mirror of
https://github.com/logos-co/logos-tutorial.git
synced 2026-08-31 04:41:08 +00:00
643 lines
24 KiB
Markdown
643 lines
24 KiB
Markdown
# Tutorial Part 3: Building a C++ UI Module (Process-Isolated)
|
|
|
|
This is Part 3 of the Logos module tutorial series. In [Part 2](tutorial-qml-ui-app.md) you built a QML-only UI plugin. Now you'll build a **ui_qml module with a C++ backend** — the backend runs in a separate `ui-host` process while the QML view loads in the host app (basecamp / standalone).
|
|
|
|
**What you'll build:** A `calc_ui_cpp` module with:
|
|
|
|
- A `.rep` file defining the remote interface (slots + properties)
|
|
- A C++ backend plugin that inherits from the generated `SimpleSource` base class
|
|
- A QML view that calls the backend via a typed replica using `logos.watch()`
|
|
- Process isolation: backend crashes can't bring down the host app
|
|
|
|
**Why C++ backend over QML-only?**
|
|
|
|
| | QML-only (Part 2) | C++ backend (Part 3) |
|
|
| ----------------- | ----------------------------------------------------------------- | --------------------------------------- |
|
|
| Compilation | None | CMake + Qt |
|
|
| Process isolation | No (QML runs in-process) | Yes (C++ in separate `ui-host` process) |
|
|
| Backend calls | `logos.callModule()` / `logos.callModuleAsync()` to other modules | `LogosModules` typed SDK in C++ |
|
|
| Type safety | Args travel as `QVariant` | C++ types preserved |
|
|
| QML ↔ backend | Direct bridge | Qt Remote Objects (typed replica) |
|
|
| `.rep` file | Not needed | Required — defines the remote interface |
|
|
|
|
**Prerequisites:**
|
|
|
|
- Completed [Part 1](tutorial-wrapping-c-library.md) — you have a working `calc_module` with the shared library built (`.so` on Linux, `.dylib` on macOS in `logos-calc-module/lib/`)
|
|
- Nix with flakes enabled
|
|
|
|
---
|
|
|
|
## Architecture
|
|
|
|
```
|
|
logos-basecamp / logos-standalone-app
|
|
┌─────────────────────────────────────────────┐
|
|
│ │
|
|
│ QML View (Main.qml) │
|
|
│ readonly property var backend: │
|
|
│ logos.module("calc_ui_cpp") │
|
|
│ logos.watch(backend.add(1,2))│
|
|
│ │ │
|
|
│ │ Qt Remote Objects (socket) │
|
|
└──────────┼──────────────────────────────────┘
|
|
│
|
|
ui-host process (separate)
|
|
┌──────────┼──────────────────────────────────┐
|
|
│ ▼ │
|
|
│ CalcUiCppPlugin (backend) │
|
|
│ : CalcUiCppSimpleSource │
|
|
│ : CalcUiCppViewPluginBase │
|
|
│ int add(int a, int b) { │
|
|
│ return m_logos->calc_module.add(a,b); │
|
|
│ } │
|
|
│ │ │
|
|
│ │ LogosModules typed SDK │
|
|
│ ▼ │
|
|
│ calc_module (loaded in ui-host) │
|
|
└─────────────────────────────────────────────┘
|
|
```
|
|
|
|
The `.rep` file declares the interface. At build time, Qt's `repc` compiler generates:
|
|
|
|
- **`CalcUiCppSimpleSource`** — base class the backend inherits from
|
|
- **`CalcUiCppReplica`** — typed replica the QML view uses
|
|
- **`calc_ui_cpp_replica_factory`** — separate plugin that the host loads to create typed replicas
|
|
|
|
---
|
|
|
|
## Step 1: Scaffold
|
|
|
|
```bash
|
|
mkdir logos-calc-ui-cpp && cd logos-calc-ui-cpp
|
|
nix flake init -t github:logos-co/logos-module-builder/tutorial-v2#ui-qml-backend
|
|
git init && git add -A
|
|
```
|
|
|
|
This creates the template. We'll customize it for our calculator.
