Thread: Drawing an image in C

I have drawn a Diamond/rhombus in C, but I don't now how i can fill the shape in, any ideas?

Code:

    #include <stdio.h>
    #include <gd.h>
     
    int main()
    {
      /* Declare and initialise variables for a new image.
         These steps are done once before using drawing functions. */
      gdImagePtr gdImage = gdImageCreate( 300, 300 );
      FILE *jpgFile = NULL;
      int red;
     
      /* The first call to gdImageColorAllocate() always sets the image background.
         This step can only be done once before using drawing functions. */
      gdImageColorAllocate( gdImage, 250, 250, 250 );
     
      /* Subsequent calls to gdImageColorAllocate() creates new colors for drawing.
         It is similar using a paint brush with a specific color. The brush can be
         used over and over. This is only needed each time a new color is required. */
      red = gdImageColorAllocate( gdImage, 255, 0, 0 );
     
      /* Most of the work is done by using drawing functions.
         These functions set the line width to 4 and draws a diagonal line. */
      gdImageSetThickness( gdImage, 2 );
      gdImageLine( gdImage, 150, 0, 0, 150, red );
      gdImageSetThickness( gdImage, 2 );
      gdImageLine( gdImage, 150, 0, 300, 150, red );
      gdImageSetThickness( gdImage, 2 );
      gdImageLine( gdImage, 150, 300, 0, 150, red );
      gdImageSetThickness( gdImage, 2 );
      gdImageLine( gdImage, 300, 150, 150, 300, red );
     
     
      /* These steps save the image in memory out to a physical file on the server.
         These steps are done once when the drawing is done. */
      jpgFile = fopen( "test.jpg", "wb" );
      gdImageJpeg( gdImage, jpgFile, -1 );
     
      /* These steps clear all memory and files used with the image.
         These steps are done once when the image is no longer used. */
      fclose( jpgFile );
      gdImageDestroy( gdImage );
    }

It looks like you're using this library. Perhaps one of the functions listed on that page might fill the bill?

google 'how to flood fill'. there are several algorithms for doing that.
Flood Fill