Need C# function to convert grayscale TIFF to black & white (monochrome/1BPP) TIFF

Question

I need a C# function that will take a Byte[] of an 8 bit grayscale TIFF, and return a Byte[] of a 1 bit (black & white) TIFF.

I\'m fairly new to working with TIF

Answer 1

Something like this might work, I haven't tested it. (Should be easy to C# it.)

    Dim bmpGrayscale As Bitmap = Bitmap.FromFile("Grayscale.tif")
    Dim bmpMonochrome As New Bitmap(bmpGrayscale.Width, bmpgrayscale.Height, Imaging.PixelFormat.Format1bppIndexed)
    Using gfxMonochrome As Graphics = Graphics.FromImage(bmpMonochrome)
        gfxMonochrome.Clear(Color.White)
    End Using
    For y As Integer = 0 To bmpGrayscale.Height - 1
        For x As Integer = 0 To bmpGrayscale.Width - 1
            If bmpGrayscale.GetPixel(x, y) <> Color.White Then
                bmpMonochrome.SetPixel(x, y, Color.Black)
            End If
        Next
    Next
    bmpMonochrome.Save("Monochrome.tif")

This might be a better way still:

Using bmpGrayscale As Bitmap = Bitmap.FromFile("Grayscale.tif")
    Using bmpMonochrome As New Bitmap(bmpGrayscale.Width, bmpgrayscale.Height, Imaging.PixelFormat.Format1bppIndexed)
        Using gfxMonochrome As Graphics = Graphics.FromImage(bmpMonochrome)
            gfxMonochrome.CompositingQuality = Drawing2D.CompositingQuality.HighQuality
            gfxMonochrome.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
            gfxMonochrome.DrawImage(bmpGrayscale, new Rectangle(0, 0, bmpMonochrome.Width, bmpMonochrome.Height)
        End Using
        bmpMonochrome.Save("Monochrome.tif")
    End Using
End Using

I believe the term you are looking for is "resampling".