Imagick::getImageOrientation

(PECL imagick 2.0.0)

Imagick::getImageOrientation — Gets the image orientation

说明

int Imagick::getImageOrientation ( void )

Gets the image orientation. The return value is one of the orientation constants.

返回值

Returns an int on success.

错误／异常

错误时抛出 ImagickException。

User Contributed Notes

orrd101 at yahoo dot com 21-Feb-2013 06:23


Here's how you can use the getImageOrientation() information to auto-rotate images to their correct orientation...





<?php


// Note: $image is an Imagick object, not a filename! See example use below.


function autoRotateImage($image) {


    $orientation = $image->getImageOrientation();





    switch($orientation) {


        case imagick::ORIENTATION_BOTTOMRIGHT: 


            $image->rotateimage("#000", 180); // rotate 180 degrees


        break;





        case imagick::ORIENTATION_RIGHTTOP:


            $image->rotateimage("#000", 90); // rotate 90 degrees CW


        break;





        case imagick::ORIENTATION_LEFTBOTTOM: 


            $image->rotateimage("#000", -90); // rotate 90 degrees CCW


        break;


    }





    // Now that it's auto-rotated, make sure the EXIF data is correct in case the EXIF gets saved with the image!


    $image->setImageOrientation(imagick::ORIENTATION_TOPLEFT);


}


?>





Example use:





<?php


$image = new Imagick('my-image-file.jpg');


autoRotateImage($image);


// - Do other stuff to the image here -


$image->writeImage('result-image.jpg');


?>

holdoffhunger at gmail dot com 01-Jul-2012 11:54


Using the getImageOrientation function, you'll get the Orientation value for an image as defined within the EXIF file format.  That means you will get back an integer representation one of the Orientation constants for ImageMagick, which looks like " imagick::ORIENTATION_UNDEFINED", with "_VALUE" values of: undefined (0), topleft (1), topright (2), bottomright (3), bottomleft (4), lefttop (5), righttop (6), rightbottom (7), and leftbottom (8).  When printed out directly, these predefined constants produce the number in parenthesis.  The undefined being set to 0 makes sense, since -- according to Wikipedia -- EXIF allows for eight possible values for an image (and not every image has a set of EXIF properties).



The EXIF Orientation is also called "the Rotation," again, according to Wikipedia: http://en.wikipedia.org/wiki/Exchangeable_image_file_format .  What's the point of that?  According to the official ImageMagick documentation, it's to rotate a photograph so that it is properly oriented after the shot.  This really seems to be a camera thing, since the ImageMagick documentation mentions: "If you pointed your camera almost straight up or down, the EXIF orientation setting may not resolve correctly. The same goes for angled or slanted shots. The orientation (and cameras) just have no senses for these situations." ( http://www.imagemagick.org/Usage/photos/ )



If you're having trouble getting this function to show the value for Image Orientation, then use the function and parameters of getImageProperties('*', FALSE); .  This produces an array of all properties associated with an image, and one of them will have the key value of exif:Orientation.  If it doesn't, then that means you will be getting back a zero from this function, indicating an "Undefined" orientation.



Some sample code :



<?php



            // Author: holdoffhunger@gmail.com

    

        // Imagick Type

        // ---------------------------------------------



    $imagick_type = new Imagick();

    

        // Open File

        // ---------------------------------------------

        

    $file_to_grab = "image_workshop_directory/test.jpg";

    

    $file_handle_for_viewing_image_file = fopen($file_to_grab, 'a+');

    

        // Grab File

        // ---------------------------------------------



    $imagick_type->readImageFile($file_handle_for_viewing_image_file);

    

        // Get Orientation Values

        // ---------------------------------------------



    $imagick_orientation = $imagick_type->getImageOrientation();

    

    switch($imagick_orientation)

    {

        case '0':

            $imagick_orientation_evaluated = "Undefined";

            break;

        

        case '1':

            $imagick_orientation_evaluated = "Top-Left";

            break;

        

        case '2':

            $imagick_orientation_evaluated = "Top-Right";

            break;

        

        case '3':

            $imagick_orientation_evaluated = "Bottom-Right";

            break;

        

        case '4':

            $imagick_orientation_evaluated = "Bottom-Left";

            break;

        

        case '5':

            $imagick_orientation_evaluated = "Left-Top";

            break;

        

        case '6':

            $imagick_orientation_evaluated = "Right-Top";

            break;

        

        case '7':

            $imagick_orientation_evaluated = "Right-Bottom";

            break;

        

        case '8':

            $imagick_orientation_evaluated = "Left-Bottom";

            break;

    }

    

        // Print Orientation Values

        // ---------------------------------------------

    

    print("# $imagick_orientation - $imagick_orientation_evaluated");



?>