WInRT中的WriteableBitmapEx调整大小函数

Question

我试着写的函数，将调整图像的大小。我将WriteableBitmapEx用于WinRT/Win8函数Resize()；

public class PictureExtension 
{
    private MemoryRandomAccessStream _memoryRandomAccessStream;
    private readonly Stream _dataStream;
    private readonly double _height;
    private readonly double _width;

    public PictureExtension(Stream dataStream, double height, double width)
    {
        _dataStream = dataStream;
        _memoryRandomAccessStream = (_dataStream.ToRandomAccessStream());
        _height = height;
        _width = width;
    }

    public byte[] ToArray(double maxSide)
    {
        if (_height <= maxSide && _width <= maxSide)
        {
            return _dataStream.ToArray();
        }
        else
        {
            var target = new WriteableBitmap((int) _width, (int) _height);

            var aspectRatio = (double)_width / _height;
            double newHeight;
            double newWidth;
            if (_width > _height)
            {
                newWidth = maxSide;
                newHeight = newWidth / aspectRatio;
            }
            else
            {
                newHeight = maxSide;
                newWidth = maxSide * aspectRatio;
            }

            int count = (int)_dataStream.Length;

            using (var bmpStream = target.PixelBuffer.AsStream())
            {
                bmpStream.Seek(0, SeekOrigin.Begin);
                bmpStream.Write(_dataStream.ToArray(), 0, _dataStream.ToArray().Length);
            }


            var resized = target.Resize((int)newWidth, (int)newHeight, WriteableBitmapExtensions.Interpolation.Bilinear);

            return resized.ToByteArray();

        }

    }
}

}

此函数返回字节数组，但它不再是图像。我测试了PNG和JPG格式。怎么了？

Answer 1

我之前已经检查过这个问题了，试试这个线程中的代码：

How to resize Image in C# WinRT/winmd?

Answer 2

最好的帮助是如果你在CodePlex站点上关注你的帖子;) http://writeablebitmapex.codeplex.com/discussions/399624

不需要交叉过帐。

Answer 3

不知道这是否会对你有帮助，但我写了一个LoadAsync()重载，以给定的解码分辨率加载一个位图，这可能会根据你的场景对你有所帮助。

http://winrtxamltoolkit.codeplex.com/SourceControl/changeset/view/0657c67a93d5#WinRTXamlToolkit%2fImaging%2fWriteableBitmapLoadExtensions.cs