Thread: Make this image in c:

Make this image in c:


You will write the following functions:
1. make_header(int w, int h) ; the same as the header we used in class
2. print_Row (int yValue, int width, int height); the purpose of this function is to make a
row of pixels from column start to column finish; yValue will provide the row number.
3. make_pixel (unsigned char r, unsigned char g, unsigned char b)

i understand that i need to use y=mx+b and tell it to display a color if it is above or below the two lines. I just don't understand how to do that.

here is my code so far:

Code:

#include <stdio.h>


//This function makes the header file for the image
void make_header(int width, int height)
{
  fprintf(stdout, "P6\n"); 
  fprintf(stdout, "%d %d %d\n", width, height, 255); 
}


//The function prints the pixels on the screen
void make_pixel (unsigned char r, unsigned char g, unsigned char b)
{
  fprintf(stdout, "%c%c%c", r, g, b);
}


/*the purpose of this function is to make a
row of pixels from column start to column finish; yValue will provide the row number.*/
void print_Row (int yValue, int width, int height)
{
  int x=0, m=(1/1), b=0;
  yValue= ((width/2) + (height/2))-1;
  int i;
    for (i = 0; i < yValue; i++)
    {
      make_pixel(255,0,0);
      b++;
      x++;
      yValue= m*x+b;
    }
    for (i = 0; i > yValue; i++)
    {
      make_pixel(0,0,255);
      b++;
      x++;
      yValue= m*x+b;
    }
}


void make_image (int width, int height)
{
  int i;
  int yValue;
  yValue= ((width/2) + (height/2))-1;
  make_header(width, height);
        for (i = 0; i < height; i++)
    {
         print_Row(yValue, width, height);
    }
}


int main (void)
{
  int width;
  int height;
  fprintf(stdin,"Enter the width and the height: ");
  fscanf(stdin, "%d %d", &width, &height);
  make_image(width, height);






  return (0);
}

Originally Posted by Salem

> This might give you some idea's perhaps:
And a health warning about how obsolete it is, and what subset of compilers it has a chance of working on.

1) It's there to show an algorithm, not a finished image.

2) Every OS has some way of printing colored text to the console. In our last discussion on this topic, we heard from several compiler users that saying that they DID have conio.h. included with their compiler. It's not as obsolete as I thought it was.

Originally Posted by Salem

If it's there for backward compatibility, then it's still obsolete.
It enables old code to be compiled and maintained (in a transition phase).

You shouldn't be lazy, and use it in new code.

C has no code to control text color.

On the contrary, it does. If you can use conio.h you can just as easily use something else. windows.h, ncurses.h, etc

Originally Posted by whiteflags

On the contrary, it does. If you can use conio.h you can just as easily use something else. windows.h, ncurses.h, etc

Windows.h, ncurses.h, etc., are not part of the C standard. Conio.h works on all versions of Windows, also works on DOS, if you happen to run across such relic hardware, and is easier to use (more concise).

Which would you rather keyboard?

conio.h:
gotoxy()

or

windows.h:
setConsoleCursorPosition()

I like standards, but I love being practical.

Not bad for a console window though.

It would be just as easy to do something like this:

Code:

$ ./program | display -

to display the PPM image output of the program. The best part is that it doesn't depend on a non-standard codepage or old, obsolete (not to mention non-standard) functions like _textcolor, so it can run on any system with the relatively ubiquitous ImageMagick package installed.

Originally Posted by christop

It would be just as easy to do something like this:

Code:

$ ./program | display -

to display the PPM image output of the program. The best part is that it doesn't depend on a non-standard codepage or old, obsolete (not to mention non-standard) functions like _textcolor, so it can run on any system with the relatively ubiquitous ImageMagick package installed.

That's OK for Linux if you have that package installed - but not for Windows. I've never heard of "ImageMagick", for Linux or Windows. My Linux PC's pretty much fold 24/7 for medical research anyway.

The conio.h functions are simple to use, and most compilers support conio.h anyway.

This is what I am trying to do in c with my program. The colors don't matter, I just need to get the math right.

Originally Posted by Adak

Not bad for a console window though.

This is what I am trying to do in c with my program. The colors don't matter, I just need to get the math right.