Bitmap/Read an image through a pipe
< Bitmap
(Redirected from Read image file through a pipe)
You are encouraged to solve this task according to the task description, using any language you may know.
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 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.
ATS
I use the magick 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 magick command of ImageMagick. The comments at the top of the earlier program thus apply doubly here.
(* 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- Output:
Using SIPI test image 4.1.07:
$ myatscc bitmap_read_through_pipe_task.dats $ ./bitmap_read_through_pipe_task 4.1.07.tiff > 4.1.07.ppm $ file 4.1.07.ppm 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 4.1.07.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16, baseline, precision 8, 256x256, components 3
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 pixmap type.
Here is the JPEG that was outputted:
AutoHotkey
Uses StdoutTovar.ahk
ppm := Run("cmd.exe /c convert lena50.jpg ppm:-")
; pipe in from imagemagick
img := ppm_read("", ppm) ;
x := img[4,4] ; get pixel(4,4)
y := img[24,24] ; get pixel(24,24)
msgbox % x.rgb() " " y.rgb()
img.write("lena50copy.ppm")
return
ppm_read(filename, ppmo=0) ; only ppm6 files supported
{
if !ppmo ; if image not already in memory, read from filename
fileread, ppmo, % filename
index := 1
pos := 1
loop, parse, ppmo, `n, `r
{
if (substr(A_LoopField, 1, 1) == "#")
continue
loop,
{
if !pos := regexmatch(ppmo, "\d+", pixel, pos)
break
bitmap%A_Index% := pixel
if (index == 4)
Break
pos := regexmatch(ppmo, "\s", x, pos)
index ++
}
}
type := bitmap1
width := bitmap2
height := bitmap3
maxcolor := bitmap4
bitmap := Bitmap(width, height, color(0,0,0))
index := 1
i := 1
j := 1
bits := pos
loop % width * height
{
bitmap[i, j, "r"] := numget(ppmo, 3 * A_Index + bits, "uchar")
bitmap[i, j, "g"] := numget(ppmo, 3 * A_Index + bits + 1, "uchar")
bitmap[i, j, "b"] := numget(ppmo, 3 * A_Index + bits + 2, "uchar")
if (j == width)
{
j := 1
i += 1
}
else
j++
}
return bitmap
}
#include bitmap_storage.ahk ; from http://rosettacode.org/wiki/Basic_bitmap_storage/AutoHotkey
#include run.ahk ; http://www.autohotkey.com/forum/viewtopic.php?t=16823
C
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 get_ppm function defined in Read ppm file is used.
image read_image(const char *name);
#include "imglib.h"
#define MAXCMDBUF 100
#define MAXFILENAMELEN 256
#define MAXFULLCMDBUF (MAXCMDBUF + MAXFILENAMELEN)
image read_image(const char *name)
{
FILE *pipe;
char buf[MAXFULLCMDBUF];
image im;
FILE *test = fopen(name, "r");
if ( test == NULL ) {
fprintf(stderr, "cannot open file %s\n", name);
return NULL;
}
fclose(test);
snprintf(buf, MAXFULLCMDBUF, "convert \"%s\" ppm:-", name);
pipe = popen(buf, "r");
if ( pipe != NULL )
{
im = get_ppm(pipe);
pclose(pipe);
return im;
}
return NULL;
}
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.
package main
// Files required to build supporting package raster are found in:
// * Bitmap
// * Read a PPM file
// * Write a PPM file
import (
"log"
"os/exec"
"raster"
)
func main() {
c := exec.Command("convert", "Unfilledcirc.png", "-depth", "1", "ppm:-")
pipe, err := c.StdoutPipe()
if err != nil {
log.Fatal(err)
}
if err = c.Start(); err != nil {
log.Fatal(err)
}
b, err := raster.ReadPpmFrom(pipe)
if err != nil {
log.Fatal(err)
}
if err = b.WritePpmFile("Unfilledcirc.ppm"); err != nil {
log.Fatal(err)
}
}
Julia
using Images, FileIO
img = load("data/bitmapOutputTest.jpg")
save("data/bitmapOutputTest.ppm", img)
Kotlin
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.
