Add SAM click-to-select with brush refinement in AI Edit tool

Backend:
- sam_service.py: auto-downloads SAM ViT-B (~375 MB) on first use with
  progress tracking; loads model to CUDA/MPS/CPU; predict_points() takes
  multi-point prompts (include/exclude labels) and returns best mask
- POST /api/segment/point: SAM point-prompt endpoint; returns mask PNG
- GET  /api/segment/install-status: poll download progress
- POST /api/segment/install: explicit trigger (also auto on first click)
- main.py: pre-download SAM on startup alongside NCNN

Frontend (ai_edit.js):
- Click mode (default): click object → SAM generates mask instantly
  Alt+click → subtract (deselect over-selected area)
  Multiple clicks accumulate for multi-object or refinement
- Brush + / Brush − modes: paint to add or erase from SAM mask by hand
- If SAM model is still downloading on first click: inline progress bar,
  user retries the click when done
- Unified action bar: Erase | Replace (inline prompt) | Upscale | Expand | Clear
- All modes share the same mask canvas; SAM and brush are fully composited

https://claude.ai/code/session_01B58MaJCU1R6KwBDJCp8AfN
This commit is contained in:
Claude
2026-06-10 18:18:33 +00:00
parent 1132656370
commit 3746c02d44
4 changed files with 613 additions and 179 deletions
+3
View File
@@ -21,6 +21,9 @@ async def lifespan(app: FastAPI):
caps = probe_upscale_capabilities()
if not caps["realesrgan_pytorch"] and not caps["realesrgan_ncnn"]:
asyncio.create_task(ensure_ncnn_installed())
# Pre-download SAM model in background so first click is fast
from app.services.sam_service import ensure_sam_installed
asyncio.create_task(ensure_sam_installed())
yield
+60
View File
@@ -348,3 +348,63 @@ async def get_config():
},
}
}
# ─── SAM (Segment Anything) ──────────────────────────────────────────────────
class SegmentPointRequest(BaseModel):
image: str # base64 PNG/JPEG
points: list[list[int]] # [[x, y], ...] original image coords
labels: list[int] # 1=include, 0=exclude — same length as points
@router.post("/segment/point")
async def segment_point(req: SegmentPointRequest):
"""
Run SAM point-prompt segmentation.
Returns a binary mask PNG (white = selected area).
Auto-downloads the SAM ViT-B model (~375 MB) on first call.
"""
if not req.points:
raise HTTPException(status_code=400, detail="At least one point required.")
if len(req.points) != len(req.labels):
raise HTTPException(status_code=400, detail="points and labels must have the same length.")
try:
image_bytes = base64.b64decode(req.image)
except Exception as e:
raise HTTPException(status_code=400, detail=f"Could not decode image: {e}")
from app.services.sam_service import predict_points, get_install_status
try:
mask_bytes = await predict_points(
image_bytes,
[tuple(p) for p in req.points],
req.labels,
)
return {
"mask": base64.b64encode(mask_bytes).decode(),
"sam_install": get_install_status(),
}
except RuntimeError as e:
raise HTTPException(status_code=503, detail=str(e))
except Exception as e:
import traceback; traceback.print_exc()
raise HTTPException(status_code=500, detail=str(e))
@router.get("/segment/install-status")
def segment_install_status():
"""Poll SAM model download progress."""
from app.services.sam_service import get_install_status, sam_model_available
status = get_install_status()
status["model_ready"] = sam_model_available()
return status
@router.post("/segment/install")
async def segment_install():
"""Trigger SAM model download explicitly (also auto-triggered on first /segment/point call)."""
from app.services.sam_service import ensure_sam_installed, get_install_status
asyncio.create_task(ensure_sam_installed())
return get_install_status()
+184
View File
@@ -0,0 +1,184 @@
"""
SAM (Segment Anything Model) service.
Auto-downloads the ViT-B checkpoint (~375 MB) on first use.
Caches the loaded model in memory; re-uses predictor across calls.
Prediction API:
predict_points(image_bytes, points, labels) -> mask_bytes (PNG, white=selected)
points: list of (x, y) in original image pixels
labels: list of 1 (include) or 0 (exclude), same length as points
"""
import asyncio
import io
import os
import urllib.request
from dataclasses import dataclass
from enum import Enum
from pathlib import Path
from typing import Optional
