Making a diamond with specific widht and height in c (gnuplot) - c

Question

So I am trying to make a program that outputs the coordinates of a diamond of n width and n height and then represent the figure.out that is done with the program with gnuplot. I have this code done already but I want to make it easier.
#include <stdio.h>
#include <stdlib.h>
#define DEF 10
int main()
{
float def_an,def_al,slope,i,j,height,width;
FILE *out = fopen ( "diamond.out", "w" );
if(out==NULL)
{
printf("Wrong output");
return 1;
}
printf("Introduce the height: ");
scanf("%f", &height);
printf("Introduce the width: ");
scanf("%f", &width);
def_al=(height/DEF);
def_an=(width/DEF);
slope=(height/width);
for(j=0;j<= height/2;j+=def_al)
{
for(i=((j-(height/2))/slope);i<=(((height/2)-j)/slope);i+=def_an)
{
printf("%.2f %.2f\n",i,j);
fprintf (out, "%.2f %.2f\n", i,j );
}
}
for(j=(0-def_al);j>= -height/2;j-=def_al)
{
for(i=(((-height/2)-j)/slope);i<=((j-(-height/2))/slope);i+=def_an)
{
printf("%.2f %.2f\n",i,j);
fprintf (out, "%.2f %.2f\n", i,j );
}
}
fclose(out);
return 0;
}

Answer 1

Plotting a bunch of customized diamonds is not as straightforward as you might think.
Of course, you can use the suggestions Eldrad mentioned in the comments, but the plotting style with polygons is for splot and "3D"-plotting (which probably could also be used for 2D as well).
So, instead of plotting data you could draw objects (check help polygon) in a for loop from data in a datablock.
The example below is just gnuplot code. You have to create this text with C or any other language and send it to gnuplot.
Code:
### plotting diamonds in custom size
reset session
# x, y, width, height
$Diamonds <<EOD
0 0 3 5
5 0 2 1
4 4 3 2
-7 5 4 4
-6 -6 3 5
6 -6 7 2
EOD
x(n) = word($Diamonds[n],1)
y(n) = word($Diamonds[n],2)
w(n) = word($Diamonds[n],3)
h(n) = word($Diamonds[n],4)
set size square
set xrange [-10:10]
set yrange [-10:10]
do for [i=1:|$Diamonds|] {
set object i polygon from x(i),y(i)+h(i)/2. to x(i)+w(i)/2.,y(i) to x(i),y(i)-h(i)/2. to x(i)-w(i)/2.,y(i) to x(i),y(i)+h(i)/2.
set object i fc lt i fillstyle solid 1.0 border
}
plot NaN notitle # empty dummy plot or plot something else
### end of code
Result: