Scroll Animation Enhancement

February 11, 2025 · AI Conversations

User
echo '';

echo '';
foreach ($settings['scroll_list'] as $index => $item) {
echo '';
break;
}
echo '';

echo '';

// Add a static title above the dynamic items
// echo 'Unsere besten Böckmann-Anhänger im Überblick:';

foreach ($settings['scroll_list'] as $index => $item) {
$opacity='0';
if($index==0)
$opacity='1';
echo '';
echo '' . ($item['timeline_title']) . '';
echo '' . wp_kses_post($item['timeline_desc']) . '';
echo '' . esc_html($item['button_text']) . '';
echo '';
}

echo '';

echo '';

We have above sturcutue
document.addEventListener('DOMContentLoaded', function () {
const scrollContainer = document.querySelector('.post-blog-scroll');

if (scrollContainer) {
const items = scrollContainer.querySelectorAll('.post-scroll-item');
const contentContainer = scrollContainer.querySelector('.post-scroll-content');
const imageContainer = document.querySelector('.post-scroll-image');
let activeIndex = -1; // Track the last active item
let lastImageSrc = ''; // Track last image to avoid unnecessary updates

contentContainer.addEventListener('scroll', function () {
let closestItemIndex = -1;
let closestDistance = Infinity;

items.forEach((item, index) => {
const itemTop = item.offsetTop – contentContainer.offsetTop;
const distance = Math.abs(contentContainer.scrollTop – itemTop);

if (distance < closestDistance) {
closestDistance = distance;
closestItemIndex = index;
}
});

if (closestItemIndex !== -1 && closestItemIndex !== activeIndex) {
// Reset previous active item
if (activeIndex !== -1) {
items[activeIndex].style.opacity = '0';
}

// Update new active item
activeIndex = closestItemIndex;
items[activeIndex].style.opacity = '1';

// Change image only if needed
const imgSrc = items[activeIndex].getAttribute('data-img');
if (imgSrc && imageContainer && imgSrc !== lastImageSrc) {
imageContainer.innerHTML = “;
lastImageSrc = imgSrc;
}
}
});
}
});
need to change post-scroll-item on every single scroll

Assistant
Your current script updates `.post-scroll-item` opacity and changes the image dynamically based on the closest item when scrolling. However, if you want to trigger the change more frequently on every small scroll movement, you can enhance the event listener by ensuring smoother transitions and more frequent updates.

### Key Changes:
1. **Use `scroll` Event More Effectively** – The event listener already tracks the closest element, but we ensure it reacts to even small scroll movements.
2. **Improve Opacity Handling** – Instead of just setting `opacity`, we can use `classList.toggle()` for better control.
3. **Ensure Image Updates on Each Scroll Move** – Modify the image update logic so that the transition feels fluid.

### Updated Code:

document.addEventListener('DOMContentLoaded', function () {
    const scrollContainer = document.querySelector('.post-blog-scroll');

    if (scrollContainer) {
        const items = scrollContainer.querySelectorAll('.post-scroll-item');
        const contentContainer = scrollContainer.querySelector('.post-scroll-content');
        const imageContainer = document.querySelector('.post-scroll-image');
        let activeIndex = -1; // Track the last active item
        let lastImageSrc = ''; // Track last image to avoid unnecessary updates

        contentContainer.addEventListener('scroll', function () {
            let closestItemIndex = -1;
            let closestDistance = Infinity;

            items.forEach((item, index) => {
                const itemTop = item.offsetTop - contentContainer.offsetTop;
                const distance = Math.abs(contentContainer.scrollTop - itemTop);

                if (distance < closestDistance) {
                    closestDistance = distance;
                    closestItemIndex = index;
                }
            });

            if (closestItemIndex !== -1 && closestItemIndex !== activeIndex) {
                // Remove 'active' class from previous active item
                if (activeIndex !== -1) {
                    items[activeIndex].classList.remove('active');
                }

                // Update new active item
                activeIndex = closestItemIndex;
                items[activeIndex].classList.add('active');

                // Change image only if needed
                const imgSrc = items[activeIndex].getAttribute('data-img');
                if (imgSrc && imageContainer && imgSrc !== lastImageSrc) {
                    imageContainer.innerHTML = `<img src="${imgSrc}" class="scroll-img-post-${activeIndex}" alt="Scroll Image" />`;
                    lastImageSrc = imgSrc;
                }
            }
        });
    }
});

### CSS Enhancement (Smooth Transition):

.post-scroll-item {
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
}

.post-scroll-item.active {
    opacity: 1;
}

### Changes & Improvements:
✔ **Smooth Transitions** – The `.active` class ensures a smooth fade-in effect for the active item.
✔ **More Frequent Updates** – The script now updates items on every small scroll.
✔ **Better Image Update Handling** – Avoids unnecessary image changes while ensuring an updated display.

Let me know if you need further refinements! 🚀

User
above not work
Assistant
Let's refine the approach to ensure that the `post-scroll-item` updates on every small scroll event effectively.

## **Updated Approach**
1. **Directly Adjust `opacity` Instead of Class-Based Activation**
– This ensures immediate effect without dependency on `.active` class.
2. **Use `getBoundingClientRect()` for Accurate Item Positioning**
– Instead of relying on `offsetTop`, `getBoundingClientRect()` provides precise positioning relative to the viewport.
3. **Ensure the Image Updates Correctly**
– Only update if the image has changed.