|
|
|
|
---
|
|
|
|
## Step 2: metadata.json
|
|
|
|
```json
|
|
{
|
|
"name": "calc_ui_cpp",
|
|
"version": "1.0.0",
|
|
"type": "ui_qml",
|
|
"category": "tools",
|
|
"description": "Calculator C++ UI — QML view with process-isolated backend",
|
|
"main": "calc_ui_cpp_plugin",
|
|
"view": "qml/Main.qml",
|
|
"icon": "icons/calc.png",
|
|
"dependencies": ["calc_module"],
|
|
|
|
"nix": {
|
|
"packages": { "build": [], "runtime": [] },
|
|
"external_libraries": [],
|
|
"cmake": { "find_packages": [], "extra_sources": [] }
|
|
}
|
|
}
|
|
```
|
|
|
|
Key fields:
|
|
|
|
- `"type": "ui_qml"` — tells the builder this is a QML view module
|
|
- `"main": "calc_ui_cpp_plugin"` — the backend Qt plugin library (without extension)
|
|
- `"view": "qml/Main.qml"` — the QML entry point
|
|
- `"dependencies": ["calc_module"]` — core modules the backend calls
|
|
|
|
---
|
|
|
|
## Step 3: The `.rep` File
|
|
|
|
Create `src/calc_ui_cpp.rep`:
|
|
|
|
```rep
|
|
class CalcUiCpp
|
|
{
|
|
PROP(QString status READWRITE)
|
|
|
|
SLOT(int add(int a, int b))
|
|
SLOT(int multiply(int a, int b))
|
|
SLOT(int factorial(int n))
|
|
SLOT(int fibonacci(int n))
|
|
SLOT(QString libVersion())
|
|
}
|
|
```
|
|
|
|
This is the **single source of truth** for the remote interface. `repc` generates:
|
|
|
|
- `rep_calc_ui_cpp_source.h` — `CalcUiCppSimpleSource` with virtual slots the backend overrides
|
|
- `rep_calc_ui_cpp_replica.h` — `CalcUiCppReplica` with typed methods and auto-synced properties
|
|
|
|
**PROP** values auto-sync from backend to QML replica. **SLOT** return values are delivered as `QRemoteObjectPendingReply` — use `logos.watch()` in QML to get them as JS Promises.
|
|
|
|
---
|
|
|
|
## Step 3.1: Update the interface header
|
|
|
|
The scaffolded template may create an interface file like `src/ui_example_interface.h`. Rename it to match this tutorial and make sure the class/IID names are updated, or the plugin metadata wiring will break.
|
|
|
|
```bash
|
|
# If your scaffold created ui_example files, rename the interface header:
|
|
mv src/ui_example_interface.h src/calc_ui_cpp_interface.h
|
|
```
|
|
|
|
Set `src/calc_ui_cpp_interface.h` to:
|
|
|
|
```cpp
|
|
#pragma once
|
|
|
|
#include <QObject>
|
|
#include <QString>
|
|
#include "interface.h"
|
|
|
|
class CalcUiCppInterface : public PluginInterface
|
|
{
|
|
public:
|
|
virtual ~CalcUiCppInterface() = default;
|
|
};
|
|
|
|
#define CalcUiCppInterface_iid "org.logos.CalcUiCppInterface"
|
|
Q_DECLARE_INTERFACE(CalcUiCppInterface, CalcUiCppInterface_iid)
|
|
```
|
|
|
|
Your plugin header should then include `calc_ui_cpp_interface.h` and use:
|
|
- `Q_PLUGIN_METADATA(IID CalcUiCppInterface_iid FILE "metadata.json")`
|
|
- `Q_INTERFACES(CalcUiCppInterface)`
|
|
|
|
If the interface filename or IID symbol doesn't match, you'll typically get build errors (missing header/symbol) or plugin-load failures at runtime.
|
|
|
|
---
|
|
|
|
## Step 4: CMakeLists.txt
|
|
|
|
```cmake
|
|
cmake_minimum_required(VERSION 3.14)
|
|
project(CalcUiCppPlugin LANGUAGES CXX)
|
|
|
|
if(DEFINED ENV{LOGOS_MODULE_BUILDER_ROOT})
|
|
include($ENV{LOGOS_MODULE_BUILDER_ROOT}/cmake/LogosModule.cmake)
|
|
else()
|
|
message(FATAL_ERROR "LogosModule.cmake not found. Set LOGOS_MODULE_BUILDER_ROOT.")
