text.c

/*
 * IPv4 Heatmap
 * (C) 2007 The Measurement Factory, Inc
 * Licensed under the GPL, version 2
 * http://maps.measurement-factory.com/
 */

/*
 * Draws text on the image
 */

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <gd.h>
#include "include/bbox.h"

extern gdImagePtr image;
extern const char *font_file_or_name;
double _text_last_sz = 0.0;

/*
 * Calculate the width and height of some text draw at some size
 */
static int *text_width_height(const char *text, double sz, int *w, int *h) {
  static int brect[8];
  char *errmsg = gdImageStringFT(NULL, &brect[0], 0, (char *)font_file_or_name,
                                 sz, 0.0, 0, 0, (char *)text);
  if (NULL != errmsg)
    errx(1, "%s", errmsg);
  *w = brect[2] - brect[0];
  *h = brect[3] - brect[5];
  return &brect[0];
}

/*
 * Draws 'text' inside the bbox bounding box with color color. The text is
 * sized to be as large as possible and still fit within the box.
 *
 * If the optional 'text2' is given, then it is drawn below the first text,
 * always
 * in a 12-point size.  This is mainly to print the CIDR prefix values
 * underneath their owner names in each /8 box.
 */
void text_in_bbox(const char *text, bbox box, int color, double maxsize) {
  double sz;
  int tw, th;
  int oneline_h;
  int *brectPtr;
  char *text_copy = calloc(1, strlen(text) + 1);
  const char *s;
  char *d;
  /*
   * convert newlines
   */
  for (s = text, d = text_copy; *s; s++, d++) {
    if (*s == '\\' && *(s + 1) == 'n')
      s++, *d = '\n';
    else
      *d = *s;
  }
  if (maxsize < 1.0)
    maxsize = 128.0;
  for (sz = maxsize; sz > 6.0; sz *= 0.9) {
    (void)text_width_height("ABCD", sz, &tw, &oneline_h);
    brectPtr = text_width_height(text_copy, sz, &tw, &th);
    if (tw > ((box.xmax - box.xmin) * 95 / 100))
      continue;
    if (th > ((box.ymax - box.ymin) * 95 / 100))
      continue;
    gdImageStringFT(image, brectPtr, color, (char *)font_file_or_name, sz, 0.0,
                    ((box.xmin + box.xmax) / 2) - (tw / 2),
                    ((box.ymin + box.ymax) / 2) - (th / 2) + oneline_h,
                    text_copy);
    _text_last_sz = sz;
    break;
  }
}