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I'm using a list of InteropBitmap in order to display a set of image frames within Image control which is customized with a datatemplate.

What I'm lookin for is to export set of images in a single image, however what I get is a bad/partial image with wrong colors.

The following is the code snippet I'm using to convert set of InteropBitmap in a single image:

 var firstInterop = this.InteropBitmapList[0]; // Get info from first frame, all other one are the same format.

  int width = firstInterop .PixelWidth;
            int height = firstInterop.PixelHeight;
            int bpp = firstInterop Format.BitsPerPixel;

            int stride = width * (bpp / 8);
            int count = this.InteropBitmapList.Count;

            byte[] buffer = new byte[stride * height * count];

            for (int i = 0; i < count; i++)
            {
                var wb = this.InteropBitmapList[i];
                wb.CopyPixels(buffer, stride, width * height * i);
            }

Finally, I use buffer array to achieve my jpeg image through GDI+ or else wpf instruments. Unfortunately, both the way doesn't work as I expected.

Is there something to wrong in my code?

@@EDIT Well, thanks to Clemens answers, now I'm able to obtain a correct image, except only for its color (all colors are altered). The issue is true only when I try to create an Image through GDI+, instead, if I use something of WPF susch as JpegBitmapEncoder all works fine.

The following code snippet allow me to achieve the right image:

byte[] buffer = MyFunc.GetBuffer();
// ...
    var bitmap = System.Windows.Media.Imaging.BitmapSource.Create(width, height, 300, 300,
       System.Windows.Media.PixelFormats.Rgb24, null, buffer, stride);
            System.IO.FileStream stream = new System.IO.FileStream("example.jpg", System.IO.FileMode.Create);
            JpegBitmapEncoder encoder = new JpegBitmapEncoder();

            encoder.QualityLevel = 100;

            encoder.Frames.Add(BitmapFrame.Create(bitmap));
            encoder.Save(stream);

Instead, the following code return me an image with wrong colors (the red become blue and so on)

byte[] buffer = MyFunc.GetBuffer(); 
// ...
IntPtr unmanagedPointer = System.Runtime.InteropServices.Marshal.AllocHGlobal(buffer.Length);
System.Runtime.InteropServices.Marshal.Copy(buffer, 0, unmanagedPointer, buffer.Length);

System.Drawing.Imaging.PixelFormat format = System.Drawing.Imaging.PixelFormat.Format24bppRgb (the equivalent of WPF format..)

System.Drawing.Image myImg = new System.Drawing.Bitmap(Width, Height, stride, format, unmanagedPointer);

myImg.Save("example.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

I haven't idea why it doesn't work when I use System.Drawing classes.

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1 回答 1

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错误在于计算i第 th 图像的缓冲区偏移量。而不是width * height * i它必须计算为stride * height * i：

wb.CopyPixels(buffer, stride, stride * height * i);

为了还支持不是整数倍的每像素位数8，您应该像这样计算步幅：

int stride = (width * bpp + 7) / 8;
于 2014-07-22T14:15:24.383 回答