|
|
endif()
|
|
|
|
logos_module(
|
|
NAME calc_ui_cpp
|
|
REP_FILE src/calc_ui_cpp.rep
|
|
SOURCES
|
|
src/calc_ui_cpp_interface.h
|
|
src/calc_ui_cpp_plugin.h
|
|
src/calc_ui_cpp_plugin.cpp
|
|
)
|
|
```
|
|
|
|
`REP_FILE` tells `logos_module()` to:
|
|
|
|
1. Run `repc` to generate source/replica headers
|
|
2. Generate `LogosViewPluginBase` (typed remoting base class)
|
|
3. Build a separate `calc_ui_cpp_replica_factory` shared library
|
|
|
|
---
|
|
|
|
## Step 5: C++ Backend Plugin
|
|
|
|
### `src/calc_ui_cpp_plugin.h`
|
|
|
|
```cpp
|
|
#pragma once
|
|
|
|
#include <QString>
|
|
#include <QVariantList>
|
|
#include "calc_ui_cpp_interface.h"
|
|
#include "LogosViewPluginBase.h"
|
|
#include "rep_calc_ui_cpp_source.h"
|
|
|
|
class LogosAPI;
|
|
class LogosModules;
|
|
|
|
class CalcUiCppPlugin : public CalcUiCppSimpleSource,
|
|
public CalcUiCppInterface,
|
|
public CalcUiCppViewPluginBase
|
|
{
|
|
Q_OBJECT
|
|
Q_PLUGIN_METADATA(IID CalcUiCppInterface_iid FILE "metadata.json")
|
|
Q_INTERFACES(CalcUiCppInterface)
|
|
|
|
public:
|
|
explicit CalcUiCppPlugin(QObject* parent = nullptr);
|
|
~CalcUiCppPlugin() override;
|
|
|
|
QString name() const override { return "calc_ui_cpp"; }
|
|
QString version() const override { return "1.0.0"; }
|
|
|
|
Q_INVOKABLE void initLogos(LogosAPI* api);
|
|
|
|
// Slots from .rep — override the generated virtuals
|
|
int add(int a, int b) override;
|
|
int multiply(int a, int b) override;
|
|
int factorial(int n) override;
|
|
int fibonacci(int n) override;
|
|
QString libVersion() override;
|
|
|
|
signals:
|
|
void eventResponse(const QString& eventName, const QVariantList& args);
|
|
|
|
private:
|
|
LogosAPI* m_logosAPI = nullptr;
|
|
LogosModules* m_logos = nullptr;
|
|
};
|
|
```
|
|
|
|
Three base classes:
|
|
|
|
- **`CalcUiCppSimpleSource`** — generated from `.rep`, provides the typed source for Qt Remote Objects
|
|
- **`CalcUiCppInterface`** — standard Logos plugin interface (`name()`, `version()`)
|
|
- **`CalcUiCppViewPluginBase`** — generated, provides `setBackend()` and `enableRemoting()`
|
|
|
|
### `src/calc_ui_cpp_plugin.cpp`
|
|
|
|
```cpp
|
|
#include "calc_ui_cpp_plugin.h"
|
|
#include "logos_api.h"
|
|
#include "logos_sdk.h"
|
|
|
|
CalcUiCppPlugin::CalcUiCppPlugin(QObject* parent)
|
|
: CalcUiCppSimpleSource(parent) {}
|
|
|
|
CalcUiCppPlugin::~CalcUiCppPlugin() { delete m_logos; }
|
|
|
|
void CalcUiCppPlugin::initLogos(LogosAPI* api)
|
|
{
|
|
m_logosAPI = api;
|
|
m_logos = new LogosModules(api);
|
|
// Register this object as the Remote Objects source
|
|
setBackend(this);
|
|
}
|
|
|
|
int CalcUiCppPlugin::add(int a, int b)
|
|
{
|
|
return m_logos->calc_module.add(a, b);
|
|
}
|
|
|
|
int CalcUiCppPlugin::multiply(int a, int b)
|
|
{
|
|
return m_logos->calc_module.multiply(a, b);
|
|
}
|
|
|
|
int CalcUiCppPlugin::factorial(int n)
|
|
{
|
|
return m_logos->calc_module.factorial(n);
|
|
}
|
|
|
|
int CalcUiCppPlugin::fibonacci(int n)
|
|
{
|
|
return m_logos->calc_module.fibonacci(n);
|
|
}
|
|
|
|
QString CalcUiCppPlugin::libVersion()
|
|
{
|
|
return m_logos->calc_module.libVersion();
|
|
}
|
|
```
|
|
|
|
Key points:
|
