从BitmapSource复制到WritableBitmap

Question

我正在尝试将BitmapSource的一部分复制到WritableBitmap。

这是我到目前为止的代码：

var bmp = image.Source as BitmapSource;
var row = new WriteableBitmap(bmp.PixelWidth, bottom - top, bmp.DpiX, bmp.DpiY, bmp.Format, bmp.Palette);
row.Lock();
bmp.CopyPixels(new Int32Rect(top, 0, bmp.PixelWidth, bottom - top), row.BackBuffer, row.PixelHeight * row.BackBufferStride, row.BackBufferStride);
row.AddDirtyRect(new Int32Rect(0, 0, row.PixelWidth, row.PixelHeight));
row.Unlock();

我得到"ArgumentException:值不在预期范围内“。在CopyPixels这一行。

我试着用row.PixelHeight * row.PixelWidth交换row.PixelHeight * row.BackBufferStride，但是我得到一个错误，说这个值太低。

我找不到一个使用这个CopyPixels重载的代码示例，所以我请求帮助。

谢谢!

Answer 1

图像的哪一部分正在尝试复制？更改目标ctor中的宽度和高度、Int32Rect中的宽度和高度以及图像中的前两个参数(0,0)，它们是x&y偏移量。或者，如果你想复制整个东西，就直接离开。

BitmapSource source = sourceImage.Source as BitmapSource;

// Calculate stride of source
int stride = source.PixelWidth * (source.Format.BitsPerPixel + 7) / 8;

// Create data array to hold source pixel data
byte[] data = new byte[stride * source.PixelHeight];

// Copy source image pixels to the data array
source.CopyPixels(data, stride, 0);

// Create WriteableBitmap to copy the pixel data to.      
WriteableBitmap target = new WriteableBitmap(
  source.PixelWidth, 
  source.PixelHeight, 
  source.DpiX, source.DpiY, 
  source.Format, null);

// Write the pixel data to the WriteableBitmap.
target.WritePixels(
  new Int32Rect(0, 0, source.PixelWidth, source.PixelHeight), 
  data, stride, 0);

// Set the WriteableBitmap as the source for the <Image> element 
// in XAML so you can see the result of the copy
targetImage.Source = target;