--- /dev/null
+<?php
+
+/**
+ * PEL: PHP Exif Library.
+ * A library with support for reading and
+ * writing all Exif headers in JPEG and TIFF images using PHP.
+ *
+ * Copyright (C) 2004, 2005, 2006 Martin Geisler.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program in the file COPYING; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301 USA
+ */
+namespace lsolesen\pel;
+
+/**
+ * Classes used to manipulate rational numbers.
+ *
+ * @author Martin Geisler <mgeisler@users.sourceforge.net>
+ * @license http://www.gnu.org/licenses/gpl.html GNU General Public
+ * License (GPL)
+ * @package PEL
+ */
+
+/**
+ * Class for holding signed rational numbers.
+ *
+ * This class can hold rational numbers, consisting of a numerator and
+ * denominator both of which are of type unsigned long. Each rational
+ * is represented by an array with just two entries: the numerator and
+ * the denominator, in that order.
+ *
+ * The class can hold either just a single rational or an array of
+ * rationals. The class will be used to manipulate any of the Exif
+ * tags which can have format {@link PelFormat::SRATIONAL}.
+ *
+ * @author Martin Geisler <mgeisler@users.sourceforge.net>
+ * @package PEL
+ */
+class PelEntrySRational extends PelEntrySLong
+{
+
+ /**
+ * Make a new entry that can hold a signed rational.
+ *
+ * @param
+ * PelTag the tag which this entry represents. This should
+ * be one of the constants defined in {@link PelTag}, e.g., {@link
+ * PelTag::SHUTTER_SPEED_VALUE}, or any other tag which can have
+ * format {@link PelFormat::SRATIONAL}.
+ *
+ * @param array $value...
+ * the rational(s) that this entry will
+ * represent. The arguments passed must obey the same rules as the
+ * argument to {@link setValue}, namely that each argument should be
+ * an array with two entries, both of which must be within range of
+ * a signed long (32 bit), that is between -2147483648 and
+ * 2147483647 (inclusive). If not, then a {@link
+ * PelOverflowException} will be thrown.
+ */
+ public function __construct($tag, $value = null)
+ {
+ $this->tag = $tag;
+ $this->format = PelFormat::SRATIONAL;
+ $this->dimension = 2;
+ $this->min = - 2147483648;
+ $this->max = 2147483647;
+
+ $value = func_get_args();
+ array_shift($value);
+ $this->setValueArray($value);
+ }
+
+ /**
+ * Format a rational number.
+ *
+ * The rational will be returned as a string with a slash '/'
+ * between the numerator and denominator. Care is taken to display
+ * '-1/2' instead of the ugly but mathematically equivalent '1/-2'.
+ *
+ * @param
+ * array the rational which will be formatted.
+ *
+ * @param
+ * boolean not used.
+ *
+ * @return string the rational formatted as a string suitable for
+ * display.
+ */
+ public function formatNumber($number, $brief = false)
+ {
+ if ($number[1] < 0) {
+ /* Turn output like 1/-2 into -1/2. */
+ return (- $number[0]) . '/' . (- $number[1]);
+ } else {
+ return $number[0] . '/' . $number[1];
+ }
+ }
+
+ /**
+ * Get the value of an entry as text.
+ *
+ * The value will be returned in a format suitable for presentation,
+ * e.g., rationals will be returned as 'x/y', ASCII strings will be
+ * returned as themselves etc.
+ *
+ * @param
+ * boolean some values can be returned in a long or more
+ * brief form, and this parameter controls that.
+ *
+ * @return string the value as text.
+ */
+ public function getText($brief = false)
+ {
+ if (isset($this->value[0])) {
+ $v = $this->value[0];
+ }
+
+ switch ($this->tag) {
+ case PelTag::SHUTTER_SPEED_VALUE:
+ // CC (e->components, 1, v);
+ // if (!v_srat.denominator) return (NULL);
+ return Pel::fmt('%.0f/%.0f sec. (APEX: %d)', $v[0], $v[1], pow(sqrt(2), $v[0] / $v[1]));
+
+ case PelTag::BRIGHTNESS_VALUE:
+ // CC (e->components, 1, v);
+ //
+ // TODO: figure out the APEX thing, or remove this so that it is
+ // handled by the default clause at the bottom.
+ return sprintf('%d/%d', $v[0], $v[1]);
+ // FIXME: How do I calculate the APEX value?
+
+ case PelTag::EXPOSURE_BIAS_VALUE:
+ // CC (e->components, 1, v);
+ // if (!v_srat.denominator) return (NULL);
+ return sprintf('%s%.01f', $v[0] * $v[1] > 0 ? '+' : '', $v[0] / $v[1]);
+
+ default:
+ return parent::getText($brief);
+ }
+ }
+}