|
|
|
- Constructor calls `CalcUiCppSimpleSource(parent)` — not `QObject(parent)`
|
|
- `initLogos()` calls `setBackend(this)` to register with the Remote Objects host
|
|
- Slots return values directly — they travel back to the QML replica via Qt Remote Objects
|
|
- `m_logos->calc_module.add(a, b)` uses the generated typed SDK (type-safe, no QVariant)
|
|
|
|
---
|
|
|
|
## Step 6: QML View
|
|
|
|
Create `src/qml/Main.qml`:
|
|
|
|
```qml
|
|
import QtQuick
|
|
import QtQuick.Controls
|
|
import QtQuick.Layouts
|
|
|
|
|
|
Item {
|
|
id: root
|
|
|
|
property string result: ""
|
|
property string errorText: ""
|
|
|
|
// Typed replica of the backend running in ui-host
|
|
readonly property var backend: logos.module("calc_ui_cpp")
|
|
|
|
// "status" property from the .rep — auto-synced via Qt Remote Objects
|
|
readonly property string status: backend ? backend.status : ""
|
|
|
|
function callCalc(method, args) {
|
|
if (!backend) {
|
|
root.errorText = "Backend not available"
|
|
return
|
|
}
|
|
root.errorText = ""
|
|
root.result = "..."
|
|
// logos.watch() wraps the pending reply in a JS Promise
|
|
logos.watch(backend[method].apply(backend, args),
|
|
function(value) { root.result = String(value) },
|
|
function(error) { root.errorText = String(error) }
|
|
)
|
|
}
|
|
|
|
ColumnLayout {
|
|
anchors.fill: parent
|
|
anchors.margins: 24
|
|
spacing: 16
|
|
|
|
Text {
|
|
text: "Calculator (C++ backend)"
|
|
font.pixelSize: 20
|
|
color: "#ffffff"
|
|
}
|
|
|
|
RowLayout {
|
|
spacing: 12
|
|
|
|
TextField {
|
|
id: inputA; placeholderText: "a"
|
|
Layout.preferredWidth: 80
|
|
validator: IntValidator {}
|
|
}
|
|
TextField {
|
|
id: inputB; placeholderText: "b"
|
|
Layout.preferredWidth: 80
|
|
validator: IntValidator {}
|
|
}
|
|
Button {
|
|
text: "Add"
|
|
onClicked: root.callCalc("add", [parseInt(inputA.text) || 0,
|
|
parseInt(inputB.text) || 0])
|
|
}
|
|
Button {
|
|
text: "Multiply"
|
|
onClicked: root.callCalc("multiply", [parseInt(inputA.text) || 0,
|
|
parseInt(inputB.text) || 0])
|
|
}
|
|
}
|
|
|
|
Rectangle {
|
|
Layout.fillWidth: true; height: 56
|
|
color: root.errorText ? "#3d1a1a" : "#1a2d1a"
|
|
radius: 8
|
|
Text {
|
|
anchors.centerIn: parent
|
|
text: root.errorText || root.result || "Press a button"
|
|
color: root.errorText ? "#f85149" : "#56d364"
|
|
font.pixelSize: 15
|
|
}
|
|
}
|
|
|
|
Text {
|
|
text: "Backend status: " + root.status
|
|
color: "#8b949e"; font.pixelSize: 13
|
|
}
|
|
}
|
|
}
|
|
```
|
|
|
|
Key patterns:
|
|
|
|
- `logos.module("calc_ui_cpp")` — gets the typed replica (auto-synced properties)
|
|
- `backend.status` — PROP from `.rep`, updates automatically
|
|
- `logos.watch(backend.add(1, 2), ...)` — SLOT return value as JS Promise
|
|
- ``— required for`logos.watch()`
|
|
|
|
---
|
|
|
|
## Step 6.5: Use the Logos Design System in your QML
|
|
|
|
The QML you load above runs inside the host (`logos-basecamp` / `logos-standalone-app`), which already has `logos-design-system` on the QML import path. Use its themed components rather than rolling your own visuals — your module gets the polished look automatically as the design system evolves.
