SnapOtter/apps/docs/tools/image/content-aware-resize.md

description

description
Seam-carving resize that adds or removes pixels along low-importance paths to preserve key content and faces.

Content-Aware Resize

Seam carving resize that intelligently removes or adds pixels along paths of least visual importance, preserving important content and optionally protecting faces.

API Endpoint

POST /api/v1/tools/image/content-aware-resize

Processing: Synchronous (returns result directly)

Model bundle: None required for basic operation. Face protection uses the face-detection bundle (200-300 MB) if enabled.

Parameters

Parameter	Type	Required	Default	Description
file	file	Yes	-	Image file (multipart)
width	number	No	-	Target width in pixels
height	number	No	-	Target height in pixels
protectFaces	boolean	No	false	Detect and protect faces from seam removal
blurRadius	number	No	4	Pre-processing blur radius for energy calculation (0-20)
sobelThreshold	number	No	2	Sobel edge detection threshold (1-20). Higher values make the algorithm more aggressive
square	boolean	No	false	Resize to a square (uses the smaller dimension)

At least one of width, height, or square must be specified.

Example Request

curl -X POST http://localhost:1349/api/v1/tools/image/content-aware-resize \
  -F "file=@landscape.jpg" \
  -F 'settings={"width":800,"protectFaces":true}'

Response (200 OK)

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "downloadUrl": "/api/v1/download/{jobId}/landscape_seam.png",
  "originalSize": 450000,
  "processedSize": 380000,
  "width": 800,
  "height": 600
}

Notes

• This custom route currently returns a synchronous 200 response.
• Uses the caire seam carving library for content-aware resizing.
• Only reduces dimensions (removes seams). Cannot expand an image beyond its original size.
• The protectFaces option uses AI face detection to mark face regions as high-energy, preventing seams from passing through faces.
• blurRadius controls smoothing before energy map calculation. Higher values make the energy map more uniform, which can help with noisy images.
• sobelThreshold affects how aggressively edges are detected. Lower values preserve more subtle edges.
• Output is always PNG format.
• Supports HEIC/HEIF, RAW, TGA, PSD, EXR, and HDR input formats via automatic decoding.