Bitmap/Read an image through a pipe: Difference between revisions

[[Category:Input Output]]

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|AutoHotkey}}==

{{works with | AutoHotkey_L}}

Uses [http://www.autohotkey.com/forum/viewtopic.php?t=16823 StdoutTovar.ahk]

; pipe in from imagemagick

img := ppm_read("", ppm) ;

#include run.ahk ; http://www.autohotkey.com/forum/viewtopic.php?t=16823

</syntaxhighlight>

=={{header|C}}==

{{works with|POSIX|.1-2001}}

Here I've used '''convert''' by ImageMagick. It is up to the program to ''understand'' the source file type; in this way, we can read theoretically any image format ImageMagick can handle. The <tt>get_ppm</tt> function defined in [[Read ppm file]] is used.

#define MAXCMDBUF 100

return NULL;

}</syntaxhighlight>

=={{header|Go}}==

This example uses convert to convert the test image for the flood fill task. It reads through the pipe as required for this task, then writes as a .ppm file convenient for the flood fill task.

// Files required to build supporting package raster are found in:

}

}</syntaxhighlight>

=={{header|Julia}}==

{{works with|Julia|0.6}}

img = load("data/bitmapOutputTest.jpg")

save("data/bitmapOutputTest.ppm", img)</syntaxhighlight>

=={{header|Kotlin}}==

{{works with|Ubuntu 16.04}}

The code for this is similar to that for the [[Bitmap/Read a PPM file]] task except that the .jpg file is converted via a pipe to .ppm format using the ImageMagick 'convert' tool and stored in a BasicBitmapStorage object. It is then converted to grayscale and saved back to disk as a .jpg file.

import java.awt.Color

}

}</syntaxhighlight>

=={{header|Lua}}==

Uses Bitmap class [[Bitmap#Lua|here]], with an RGB tuple pixel representation, and the rudimentary PPM support [[Bitmap/Flood_fill#Lua|here]], and the Lenna image [[:File:Lenna100.jpg|here]].

First, the <code>loadPPM()</code> method is altered to allow passing an existing file handle:

if not fp then fp = io.open(filename, "rb") end

if not fp then return end

end</syntaxhighlight>

Then, for the actual "read-from-pipe" task, a Lua environment that supports <code>io.popen()</code> is required:

fp = io.popen("magick Lenna100.jpg ppm:-", "rb")

bitmap:loadPPM(nil, fp)

bitmap:savePPM("Lenna100.ppm") -- just as "proof"</syntaxhighlight>

=={{header|Mathematica}}/{{header|Wolfram Language}}==

Based off the Julia program.

=={{header|Nim}}==

Using "jpegtopnm" from Netpbm suite. Input is a JPEG file and result (the PPM file) is sent to stdout. The procedure "readPPM" reads directly from the stream and build the image container.

import osproc

import ppm_read

echo image.w, " ", image.h

p.close()</syntaxhighlight>

=={{header|OCaml}}==

The <code>read_ppm</code> function of the page [[read ppm file]] and used by the code below would need to be changed to take as parameter an input channel instead of the filename.

if not(Sys.file_exists filename)

then failwith(Printf.sprintf "the file %s does not exist" filename);

(img)

;;</syntaxhighlight>

=={{header|Perl}}==

use strict;

magick identify output.ppm

output.ppm PPM 512x512 512x512+0+0 8-bit sRGB 786464B 0.000u 0:00.014</pre>

=={{header|Phix}}==

Uses the demo\rosetta\viewppm.exw utility to accomplish this task.<br>

The returned data is raw binary, so you can either write it direct or chuck it through read_ppm/write_ppm.

<span style="color: #000080;font-style:italic;">-- demo\rosetta\Bitmap_Read_an_image_through_a_pipe.exw</span>

<span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- file i/o, system_exec(), pipes[!!]</span>

<span style="color: #0000FF;">{}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">wait_key</span><span style="color: #0000FF;">()</span>

<!--</syntaxhighlight>-->

=={{header|PicoLisp}}==

=={{header|Python}}==

"""

Adapted from https://stackoverflow.com/questions/26937143/ppm-to-jpeg-jpg-conversion-for-python-3-4-1

Does not need to pipe through a conversion utility

because the Pillow module does the conversion.

=={{header|Racket}}==

(define (read-ppm port)

(image->bmp "input.jpg")</syntaxhighlight>

=={{header|Raku}}==

(formerly Perl 6)

Uses imagemagick convert to pipe the image in.

class Bitmap {

has UInt ($.width, $.height);

See [https://github.com/thundergnat/rc/blob/master/img/camelia.png camelia image here].

=={{header|Ruby}}==

Uses [[Raster graphics operations/Ruby]].

require_relative 'raster_graphics'

bitmap.save('foto.ppm')

</syntaxhighlight>

=={{header|Tcl}}==

{{works with|Tcl|8.6}}

{{libheader|Tk}}

proc magickalReadImage {bufferImage fileName} {

}

}</syntaxhighlight>

=={{header|Wren}}==

{{libheader|DOME}}

We can now use this plug-in in the following script which calls ''ImageMagick'' to convert the ''output_piped.jpg'' file to a ''ppm'' file so that we can load the latter, convert it to a gray scale image, display it and save it to a .jpg file.

import "dome" for Window, Process

import "io" for FileSystem

var Game = Bitmap.new("output_piped.jpg", "output_piped.ppm", "output_piped_gs.jpg", 350, 350)</syntaxhighlight>

=={{header|zkl}}==

{{trans|C}}

Using the convert utility by ImageMagick:

img:=PPM.readPPM(p); p.close();</syntaxhighlight>

{{omit from|PARI/GP}}