To get any root of a number your can use the pow() function:
pow(8, 1/3)
which gives you the third root of eight.
Jouhni
(PHP 4, PHP 5, PHP 7)
sqrt — Square root
$arg
)
Returns the square root of arg.
argThe argument to process
The square root of arg
or the special value NAN for negative numbers.
Example #1 sqrt() example
<?php
// Precision depends on your precision directive
echo sqrt(9); // 3
echo sqrt(10); // 3.16227766 ...
?>
To get any root of a number your can use the pow() function:
pow(8, 1/3)
which gives you the third root of eight.
Jouhni
As we all know, the square of the hypotenuse is equal to the sum of the squares of the other two sides of a right triangle (a2 + b2 = c2).
With that in mind I created a quick way to reduce images to a maximum area without messing up width/height constraints.
<?php
list($width_orig, $height_orig) = getimagesize($img);
$max_a = 500000; // maximum area in pixels
$width = $width_orig;
$height = $height_orig;
$area = $width * $height;
if ($area > $max_a) {
$mult = sqrt($max_a) / sqrt($height * $width);
$width *= $mult;
$height *= $mult;
}
?>