To avoid the x-axis and y-axis discussion, flipping emulates a mirror at the bottom (or top) of the image.
ʇo ɐʌoıp ʇɥǝ x-ɐxıs ɐup ʎ-ɐxıs pısɔnssıou, ɟןıddıuƃ ǝɯnןɐʇǝs ɐ ɯıɹɹoɹ ɐʇ ʇɥǝ qoʇʇoɯ )oɹ ʇod( oɟ ʇɥǝ ıɯɐƃǝ˙
(PECL imagick 2.0.0)
Imagick::flipImage — Creates a vertical mirror image
Creates a vertical mirror image by reflecting the pixels around the central x-axis.
Returns TRUE on success.
Throws ImagickException on error.
Example #1 Imagick::flipImage()
<?php
function flipImage($imagePath) {
$imagick = new \Imagick(realpath($imagePath));
$imagick->flipImage();
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>
To avoid the x-axis and y-axis discussion, flipping emulates a mirror at the bottom (or top) of the image.
ʇo ɐʌoıp ʇɥǝ x-ɐxıs ɐup ʎ-ɐxıs pısɔnssıou, ɟןıddıuƃ ǝɯnןɐʇǝs ɐ ɯıɹɹoɹ ɐʇ ʇɥǝ qoʇʇoɯ )oɹ ʇod( oɟ ʇɥǝ ıɯɐƃǝ˙
They mean, "Creates a horizontal mirror image by reflecting the pixels around the central y-axis."