|
|
|
|
```qml
|
|
import Logos.Theme
|
|
import Logos.Controls
|
|
import Logos.Icons // optional shared icon assets
|
|
|
|
LogosButton {
|
|
text: qsTr("Add")
|
|
onClicked: root.callCalc("add", [parseInt(inputA.text) || 0,
|
|
parseInt(inputB.text) || 0])
|
|
}
|
|
|
|
LogosTextField {
|
|
id: inputA
|
|
placeholderText: qsTr("a")
|
|
}
|
|
|
|
Rectangle {
|
|
color: Theme.palette.backgroundSecondary
|
|
radius: Theme.spacing.radiusSmall
|
|
LogosText { text: qsTr("Result"); color: Theme.palette.text }
|
|
}
|
|
```
|
|
|
|
**Discover what's available** by running the storybook:
|
|
|
|
```bash
|
|
cd repos/logos-design-system && nix run
|
|
```
|
|
|
|
The sidebar splits components into:
|
|
|
|
- **Controls** — designed per Figma, production-ready (`LogosButton`, `LogosBadge`, `LogosCheckbox`, `LogosComboBox`, `LogosIconButton`, `LogosPaginator`, `LogosSearchBar`, `LogosTabBar`, `LogosTable`, `LogosText`, `LogosTextField`, `LogosToolTip`, …).
|
|
- **Controls (not designed)** — placeholders with stable APIs but unstyled visuals (`LogosDialog`, `LogosDrawer`, `LogosScrollView`, `LogosSpinner`, `LogosTextArea`, `LogosSwitch`, …). You can ship with them; they'll get the polished look applied later without you having to change your QML.
|
|
|
|
**Theme tokens** (use these instead of hex literals or magic font sizes):
|
|
|
|
- `Theme.palette.*` — `background`, `backgroundSecondary`, `surface`, `text`, `textSecondary`, `border`, `primary`, `success`, `warning`, `error`, `info`, `hover`, `pressed`, …
|
|
- `Theme.spacing.*` — `tiny`, `small`, `medium`, `large`, `xlarge`, `xxlarge`, `radiusSmall`, `radiusMedium`, `radiusLarge`
|
|
- `Theme.typography.*` — `pageTitleText` (36), `titleText` (30), `panelTitleText` (24), `subtitleText` (16), `primaryText` (14), `secondaryText` (12); `weightRegular` / `weightMedium` / `weightBold`; `publicSans`
|
|
- `Logos.Icons.LogosIcons.*` — `arrowLeft`, `arrowRight`, `refresh`, `install`, `trash`, `more`, `search`, …
|
|
|
|
**Feedback and contributions**
|
|
|
|
Feel free to report bugs, file feature requests, or contribute components / theme tokens upstream — all welcome at `logos-co/logos-design-system`. The same fix lifts every consumer, so upstreaming is the most impactful path. If you can sketch the public API you'd like to use in a feature request, it makes review and implementation much faster.
|
|
|
|
---
|
|
|
|
## Step 7: flake.nix
|
|
|
|
```nix
|
|
{
|
|
description = "Calculator C++ UI plugin — QML view with process-isolated backend";
|
|
|
|
inputs = {
|
|
logos-module-builder.url = "github:logos-co/logos-module-builder/tutorial-v2";
|
|
|
|
# Option A: point to a remote repo (for CI or when calc_module is published)
|
|
calc_module.url = "github:logos-co/logos-tutorial/tutorial-v2?dir=logos-calc-module";
|
|
|
|
# Option B: point to your local checkout (for local development)
|
|
# calc_module.url = "path:../logos-calc-module";
|
|
};
|
|
|
|
outputs = inputs@{ logos-module-builder, ... }:
|
|
logos-module-builder.lib.mkLogosQmlModule {
|
|
src = ./.;
|
|
configFile = ./metadata.json;
|
|
flakeInputs = inputs;
|
|
};
|
|
}
|
|
```
|
|
|
|
The `calc_module` input attribute name must match the dependency name in `metadata.json`. The URL can be:
|
|
|
|
- **`github:`** — fetches from a remote GitHub repo. Use for CI or when `calc_module` is published.
