Bitmap/PPM conversion through a pipe
Using the data storage type defined on this page for raster images, delegate writing a JPEG file through a pipe using the output_ppm function defined on this other page.
You are encouraged to solve this task according to the task description, using any language you may know.
There are various utilities that can be used for this task, for example: cjpeg (package "jpeg-progs" on Linux), ppmtojpeg (package "netpbm" on Linux), convert (from ImageMagick, multi-platform).
C
This one uses the ImageMagick convert tool.
<lang c>/* interface */ void print_jpg(image img, int qual);</lang>
<lang c>#define MAXCMDBUF 100 void print_jpg(image img, int qual) {
char buf[MAXCMDBUF]; unsigned int n; FILE *pipe; snprintf(buf, MAXCMDBUF, "convert ppm:- -quality %d jpg:-", qual); pipe = popen(buf, "w"); if ( pipe != NULL ) { fprintf(pipe, "P6\n%d %d\n255\n", img->width, img->height); n = img->width * img->height; fwrite(img->buf, sizeof(pixel), n, pipe); pclose(pipe); }
}</lang>
The code that writes to the pipe is the same of output_ppm of course. A complete example is
<lang c>#include "imglib.h"
int main() {
image img; img = alloc_img(100,100); fill_img(img, 50, 20, 200); draw_line(img, 0, 0, 80, 80, 255, 0, 0); print_jpg(img, 75); free_img(img);
}</lang>
In order to make it working, you must link it with the raster image functions given by the codes here and here
Go
(Go 1 should be close)
Using cjpeg: <lang go>package main
// Files required to build supporting package raster are found in: // * Bitmap // * Write a PPM file
import (
"fmt" "math/rand" "os/exec" "raster"
)
func main() {
b := raster.NewBitmap(400, 300) // a little extravagant, this draws a design of dots and lines b.FillRgb(0xc08040) for i := 0; i < 2000; i++ { b.SetPxRgb(rand.Intn(400), rand.Intn(300), 0x804020) } for x := 0; x < 400; x++ { for y := 240; y < 245; y++ { b.SetPxRgb(x, y, 0x804020) } for y := 260; y < 265; y++ { b.SetPxRgb(x, y, 0x804020) } } for y := 0; y < 300; y++ { for x := 80; x < 85; x++ { b.SetPxRgb(x, y, 0x804020) } for x := 95; x < 100; x++ { b.SetPxRgb(x, y, 0x804020) } }
// pipe logic c := exec.Command("cjpeg", "-outfile", "pipeout.jpg") pipe, err := c.StdinPipe() if err != nil { fmt.Println(err) return } err = c.Start() if err != nil { fmt.Println(err) return } err = b.WritePpmTo(pipe) if err != nil { fmt.Println(err) return } err = pipe.Close() if err != nil { fmt.Println(err) }
}</lang>
Julia
<lang julia>using Images, FileIO
ppmimg = load("data/bitmapInputTest.ppm") save("data/bitmapOutputTest.jpg", ppmimg)</lang>
Kotlin
In order to provide a complete runnable example, we repeat bits of code from other relevant tasks and add code which pipes .ppm data to ImageMagick's 'convert' tool which then writes the corresponding .jpg file to disk. <lang scala>// Version 1.2.40
import java.awt.Color import java.awt.Graphics import java.awt.image.BufferedImage
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 main(args: Array<String>) {
// create BasicBitmapStorage object val width = 640 val height = 640 val bbs = BasicBitmapStorage(width, height) for (y in 0 until height) { for (x in 0 until width) { val c = Color(x % 256, y % 256, (x * y) % 256) bbs.setPixel(x, y, c) } }
// now write the object in PPM format to ImageMagick's STDIN via a pipe // so it can be converted to a .jpg file and written to disk val pb = ProcessBuilder("convert", "-", "output_piped.jpg") pb.directory(null) pb.redirectInput(ProcessBuilder.Redirect.PIPE) val buffer = ByteArray(width * 3) // write one line at a time val proc = pb.start() val pStdIn = proc.outputStream pStdIn.use { val header = "P6\n$width $height\n255\n".toByteArray() with (it) { write(header) for (y in 0 until height) { for (x in 0 until width) { val c = bbs.getPixel(x, y) buffer[x * 3] = c.red.toByte() buffer[x * 3 + 1] = c.green.toByte() buffer[x * 3 + 2] = c.blue.toByte() } write(buffer) } } }
