Size Qwen 2.1 Generate from the bench aspect table.

Wire EmptyLatentImage to the official ~1 MP grid so 16:9 lands at 1536×864, keep PE wh_ratio advisory, and leave Edit on the encode latent from image_1.

Co-authored-by: Cursor <cursoragent@cursor.com>

shared/studio2/qwen21-size.mjs

@@ -0,0 +1,58 @@
+/** Qwen-safe ~1 MP grid (÷32). Do not use native 2K bins on 16 GB. */
+export const QWEN21_SIZE_TABLE = {
+  '1:1': [1024, 1024],
+  '16:9': [1536, 864],
+  '9:16': [864, 1536],
+  '4:3': [1152, 864],
+  '3:4': [864, 1152],
+  '3:2': [1248, 832],
+  '2:3': [832, 1248],
+  '21:9': [1536, 672],
+  '9:21': [672, 1536]
+}
+
+export const QWEN21_ASPECT_IDS = new Set(['auto', ...Object.keys(QWEN21_SIZE_TABLE)])
+
+function parseAspectRatio(aspect) {
+  const m = String(aspect || '').trim().match(/^(\d+(?:\.\d+)?)\s*:\s*(\d+(?:\.\d+)?)$/)
+  if (!m) return null
+  const w = Number(m[1]), h = Number(m[2])
+  if (!(w > 0 && h > 0)) return null
+  return w / h
+}
+
+function nearestQwen21Aspect(aspect) {
+  const target = parseAspectRatio(aspect)
+  if (target == null) return null
+  let best = '1:1', bestDiff = Infinity
+  for (const [key, [w, h]] of Object.entries(QWEN21_SIZE_TABLE)) {
+    const diff = Math.abs(w / h - target)
+    if (diff < bestDiff) { bestDiff = diff; best = key }
+  }
+  return best
+}
+
+export function resolveQwen21Size(aspect, source) {
+  const key = String(aspect || 'auto').trim()
+  if (QWEN21_SIZE_TABLE[key]) {
+    const [width, height] = QWEN21_SIZE_TABLE[key]
+    return { width, height }
+  }
+  if (key === 'auto') {
+    if (source?.width && source?.height) {
+      const nearest = nearestQwen21Aspect(`${source.width}:${source.height}`)
+      if (nearest) {
+        const [width, height] = QWEN21_SIZE_TABLE[nearest]
+        return { width, height }
+      }
+    }
+    return { width: 1024, height: 1024 }
+  }
+  const nearest = nearestQwen21Aspect(key)
+  if (nearest) {
+    const [width, height] = QWEN21_SIZE_TABLE[nearest]
+    return { width, height }
+  }
+  console.warn(`[qwen21] unknown aspect "${key}"; using 1024×1024`)
+  return { width: 1024, height: 1024 }
+}