|
|
- **`path:`** — points to a local directory on disk (e.g., `path:../logos-calc-module`). Use during local development.
|
|
|
|
> **Important:** `calc_module` bundles a small C library (`libcalc`) compiled **from source** during its own Nix build — there's no prebuilt `.so`/`.dylib` to stage. Building `calc_module` (which happens automatically when this app pulls it in) compiles it for you. See [Part 1, Step 1.5](tutorial-wrapping-c-library.md#15-add-a-makefile-to-build-the-library).
|
|
|
|
`mkLogosQmlModule` handles everything: compiles the C++ backend (because `main` is set), bundles the QML view, generates LGX packages, and wires up `nix run`.
|
|
|
|
---
|
|
|
|
## Step 8: Build and Run
|
|
|
|
First, make sure your local `calc_module` builds cleanly — its C library is compiled from source during the Nix build (from `lib/libcalc.c` via `lib/Makefile`), so there's nothing to pre-build by hand (see [Part 1, Step 1.5](tutorial-wrapping-c-library.md#15-add-a-makefile-to-build-the-library)):
|
|
|
|
```bash
|
|
cd ../logos-calc-module && git add -A && nix build && cd -
|
|
```
|
|
|
|
Then build and run. Choose the approach that matches your `flake.nix` setup:
|
|
|
|
```bash
|
|
git add -A
|
|
|
|
# If flake.nix uses path:../logos-calc-module — just run directly:
|
|
nix run
|
|
|
|
# If flake.nix uses github: — override to use your local checkout:
|
|
nix run --override-input calc_module path:../logos-calc-module
|
|
|
|
# Or from the workspace:
|
|
./scripts/ws run logos-calc-ui-cpp --local logos-calc-ui-cpp logos-calc-module
|
|
```
|
|
|
|
### Live reloading QML with `DEV_QML_PATH`
|
|
|
|
For QML iteration, point `DEV_QML_PATH` at the directory that contains your view entry's **basename** (from `metadata.json` `"view"`). This tutorial sets `"view": "qml/Main.qml"`, so the directory must contain `Main.qml` (here: `qml/` at the repo root):
|
|
|
|
```bash
|
|
DEV_QML_PATH=$PWD/qml nix run .
|
|
```
|
|
|
|
When `DEV_QML_PATH` is set, `logos-standalone-app` loads QML from your source tree at runtime instead of the installed copy — so edits to `Main.qml` (and any QML under that tree) are picked up on the next relaunch without you having to re-sync files.
|
|
|
|
**Important — what this does *not* skip.** `nix run` always re-evaluates the flake and rehashes the source tree before launching. By default `src = ./.` includes every tracked file, including `*.qml` — so:
|
|
|
|
- **Any source change, including QML edits, rebuilds the plugin** before the app starts. `DEV_QML_PATH` only kicks in *after* the build is done; it doesn't shortcut the rebuild itself.
|
|
- **C++ / `.rep` / `metadata.json` / CMake changes** rebuild as normal.
|
|
- The flake-evaluation overhead on each `nix run` is fixed and unavoidable while invoking through nix.
|
|
|
|
For the absolute fastest loop (no nix involvement after the first build), do the build once and run the resulting binary directly:
|
|
|
|
```bash
|
|
# Build once — populates result/ in the nix store
|
|
nix build .
|
|
|
|
# Subsequent runs: invoke the bundled standalone wrapper directly,
|
|
# skipping nix entirely. DEV_QML_PATH still redirects QML loading.
|
|
DEV_QML_PATH=$PWD/qml ./result/bin/run-logos-standalone-ui
|
|
```
|
|
|
|
(Adjust the binary name to whatever `ls result/bin/` shows on your build.)
|
|
|
|
> **Naming:** Only `DEV_QML_PATH` is honored by `logos-standalone-app`. See `repos/logos-standalone-app/README.md`.
|
|
|
|
> This does not work with `logos-basecamp` — Basecamp loads QML plugins from its own install tree, so source edits are not picked up until you rebuild and reinstall the `.lgx`.
