photo26/photologue/static/gallery_justified.js

75 lines
2.7 KiB
JavaScript

// Justified photo grid layout (Google Photos style)
// Inspired by https://github.com/flickr/justified-layout
(function () {
const SPACING = 3;
const PADDING = 3;
function applyLayout() {
const container = document.getElementById('lightgallery');
if (!container) return;
const items = [...container.querySelectorAll('.photo-item')];
if (!items.length) return;
const containerWidth = container.offsetWidth - PADDING * 2;
const TARGET_HEIGHT = Math.min(220, Math.floor(containerWidth * 0.4));
const ratios = items.map(a => {
const w = parseInt(a.dataset.width) || 1;
const h = parseInt(a.dataset.height) || 1;
return w / h;
});
// Group items into rows
const rows = [];
let rowStart = 0;
while (rowStart < ratios.length) {
let sum = 0;
let end = rowStart;
while (end < ratios.length) {
sum += ratios[end];
const rowWidth = sum * TARGET_HEIGHT + SPACING * (end - rowStart);
end++;
if (rowWidth >= containerWidth) break;
}
rows.push({ start: rowStart, end });
rowStart = end;
}
// Position each item
let top = PADDING;
rows.forEach(({ start, end }, rowIndex) => {
const isLastRow = rowIndex === rows.length - 1;
const count = end - start;
const sumRatios = ratios.slice(start, end).reduce((a, b) => a + b, 0);
const totalSpacing = SPACING * (count - 1);
// Don't stretch the last row if it's not full
const rowHeight = isLastRow && count < 3
? TARGET_HEIGHT
: (containerWidth - totalSpacing) / sumRatios;
let left = PADDING;
for (let i = start; i < end; i++) {
const width = Math.round(ratios[i] * rowHeight);
const height = Math.round(rowHeight);
const item = items[i];
item.style.top = top + 'px';
item.style.left = left + 'px';
item.style.width = width + 'px';
item.style.height = height + 'px';
left += width + SPACING;
}
top += Math.round(rowHeight) + SPACING;
});
container.style.height = (top - SPACING + PADDING) + 'px';
items.forEach(item => {
item.style.visibility = 'visible';
const img = item.querySelector('img[data-lazy]');
if (img) img.src = img.dataset.lazy;
});
}
document.addEventListener('DOMContentLoaded', applyLayout);
window.addEventListener('resize', applyLayout);
})();