareBitmap softwareBitmap, uint x, uint y, uint width, uint height)
{
using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream())
{
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.BmpEncoderId, stream);
encoder.SetSoftwareBitmap(softwareBitmap);
encoder.BitmapTransform.Bounds = new BitmapBounds()
{
X = x,
Y = y,
Height = height,
Width = width
};
await encoder.FlushAsync();
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(stream);
return await decoder.GetSoftwareBitmapAsync(softwareBitmap.BitmapPixelFormat, softwareBitmap.BitmapAlphaMode);
}
}
//实例:
WriteableBitmap wb = this.imageSource1.Source as WriteableBitmap; ;
SoftwareBitmap sb = new SoftwareBitmap(BitmapPixelFormat.Bgra8, wb.PixelWidth, wb.PixelHeight);
sb.CopyFromBuffer(wb.PixelBuffer);//WriteableBitmap转为SoftwareBitmap
var sbmp = await GetCroppedBitmapAsync(sb, 0, 50, 100, 100);//调用裁切方法
WriteableBitmap writeableBitmap = new WriteableBitmap(sbmp.PixelWidth, sbmp.PixelHeight);
sbmp.CopyToBuffer(writeableBitmap.PixelBuffer);//SoftwareBitmap转为WriteableBitmap
this.imageTarget2.Source = writeableBitmap;//设置目标图ImageSource为WriteableBitmap类型
