C# - 将 WPF Image.source 转换为 System.Drawing.Bitmap [英] C# - Convert WPF Image.source to a System.Drawing.Bitmap

问题描述

我发现很多人将 BitmapSource 转换为 Bitmap，但是如何将 ImageSource 转换为 Bitmap>?我正在制作一个成像程序，我需要从 Image 元素中显示的图像中提取位图.有人知道怎么做吗?

I've found loads of people converting a BitmapSource to a Bitmap, but what about ImageSource to Bitmap? I am making an imaging program and I need to extract bitmaps from the image displayed in the Image element. Does anyone know how to do this?

编辑 1:

这是一个将BitmapImage 转换为Bitmap 的函数.请记住在编译器首选项中设置不安全"选项.

This is a function for converting the BitmapImage to a Bitmap. Remember to set the 'unsafe' option in the compiler preferences.

public static System.Drawing.Bitmap BitmapSourceToBitmap(BitmapSource srs)
{
    System.Drawing.Bitmap btm = null;

    int width = srs.PixelWidth;

    int height = srs.PixelHeight;

    int stride = width * ((srs.Format.BitsPerPixel + 7) / 8);

    byte[] bits = new byte[height * stride];

    srs.CopyPixels(bits, stride, 0);

    unsafe
    {
        fixed (byte* pB = bits)
        {
            IntPtr ptr = new IntPtr(pB);

            btm = new System.Drawing.Bitmap(width, height, stride, System.Drawing.Imaging.PixelFormat.Format1bppIndexed, ptr);
        }
    }
    return btm;
}

接下来是获取BitmapImage:

RenderTargetBitmap targetBitmap = new RenderTargetBitmap(
    (int)inkCanvas1.ActualWidth,
    (int)inkCanvas1.ActualHeight,
    96d, 96d,
    PixelFormats.Default);

targetBitmap.Render(inkCanvas1);

MemoryStream mse = new MemoryStream();
System.Windows.Media.Imaging.BmpBitmapEncoder mem = new BmpBitmapEncoder();
mem.Frames.Add(BitmapFrame.Create(targetBitmap));
mem.Save(mse);

mse.Position = 0;
BitmapImage bi = new BitmapImage();
bi.BeginInit();
bi.StreamSource = mse;
bi.EndInit();

接下来就是转换了:

Bitmap b = new Bitmap(BitmapSourceToBitmap(bi));

推荐答案

其实你不需要使用不安全的代码.有一个接受 IntPtr 的 CopyPixels 重载:

Actually you don't need to use unsafe code. There's an overload of CopyPixels that accepts an IntPtr:

public static System.Drawing.Bitmap BitmapSourceToBitmap2(BitmapSource srs)
{
    int width = srs.PixelWidth;
    int height = srs.PixelHeight;
    int stride = width * ((srs.Format.BitsPerPixel + 7) / 8);
    IntPtr ptr = IntPtr.Zero;
    try
    {
        ptr = Marshal.AllocHGlobal(height * stride);
        srs.CopyPixels(new Int32Rect(0, 0, width, height), ptr, height * stride, stride);
        using (var btm = new System.Drawing.Bitmap(width, height, stride, System.Drawing.Imaging.PixelFormat.Format1bppIndexed, ptr))
        {
            // Clone the bitmap so that we can dispose it and
            // release the unmanaged memory at ptr
            return new System.Drawing.Bitmap(btm);
        }
    }
    finally
    {
        if (ptr != IntPtr.Zero)
            Marshal.FreeHGlobal(ptr);
    }
}

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