1-bit Image Support

[n-rode]

I am having trouble saving 1 bit images. Do you know of a method that should work?
I am using →

[731e570b] TiffImages v0.11.0 in Julia
julia> versioninfo()
Julia Version 1.10.0
Commit 3120989f39 (2023-12-25 18:01 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 24 × 12th Gen Intel(R) Core(TM) i9-12950HX
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, alderlake)
  Threads: 1 on 24 virtual cores
Environment:
  JULIA_EDITOR = code
  JULIA_NUM_THREADS =

using Pkg
Pkg.activate(".")

##
using TiffImages

## Make a grid pattern to of true values
image_data = fill(false, (100,100))
image_data[5:10:end,:] .= true
image_data[:,10:10:end] .= true

## Convert to color space data
image_gray_bool = Gray{Bool}.(image_data)

## Add tags to edit
image_tiff = TiffImages.DenseTaggedImage(image_gray_bool)
ifd = ifds(bit2Tiff)

# Tag 258 is BitsPerSample
ifd[UInt16(258)] = 0x0001

# Tag 262 is PhotmetricInterpretation
ifd[UInt16(262)] = 0x0000

# Tag 277 is SamplesPerPixel
 ifd[UInt16(277)] = 0x0001

## Save the image from the Gray{Bool},2 data
save_path = pwd() * "\\gray_bool.tif"
TiffImages.save(save_path, image_tiff)

##
inspection_image = TiffImages.load(save_path)
println(typeof(inspection_image))

The result is "TiffImages.DenseTaggedImage{Gray{N0f8}, 2, UInt32, Matrix{Gray{N0f8}}}", an 8 bit image.

I have also tried the FixedPointNumbers approach.

using Pkg
Pkg.activate(".")

##
using TiffImages

## Make a grid pattern to of true values
image_data = fill(false, (100,100))
image_data[5:10:end,:] .= true
image_data[:,10:10:end] .= true

## Convert to color space data
image_gray_N7f1 = Gray{N7f1}.(image_data)

## Add tags to edit
image_tiff = TiffImages.DenseTaggedImage(image_gray_N7f1)
ifd = ifds(bit2Tiff)

# Tag 258 is BitsPerSample
ifd[UInt16(258)] = 0x0001

# Tag 262 is PhotmetricInterpretation
ifd[UInt16(262)] = 0x0000

# Tag 277 is SamplesPerPixel
 ifd[UInt16(277)] = 0x0001

## Save the image from the Gray{Bool},2 data
save_path = pwd() * "\\gray_N7f1.tif"
TiffImages.save(save_path, image_tiff)

##
inspection_image = TiffImages.load(save_path)
println(typeof(inspection_image))

The result is TiffImages.DenseTaggedImage{Gray{N7f1}, 2, UInt32, Matrix{Gray{N7f1}}}, a 1 bit image. However, the data is distorted with seven 0's encoded before each 1 in the output. The image previews correctly in the Plots window in VSCode before saving.

Before from plots →

After save →

BitMatrix arrays have no supporting method and break the colors paradigm.