// Version 1.2.40
import java.awt.Color
import java.awt.Graphics
import java.awt.image.BufferedImage
import java.io.PushbackInputStream
import java.io.File
import javax.imageio.ImageIO
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
fun fill(c: Color) {
val g = image.graphics
g.color = c
g.fillRect(0, 0, image.width, image.height)
}
fun setPixel(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB())
fun getPixel(x: Int, y: Int) = Color(image.getRGB(x, y))
fun toGrayScale() {
for (x in 0 until image.width) {
for (y in 0 until image.height) {
var rgb = image.getRGB(x, y)
val red = (rgb shr 16) and 0xFF
val green = (rgb shr 8) and 0xFF
val blue = rgb and 0xFF
val lumin = (0.2126 * red + 0.7152 * green + 0.0722 * blue).toInt()
rgb = (lumin shl 16) or (lumin shl 8) or lumin
image.setRGB(x, y, rgb)
}
}
}
}
fun PushbackInputStream.skipComment() {
while (read().toChar() != '\n') {}
}
fun PushbackInputStream.skipComment(buffer: ByteArray) {
var nl: Int
while (true) {
nl = buffer.indexOf(10) // look for newline at end of comment
if (nl != -1) break
read(buffer) // read another buffer full if newline not yet found
}
val len = buffer.size
if (nl < len - 1) unread(buffer, nl + 1, len - nl - 1)
}
fun Byte.toUInt() = if (this < 0) 256 + this else this.toInt()
fun main(args: Array<String>) {
// use file, output_piped.jpg, created in the
// Bitmap/PPM conversion through a pipe task
val pb = ProcessBuilder("convert", "output_piped.jpg", "ppm:-")
pb.directory(null)
pb.redirectOutput(ProcessBuilder.Redirect.PIPE)
val proc = pb.start()
val pStdOut = proc.inputStream
val pbis = PushbackInputStream(pStdOut, 80)
pbis.use {
with (it) {
val h1 = read().toChar()
val h2 = read().toChar()
val h3 = read().toChar()
if (h1 != 'P' || h2 != '6' || h3 != '\n') {
println("Not a P6 PPM file")
System.exit(1)
}
val sb = StringBuilder()
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == ' ') break // read until space reached
sb.append(r.toChar())
}
val width = sb.toString().toInt()
sb.setLength(0)
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == '\n') break // read until new line reached
sb.append(r.toChar())
}
val height = sb.toString().toInt()
sb.setLength(0)
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == '\n') break // read until new line reached
sb.append(r.toChar())
}
val maxCol = sb.toString().toInt()
if (maxCol !in 0..255) {
println("Maximum color value is outside the range 0..255")
System.exit(1)
}
var buffer = ByteArray(80)
// get rid of any more opening comments before reading data
while (true) {
read(buffer)
if (buffer[0].toChar() == '#') {
skipComment(buffer)
}
else {
unread(buffer)
break
}
}
// read data
val bbs = BasicBitmapStorage(width, height)
buffer = ByteArray(width * 3)
var y = 0
while (y < height) {
read(buffer)
for (x in 0 until width) {
val c = Color(
buffer[x * 3].toUInt(),
buffer[x * 3 + 1].toUInt(),
buffer[x * 3 + 2].toUInt()
)
bbs.setPixel(x, y, c)
}
y++
}
// convert to grayscale and save to a file
bbs.toGrayScale()
val grayFile = File("output_piped_gray.jpg")
ImageIO.write(bbs.image, "jpg", grayFile)
}
}
}
Lua
Uses Bitmap class here, with an RGB tuple pixel representation, and the rudimentary PPM support here, and the Lenna image here.
First, the loadPPM() method is altered to allow passing an existing file handle:
function Bitmap:loadPPM(filename, fp)
if not fp then fp = io.open(filename, "rb") end
if not fp then return end
local head, width, height, depth, tail = fp:read("*line", "*number", "*number", "*number", "*line")
self.width, self.height = width, height
self:alloc()
for y = 1, self.height do
for x = 1, self.width do
self.pixels[y][x] = { string.byte(fp:read(1)), string.byte(fp:read(1)), string.byte(fp:read(1)) }
end
end
fp:close()
end
Then, for the actual "read-from-pipe" task, a Lua environment that supports io.popen() is required:
local bitmap = Bitmap(0,0)
fp = io.popen("magick Lenna100.jpg ppm:-", "rb")
bitmap:loadPPM(nil, fp)
bitmap:savePPM("Lenna100.ppm") -- just as "proof"
Mathematica /Wolfram Language
Based off the Julia program.
Export["data/bitmapOutputTest.ppm",Import["data/bitmapOutputTest.jpg"]];
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 bitmap
import osproc
import ppm_read
import streams
# Launch Netpbm "jpegtopnm".
# Input is taken from "input.jpeg" and result sent to stdout.
let p = startProcess("jpegtopnm", args = ["input.jpeg"], options = {poUsePath})
let stream = FileStream(p.outputStream())
let image = stream.readPPM()
echo image.w, " ", image.h
p.close()
OCaml
The read_ppm 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.
