Problems with Imagick not passing checks

[thartl]

We run a custom server & app with ImageMagick 3.7.
Because of our version, check_imagick() defaults to GD - line 980 in current Image Watermark, version 1.7.3.
This is a problem, because GD causes a color shift in the watermarked images.
So adjusting the version check would help us.

Aditionally, also in check_imagick(), some of the methods in our version of Imagick / Imagemagic come out camel-cased.
array_map('strtolower', get_class_methods('Imagick') resolves that.

Lastly, it looks like the watermark can "pollute" the color space and/or color profiles of the result.
This seems to help:

// copy color space from original image to watermark
$watermark->transformImageColorspace( $image->getColorspace() );

// remove existing color profiles from the watermark image
$watermark->stripImage();

// copy all color profiles from the original image to the watermark
$profiles = $image->getImageProfiles('*', false);
foreach ($profiles as $profile) {
$profileData = $image->getImageProfile($profile);
$watermark->profileImage($profile, $profileData);
}

I can do a pull request for all that if you are interested.

[jingcodeguy]

In addition to @thartl's description, I am also using 3.7.0 in local development and examing the IW, I found that the checking method get_class_methods() is not actually reliable. In actual instantiation of Imagick class, writeimage and getimage are actually exist. get_class_methods() does not reflect all kinds of methods.

To comprehensively do a deep test, use reflection instead:

$imagick_class = new ReflectionClass('Imagick');
$im_class_method_names = array_map(function($method) {
    return strtolower($method->getName());
}, $imagick_class->getMethods(ReflectionMethod::IS_PUBLIC));

if (!empty(array_diff([
    'clear', 'destroy', 'valid', 'getimage', 'writeimage', 'getimagegeometry', 'getimageformat', 'setimageformat', 'setimagecompression', 'setimagecompressionquality', 'scaleimage'
], $im_class_method_names)))
    return false;