Current Print Workflow

Mon, 01 Jan 0001 00:00:00 +0000

Current Print Workflow

This document describes the actual print workflow across the C client, C SDK, and tijet_1/tincore gRPC server.

This document only describes the current codebase and client behavior, and does not include future refactoring plans.

Source Baseline

Module	Repository	Branch
Proto contracts & C SDK	`tijet_1/sw-grpc-libraries`	`master`
tincore gRPC server	`tijet_1/tincore`	`feature-grpc-cpp`

Participants

Participant	Responsibility
Qt Client Business Layer	Register event callbacks, upload print data, retry `START_PRINT`, wait for final result
C SDK Call Thread	Encapsulate `SetPrintData` and `StartPrint` RPC calls
C SDK Event Thread	Continuously read `SubscribeEvents` server stream and invoke registered callbacks
`TinCoreServiceImpl`	gRPC protocol layer, dispatches RPC requests to server Handlers
`DefaultTinCoreHandlers`	Handles print data reception, data readiness validation, and async print start logic
`gAFBridge` / Printhead Hardware	Processes print data in background, controls driver board power, communicates with printhead and enables high voltage

Current Call Sequence

sequenceDiagram
 autonumber
 participant Caller as Caller
 participant Callee as Callee

 Caller->>Callee: tijet_client_set_event_callback(callback, user_data)
 Callee-->>Caller: Callback registered

 Caller->>Callee: tijet_client_start_event_subscription()
 Callee-->>Caller: TIJET_OK
 Note over Callee: Background event thread created
 Note over Callee: SubscribeEvents() polling

 Caller->>Callee: tijet_client_set_print_data(data, index, is_static)
 Callee-->>Caller: SetPrintDataResponse{success=true}
 Note over Callee: Print data enters background processing
 Note over Callee: DATA_READY may still be 0 on return

 loop START_PRINT retry, total timeout 10s
 Caller->>Callee: tijet_client_print_control(START_PRINT)
 alt DATA_READY == 0
 Callee-->>Caller: TIJET_ERR_SERVER
 Note over Caller: Wait 1s before retry
 else DATA_READY != 0
 Callee-->>Caller: TIJET_OK
 Note over Callee: High-voltage thread created
 end
 end

 Note over Caller: After START_PRINT success, wait for PrintStarted

 alt High voltage successful
 Callee-->>Caller: PrintStarted{success=true}
 Note over Caller: Ready for printing
 else High voltage failed
 Callee-->>Caller: PrintStarted{success=false}
 Note over Caller: Failure, message contains failed head count
 else PrintStarted not received within 10s
 Note over Caller: Timeout
 end

Retry & Timeout Flow

flowchart TD
 A["Caller: Connect to server"] --> B["Caller: Register callback<br/>Start event subscription"]
 B --> C["Caller: set_print_data() upload print data"]
 C --> D{"Callee: Upload RPC successful?"}

 D -->|"No"| D1["Failed, flow ends"]
 D -->|"Yes"| E["Callee: Data enters background processing<br/>DATA_READY may still be 0"]

 E --> F["Caller: Start START_PRINT retry timer"]
 F --> G["Caller: print_control(START_PRINT)"]
 G --> H{"Callee: Is DATA_READY == 0?"}

 H -->|"Yes: data not ready"| I{"Total retry time reached 10s?"}
 I -->|"No"| J["Caller: Wait 1s"]
 J --> G
 I -->|"Yes"| K["Failed: Print data preparation timeout"]

 H -->|"No: data ready"| L["Callee: Create high-voltage thread<br/>Return TIJET_OK"]
 L --> M["Caller: Wait for PrintStarted event<br/>timeout 10s"]
 M --> N{"Result"}

 N -->|"success=true"| O["Success: High voltage enabled<br/>Ready for printing"]
 N -->|"success=false"| P["Failed: High voltage activation failed"]
 N -->|"Timeout"| Q["Failed: High voltage activation timed out"]

Current Return Value Semantics

Location	Return Value	Current Actual Meaning
`tijet_client_set_print_data()`	`TIJET_OK`	Print data upload RPC completed; does NOT mean backend processing is done or `DATA_READY=1`
`tijet_client_print_control(..., "START_PRINT")`	`TIJET_ERR_SERVER`	gRPC call failed, or server returned `success=false`; client does not distinguish cause, retries after 1s
`tijet_client_print_control(..., "START_PRINT")`	`TIJET_OK`	Server sync validation passed and created high-voltage start thread; does NOT mean high voltage is enabled
`PrintStarted.success`	`true`	High voltage enabled successfully, `setDataParamReady(true)` called
`PrintStarted.success`	`false`	High voltage activation failed, `message` contains count of failed heads

Source Index

C SDK

sdk/c/src/tijet_core.cpp:342: tijet_client_set_print_data().
sdk/c/src/tijet_core.cpp:396: Register event callback.
sdk/c/src/tijet_core.cpp:408: Start event subscription and create event thread.
sdk/c/src/tijet_core.cpp:641: tijet_client_print_control().
sdk/c/src/tijet_core.cpp:655: Match START_PRINT and call StartPrint RPC.
sdk/c/include/tijet_core.h:441: Print data upload C API declaration.
sdk/c/include/tijet_core.h:480: Event callback registration C API declaration.
sdk/c/include/tijet_core.h:500: Event subscription C API declaration.
sdk/c/include/tijet_core.h:650: Print control C API declaration.

Proto Contracts

proto/print.proto:7: SetPrintDataRequest.
proto/print.proto:19: StartPrintRequest.
proto/print.proto:22: StartPrintResponse.
proto/event.proto:48: PrintDataStatus.
proto/event.proto:53: PrintStarted.
proto/tincore.proto:27: SetPrintData RPC.
proto/tincore.proto:28: StartPrint RPC.
proto/tincore.proto:33: SubscribeEvents RPC.

`tijet_1/tincore` gRPC Server

The following paths are relative to the feature-grpc-cpp branch of tijet_1/tincore:

PC SDK on TiJet

Current Print Workflow

Current Print Workflow

Source Baseline

Participants

Current Call Sequence

Retry & Timeout Flow

Current Return Value Semantics

Source Index

C SDK

Proto Contracts

tijet_1/tincore gRPC Server

`tijet_1/tincore` gRPC Server