### Configure qmake project file

Source: https://photoflare.github.io/photoflare/plugins.html

Standard qmake configuration for a Photoflare plugin library, ensuring correct build settings and file inclusion.

```qmake
QT       += core gui widgets
CONFIG   += plugin c++17
CONFIG   -= app_bundle
TEMPLATE  = lib

TARGET = myplugin

INCLUDEPATH += /path/to/photoflare/src/plugins

SOURCES += MyPlugin.cpp
OTHER_FILES += myplugin.json

DESTDIR = $$OUT_PWD/plugins
```

--------------------------------

### Implement a minimal exporter plugin

Source: https://photoflare.github.io/photoflare/plugins.html

Defines a class inheriting from QObject and IExporterPlugin, providing metadata and the exportImage logic.

```cpp
#include <QObject>
#include <QtPlugin>
#include <QImage>
#include <QImageWriter>
#include "IPhotoflarePlugin.h"
#include "AppContext.h"

class MyExporterPlugin : public QObject, public IExporterPlugin
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID "org.photoflare.ExporterPlugin/1.0" FILE "myexporter.json")
    Q_INTERFACES(IPhotoflarePlugin IExporterPlugin)
public:
    QString     pluginId()    const override { return "com.example.myexporter"; }
    QString     displayName() const override { return "My Format Exporter"; }
    QString     version()     const override { return "1.0.0"; }
    QString     author()      const override { return "Your Name"; }
    QString     formatName()  const override { return "My Format"; }
    QStringList supportedExtensions() const override { return { "myf" }; }

    void initialise(AppContext* ctx) override { m_ctx = ctx; }

    bool exportImage(const QImage&      image,
                     const QString&     filePath,
                     const QVariantMap& settings,
                     QString&           errorMessage) const override
    {
        // write image to filePath; return false and set errorMessage on failure
        if (!image.save(filePath)) {
            errorMessage = "Failed to save image.";
            return false;
        }
        return true;
    }

private:
    AppContext* m_ctx = nullptr;
};

#include "MyExporterPlugin.moc"
```

--------------------------------

### Implement a Minimal Filter Plugin

Source: https://photoflare.github.io/photoflare/plugins.html

A basic implementation of a filter plugin using the IFilterPlugin interface, including metadata and parameter definitions.

```cpp
#include <QObject>
#include <QtPlugin>
#include <QImage>
#include "IPhotoflarePlugin.h"
#include "AppContext.h"

class MyFilterPlugin : public QObject, public IFilterPlugin
{
    Q_OBJECT
    Q_PLUGIN_METADATA(IID "org.photoflare.FilterPlugin/1.0" FILE "myplugin.json")
    Q_INTERFACES(IPhotoflarePlugin IFilterPlugin)
public:
    QString pluginId()    const override { return "com.example.myplugin"; }
    QString displayName() const override { return "My Filter"; }
    QString version()     const override { return "1.0.0"; }
    QString author()      const override { return "Your Name"; }
    QString menuPath()    const override { return "Filters/My Plugins"; }

    void initialise(AppContext* ctx) override { m_ctx = ctx; }

    QList<PluginParam> parameters() const override
    {
        return {
            { "strength", "Strength", PluginParam::Float, 0.5, 0.0, 1.0, {} },
        };
    }

    QImage apply(const QImage& input, const QVariantMap& params) const override
    {
        const float strength = params.value("strength", 0.5f).toFloat();
        // ... transform the image ...
        return input; // replace with your result
    }

private:
    AppContext* m_ctx = nullptr;
};

#include "MyFilterPlugin.moc"
```

--------------------------------

### AppContext API Methods

Source: https://photoflare.github.io/photoflare/plugins.html

Methods available on the AppContext object passed to plugins during initialization.

```APIDOC
## AppContext Methods

### currentImage()
Returns a pointer to the currently open image, or nullptr if no image is open.

### markCanvasDirty()
Commits direct modifications to the current image back to the canvas and triggers a repaint.

### pushUndoState(const QString& label)
Snapshots the current image into the undo stack.

### registerMenuAction(const QString& path, QAction* action)
Adds an action to the menu bar using a path separator (e.g., "Tools/My Plugin").

### registerDockPanel(const QString& title, QWidget* panel)
Registers a widget as a dockable side panel.

### showStatusMessage(const QString& msg, int ms)
Displays a transient message in the status bar for a specified duration.

### pluginSettings(const QString& pluginId)
Returns a QSettings instance scoped to the provided plugin ID.

### mainWindow()
Returns the main window pointer for parenting dialogs.

### appVersion()
Returns the Photoflare version string.
```

--------------------------------

### Define plugin metadata

Source: https://photoflare.github.io/photoflare/plugins.html

The JSON metadata file is embedded into the compiled library at build time via Q_PLUGIN_METADATA and does not require distribution.

```json
{
    "id":          "com.example.myplugin",
    "name":        "My Plugin",
    "version":     "1.0.0",
    "description": "A short description."
}
```

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