Image · CFITSIO.jl

Image HDU Routines

CFITSIO.fits_get_img_dim — Function

fits_get_img_dim(f::FITSFile)

Return the number of dimensions in the current image HDU.

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CFITSIO.fits_get_img_size — Function

fits_get_img_size(f::FITSFile)

Return the size along each dimension in the current Image HDU.

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CFITSIO.fits_get_img_type — Function

fits_get_img_type(f::FITSFile)

Return the datatype (bitpix) of the current image HDU. This may be converted to a Julia type by using the function type_from_bitpix.

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CFITSIO.fits_get_img_param — Function

fits_get_img_param(f::FITSFile)

Return the bitpix, number of dimensions and the size along each dimension of the current image HDU.

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CFITSIO.fits_create_img — Function

fits_create_img(f::FITSFile, T::Type, naxes::Vector{<:Integer})

Create a new primary array or IMAGE extension with the specified data type T and size naxes.

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fits_create_img(f::FITSFile, A::AbstractArray)

Create a new primary array or IMAGE extension with the element type and size of A, that is capable of storing the entire array A.

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CFITSIO.fits_create_empty_img — Function

fits_create_empty_img(f::FITSFile)

Create an empty image HDU with no dimensions, and of type Int. See fits_create_img.

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CFITSIO.fits_insert_img — Function

fits_insert_img(f::FITSFile, T::Type,
                naxes::Union{Vector{<:Integer}, Tuple{Vararg{Integer}}}; prepend_primary::Bool = false)

Insert a new image extension immediately following the current HDU (CHDU), or insert a new primary array at the beginning of the file.

A new primary array may be inserted at the beginning of the FITS file by calling fits_insert_img with prepend_primary set to true. In this case, the existing primary HDU is converted to an image extension, and the new primary array will become the CHDU.

The inserted array has an eltype T and size naxes.

fits_insert_img(f::FITSFile, a::AbstractArray{<:Real}; prepend_primary::Bool = false)

Insert a new image HDU with an element type of eltype(a) and a size of size(a) that is capable of storing the array a. The flag prepend_primary may be specified to insert a new primary array at the beginning of the FITS file.

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CFITSIO.fits_write_pix — Function

fits_write_pix(f::FITSFile,
               fpixel::Union{Vector{<:Integer}, Tuple{Vararg{Integer}}},
               nelements::Integer, data::StridedArray)

Write nelements pixels from data into the FITS file starting from the pixel fpixel.

Note

The HDU must have been created previously, and its size must match the number of elements being written.

Note

data needs to be stored contiguously in memory.

See also: fits_read_pix

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CFITSIO.fits_read_imghdr — Function

fits_read_imghdr(f::FITSFile, maxdim::Integer = 99)

Read the header of an image HDU, where maxdim represents the maximum number of dimensions to read. By default, maxdim == 99 will read the size along every dimension of the image. The function returns the values of SIMPLE::Bool, BITPIX::Int, NAXIS::Int, NAXES::Vector{Int}, PCOUNT::Int, GCOUNT::Int, and EXTEND::Bool. The length of NAXES is set equal to min(NAXIS, maxdim).

The BITPIX value indicates the data type of the image, and it may be converted to a Julia type using the type_from_bitpix function.

Note

PCOUNT is typically 0 for image HDUs, and GCOUNT is typically 1 for modern files.

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CFITSIO.fits_copy_image_section — Function

fits_copy_image_section(fin::FITSFile, fout::FITSFile, section::String)

Copy a rectangular section of an image from fin and write it to a new FITS primary image or image extension in fout. The section specifier is described on the CFITSIO website.

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CFITSIO.fits_write_null_img — Function

fits_write_null_img(f::FITSFile, firstelem::Integer, nelements::Integer)

Set a stretch of elements to the appropriate null value, starting from the pixel number firstelem and extending over nelements pixels.

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CFITSIO.fits_resize_img — Function

fits_resize_img(f::FITSFile, T::Type, naxis::Integer,
                sz::Union{Vector{<:Integer}, Tuple{Vararg{Integer}}})

Modify the size, dimensions and optionally the element type of the image in f. The new image will have an element type T, be a naxis-dimensional image with size sz. If the new image is larger than the existing one, it will be zero-padded at the end. If the new image is smaller, existing image data will be truncated.

Note

This method reinterprets the data instead of coercing the elements.

Example

julia> f = fits_clobber_file(tempname());

julia> a = [1 2; 3 4];

julia> fits_create_img(f, a);

julia> fits_write_pix(f, a);

julia> fits_get_img_size(f)
2-element Vector{Int64}:
 2
 2

julia> fits_resize_img(f, [3,3]);

julia> fits_get_img_size(f)
2-element Vector{Int64}:
 3
 3

julia> b = similar(a, (3,3));

julia> fits_read_pix(f, b); b
3×3 Matrix{Int64}:
 1  4  0
 3  0  0
 2  0  0

julia> fits_resize_img(f, [4]);

julia> b = similar(a, (4,));

julia> fits_read_pix(f, b); b
4-element Vector{Int64}:
 1
 3
 2
 4

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fits_resize_img(f::FITSFile, sz::Union{Vector{<:Integer}, Tuple{Vararg{Integer}}})

Resize the image to the new size sz. The element type is preserved, and the number of dimensions is set equal to length(sz).

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fits_resize_img(f::FITSFile, T::Type)

Change the element type of the image to T, leaving the size unchanged.

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