phase 5

backend/app/images/processing.py

@@ -0,0 +1,98 @@
+"""Image processing utilities - thumbnail generation."""
+
+import contextlib
+import io
+from uuid import UUID
+
+from PIL import Image as PILImage
+
+from app.core.storage import get_storage_client
+
+# Thumbnail sizes (width in pixels, height proportional)
+THUMBNAIL_SIZES = {
+    "low": 800,  # For slow connections
+    "medium": 1600,  # For medium connections
+    "high": 3200,  # For fast connections
+}
+
+
+def generate_thumbnails(image_id: UUID, original_path: str, contents: bytes) -> dict[str, str]:
+    """
+    Generate thumbnails at different resolutions.
+
+    Args:
+        image_id: Image ID for naming thumbnails
+        original_path: Path to original image
+        contents: Original image contents
+
+    Returns:
+        Dictionary mapping quality level to thumbnail storage path
+    """
+    storage = get_storage_client()
+    thumbnail_paths = {}
+
+    # Load original image
+    image = PILImage.open(io.BytesIO(contents))
+
+    # Convert to RGB if necessary (for JPEG compatibility)
+    if image.mode in ("RGBA", "LA", "P"):
+        # Create white background for transparent images
+        background = PILImage.new("RGB", image.size, (255, 255, 255))
+        if image.mode == "P":
+            image = image.convert("RGBA")
+        background.paste(image, mask=image.split()[-1] if image.mode in ("RGBA", "LA") else None)
+        image = background
+    elif image.mode != "RGB":
+        image = image.convert("RGB")
+
+    # Get original dimensions
+    orig_width, orig_height = image.size
+
+    # Generate thumbnails for each size
+    for quality, max_width in THUMBNAIL_SIZES.items():
+        # Skip if original is smaller than thumbnail size
+        if orig_width <= max_width:
+            thumbnail_paths[quality] = original_path
+            continue
+
+        # Calculate proportional height
+        ratio = max_width / orig_width
+        new_height = int(orig_height * ratio)
+
+        # Resize image
+        thumbnail = image.resize((max_width, new_height), PILImage.Resampling.LANCZOS)
+
+        # Convert to WebP for better compression
+        output = io.BytesIO()
+        thumbnail.save(output, format="WEBP", quality=85, method=6)
+        output.seek(0)
+
+        # Generate storage path
+        thumbnail_path = f"thumbnails/{quality}/{image_id}.webp"
+
+        # Upload to MinIO
+        storage.put_object(
+            bucket_name="webref",
+            object_name=thumbnail_path,
+            data=output,
+            length=len(output.getvalue()),
+            content_type="image/webp",
+        )
+
+        thumbnail_paths[quality] = thumbnail_path
+
+    return thumbnail_paths
+
+
+async def delete_thumbnails(thumbnail_paths: dict[str, str]) -> None:
+    """
+    Delete thumbnails from storage.
+
+    Args:
+        thumbnail_paths: Dictionary of quality -> path
+    """
+    storage = get_storage_client()
+    for path in thumbnail_paths.values():
+        with contextlib.suppress(Exception):
+            # Log error but continue
+            storage.remove_object(bucket_name="webref", object_name=path)