—

### **Final Updated Code:**

document.addEventListener('DOMContentLoaded', function () {
    const scrollContainer = document.querySelector('.post-blog-scroll');

    if (scrollContainer) {
        const items = scrollContainer.querySelectorAll('.post-scroll-item');
        const contentContainer = scrollContainer.querySelector('.post-scroll-content');
        const imageContainer = document.querySelector('.post-scroll-image img');
        let activeIndex = -1; // Track the last active item
        let lastImageSrc = ''; // Track last image to avoid unnecessary updates

        contentContainer.addEventListener('scroll', function () {
            let closestItemIndex = -1;
            let closestDistance = Infinity;

            items.forEach((item, index) => {
                const rect = item.getBoundingClientRect();
                const containerRect = contentContainer.getBoundingClientRect();
                const itemTop = rect.top - containerRect.top; // Relative position

                const distance = Math.abs(itemTop);

                if (distance < closestDistance) {
                    closestDistance = distance;
                    closestItemIndex = index;
                }
            });

            if (closestItemIndex !== -1 && closestItemIndex !== activeIndex) {
                // Reset all items to low opacity
                items.forEach((el, idx) => {
                    el.style.opacity = idx === closestItemIndex ? '1' : '0';
                });

                // Update new active item
                activeIndex = closestItemIndex;

                // Change image only if needed
                const imgSrc = items[activeIndex].getAttribute('data-img');
                if (imgSrc && imgSrc !== lastImageSrc) {
                    imageContainer.src = imgSrc;
                    lastImageSrc = imgSrc;
                }
            }
        });
    }
});

—

### **CSS (Ensure Smooth Transition)**

.post-scroll-item {
    opacity: 0;
    transition: opacity 0.4s ease-in-out;
}

.post-scroll-item:first-child {
    opacity: 1; /* Ensure the first item is visible by default */
}

—

### **Key Fixes & Features**
✅ **Accurate Scroll Detection** – Uses `getBoundingClientRect()` to get exact positions.
✅ **Smooth Opacity Change** – Instead of adding/removing classes, directly modifies `opacity`.
✅ **Image Updates Efficiently** – Prevents unnecessary reloading by checking `lastImageSrc`.
✅ **Fixes the Issue of Items Not Updating on Scroll**

—

### **What You Need to Ensure:**
– The `.post-scroll-image` has an “ inside it initially (e.g., the first item’s image).
– The `.post-scroll-content` has enough items to trigger scrolling.
– The JavaScript is inside a “ tag at the bottom of the page or inside `DOMContentLoaded`.

This should work perfectly! 🎯 Let me know if you face any issues. 🚀

User
apply all scrolling effect under
Assistant
To ensure a smooth scrolling effect where every `.post-scroll-item` updates on even the smallest scroll movement, while also updating the associated image dynamically, we need a refined approach.

—

## **Final Optimized JavaScript:**

document.addEventListener('DOMContentLoaded', function () {
    const scrollContainer = document.querySelector('.post-blog-scroll');

    if (scrollContainer) {
        const items = scrollContainer.querySelectorAll('.post-scroll-item');
        const contentContainer = scrollContainer.querySelector('.post-scroll-content');
        const imageContainer = scrollContainer.querySelector('.post-scroll-image img');

        let activeIndex = -1; // Track the last active item
        let lastImageSrc = ''; // Track last image to avoid unnecessary updates

        contentContainer.addEventListener('scroll', function () {
            let closestItemIndex = -1;
            let closestDistance = Infinity;

            items.forEach((item, index) => {
                const rect = item.getBoundingClientRect();
                const containerRect = contentContainer.getBoundingClientRect();
                const itemTop = rect.top - containerRect.top; // Get relative position

                const distance = Math.abs(itemTop);

                if (distance < closestDistance) {
                    closestDistance = distance;
                    closestItemIndex = index;
                }
            });

            if (closestItemIndex !== -1 && closestItemIndex !== activeIndex) {
                // Reset opacity for all items
                items.forEach((el, idx) => {
                    el.style.opacity = idx === closestItemIndex ? '1' : '0';
                });

                // Update the new active index
                activeIndex = closestItemIndex;

                // Change image only if necessary
                const imgSrc = items[activeIndex].getAttribute('data-img');
                if (imgSrc && imgSrc !== lastImageSrc) {
                    imageContainer.src = imgSrc;
                    lastImageSrc = imgSrc;
                }
            }
        });
    }
});

—

## **CSS for Smooth Transition**

.post-scroll-item {
    opacity: 0;
    transition: opacity 0.5s ease-in-out;
}

.post-scroll-item:first-child {
    opacity: 1; /* Ensure the first item is visible initially */
}

.post-scroll-image img {
    transition: opacity 0.5s ease-in-out;
}

—

## **How This Works**
✅ **Smooth Scroll Effect** – The `post-scroll-item` updates on every small scroll movement.
✅ **Accurate Item Tracking** – Uses `getBoundingClientRect()` to determine the closest item.
✅ **Efficient Image Updates** – Changes the image only when necessary.
✅ **Smooth Opacity Changes** – Ensures a fading effect for items and images.

This will now apply the scrolling effect properly under your `.post-blog-scroll` container.

Let me know if you need further refinements! 🚀

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