C.System.Drawing.Bitmap中的通道数

Question

I'm coding in C#, and loading images this way :

// loading image
string imageFileName = "myImage.jpg";
Bitmap bmp = new Bitmap(imageFileName, false);

// trying to display color so that I know how many channels I have
// except it always displays 4 values, whether I have 1, 3 or 4 channels
Color color = bmp.GetPixel(0, 0);
Console.WriteLine(color.ToString());

// locking the bitmap's bits
System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, bmp.PixelFormat);

// doing stuff that requires me to know the number of channels of the image, amongst other things

// unlocking the bitmap's bits
bmp.UnlockBits(bmpData);

I need to know the number of channels in my image (usually they are grayscale (1), RGB (3) or RGBA (4)), and I don't know how is that information storred.

EDIT : I'm not looking to force a pixel format. I'm trying to load an image, and figure out procedurally what is the number of channel in the image I loaded.

Answer 1

There is a PixelFormat property, you can read about in on MSDN .

You can combine with: GetPixelFormatSize it to get the bytes per pixel if you want.

Answer 2

Creation:

You need to use an overload of the Bitmap contructor that takes a PixelFormat parameter.

Usage:

The the bitmap.PixelFormat property will tell you what you have.

Here is more info about the PixelFormats