AI Canvas Expand

Expand the canvas of an image with AI-powered fill (outpainting). Extends the image in any direction and fills the new areas with AI-generated content that matches the existing image.

API Endpoint

POST /api/v1/tools/ai-canvas-expand

Processing: Asynchronous (returns 202, poll /api/v1/jobs/{jobId}/progress for status via SSE)

Model bundle: object-eraser-colorize (1-2 GB)

Parameters

Parameter	Type	Required	Default	Description
file	file	Yes	-	Image file (multipart)
extendTop	integer	No	0	Pixels to extend at the top
extendRight	integer	No	0	Pixels to extend at the right
extendBottom	integer	No	0	Pixels to extend at the bottom
extendLeft	integer	No	0	Pixels to extend at the left
tier	string	No	"balanced"	Quality tier: fast, balanced, high
format	string	No	"auto"	Output format: auto, png, jpg, jpeg, webp, tiff, gif, avif, heic, heif, jxl
quality	integer	No	95	Output quality (1-100)

At least one extend direction must be greater than 0.

Example Request

curl -X POST http://localhost:13490/api/v1/tools/ai-canvas-expand \
  -F "[email protected]" \
  -F 'settings={"extendTop":200,"extendBottom":200,"extendLeft":100,"extendRight":100,"tier":"balanced"}'

Response

Initial Response (202 Accepted)

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "async": true
}

Progress (SSE at /api/v1/jobs/{jobId}/progress)

event: progress
data: {"phase":"processing","stage":"Expanding canvas...","percent":50}

Final Result (via SSE)

{
  "phase": "complete",
  "percent": 100,
  "result": {
    "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "downloadUrl": "/api/v1/download/{jobId}/photo_extended.png",
    "previewUrl": "/api/v1/download/{jobId}/preview.webp",
    "originalSize": 300000,
    "processedSize": 520000
  }
}

Notes

• Requires the object-eraser-colorize model bundle to be installed (1-2 GB).
• Uses LaMa-based outpainting to generate content for the expanded regions.
• The tier parameter trades speed for quality: fast produces results quickly with potential artifacts, high takes longer but produces smoother, more coherent fills.
• Extend values are in pixels. The final image dimensions will be: original width + extendLeft + extendRight by original height + extendTop + extendBottom.
• For non-browser-previewable output formats (HEIC, JXL, TIFF), a WebP preview is generated alongside the main output.
• Supports HEIC/HEIF, RAW, TGA, PSD, EXR, and HDR input formats via automatic decoding.