【C#/WPF】图片的切割/切图/裁剪图片

前台准备两个Image控件。上面是显示原图，下面显示切割后的效果。

<StackPanel Orientation="Vertical">
    <Image Width="450" Height="383" Source="C:\Users\Administrator\Documents\Visual Studio 2015\Projects\SplitPic\SplitPic\Images\1.jpg"/>
    <Image x:Name="img" Stretch="None" Width="450" Height="383" />
</StackPanel>

对应的后台代码：

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        // 设置原图
        img.Source = new BitmapImage(new Uri(@"Images/1.jpg", UriKind.Relative));
        // 切割图片
        ImageSource imageSource = img.Source;
        Bitmap bitmap = SystemUtils.ImageSourceToBitmap(imageSource);
        BitmapSource bitmapSource = SystemUtils.BitmapToBitmapImage(bitmap);
        BitmapSource newBitmapSource = SystemUtils.CutImage(bitmapSource, new Int32Rect(125, 60, 235, 285));
        // 使用切割后的图源
        img.Source = newBitmapSource;
    }
}
// 图像工具类
public static class SystemUtils
{
    /// <summary>
    /// 切图
    /// </summary>
    /// <param name="bitmapSource">图源</param>
    /// <param name="cut">切割区域</param>
    /// <returns></returns>
    public static BitmapSource CutImage(BitmapSource bitmapSource, Int32Rect cut)
    {
        //计算Stride
        var stride = bitmapSource.Format.BitsPerPixel * cut.Width / 8;
        //声明字节数组
        byte[] data = new byte[cut.Height * stride];
        //调用CopyPixels
        bitmapSource.CopyPixels(cut, data, stride, 0);
        return BitmapSource.Create(cut.Width, cut.Height, 0, 0, PixelFormats.Bgr32, null, data, stride);
    }
    // ImageSource --> Bitmap
    public static System.Drawing.Bitmap ImageSourceToBitmap(ImageSource imageSource)
    {
        BitmapSource m = (BitmapSource)imageSource;
        System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(m.PixelWidth, m.PixelHeight, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
        System.Drawing.Imaging.BitmapData data = bmp.LockBits(
        new System.Drawing.Rectangle(System.Drawing.Point.Empty, bmp.Size), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
        m.CopyPixels(Int32Rect.Empty, data.Scan0, data.Height * data.Stride, data.Stride); bmp.UnlockBits(data);
        return bmp;
    }
    // Bitmap --> BitmapImage
    public static BitmapImage BitmapToBitmapImage(Bitmap bitmap)
    {
        using (MemoryStream stream = new MemoryStream())
        {
            bitmap.Save(stream, ImageFormat.Bmp);
            stream.Position = 0;
            BitmapImage result = new BitmapImage();
            result.BeginInit();
            // According to MSDN, "The default OnDemand cache option retains access to the stream until the image is needed."
            // Force the bitmap to load right now so we can dispose the stream.
            result.CacheOption = BitmapCacheOption.OnLoad;
            result.StreamSource = stream;
            result.EndInit();
            result.Freeze();
            return result;
        }
    }
}

运行后的效果如下：

补充：关于剪裁的位置和区域的填写说明，如下图。