let read_image ~filename =
if not(Sys.file_exists filename)
then failwith(Printf.sprintf "the file %s does not exist" filename);
let cmd = Printf.sprintf "convert \"%s\" ppm:-" filename in
let ic, oc = Unix.open_process cmd in
let img = read_ppm ~ic in
(img)
;;
Perl
# 20211226 Perl programming solution
use strict;
use warnings;
use Imager;
my $raw;
open my $fh, '-|', 'cat Lenna50.jpg' or die;
binmode $fh;
while ( sysread $fh , my $chunk , 1024 ) { $raw .= $chunk }
close $fh;
my $enable = $Imager::formats{"jpeg"}; # some kind of tie ?
my $IO = Imager::io_new_buffer $raw or die;
my $im = Imager::File::JPEG::i_readjpeg_wiol $IO or die;
open my $fh2, '>', 'output.ppm' or die;
binmode $fh2;
my $IO2 = Imager::io_new_fd(fileno $fh2);
Imager::i_writeppm_wiol $im, $IO2 ;
close $fh2;
undef($im);
- Output:
file output.ppm output.ppm: Netpbm PPM "rawbits" image data, size = 512 x 512 magick identify output.ppm output.ppm PPM 512x512 512x512+0+0 8-bit sRGB 786464B 0.000u 0:00.014
Phix
Uses the demo\rosetta\viewppm.exw utility to accomplish this task.
The returned data is raw binary, so you can either write it direct or chuck it through read_ppm/write_ppm.
-- demo\rosetta\Bitmap_Read_an_image_through_a_pipe.exw without js -- file i/o, system_exec(), pipes[!!] include builtins\pipeio.e include ppm.e -- read_ppm(), write_ppm() sequence pipes = repeat(0,3) pipes[PIPOUT] = create_pipe(INHERIT_READ) -- Create the child process, with replacement stdout. string cmd = sprintf("%s viewppm -load test.jpg",{get_interpreter(true)}) atom hProc = system_exec(cmd, 12, pipes), hPipe = pipes[PIPOUT][READ_PIPE] string ppm = read_from_pipe(hPipe, hProc) while true do object chunk = read_from_pipe(hPipe, hProc) if chunk=-1 then exit end if ppm &= chunk end while pipes = close_handles(pipes) if 0 then sequence img = read_ppm(ppm,bText:=true) write_ppm("Lenapipe.ppm", img) else -- or integer fn = open("Lenapipe.ppm","wb") puts(fn,ppm) close(fn) end if ?"done" {} = wait_key()
PicoLisp
(setq *Ppm (ppmRead '("convert" "img.jpg" "ppm:-")))Python
"""
Adapted from https://stackoverflow.com/questions/26937143/ppm-to-jpeg-jpg-conversion-for-python-3-4-1
Requires pillow-5.3.0 with Python 3.7.1 32-bit on Windows.
Sample ppm graphics files from http://www.cs.cornell.edu/courses/cs664/2003fa/images/
"""
from PIL import Image
# boxes_1.jpg is the jpg version of boxes_1.ppm
im = Image.open("boxes_1.jpg")
im.save("boxes_1v2.ppm")
Does not need to pipe through a conversion utility because the Pillow module does the conversion.
Racket
(define (read-ppm port)
(parameterize ([current-input-port port])
(define magic (read-line))
(match-define (list w h) (string-split (read-line) " "))
(define width (string->number w))
(define height (string->number h))
(define maxcol (string->number (read-line)))
(define bm (make-object bitmap% width height))
(define dc (new bitmap-dc% [bitmap bm]))
(send dc set-smoothing 'unsmoothed)
(define (adjust v) (* 255 (/ v maxcol)))
(for/list ([x width])
(for/list ([y height])
(define red (read-byte))
(define green (read-byte))
(define blue (read-byte))
(define color (make-object color% (adjust red) (adjust green) (adjust blue)))
(send dc set-pen color 1 'solid)
(send dc draw-point x y)))
bm))
(define (image->bmp filename)
(define command (format "convert ~a ppm:-" filename))
(match-define (list in out pid err ctrl) (process command))
(define bmp (read-ppm in))
(close-input-port in)
(close-output-port out)
bmp)
(image->bmp "input.jpg")
Raku
(formerly Perl 6)
Uses pieces from Bitmap and Read a PPM file tasks. Included here to make a complete, runnable program.
Uses imagemagick convert to pipe the image in.
class Pixel { has UInt ($.R, $.G, $.B) }
class Bitmap {
has UInt ($.width, $.height);
has Pixel @.data;
}
role PPM {
method P6 returns Blob {
"P6\n{self.width} {self.height}\n255\n".encode('ascii')
~ Blob.new: flat map { .R, .G, .B }, self.data
}
}
sub getline ( $proc ) {
my $line = '#'; # skip comment when reading a .png
$line = $proc.out.get while $line.substr(0,1) eq '#';
$line;
}
my $filename = './camelia.png';
my $proc = run 'convert', $filename, 'ppm:-', :enc('ISO-8859-1'), :out;
my $type = getline($proc);
my ($width, $height) = getline($proc).split: ' ';
my $depth = getline($proc);
my Bitmap $b = Bitmap.new( width => $width.Int, height => $height.Int) but PPM;
$b.data = $proc.out.slurp.ords.rotor(3).map:
{ Pixel.new(R => .[0], G => .[1], B => .[2]) };
'./camelia.ppm'.IO.open(:bin, :w).write: $b.P6;
See camelia image here.
