clipboard2image.jl

using Colors, FixedPointNumbers
const DWORD = Culong
const LONG = Clong
const WORD = Cushort
const CIEXYZTRIPLE = NTuple{3, XYZ{Float32}}

struct BITMAPV5HEADER
  bV5Size::DWORD
  bV5Width::LONG
  bV5Height::LONG
  bV5Planes::WORD
  bV5BitCount::WORD
  bV5Compression::DWORD
  bV5SizeImage::DWORD
  bV5XPelsPerMeter::LONG
  bV5YPelsPerMeter::LONG
  bV5ClrUsed::DWORD
  bV5ClrImportant::DWORD
  bV5RedMask::DWORD
  bV5GreenMask::DWORD
  bV5BlueMask::DWORD
  bV5AlphaMask::DWORD
  bV5CSType::DWORD
  bV5Endpoints::CIEXYZTRIPLE
  bV5GammaRed::DWORD
  bV5GammaGreen::DWORD
  bV5GammaBlue::DWORD
  bV5Intent::DWORD
  bV5ProfileData::DWORD
  bV5ProfileSize::DWORD
  bV5Reserved::DWORD
end

function clipboard_image()
  if ccall((:OpenClipboard, "user32"), stdcall, Cint, (Ptr{Cvoid},), C_NULL) == 0
    error("couldn't open clipboard")
  end
  pdata = ccall((:GetClipboardData, "user32"), stdcall, Ptr{UInt16}, (UInt32,), 17)
  if ccall((:CloseClipboard, "user32"), stdcall, Cint, ()) == 0
    error("couldn't close clipboard")
  end
  pdata == C_NULL && return nothing
  plock = ccall((:GlobalLock, "kernel32"), stdcall, Ptr{UInt16}, (Ptr{UInt16},), pdata)
  header = unsafe_load(Ptr{BITMAPV5HEADER}(plock), 1)
  CType = header.bV5BitCount == 32 ? BGRA{N0f8} : RGB{N0f8}
  offset = sizeof(header) + header.bV5ClrUsed * sizeof(CType)
  data = rotl90(unsafe_wrap(Array, Ptr{CType}(plock + offset), (header.bV5Width, header.bV5Height)))
  @assert ccall((:GlobalUnlock, "kernel32"), stdcall, Cint, (Ptr{UInt16},), plock) != 0 
  return data
end