kplot – Cairo plotting library

#include <cairo.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <kplot.h>

int
main(void)
{
  struct kpair points1[50], points2[50];
  struct kdata *d1, *d2;
  struct kplot *p;
  cairo_surface_t *surf;
  size_t i;
  cairo_t *cr;

  for (i = 0; i < 50; i++) {
    points1[i].x = points2[i].x = (i + 1) / 50.0;
    points1[i].y = log((i + 1) / 50.0);
    points2[i].y = -log((i + 1) / 50.0) + points1[0].y;
  }
  d1 = kdata_array_alloc(points1, 50);
  d2 = kdata_array_alloc(points2, 50);
  p = kplot_alloc(NULL);
  kplot_attach_data(p, d1, KPLOT_POINTS, NULL);
  kplot_attach_data(p, d2, KPLOT_LINES, NULL);
  kdata_destroy(d1);
  kdata_destroy(d2);
  surf = cairo_image_surface_create
    (CAIRO_FORMAT_ARGB32, 600, 400);
  cr = cairo_create(surf);
  cairo_surface_destroy(surf);
  kplot_draw(p, 600.0, 400.0, cr);
  cairo_surface_write_to_png
    (cairo_get_target(cr), "example0.png");
  cairo_destroy(cr);
  kplot_free(p);
  return(EXIT_SUCCESS);
}