将 Bitmap 转换为 1 位单色/黑白 Bitmap VB.net

Question

I have a BMP file.. a basic barcode image.. When I go to save it Bitmap.save(File) it saves the BMP file all fine, but when I open it in photoshop its a indexed or RGB color bmp files.

I need the file to be a 1bit black and white bmp file. Its just a barcode...

I have been googling for hours, and I am unable to convert the c# examples (often uses Unsafe code) and all other examples are also just creating what photoshop sees as a RGB image.

I need the file to be 1bit bmp as its loaded onto a ePaper device (like a kindle reader) and the device supplier has provided sample bitmaps that when loaded into photoshop as a mode Bitmap... not RGB or indexed.

Any tips on how to get the file saved correctly?

HPD

Answer 1

here is sample conversion code in c#:

private static ImageCodecInfo GetEncoder(ImageFormat format)
{
    ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

    foreach (ImageCodecInfo codec in codecs) {
        if (codec.FormatID == format.Guid) {
            return codec;
        }
    }

    return null;
}

static void Main(string[] args)
{
    var input = new Bitmap(@"d:\test.bmp");
    var output = input.Clone(
        new Rectangle(0, 0, input.Width, input.Height),
        PixelFormat.Format1bppIndexed);

    var encoder = GetEncoder(ImageFormat.Bmp);
    var param = new EncoderParameter(Encoder.ColorDepth, 1L);
    var paramss = new EncoderParameters(1);
    paramss.Param[0] = param;

    output.Save(@"d:\test_out.bmp", encoder, paramss);
}

and it produces bitmap mode bmp