Create 1bpp mask from image

Question

How do you create a 1 bit per pixel mask from an image using GDI in C#? The image I am trying to create the mask from is held in a System.Drawing.Graphics object.

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Answer 1

Do you mean LockBits? Bob Powell has an overview of LockBits here; this should provide access to the RGB values, to do what you need. You might also want to look at ColorMatrix, like so.