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Bitmap/PPM conversion through a pipe: Difference between revisions
Bitmap/PPM conversion through a pipe (view source)
Revision as of 23:48, 21 March 2020
, 4 years ago→{{header|Standard ML}}: + faf version
(→{{header|Standard ML}}: + faf version) |
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=={{header|Standard ML}}==
This function uses convert, and retrieves its output
<lang Standard ML>
val useOSConvert = fn ppm =>
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fromList[0wxFF, 0wxD8, 0wxFF, 0wxE0, 0wx0, 0wx10, 0wx4A, 0wx46, 0wx49,
0wx46, ...]: BinIO.vector
</lang>
This is the fire-and-forget version.
<lang Standard ML>
val demo = fn () =>
let
val useOSConvert = fn ppmf =>
let
val appopt = ("/usr/local/bin/convert", ["convert","-", "/tmp/out.jpeg"])
val p = Posix.IO.pipe () ;
val me = Posix.Process.fork ()
in
case me of SOME cpd =>
( Posix.IO.close (#outfd p);
Posix.IO.dup2 {old=(#infd p), new= Posix.FileSys.stdin } ;
Posix.IO.close (#infd p);
Posix.Process.exec appopt
)
| _ =>
( Posix.IO.close (#infd p);
ppmf (#outfd p) ;
Posix.IO.close (#outfd p) ;
OS.Process.exit OS.Process.success
)
end;
fun output_ppm fd = (* placeholder for the ppm/bitmap functionality *)
Posix.IO.writeVec ( fd ,
Word8VectorSlice.full ( Byte.stringToBytes
"P3 3 2 255 255 0 0 0 255 0 0 0 255 255 255 0 255 255 255 0 0 0 " )
)
in
useOSConvert output_ppm
end ;
</lang>
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