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src/utils/pasteImage.js

@@ -0,0 +1,25 @@
+export async function readClipboardImage() {
+  const items = await navigator.clipboard.read();
+  for (const item of items) {
+    for (const type of item.types) {
+      if (type.startsWith('image/')) {
+        return item.getType(type);
+      }
+    }
+  }
+  return null;
+}
+
+/**
+ * Try clipboard image first; run onMissing when none found or clipboard unavailable.
+ */
+export async function pasteImageOrFallback(onMissing) {
+  try {
+    const image = await readClipboardImage();
+    if (image) return image;
+  } catch {
+    // Clipboard API unavailable or denied.
+  }
+  onMissing();
+  return null;
+}

src/utils/prepareArticlePhoto.js

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+const MAX_EDGE = 1000;
+const AVIF_MIME = 'image/avif';
+const AVIF_QUALITY = 0.8;
+
+function scaledDimensions(width, height) {
+  const scale = Math.min(1, MAX_EDGE / width, MAX_EDGE / height);
+  return {
+    width: Math.round(width * scale),
+    height: Math.round(height * scale),
+  };
+}
+
+/**
+ * Resize to fit within 1000×1000 (aspect ratio kept, no upscale) and encode as AVIF.
+ * @param {Blob|File} input
+ * @returns {Promise<File>}
+ */
+export async function prepareArticlePhoto(input) {
+  if (!(input instanceof Blob)) {
+    throw new Error('Kein Bild.');
+  }
+  if (!input.type.startsWith('image/')) {
+    throw new Error('Kein Bild.');
+  }
+
+  const bitmap = await createImageBitmap(input);
+  try {
+    const { width, height } = scaledDimensions(bitmap.width, bitmap.height);
+    const canvas = document.createElement('canvas');
+    canvas.width = width;
+    canvas.height = height;
+
+    const ctx = canvas.getContext('2d');
+    if (!ctx) {
+      throw new Error('Canvas nicht verfügbar.');
+    }
+    ctx.drawImage(bitmap, 0, 0, width, height);
+
+    const avifBlob = await new Promise((resolve, reject) => {
+      canvas.toBlob(
+        (blob) => {
+          if (!blob || blob.type !== AVIF_MIME) {
+            reject(new Error('AVIF wird von diesem Browser nicht unterstützt.'));
+            return;
+          }
+          resolve(blob);
+        },
+        AVIF_MIME,
+        AVIF_QUALITY,
+      );
+    });
+
+    const baseName = input instanceof File && input.name
+      ? input.name.replace(/\.[^.]+$/, '')
+      : 'photo';
+
+    return new File([avifBlob], `${baseName}.avif`, { type: AVIF_MIME });
+  } finally {
+    bitmap.close();
+  }
+}