QtWayland

In a Qt Wayland Compositor, QWaylandSeat represents a group of input devices (keyboard, pointer, touch) that share a common set of input events. It is used to manage input focus and dispatch hardware or synthetic input events to Wayland clients.

Key Capabilities

You can define the capabilities of a seat using CapabilityFlags:

• Pointer (0x01)
• Keyboard (0x02)
• Touch (0x04)
• DefaultCapabilities (Pointer | Keyboard | Touch)

Input Focus Management

• Keyboard Focus: Use setKeyboardFocus(QWaylandSurface *surface) to direct keyboard input to a specific surface. Use keyboardFocus() to retrieve the current focused surface.
• Mouse Focus: Use setMouseFocus(QWaylandView *view) to set the current mouse focus. Use mouseFocus() to retrieve it.

Event Dispatching

QWaylandSeat provides methods to manually inject input events into the Wayland protocol:

• Mouse: sendMouseMoveEvent, sendMousePressEvent, sendMouseReleaseEvent, and sendMouseWheelEvent.
• Keyboard: sendKeyPressEvent, sendKeyReleaseEvent, or sendKeyEvent (for Qt key codes).
• Touch: sendTouchPointPressed, sendTouchPointMoved, sendTouchPointReleased, and sendTouchFrameEvent.

QML Integration

The class is available in QML as WaylandSeat (version 1.0).

// Example: Creating a seat with specific capabilities
QWaylandSeat *seat = new QWaylandSeat(compositor, QWaylandSeat::Keyboard | QWaylandSeat::Pointer);

// Example: Sending a mouse move event to a view
seat->sendMouseMoveEvent(view, QPointF(100.0, 100.0));

// Example: Setting keyboard focus to a surface
seat->setKeyboardFocus(surface);

In a Qt Wayland Compositor, QWaylandSurface represents a Wayland surface provided by a client. It acts as the container for buffers, roles, and input regions. Developers use it to track surface properties like size, scale, and orientation, and to manage how the surface is presented via QWaylandView objects.

Key responsibilities include:

• Role Management: Assigning a QWaylandSurfaceRole to define how the surface should be treated (e.g., as a top-level window or a sub-surface).
• Buffer Tracking: Monitoring bufferSize, bufferScale, and hasContent to know when new pixel data is available.
• Input Handling: Using inputRegionContains(position) to determine if a specific coordinate falls within the surface's interactive area.
• Lifecycle: Managing the surface via initialize() and destroy() methods.

// Example: Checking surface content and size
if (surface->hasContent()) {
    QSize size = surface->bufferSize();
    int scale = surface->bufferScale();
    // Process the surface content...
}

Since Qt does not provide a direct API for setting the unique IDs required by the ivi-application and ivi-controller protocols, you must use the QT_IVI_SURFACE_ID environment variable.

ID Generation Rules

• Manual Setting: Set QT_IVI_SURFACE_ID to define the base ID. This value is used for both the ivi-surface and the ivi-layer.
• Automatic Increment: If an application requires more than two surfaces, the ivi-surface IDs will be incremented automatically.
• Internal Generation: If QT_IVI_SURFACE_ID is not set, the IDs for ivi-surface and ivi-layer will be generated internally by the system.

ID Bit Structure

The QT_IVI_SURFACE_ID is a 32-bit value composed of a process ID and a surface ID:

• Bits 0 to 22: Process ID.
• Bits 23 to 32: Surface ID within that process.

Example: If the process ID is 0x765 and there are two surfaces:

• The ivi-layer ID is 0x765.
• The first ivi-surface ID is 0x765.
• The second ivi-surface ID is 0x00400765.

# Example of setting the environment variable before running the application
export QT_IVI_SURFACE_ID=0x765
./your_ivi_application

If you are building a custom compositor, you can use QWaylandSeat to translate host input events (like those from a mouse or keyboard) into Wayland protocol events for clients.

Mouse Events

• void sendMouseMoveEvent(QWaylandView *surface, const QPointF &localPos, const QPointF &outputSpacePos = QPointF())
• void sendMousePressEvent(Qt::MouseButton button)
• void sendMouseReleaseEvent(Qt::MouseButton button)
• void sendMouseWheelEvent(Qt::Orientation orientation, int delta)

Keyboard Events

• void sendKeyPressEvent(uint code)
• void sendKeyReleaseEvent(uint code)
• void sendKeyEvent(int qtKey, bool pressed): Uses Qt key codes.
• void sendUnicodeKeyPressEvent(uint unicode) (Available since version 6.7)
• void sendUnicodeKeyReleaseEvent(uint unicode) (Available since version 6.7)

Touch Events

• uint sendTouchPointPressed(QWaylandSurface *surface, int id, const QPointF &position)
• uint sendTouchPointMoved(QWaylandSurface *surface, int id, const QPointF &position)
• uint sendTouchPointReleased(QWaylandSurface *surface, int id, const QPointF &position)
• void sendTouchFrameEvent(QWaylandClient *client)
• void sendTouchCancelEvent(QWaylandClient *client)