|
|
|
|
---
|
|
|
|
## Step 9: How the Pieces Connect
|
|
|
|
1. `nix build` → compiles the C++ plugin + replica factory, bundles QML view
|
|
2. `nix run` → launches `logos-standalone-app` which:
|
|
- Loads `calc_module` (dependency)
|
|
- Spawns a `ui-host` child process with `calc_ui_cpp_plugin.so`
|
|
- `ui-host` calls `initLogos()` → `setBackend(this)` → `enableRemoting(host)`
|
|
- Backend is now accessible over a local socket
|
|
3. Host app loads `calc_ui_cpp_replica_factory.dylib` → creates a typed replica
|
|
4. QML gets the replica via `logos.module("calc_ui_cpp")`
|
|
5. `backend.add(1, 2)` → Qt Remote Objects sends call to ui-host → backend runs → returns result
|
|
6. `backend.status` auto-syncs whenever the backend calls `setStatus(...)`
|
|
|
|
---
|
|
|
|
## Step 10: UI Integration Tests (Optional)
|
|
|
|
Add automated UI tests using the [logos-qt-mcp](https://github.com/logos-co/logos-qt-mcp) test framework. Just create `.mjs` files in `tests/` and `logos-module-builder` auto-wires `nix build .#integration-test`.
|
|
|
|
Create `tests/ui-tests.mjs`:
|
|
|
|
```javascript
|
|
import { resolve } from "node:path";
|
|
|
|
// CI sets LOGOS_QT_MCP automatically; for interactive use: nix build .#test-framework -o result-mcp
|
|
const root =
|
|
process.env.LOGOS_QT_MCP ||
|
|
new URL("../result-mcp", import.meta.url).pathname;
|
|
const { test, run } = await import(
|
|
resolve(root, "test-framework/framework.mjs")
|
|
);
|
|
|
|
test("calc_ui_cpp: loads and shows title", async (app) => {
|
|
await app.waitFor(
|
|
async () => {
|
|
await app.expectTexts(["UI Example (C++ backend)"]);
|
|
},
|
|
{ timeout: 15000, interval: 500, description: "UI to load" },
|
|
);
|
|
});
|
|
|
|
test("calc_ui_cpp: shows connection status", async (app) => {
|
|
await app.expectTexts(["Connecting to backend..."]);
|
|
});
|
|
|
|
test("calc_ui_cpp: add button visible", async (app) => {
|
|
await app.expectTexts(["Add"]);
|
|
});
|
|
|
|
run();
|
|
```
|
|
|
|
```bash
|
|
git add tests/
|
|
|
|
# Hermetic CI test
|
|
nix build .#integration-test -L
|
|
|
|
# Interactive
|
|
nix build .#test-framework -o result-mcp
|
|
nix run . # app with inspector on :3768
|
|
node tests/ui-tests.mjs # in another terminal
|
|
```
|
|
|
|
---
|
|
|
|
## Comparison: .rep Interface Patterns
|
|
|
|
| Pattern | .rep declaration | Backend C++ | QML usage |
|
|
| ---------------- | ------------------------------------ | ------------------------------------------- | ---------------------------------------------------------------------- |
|
|
| **Return value** | `SLOT(int add(int a, int b))` | `int add(...) override { return ...; }` | `logos.watch(backend.add(1,2), cb)` |
|
|
| **Property** | `PROP(QString status READWRITE)` | `setStatus("Ready")` (inherited) | `backend.status` (auto-syncs) |
|
|
| **Signal** | `SIGNAL(errorOccurred(QString msg))` | `emit errorOccurred("fail")` | `Connections { target: backend; function onErrorOccurred(msg) {...} }` |
|
|
| **Model** | (use Q_PROPERTY on backend) | `Q_PROPERTY(QAbstractItemModel* items ...)` | `logos.model("calc_ui_cpp", "items")` |
|
|
|
|
---
|
|
|
|
## Next Steps
|
|
|
|
- Add more `.rep` properties/signals for richer UI state
|
|
- Use `logos.model()` for list views backed by `QAbstractItemModel`
|
|
- Package as `.lgx` for distribution: `nix build .#lgx`
|
|
- **Use the Logos Design System** in your QML — see [Step 6.5](#step-65-use-the-logos-design-system-in-your-qml). Browse components in the storybook (`cd repos/logos-design-system && nix run`); file issues at `logos-co/logos-design-system` (bugs on designed components, *feature* type for new components / variants / theme tokens).
|
|
- See [logos-package-manager-ui](https://github.com/logos-co/logos-package-manager-ui) for a production example
|