Angle Alchemy

Radiance provides simple, lightweight classes to make it easy for your PHP applications to deal with 360° circle-based angles, such as converting between various formats, adding and subtracting, normalizing, and finding distances and midpoints.

Installation

NOTE: Radiance requires PHP ^8.1 and the BCMath extension.

composer require theriftlab/radiance

Usage

Examples

Radiance offers three main classes: Angle, Latitude and Longitude. Being fairly simple classes, their underlying structure is much the same, with only a few differences.

use RiftLab\Radiance\Angle;

$angle = Angle::make(-51.477928);

echo $angle;
// Output: -51°28'41"

$angle2 = Angle::make('10°');

echo $angle->distanceTo($angle2);
// Output: 61°28'41"
echo $angle->distanceFrom($angle2);
// Output: -61°28'41"
echo $angle2->distanceTo($angle);
// Output: -61°28'41"
echo $angle->distanceTo(10);
// Output: 61°28'41"

echo $angle->add($angle2);
// Output: -41°28'41"
echo $angle->add(10);
// Output: -41°28'41"
echo $angle->sub($angle2);
// Output: -61°28'41"
echo $angle->sub(10);
// Output: -61°28'41"
echo $angle->add($angle2)->distanceTo($angle);
// Output: -10°00'00"

echo Angle::make(350)->midpointWith(20);
// Output: 05°00'00

Instantiation

Objects can be constructed from almost any format. A few more examples using Angle:

// These will all produce identical objects:
$angle1 = Angle::make(-51.477928);
$angle2 = Angle::make('-51°28\'40.5408"');
$angle3 = Angle::make('51°28\'40.5408"W');
$angle4 = Angle::make('51w28\'40.5408');
$angle5 = Angle::make('51s28.67568');

var_dump($angle1 == $angle2);
// Output: bool(true)
var_dump($angle2 == $angle3);
// Output: bool(true)
// ..etc.

Coordinate Classes

In addition to the basic Angle class, there are also Latitude and Longitude classes. These behave the same as the Angle class, only they are limited to their geographical boundaries: -90° to 90° for Latitude and -180° to 180° for Longitude. Attempting to instantiate with angles outside these limits, or to add() / sub() values that would push them outside of these limits, will throw an exception.

Although the output for all types can be customized (see the String Formatting section below), the only other difference with the coordinate classes is their default string format:

$lat = Latitude::make(-51.477928);
echo $lat;
// Output: 51s28.68

echo $lat->add(60);
// Output: 8n31.32

echo $lat->midpointWith(10);
// Output: 20s44.34

echo $lat->sub(40);
// Below -90°: LatitudeBoundaryError thrown

$dist = Angle::make(40);
echo $lat->sub($dist);
// LatitudeBoundaryError still thrown

Negative Angles

Radiance is fairly non-opinionated about the angles you wish to represent with an Angle instance. You can construct one from a negative angle, although it will be normalized:

echo Angle::make(-560);
// Output: -200°0'0"

However, since the distanceTo() / distanceFrom() and midpointWith() calculations are designed to find the shortest distance between two points on a 0-360° circle, using negative angles might yield results that appear less than intuitive at first glance:

$angle = Angle::make(-200);     // 160° on a circle

echo $angle;
// Output: -200°0'0"
echo $angle->distanceTo(140);   // 160° to 140°
// Output: -20°0'0"
echo $angle->distanceTo(180);   // 160° to 180°
// Output: 20°0'0"

If we get really weird and mix our negatives, they still stack up:

$angle = Angle::make(-560);     // still 160°

echo $angle;
// Output: -200°0'0"
echo $angle->distanceTo(-220);  // 140° on a circle, so still 160° to 140°
// Output: -20°0'0"
echo $angle->distanceTo(-180);  // 180° on a circle, so still 160° to 180°
// Output: 20°0'0"

Diffs

Although not designed for direct instantiation, an instance of the Diff class is returned for all distanceTo() and distanceFrom() operations. This is essentially the same as the Angle class but limited to output functionality only, without any further operations available. Its default formatting will reflect whatever class it is calculated from:

echo Angle::make(10)->distanceTo(30);
// Output: 20°00'00"

echo Latitude::make(10)->distanceTo(30);
// Output: 20n0.00

echo Longitude::make(10)->distanceTo(30);
// Output: 20e0.00

See the String Formatting section below for details on how to customize the output.

