11 — User Interface

Source: src/vocal10n/ui/. Framework: PySide6 (Qt6, LGPL).

Window Structure

The main window splits vertically into two regions:

flowchart TB
    subgraph A["Section A — Monitoring"]
        direction LR
        subgraph A1["A1 · Live text"]
            direction TB
            A1a["A1a · Source stream"]
            A1b["A1b · Translation stream"]
        end
        subgraph A2["A2 · Metrics + Status"]
            direction TB
            M1["GPU / VRAM"]
            M2["STT / LLM / TTS latency"]
            M3["Module status flags"]
        end
    end
    subgraph B["Section B — QTabWidget"]
        direction LR
        T1["STT"] --- T2["Translation"] --- T3["TTS"] --- T4["Output"] --- T5["OBS"] --- T6["KB"] --- T7["Training"]
    end
    A --- B

section_a.py and section_b.py build these regions; main_window.py puts them together and adds the menu bar and the Simple/Pro mode toggle (see chapter 12).

Section A — Monitoring

A1 streams text in two stacked panes:

A1a: source language (live + accumulated, split 30 / 70 by default — see commit 971bf66).
A1b: target language (same layout).

A2 shows:

GPU utilisation (%) and VRAM used / total (from utils.gpu).
Three latencies: STT-to-OBS partial, STT confirmed, translation, and TTS TTFA.
Status flags for STT loaded / running, OBS overlay running, current source language, LLM running, current target language, TTS running.

Section B Tabs (Pro Mode)

Tab	File	Purpose
STT	`tabs/stt_tab.py`	Enable, model picker, load/unload, language, parameters with tooltips, term-file capacity.
Translation	`tabs/translation_tab.py`	Enable, backend, source/target language, prompt editor, KB mount, parameters.
TTS	`tabs/tts_container_tab.py` (+ `tts_tab.py`, `qwen3_tts_tab.py`)	Backend selector, source/target enable, device routing, reference audio, parameters.
Output	`tabs/output_tab.py`	Per-format file output toggles, output directory.
OBS	`tabs/obs_tab.py`	Overlay enable, per-language styling, live preview.
KB	`tabs/kb_tab.py`	STT term files (file table + editor) and hallucination filter editor. Consolidated in commit `eb263e5`.
Training	`tabs/training_tab.py`	SRT-based training data review (placeholder for future training tooling).

Reusable Widgets

param_slider.py — labelled slider/input with an info tooltip describing the parameter and a per-parameter reset button (matches the spec in initialplan.md).
model_selector.py — model dropdown plus Load / Unload buttons that mirror SystemState. Custom-painted dropdown arrow (ArrowComboBox) for legibility.
stream_text.py — append-only streaming text widget with a partial tail that gets replaced when text is confirmed.
term_file_list.py — drag-drop file table for STT term files.
filter_list_editor.py — editor for config/filters.txt.
simple_mode_panel.py — see chapter 12.

Theming

styles/theme.qss provides a dark theme. Several iterations went into making QComboBox arrows and per-button hit areas legible (commits bfccf49, c500a0b, ec49e38, 2f7e207, 9f14379, e272bbe, a2a7031, 2e3bcef).

Layout Reset

Commit d4055ca introduced a clean reset of both source and translation panes that the Simple-mode Stop button calls so users always see a predictable, empty starting state.