Feature Request: Enable Animation

[aapatre]

Hi @sneas, hope you are doing well
Is it possible to add a feature to animate the divider? :)

As done in this slider: https://github.com/OnurErtugral/react-image-comparison-slider

Thanks & Regards,
Antariksh

[sneas]

Hi Antariksh,

There is no such functionality per-se, but you can build one yourself based on what the component already has. The code example would be:

const slider = document.getElementById('slider');

let direction = 'right';

let move = () => {
    slider.value = slider.value + 0.15 * (direction === 'right' ? 1  : -1);
    if (slider.value >= 100) {
       direction = 'left';
    }

    if (slider.value <= 0) {
        direction = 'right';
    }
}

let animationId;

let animate = () => {
  move();
  animationId = requestAnimationFrame(animate);
}

animationId = requestAnimationFrame(animate);

[aapatre]

Thanks a lot, @sneas
I will try this out :)

[Vantadaga]

Is it possible to make this work with this project?

[saas786]

I've implemented this code and think it could be helpful to others. Sharing it here in case someone finds it useful. Feedback welcome to improve my code.

function animateImageComparison() {
    const slider = document.getElementById('slider');

    if (!slider) {
        return;
    }

    const originalValue = slider.value;
    // Amount to move the handle.
    const shakeAmount = 5;
    const shakeDuration = 300;
    const resetDuration = 300;

    let animationFrameId = null;

    const animateValue = (startValue, endValue, duration, onComplete) => {
        const startTime = performance.now();

        const step = (currentTime) => {
            const elapsedTime = currentTime - startTime;
            const progress = Math.min(elapsedTime / duration, 1);
            slider.value = startValue + (endValue - startValue) * progress;

            if (progress < 1) {
                animationFrameId = requestAnimationFrame(step);
            }
            else {
                onComplete();
            }
        };

        animationFrameId = requestAnimationFrame(step);
    };

    const cancelAnimation = () => {
        if (animationFrameId) {
            cancelAnimationFrame(animationFrameId);
            animationFrameId = null;
        }
    };

    const shake = () => {
        const moveRight = () => {
            animateValue(originalValue, Math.min(originalValue + shakeAmount, 100), shakeDuration, moveLeft);
        };

        const moveLeft = () => {
            animateValue(Math.min(originalValue + shakeAmount, 100), Math.max(originalValue - shakeAmount, 0), shakeDuration, reset);
        };

        const reset = () => {
            animateValue(slider.value, originalValue, resetDuration, cancelAnimation);
        };

        moveRight();
    };

    const handleVisibilityChange = (entries, observer) => {
        entries.forEach((entry) => {
            if (entry.isIntersecting) {
                shake();
                // Stop observing after the element is in view.
                observer.disconnect();
            }
        });
    };

    const observer = new IntersectionObserver(handleVisibilityChange, {
        // Adjust the threshold as needed.
        threshold: 0.1,
    });

    observer.observe(slider);

    // Cancel ongoing animation if the page is unloaded or slider is out of view.
    window.addEventListener('beforeunload', cancelAnimation);

    document.addEventListener('visibilitychange', () => {
        if (document.hidden) {
            cancelAnimation();
        }
    });
}

window.addEventListener('load', animateImageComparison);

[sneas]

This is amazing, @saas786 ! Thanks a lot!