Proportional Resize
Resizes an Image while mantaining aspect ratio (not distorcing the image).
Because of Aspect Ration constrains, the final image might not have the specified size, but it will have the closest possible without distorcing the image.
Code:
$phMagick = new \phMagick\Core\Runner();
$resizeAction = new \phMagick\Action\Resize\Proportional($this->originalFile, $this->newFile);
$resizeAction->setWidth(100);
$phMagick->run($resizeAction);