sending an specific file to print using under a c program

Question

i am writing an opencv program, changing the image color and saving the image with a name given by the user, that name is stored at some variable. I want to use popen to send that file to print.

#include <stdio.h>
#include "cv.h"
#include "highgui.h"

int main (int argc, char ** argv)
{
    int p[3];
    p[0] = CV_IMWRITE_JPEG_QUALITY;
    p[1] = 10;
    p[2] = 0;
    char name[10];
    IplImage* in = cvLoadImage("imagenoise1.jpg",3);
    IplImage* gray = cvCreateImage( cvSize(in->width, in->height),IPL_DEPTH_8U, 1 );
    cvCvtColor( in, gray, CV_BGR2GRAY );

    cvNamedWindow("in", CV_WINDOW_AUTOSIZE );
    cvNamedWindow("gray", CV_WINDOW_AUTOSIZE );
    cvShowImage("in",in);
    cvShowImage("gray",gray);
    printf("Con que nombre desea guardar la imagen en escala de grises ( no mas de 9 caracteres ):\n");
    scanf("%s", name);
    cvSaveImage( name, gray, p );
     FILE *pipe = popen("lp name","w");
    close(pipe);
    cvWaitKey(0);
    cvDestroyWindow( "in" );
    cvDestroyWindow( "gray" );
    cvReleaseImage( &in );
    cvReleaseImage( &gray );



    return 0;
}

So i am trying to send the specific name i gives before, but nothing seems to work, any idea?, i think i am missing something because send a file that does not exist.

Sorry, i edited the question. The file does not exist according to the computer. Perhaps the way i give the name to popen is wrong. — mrmurmanks, Feb 08 '14 at 23:15

score 0 · Answer 1 · answered Feb 09 '14 at 01:09

You try to open imagenoise1.jpg which is not given by user and maybe that's why you receive FILE_NOT_FOUND exception.

IplImage* in = cvLoadImage("imagenoise1.jpg",3);

I think you should change your code in this way:

IplImage* in = cvLoadImage(argv[1], 3);

And you should run/debug your application by passing parameter: test.exe imagenoise.jpg

score 0 · Accepted Answer · answered Feb 09 '14 at 01:48

This code is suspicious to me:

scanf("%s", name);
cvSaveImage( name, gray, p );
FILE *pipe = popen("lp name","w");

It looks as though you need to do:

if (scanf("%s", name) == 1)
{
    char cmd[256];
    snprintf(cmd, sizeof(cmd), "lp %s", name);
    system(cmd);
}

You neither write anything to the pipe nor read anything from it, so you don't need popen() and system() should work just as well if not better.

sending an specific file to print using under a c program

2 Answers2