import numpy as np
from PIL import Image
# ── Model download ────────────────────────────────────────────────────────────
SAM_DIR = Path("/app/data/models/sam")
SAM_FILENAME = "sam_vit_b_01ec64.pth"
SAM_URL = f"https://dl.fbaipublicfiles.com/segment_anything/{SAM_FILENAME}"
SAM_PATH = SAM_DIR / SAM_FILENAME
class SamInstallState(str, Enum):
idle = "idle"
downloading = "downloading"
done = "done"
failed = "failed"
@dataclass
class SamInstallStatus:
state: SamInstallState = SamInstallState.idle
progress: int = 0
message: str = ""
error: str = ""
_install_status = SamInstallStatus()
_install_lock = asyncio.Lock()
def get_install_status() -> dict:
s = _install_status
return {"state": s.state.value, "progress": s.progress,
"message": s.message, "error": s.error}
def sam_model_available() -> bool:
return SAM_PATH.exists() and SAM_PATH.stat().st_size > 100_000_000
async def ensure_sam_installed() -> bool:
"""Download SAM ViT-B checkpoint if not present. Returns True on success."""
global _install_status
if sam_model_available():
_install_status = SamInstallStatus(state=SamInstallState.done, progress=100,
message="SAM model ready.")
return True
async with _install_lock:
if sam_model_available():
_install_status = SamInstallStatus(state=SamInstallState.done, progress=100,
message="SAM model ready.")
return True
if _install_status.state == SamInstallState.downloading:
return False
try:
SAM_DIR.mkdir(parents=True, exist_ok=True)
_install_status = SamInstallStatus(
state=SamInstallState.downloading, progress=0,
message="Downloading SAM ViT-B model (~375 MB)…",
)
def _download():
def _progress(count, block, total):
if total > 0:
_install_status.progress = min(99, int(count * block * 99 / total))
tmp = SAM_PATH.with_suffix(".tmp")
urllib.request.urlretrieve(SAM_URL, tmp, _progress)
tmp.rename(SAM_PATH)
loop = asyncio.get_event_loop()
await loop.run_in_executor(None, _download)
_install_status = SamInstallStatus(state=SamInstallState.done, progress=100,
message="SAM model ready.")
return True
except Exception as exc:
_install_status = SamInstallStatus(
state=SamInstallState.failed, error=str(exc),
message="SAM download failed.",
)
print(f"[sam] Download failed: {exc}")
return False
# ── Model cache ───────────────────────────────────────────────────────────────
_predictor = None
_predictor_lock = asyncio.Lock()
def _load_predictor():
"""Load SAM model and return a SamPredictor. Called in thread pool."""
global _predictor
if _predictor is not None:
return _predictor
import torch
from segment_anything import sam_model_registry, SamPredictor
if torch.cuda.is_available():
device = "cuda"
elif hasattr(torch.backends, "mps") and torch.backends.mps.is_available():
device = "mps"
else:
device = "cpu"
print(f"[sam] Loading SAM ViT-B on {device}")
sam = sam_model_registry["vit_b"](checkpoint=str(SAM_PATH))
sam.to(device)
_predictor = SamPredictor(sam)
print("[sam] Model loaded.")
return _predictor
# ── Prediction ────────────────────────────────────────────────────────────────
def _predict_sync(image_bytes: bytes,
points: list[tuple[int, int]],
labels: list[int]) -> bytes:
"""
Run SAM prediction synchronously (call via run_in_executor).
Returns PNG bytes: white = selected, black = background.
"""
predictor = _load_predictor()
image = Image.open(io.BytesIO(image_bytes)).convert("RGB")
img_array = np.array(image)
predictor.set_image(img_array)
pt_array = np.array(points, dtype=np.float32) # [[x, y], ...]
lbl_array = np.array(labels, dtype=np.int32) # [1=fg, 0=bg, ...]
masks, scores, _ = predictor.predict(
point_coords=pt_array,
point_labels=lbl_array,
multimask_output=True,
)
# Pick the highest-confidence mask
best = masks[int(np.argmax(scores))] # bool array H×W
mask_img = Image.fromarray((best * 255).astype(np.uint8), mode="L")
buf = io.BytesIO()
mask_img.save(buf, format="PNG")
return buf.getvalue()
async def predict_points(image_bytes: bytes,
points: list[tuple[int, int]],
labels: list[int]) -> bytes:
"""Async wrapper for SAM point prediction."""
if not sam_model_available():
ok = await ensure_sam_installed()
if not ok:
raise RuntimeError("SAM model not available.")
loop = asyncio.get_event_loop()
return await loop.run_in_executor(None, _predict_sync, image_bytes, points, labels)