Resize animated GIF file without destroying animation

I've been going through the Imagick documentation for a while, and tried a couple of things... But I didn't manage to do what you want either -- so, we are at least two who can't find out a clean way ^^

Anyway, the only way I managed to remove a frame for an animated GIF image was by creating a new one, containing only the frames I didn't want to remove :-(

Considering I loaded an image this way :

// Load the existing image
$image = new Imagick(dirname(__FILE__) . '/animated-gif-source.gif');

(This is an animated gif, with 3 frames ; I want to "remove" the second one).

As I said, only way I found to "remove a frame" is this one :

$new_image = new Imagick();

$i = 1;
foreach ($image as $frame) {
    if ($i===1 || $i===3) {
        // 3 frames ; we keep the first and third one
        // ie, remove the second one
        $new_image->addImage($frame->getImage());
    }
    $i++;
}

So :

• create a new image
• iterate over the frames of the orignal one
• if the current frame is one I want to keep, copy it to the new image

And, in the end, to output the image to the browser :

// To directly output to the browser
header('Content-Type: image/gif');
echo $new_image->getImagesBlob();

Or, to write it to a file :

// To write the new image to a file
// Must use writeImages, and not writeImage (multi-frames ! )
$new_image->writeImages(dirname(__FILE__) . '/animated-gif-output.gif', true);

Each one of these outputs only contain the first and third frames ; so, it's working...
But, as you said, it doesn't feel good :-(

It will probably work just fine for most images, I think ; you might encouter troubles with big images, but animated GIFs are generally not that big... are they ?

Other way might be using convert from the command line... But... not that great, and I didn't find a way to just remove a frame with those either :-(

The best examples are located in the unit-tests shipped with the code. wand/tests/sequence_test.py for example.

For creating an animated gif with wand, remember to load the image into the sequence, and then set the additional delay/optimize handling after all frames are loaded.

from wand.image import Image

with Image() as wand:
    # Add new frames into sequance
    with Image(filename='1.png') as one:
        wand.sequence.append(one)
    with Image(filename='2.png') as two:
        wand.sequence.append(two)
    with Image(filename='3.png') as three:
        wand.sequence.append(three)
    # Create progressive delay for each frame
    for cursor in range(3):
        with wand.sequence[cursor] as frame:
            frame.delay = 10 * (cursor + 1)
    # Set layer type
    wand.type = 'optimize'
    wand.save(filename='animated.gif')