Ruby
Uses Raster graphics operations/Ruby.
# frozen_string_literal: true
require_relative 'raster_graphics'
class Pixmap
def self.read_ppm(ios)
format = ios.gets.chomp
width, height = ios.gets.chomp.split.map(&:to_i)
max_colour = ios.gets.chomp
if !PIXMAP_FORMATS.include?(format) ||
(width < 1) || (height < 1) ||
(max_colour != '255')
ios.close
raise StandardError, "file '#{filename}' does not start with the expected header"
end
ios.binmode if PIXMAP_BINARY_FORMATS.include?(format)
bitmap = new(width, height)
height.times do |y|
width.times do |x|
# read 3 bytes
red, green, blue = case format
when 'P3' then ios.gets.chomp.split
when 'P6' then ios.read(3).unpack('C3')
end
bitmap[x, y] = RGBColour.new(red, green, blue)
end
end
ios.close
bitmap
end
def self.open(filename)
read_ppm(File.open(filename, 'r'))
end
def self.open_from_jpeg(filename)
read_ppm(IO.popen("convert jpg:#{filename} ppm:-", 'r'))
end
end
bitmap = Pixmap.open_from_jpeg('foto.jpg')
bitmap.save('foto.ppm')
Tcl
package require Tk
proc magickalReadImage {bufferImage fileName} {
set f [open |[list convert [file normalize $fileName] ppm:-] "rb"]
try {
$bufferImage put [read $f] -format ppm
} finally {
close $f
}
}
Wren
As DOME doesn't have a method for calling an external process (ImageMagick in this case), we re-use the small plug-in (pipeconv.so) we created in the 'PPM conversion through a pipe' task to add this functionality.
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 "graphics" for Canvas, ImageData, Color
import "dome" for Window, Process
import "io" for FileSystem
import "plugin" for Plugin
Plugin.load("pipeconv")
import "pipeconv" for PipeConv
class Bitmap {
construct new(fileName, fileName2, fileName3, width, height) {
Window.title = "Bitmap - read image via pipe"
Window.resize(width, height)
Canvas.resize(width, height)
_w = width
_h = height
_fn3 = fileName3
// convert .jpg file to .ppm via a pipe
PipeConv.convert(fileName, fileName2)
// load the .ppm file
loadPPMFile(fileName2)
}
init() {
toGrayScale()
// display gray scale image
_bmp2.draw(0, 0)
// save it to file
_bmp2.saveToFile(_fn3)
}
loadPPMFile(fileName) {
var ppm = FileSystem.load(fileName)
var count = ppm.count //ensure file is fully loaded before proceeding
if (ppm[0..1] != "P6") {
System.print("The loaded file is not a P6 file.")
Process.exit()
}
var lines = ppm.split("\n")
if (Num.fromString(lines[2]) > 255) {
System.print("The maximum color value can't exceed 255.")
Process.exit()
}
var wh = lines[1].split(" ")
var w = Num.fromString(wh[0])
var h = Num.fromString(wh[1])
_bmp = ImageData.create(fileName, w, h)
var bytes = ppm.bytes
var i = bytes.count - 3 * w * h
for (y in 0...h) {
for (x in 0...w) {
var r = bytes[i]
var g = bytes[i+1]
var b = bytes[i+2]
var c = Color.rgb(r, g, b)
pset(x, y, c)
i = i + 3
}
}
}
toGrayScale() {
_bmp2 = ImageData.create("gray scale", _bmp.width, _bmp.height)
for (x in 0..._bmp.width) {
for (y in 0..._bmp.height) {
var c1 = _bmp.pget(x, y)
var lumin = (0.2126 * c1.r + 0.7152 * c1.g + 0.0722 * c1.b).floor
var c2 = Color.rgb(lumin, lumin,lumin, c1.a)
_bmp2.pset(x, y, c2)
}
}
}
pset(x, y, col) { _bmp.pset(x, y, col) }
pget(x, y) { _bmp.pget(x, y) }
update() {}
draw(alpha) {}
}
var Game = Bitmap.new("output_piped.jpg", "output_piped.ppm", "output_piped_gs.jpg", 350, 350)
zkl
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
Using the convert utility by ImageMagick:
p:=System.popen(0'|convert "fractalTree.jpg" ppm:-|,"r");
img:=PPM.readPPM(p); p.close();