Gallery: true justified layout (row-height scaling, no crop, no spacer)

frontend/src/components/Gallery.jsx

@@ -1,23 +1,66 @@
+import { useEffect, useRef, useState } from 'react'
 import { imgUrl } from '../api'
 
-// Justified gallery: rows are built with flexbox, each tile's flex-grow is
-// proportional to its aspect ratio so rows fill the container edge to edge.
-// When `selected`/`onToggleSelect` are provided, tiles get a select checkmark;
-// selection state lives in the parent so it survives lightbox open/close.
+// True justified layout: pack photos greedily into rows at their real aspect
+// ratios, then scale each row's height so it fills the container width
+// exactly. No cropping, no stretch, and the last row simply renders at the
+// target height instead of being padded by a spacer.
+function layoutRows(photos, containerWidth, targetHeight, gap) {
+  const rows = []
+  let row = []
+  let arSum = 0
+  let index = 0
+  for (const photo of photos) {
+    const ar = photo.width && photo.height ? photo.width / photo.height : 1.5
+    row.push({ photo, ar, index: index++ })
+    arSum += ar
+    const gaps = (row.length - 1) * gap
+    if (arSum * targetHeight + gaps >= containerWidth) {
+      rows.push({ items: row, height: (containerWidth - gaps) / arSum })
+      row = []
+      arSum = 0
+    }
+  }
+  if (row.length > 0) {
+    const gaps = (row.length - 1) * gap
+    rows.push({
+      items: row,
+      height: Math.min(targetHeight, (containerWidth - gaps) / arSum),
+    })
+  }
+  return rows
+}
+
 export default function Gallery({ photos, onOpen, overlay, selected, onToggleSelect }) {
+  const containerRef = useRef(null)
+  const [width, setWidth] = useState(0)
+
+  useEffect(() => {
+    const el = containerRef.current
+    if (!el) return
+    const observer = new ResizeObserver((entries) => setWidth(entries[0].contentRect.width))
+    observer.observe(el)
+    return () => observer.disconnect()
+  }, [])
+
   if (photos.length === 0) return null
+  const gap = 6
+  const targetHeight = width < 700 ? 170 : 240
+  const rows = width > 0 ? layoutRows(photos, width, targetHeight, gap) : []
   const selecting = selected && selected.size > 0
+
   return (
-    <div className={`gallery${selecting ? ' selecting' : ''}`}>
-      {photos.map((p, i) => {
-        const ar = p.width && p.height ? p.width / p.height : 1.5
+    <div ref={containerRef} className={`gallery${selecting ? ' selecting' : ''}`}>
+      {rows.map((row) => (
+        <div key={row.items[0].photo.id} className="g-row" style={{ height: row.height }}>
+          {row.items.map(({ photo: p, ar, index }) => {
             const isSelected = selected ? selected.has(p.id) : false
             return (
               <div
                 key={p.id}
                 className={`g-item${isSelected ? ' selected' : ''}`}
-            style={{ '--ar': ar }}
-            onClick={() => onOpen && onOpen(i)}
+                style={{ width: ar * row.height }}
+                onClick={() => onOpen && onOpen(index)}
               >
                 <img src={imgUrl(p, 'thumb')} loading="lazy" alt={p.filename} />
                 {onToggleSelect && (
@@ -36,7 +79,8 @@ export default function Gallery({ photos, onOpen, overlay, selected, onToggleSel
               </div>
             )
           })}
-      <div className="g-spacer" />
+        </div>
+      ))}
     </div>
   )
 }

frontend/src/styles.css

@@ -191,15 +191,17 @@ input:focus {
 /* justified gallery */
 .gallery {
   display: flex;
-  flex-wrap: wrap;
+  flex-direction: column;
   gap: 6px;
   margin: 1rem 0;
 }
+.g-row {
+  display: flex;
+  gap: 6px;
+}
 .g-item {
   position: relative;
-  height: 240px;
-  flex-grow: calc(var(--ar) * 100);
-  flex-basis: calc(var(--ar) * 240px);
+  flex: none;
   border-radius: 4px;
   overflow: hidden;
   cursor: pointer;
@@ -211,11 +213,6 @@ input:focus {
   object-fit: cover;
   display: block;
 }
-.g-spacer {
-  flex-grow: 1000000;
-  flex-basis: 0;
-  height: 0;
-}
 .g-overlay {
   position: absolute;
   bottom: 0;
@@ -556,10 +553,6 @@ progress {
 }
 
 @media (max-width: 700px) {
-  .g-item {
-    height: 160px;
-    flex-basis: calc(var(--ar) * 160px);
-  }
   .lb-stage {
     padding: 0 0.5rem;
   }