}</lang>
Mathematica
The Windows command line does not like quotes in the middle of text, so strings have been turned into character codes. <lang Mathematica>convert[image_,out_]:=Module[{process=StartProcess[{ "wolfram","-noinit","-noprompt","-run", "Export[FromCharacterCode["~~ToString[ToCharacterCode[out]]~~"],ImportString[StringRiffle[Table[InputString[],{4}],FromCharacterCode[10]],FromCharacterCode[{80,80,77}]]]" }]}, WriteLine[process,image]; WriteLine[process,"Quit[]"]; ];</lang>
OCaml
<lang ocaml>let print_jpeg ~img ?(quality=96) () =
let cmd = Printf.sprintf "cjpeg -quality %d" quality in (* let cmd = Printf.sprintf "ppmtojpeg -quality %d" quality in let cmd = Printf.sprintf "convert ppm:- -quality %d jpg:-" quality in *) let ic, oc = Unix.open_process cmd in output_ppm ~img ~oc; try while true do let c = input_char ic in print_char c done with End_of_file -> ()
- </lang>
PicoLisp
<lang PicoLisp># Create an empty image of 120 x 90 pixels (setq *Ppm (make (do 90 (link (need 120)))))
- Fill background with green color
(ppmFill *Ppm 0 255 0)
- Draw a diagonal line
(for I 80 (ppmSetPixel *Ppm I I 0 0 0))
- Write to "img.jpg" through a pipe
(ppmWrite *Ppm '("convert" "-" "img.jpg"))</lang>
Racket
<lang racket> (define (ppm->jpeg bitmap [jpg-file "output"] [quality 75])
(define command (format "convert ppm:- -quality ~a jpg:~a.jpg" quality jpg-file)) (match-define (list in out pid err ctrl) (process command)) (bitmap->ppm bitmap out) (close-input-port in) (close-output-port out))
(ppm->jpeg bm)</lang>
Ruby
Extends Write ppm file#Ruby. Uses the ImageMagick convert
tool.
Additionally, for debugging, allow writing in pixmap P3 (ascii) format.
<lang ruby>class Pixmap
PIXMAP_FORMATS = ["P3", "P6"] # implemented output formats PIXMAP_BINARY_FORMATS = ["P6"] # implemented output formats which are binary
def write_ppm(ios, format="P6") if not PIXMAP_FORMATS.include?(format) raise NotImplementedError, "pixmap format #{format} has not been implemented" end ios.puts format, "#{@width} #{@height}", "255" ios.binmode if PIXMAP_BINARY_FORMATS.include?(format) @height.times do |y| @width.times do |x| case format when "P3" then ios.print @data[x][y].values.join(" "),"\n" when "P6" then ios.print @data[x][y].values.pack('C3') end end end end
def save(filename, opts={:format=>"P6"}) File.open(filename, 'w') do |f| write_ppm(f, opts[:format]) end end
def print(opts={:format=>"P6"}) write_ppm($stdout, opts[:format]) end
def save_as_jpeg(filename, quality=75) pipe = IO.popen("convert ppm:- -quality #{quality} jpg:#{filename}", 'w') write_ppm(pipe) pipe.close end
end
image = Pixmap.open('file.ppm') image.save_as_jpeg('file.jpg')</lang>
Tcl
Referring to Write ppm file#Tcl and Basic bitmap storage#Tcl
<lang tcl>package require Tk
proc output_jpeg {image filename {quality 75}} {
set f [open |[list convert ppm:- -quality $quality jpg:- > $filename] w] fconfigure $f -translation binary puts -nonewline $f [$image data -format ppm] close $f
}</lang>
However, it is more normal to do this directly with the
which is bundled with many Tcl distributions.
<lang tcl>package require Tk package require img::jpeg
proc output_jpeg {image filename} {
$image write $filename -format jpeg
} set img [image create photo -filename filename.ppm] output_jpeg $img filename.jpg</lang>
zkl
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
Using the convert utility by ImageMagick: <lang zkl>img:=PPM.readPPMFile("fractal.ppm"); p:=System.popen(0'|convert ppm:- jpg:"fractal.jpg"|,"w"); img.write(p); p.close();</lang>