feat: manage saved thumbnail plans and select plans for tasks

pigway_frame_flow/display/thumbnail_plans.py

@@ -0,0 +1,45 @@
+"""Saved thumbnail rendering parameters; source pixels are never decorated."""
+
+from pydantic import Field
+
+from pigway_frame_flow.errors import ErrorCode as E
+from pigway_frame_flow.errors import FlowError
+from pigway_frame_flow.models import StrictModel
+from pigway_frame_flow.renderers.images import convert
+from pigway_frame_flow.storage.database import encode
+
+
+class ThumbnailPlan(StrictModel):
+    name: str = Field(min_length=1, max_length=120)
+    width: int = Field(default=410, ge=16, le=2048)
+    height: int = Field(default=502, ge=16, le=2048)
+    fit: str = Field(default="cover", pattern="^(cover|contain)$")
+    center_x: float = Field(default=0.5, ge=0, le=1, allow_inf_nan=False)
+    center_y: float = Field(default=0.5, ge=0, le=1, allow_inf_nan=False)
+    quality: int = Field(default=85, ge=40, le=95)
+
+
+def get_plan(service, plan_id):
+    row = service.db.one(
+        "SELECT payload FROM app_config WHERE key=?", ("thumbnail-plan:" + plan_id,)
+    )
+    if not row:
+        raise FlowError(E.NOT_FOUND, "Thumbnail plan not found", 404)
+    return ThumbnailPlan.model_validate_json(row["payload"])
+
+
+def render(data, plan):
+    return convert(
+        data,
+        plan.fit,
+        size=(plan.width, plan.height),
+        centering=(plan.center_x, plan.center_y),
+        quality=plan.quality,
+    )
+
+
+def save_plan(service, plan_id, plan):
+    service.db.execute(
+        "INSERT OR REPLACE INTO app_config VALUES(?,?)",
+        ("thumbnail-plan:" + plan_id, encode(plan.model_dump())),
+    )