SingleStrip TIFF

[tdbrown1]

I need to be able to produce a FED TIFF image that requires 1 bit per pixel and single strip. I dont see how to do that with this library.

I saw a PR to do this but it isn't in the latest build.
#1537

Maybe a simple change would be to do something like this:
Please don't take this as an exact solution.

public enum StripsPerRow { Auto, Multiple, Single }
public class TiffEncoder : QuantizingImageEncoder { public StripsPerRow StripsPerRow  { get; init; } = StripsPerRow.Auto; ... }


internal sealed class TiffEncoderCore : IImageEncoderInternals {
...
    private readonly StripsPerRow  stripsPerRow;
   public TiffEncoderCore(TiffEncoder options, MemoryAllocator memoryAllocator)
   {
      ...
      stripsPerRow = options.StripsPerRow;
   }
    private static int CalcRowsPerStrip(int height, int bytesPerRow, TiffCompression? compression)
    {
        DebugGuard.MustBeGreaterThan(height, 0, nameof(height));
        DebugGuard.MustBeGreaterThan(bytesPerRow, 0, nameof(bytesPerRow));

       if(stripsPerRow == StripsPerRow.Single)
         return 1;

...
        return 1;
    }

[tdbrown1]

Fun

[JimBobSquarePants]

That PR was merged over 2 years ago. There's been multiple builds including a major since.

[tdbrown1]

I cannot find it in the library. Is it in an extension library?

[JimBobSquarePants]

No, the way it was calculated was changed. It's based upon the TiffCompression value. Only TiffCompression.Jpeg uses a single strip at the moment.

@brianpopow @IldarKhayrutdinov You guys are both much better with the specification than me. Is the suggestion above reasonable?

[IldarKhayrutdinov]

@JimBobSquarePants Right.

@tdbrown1 If you want one strip to consist one image row, at the moment it's auto calculating, only jpeg is used RowsPerStrip = 1.

ImageSharp/src/ImageSharp/Formats/Tiff/TiffEncoderCore.cs

Lines 262 to 288 in 77d49e6

	private static int CalcRowsPerStrip(int height, int bytesPerRow, TiffCompression? compression)
	{
	DebugGuard.MustBeGreaterThan(height, 0, nameof(height));
	DebugGuard.MustBeGreaterThan(bytesPerRow, 0, nameof(bytesPerRow));
	// Jpeg compressed images should be written in one strip.
	if (compression is TiffCompression.Jpeg)
	{
	return height;
	}
	// If compression is used, change stripSizeInBytes heuristically to a larger value to not write to many strips.
	int stripSizeInBytes = compression is TiffCompression.Deflate || compression is TiffCompression.Lzw ? TiffConstants.DefaultStripSize * 2 : TiffConstants.DefaultStripSize;
	int rowsPerStrip = stripSizeInBytes / bytesPerRow;
	if (rowsPerStrip > 0)
	{
	if (rowsPerStrip < height)
	{
	return rowsPerStrip;
	}
	return height;
	}
	return 1;
	}

ImageSharp/src/ImageSharp/Formats/Tiff/Writers/TiffBaseColorWriter{TPixel}.cs

Line 32 in 77d49e6

public int BytesPerRow => (int)(((uint)(this.Image.Width * this.BitsPerPixel) + 7) / 8);

ImageSharp/src/ImageSharp/Formats/Tiff/Constants/TiffConstants.cs

Line 59 in 77d49e6

public const int DefaultStripSize = 8 * 1024;

RowsPerStrip = 1 - only if row bytes doesn't fit into DefaultStripSize * 2 or DefaultStripSize.