Functions

The following functions are available for all class types, including Diff:

Method	Return Type	Parameters	Default	Description
isNegative()	bool	None	None	Returns whether the angle is negative.
getDegrees()	float	int $decimalPlaces	null	Returns the unsigned degrees portion of the angle. If $decimalPlaces is set to -1 it will be floor()ed, and passing 0 and upward will round it as normal. The default null will round to 8 decimal places.
getMinutes()	float	int $decimalPlaces	null	The same as above but for minutes.
getSeconds()	float	int $decimalPlaces	null	The same as above but for seconds.
toDecimal()	float	int $decimalPlaces	null	The same as above but returns the underlying float angle. Essentially the same as getDegrees() but signed. Since PHP's float type is limited to 14 significant digits, if you require more precision then use the toRawDecimal() function described below.
toRawDecimal()	string	None	None	Returns the angle's underlying BCMath string.
toArray()	array	None	None	Returns an array with the following elements: * direction: either - or +. * degrees: floored int representing degrees. * minutes: floored int representing minutes. * seconds: a float representing seconds, rounded to 8 decimal places.
toString()	string	string $format	Dependent on type	Formats the angle as requested. See the String Formatting section below for details. Calling this with no arguments will yield the default format depending on the calling instance's class type, as demonstrated in the examples above.

The following additional operations are available for the Angle, Latitude and Longitude classes which implement AngleInterface:

Method	Return Type	Parameters	Default	Description
add()	self	AngleInterface | float $angle	None	Adds either another AngleInterface instance or a float, and returns a new instance of the calling class' type constructed from the result.
sub()	self	AngleInterface | float $angle	None	The same as above but for subtraction.
distanceTo()	Diff	AngleInterface | float $angle	None	Calculates the shortest distance on a circle between the calling instance and the passed AngleInterface instance or float, and returns a new instance of the calling class' type constructed from the result. As seen in the examples above, the result will be negative if the passed angle is behind the first, and positive if ahead.
distanceFrom()	Diff	AngleInterface | float $angle	None	The inverse of the above function.
midpointWith()	self	AngleInterface | float $angle	None	Calculates the midpoint of the shortest distance on a circle between the calling instance and the passed AngleInterface instance or float, and returns a new instance of the calling class' type constructed from the result.

The Angle class itself has one additional function:

Method	Return Type	Parameters	Default	Description
normalizeTo()	Angle	int $size	None	Normalizes the angle to the passed integer and returns a new Angle instance constructed from the result. For example, if a circle is split into quadrants and you only wish to know the angle within its own quadrant, you would pass 90 to this function.

String Formatting

The toString() function accepts a string of placeholders to dictate its formatting. The default format strings for each class type are as follows:

Class	Format String	Output
Angle	'{D}{dd.-1}°{mm.-1}\'{ss.0}"'	Degrees, minutes, and seconds with leading zeroes. Seconds are rounded, and the output is prefixed by a - sign if negative.
Latitude	'{d.-1}{D}{m.2f}'	Geographical latitude. Degrees, North / South direction, and a decimal minute rounded to two places.
Longitude	'{d.-1}{D}{m.2f}'	Geographical longitude. Similar to above: degrees, West / East direction, and a decimal minute rounded to two places.

To pass your own format, the following placeholders are available for all class types:

Placeholder	Output
{S}	Sign: a - symbol if the angle is negative, otherwise nothing.
{SS}	Sign: a - symbol if the angle is negative, otherwise +.
{d.X}	Degrees, rounded to X places, with X being analogous to the $decimalPlaces parameter described above in the functions table. To force X amount of decimal places regardless of trailing zeros, append f - eg. for 23.5° {d.2} will output 23.5 vs {d.2f} which will output 23.50. To pass null simply omit the decimal point, ie. {d}.
{m.X}	The same as above, but for minutes.
{s.X}	The same as above, but for seconds.
{dd.X}	Degrees as above, but with leading zero to ensure double digits.
{mm.X}	The same as above, but for minutes.
{ss.X}	The same as above, but for seconds.

For the Latitude class only, the following additional placeholders are available:

Placeholder	Output
{D}	Direction: a lowercase s if the angle is negative, otherwise lowercase n.
{DD}	Direction: the same as above but uppercase.

For the Longitude class only, the following additional placeholders are available:

Placeholder	Output
{D}	Direction: a lowercase w if the angle is negative, otherwise lowercase e.
{DD}	Direction: the same as above but uppercase.

Tests

Tests are included via Pest:

./vendor/bin/pest