save a high color Image as 256 color or fewer.

[Mohammad]

Hello.
How I can write a program that save a high color image
as 256 color or fewer with .BMP format , just like
Microsoft Paint.
I want to write this Program with C# .NET , NOT with MFC .
Thank you.

 

[Michael Mayer]

Hello.
How I can write a program that save a high color image
as 256 color or fewer with .BMP format , just like
Microsoft Paint.
I want to write this Program with C# .NET , NOT with MFC .
Thank you.

Use GDI+ and unsafe code. Take a look at this link. There's an example that
converts to black and white which would be quite similar to what you want:

http://www.codeproject.com/cs/media/csharpgraphicfilters11.asp

 

[Bytz]

Not a bad link! Though it's missing the palette generation and dithering
aspects that you'll need to get good images. You need a palette for 256
color and below, there are many different ways to create one like median
cut or using a "standard" palette...

Dithereing is a method of spreading the difference (error) from the actual
pixel value and the closest palette color to surrounding pixels. This has
the effect of reducing banding