Bitmap/Read an image through a pipe: Difference between revisions
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This task is the ''opposite'' of the [[PPM conversion through a pipe]]. In this task, using a delegate tool (like '''cjpeg''', one of the netpbm package, or '''convert''' of the ImageMagick package) we read an image file and load it into the data storage type [[Basic bitmap storage|defined here]]. We can also use the code from [[Read ppm file]], so that we can use PPM format like a (natural) bridge between the foreign image format and our simple data storage.
=={{header|ATS}}==
I use the <code>magick</code> command from ImageMagick. You need all the source files from [[Bitmap#ATS]], [[Bitmap/Read_a_PPM_file#ATS]], and [[Bitmap/Write_a_PPM_file#ATS]]. (You do ''not'' need the files from [[Grayscale_image#ATS]].)
Because I wrote this program by modifying [[Bitmap/PPM_conversion_through_a_pipe#ATS]], it both reads ''and writes'' the file by piping through the <code>magick</code> command of ImageMagick. The comments at the top of the earlier program thus apply doubly here.
<syntaxhighlight lang="ats">
(* I both read AND write the image through pipes connected to
ImageMagick. One can also pass options and such but I won't go into
the details. *)
(*
##myatsccdef=\
patscc -std=gnu2x -g -O2 -DATS_MEMALLOC_LIBC \
-o $fname($1) $1 \
bitmap{,_{read,write}_ppm}_task.{s,d}ats
*)
#include "share/atspre_staload.hats"
staload "bitmap_task.sats"
staload "bitmap_read_ppm_task.sats"
staload "bitmap_write_ppm_task.sats"
staload _ = "bitmap_task.dats"
staload _ = "bitmap_read_ppm_task.dats"
staload _ = "bitmap_write_ppm_task.dats"
(*------------------------------------------------------------------*)
(* There is support for pipe-I/O in libats/libc, but I cannot (at
least when in a hurry) figure out how it is supposed to be
used. So, as elsewhere in the "raster graphics operations"
category, what is not in the prelude itself I implement with the
foreign function interfaces. :) Using FFI is a typical part of ATS
programming, and one should get used to doing it.
Anyway, here is some UNSAFE support for pipe-I/O. *)
typedef charstar = $extype"char *"
typedef FILEstar = $extype"FILE *"
fn {}
fileref_popen_unsafe (command : string,
mode : string)
: Option_vt FILEref =
let
val p = $extfcall (ptr, "popen", $UNSAFE.cast{charstar} command,
$UNSAFE.cast{charstar} mode)
in
if iseqz p then
None_vt ()
else
Some_vt ($UNSAFE.cast{FILEref} p)
end
fn {}
fileref_pclose_unsafe (f : FILEref)
: int = (* Returns the exit status of the command. *)
$extfcall (int, "pclose", $UNSAFE.cast{FILEstar} f)
(*------------------------------------------------------------------*)
implement
main0 (argc, argv) =
let
val args = listize_argc_argv (argc, argv)
val nargs = length args
val inpf_name = if nargs < 2 then "-" else args[1]
val command = string_append ("magick ", inpf_name, " ppm:-")
val pipe_opt =
(* Temporarily treating a strptr as a string, just to make a
function call of this sort, is not actually unsafe. *)
fileref_popen_unsafe ($UNSAFE.strptr2string command, "r")
val () = free command
in
case+ pipe_opt of
| ~ None_vt () =>
begin
free args;
println! ("For some reason, I failed to open a pipe ",
"for reading from magick.");
exit 1
end
| ~ Some_vt inpf =>
let
val pix_opt = pixmap_read_ppm<rgb24> inpf
in
ignoret (fileref_pclose_unsafe inpf);
case+ pix_opt of
| ~ None_vt () =>
begin
free args;
println! ("For some reason, I failed to pipe the image ",
"from magick.");
exit 1
end
| ~ Some_vt @(pfgc1 | pix1) =>
let
val outf_name = if nargs < 3 then "-" else args[2]
val command = string_append ("magick ppm:- ", outf_name)
val () = free args
val pipe_opt =
(* Temporarily treating a strptr as a string, just to
make a function call of this sort, is not actually
unsafe. *)
fileref_popen_unsafe
($UNSAFE.strptr2string command, "w")
val () = free command
in
case+ pipe_opt of
| ~ None_vt () =>
begin
free (pfgc1 | pix1);
println! ("For some reason, I failed to open a pipe ",
"for writing to magick.");
exit 3
end
| ~ Some_vt outf =>
let
val success = pixmap_write_ppm<rgb24> (outf, pix1)
in
ignoret (fileref_pclose_unsafe outf);
free (pfgc1 | pix1);
if ~success then
begin
println! ("For some reason, I failed to pipe ",
"the image to magick.");
exit 2
end
end
end
end
end
</syntaxhighlight>
{{out}}
Using SIPI test image 4.1.07:
<pre>$ myatscc bitmap_read_through_pipe_task.dats
$ ./bitmap_read_through_pipe_task 4.1.07.tiff > bitmap_read_through_pipe_task_ATS.ppm
$ file 4.1.07.ppm (~/src/chemoelectric/rosettacode-contributions)
4.1.07.ppm: Netpbm image data, size = 256 x 256, rawbits, pixmap
$ ./bitmap_read_through_pipe_task 4.1.07.tiff 4.1.07.jpg
$ file 4.1.07.jpg (~/src/chemoelectric/rosettacode-contributions)
4.1.07.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16, baseline, precision 8, 256x256, components 3</pre>
Notice that, when I did not specify an output file, I got a PPM (PPM being what was sent through the output pipe to magick). Both times, though, the input pipe converts a TIFF image to PPM, which then is read into the internal <code>pixmap</code> type.
Here is the JPEG that was outputted:
[[File:Bitmap read through pipe task ATS.jpg|none|alt=SIPI test image of jellybeans.]]
=={{header|AutoHotkey}}==
{{works with | AutoHotkey_L}}
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#include run.ahk ; http://www.autohotkey.com/forum/viewtopic.php?t=16823
</syntaxhighlight>
=={{header|C}}==
{{works with|POSIX|.1-2001}}
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