Q:
How can I convert PDF page to 8 bpp grayscale or monochrome TIFF?
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A:
PDFNet built-in rasterizer renders images to 24-BPP RGB Color image or
8-BPC GrayScale images.
Rendering to monochrome (1 BPC) would involve significant loss of
image quality and is as a result not directly supported at the moment.
You can produce 8 BPC grayscale image you could specify 'ColorSpace'
parameter as a hint in the pdfdraw.Export() method. For example:
// In C++
Dict enc_param;
enc_param.Put("ColorSpace", new Name("Gray")); pdfdraw.Export(page,
filename, "TIFF", &enc_param);
// In C#
Dict enc_param = Obj.CreateDict();
enc_param.Put("ColorSpace", Obj.CreateName("Gray"));
pdfdraw.Export(page, filename, "TIFF", enc_param);
To export monochrome images, you could use pdfdraw.GetBitmap() and
then convert the System.Darwing.Bitmap to monochrome bitmap before
saving to TIFF (for an example of how this can be done, please see
http://www.bobpowell.net/onebit.htm).