CODEWITHSUNDEEP
phpimagemagickimagick
Dennis Haarbrink
Dennis Haarbrink

Reputation: 3760

How to use Imagick to merge and mask images?

I know very little of image processing and even less of the terminology used, so please bear with me.

Basically, I want to merge two images together where one of them will act as a mask. That image looks something like this:
Example
Where the blue and yellow background are both transparent in reality.

This image is being used as a mask for regular photo's. Parts of the photo that 'stick out' of the circle need to be 'cropped' (be made invisible) while the inside remains visible.
So everything that comes in the blue area is invisible, everything in the yellow area is visible.

I honestly have no clue how to go about it so any help would be greatly appreciated!

Edit:
I use the API version of Imagick, not the commandline version

Edit:
To get a feel of what I want to achieve, here is an example.

The input images are thus:
enter image description here
This is the mask image, always the same

enter image description here
This is an example of a picture, dynamic

enter image description here
This is what the end result should look like

Upvotes: 27

Views: 30570

Answers (4)

anthony
anthony

Reputation: 7875

This type of masking is exampled using a number of different techniques in ImageMagick Examples, Thumbnails, Mask and Paint http://www.imagemagick.org/Usage/thumbnails/#mask_paint

Be warned however that the masking and the edges of the overlay image SHOULD NOT MATCH this is important or you may get problems with edge aliasing effects that is best avoided.

Extracting an alpha mask of the ring, can be done using morphology operators to thin it down to a centerline can be used to generate a mask for any random 'ring' shape. ImageMagick Examples, Skeletons by Thinning, and Pruning http://www.imagemagick.org/Usage/morphology/#thinning_skeleton

Anthony Thyssen Web Master for ImageMagick Examples, and Developer for ImageMagick

PS: nice photo from Elfling

Upvotes: 0

user703016
user703016

Reputation: 37995

So, finally, this should do what you need:

Original image:

https://i.sstatic.net/b7seR.png

Opacity mask:

enter image description here

Overlay:

https://i.sstatic.net/3ulkM.png

Output:

enter image description here

The code:

<?php
$base = new Imagick('U0R4F.png');
$mask = new Imagick('mask.png');
$over = new Imagick('3ulkM.png');

// Setting same size for all images
$base->resizeImage(274, 275, Imagick::FILTER_LANCZOS, 1);

// Copy opacity mask
$base->compositeImage($mask, Imagick::COMPOSITE_DSTIN, 0, 0, Imagick::CHANNEL_ALPHA);

// Add overlay
$base->compositeImage($over, Imagick::COMPOSITE_DEFAULT, 0, 0);

$base->writeImage('output.png');
header("Content-Type: image/png");

echo $base;
?>

I hope it's right now! Note: In your example it looks like you downscaled the base image, which I didn't (my goal is just to show how the masking is done).

Upvotes: 71

Justin T.
Justin T.

Reputation: 3701

Did you try this solution here as described by : https://stackoverflow.com/a/2351173/1093649 ?

Run this in your server (with the right image names!), and let us know, thanks.

nb : credits go to jspash

Upvotes: 1

Viruzzo
Viruzzo

Reputation: 3025

http://www.imagemagick.org/Usage/compose/#dstin should do the trick, but you need to use images with alpha channels (that shouldn't be a problem).

Edit: in PHP you have to pass it (imagick::COMPOSITE_DSTIN) as a parameter in compositeimage. Other filters in Composite Operator Constants may also be useful to you.

Upvotes: 0

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