- Qt 5.15
- Qt Wayland Compositor
- C++ Classes
- QWaylandBufferRef
- Qt 5.15.18 Reference Documentation

# QWaylandBufferRef Class

The QWaylandBufferRef class holds the reference to a surface buffer. More...

Header: | #include <QWaylandBufferRef>
qmake: | QT += waylandcompositor
Since: | Qt 5.8

This class was introduced in Qt 5.8.

- List of all members, including inherited members

## Public Functions

| QWaylandBufferRef(const QWaylandBufferRef &ref)
| QWaylandBufferRef()
QWaylandBufferRef & | operator=(const QWaylandBufferRef &ref)
| ~QWaylandBufferRef()
bool | hasBuffer() const
bool | hasContent() const
QImage | image() const
bool | isDestroyed() const
bool | isNull() const
bool | isSharedMemory() const
quintptr | lockNativeBuffer()
QWaylandSurface::Origin | origin() const
QSize | size() const
QOpenGLTexture * | toOpenGLTexture(int plane = 0) const
void | unlockNativeBuffer(quintptr handle)
struct wl_resource * | wl_buffer() const
bool | operator!=(const QWaylandBufferRef &ref)
bool | operator==(const QWaylandBufferRef &ref)

## Detailed Description

This class can be used to reference a surface buffer. As long as a reference to the buffer exists, it is owned by the compositor and the client cannot modify it.

## Member Function Documentation

### QWaylandBufferRef::QWaylandBufferRef(const QWaylandBufferRef &ref)

Creates a new reference to the buffer referenced by ref.

### QWaylandBufferRef::QWaylandBufferRef()

Constructs a null buffer ref.

### QWaylandBufferRef &QWaylandBufferRef::operator=(const QWaylandBufferRef &ref)

Assigns ref to this buffer and adds a reference to it. The previously referenced buffer is dereferenced.

### QWaylandBufferRef::~QWaylandBufferRef()

Dereferences the buffer.

### bool QWaylandBufferRef::hasBuffer() const

Returns true if this QWaylandBufferRef references a buffer. Otherwise returns false.

See also isNull() and hasContent().

### bool QWaylandBufferRef::hasContent() const

Returns true if this QWaylandBufferRef references a buffer that has content. Otherwise returns false.

See also isNull() and hasBuffer().

### QImage QWaylandBufferRef::image() const

Returns an image with the contents of the buffer.

### bool QWaylandBufferRef::isDestroyed() const

Returns true if this QWaylandBufferRef references a buffer that has been destroyed. Otherwise returns false.

### bool QWaylandBufferRef::isNull() const

Returns true if this QWaylandBufferRef does not reference a buffer. Otherwise returns false.

See also hasBuffer() and hasContent().

### bool QWaylandBufferRef::isSharedMemory() const

Returns true if the buffer is a shared memory buffer. Otherwise returns false.

### quintptr QWaylandBufferRef::lockNativeBuffer()

Returns the native handle for this buffer, and marks it as locked so it will not be released until unlockNativeBuffer() is called.

Returns 0 if there is no native handle for this buffer, or if the lock was unsuccessful.

### QWaylandSurface::Origin QWaylandBufferRef::origin() const

Returns the origin of the buffer. If the buffer referenced is null, QWaylandSurface::OriginBottomLeft is returned.

### QSize QWaylandBufferRef::size() const

Returns the size of the buffer. If the buffer referenced is null, an invalid QSize() is returned.

### QOpenGLTexture *QWaylandBufferRef::toOpenGLTexture(int plane = 0) const

Returns an OpenGL texture for the buffer. plane is the index for multi-plane formats, such as YUV.

The returned texture is owned by the buffer. The texture is only valid for as long as the buffer reference exists. The caller of this function must not delete the texture, and must keep a reference to the buffer for as long as the texture is being used.

Returns `nullptr` if there is no valid buffer, or if no texture can be created.

### void QWaylandBufferRef::unlockNativeBuffer(quintptr handle)

Marks the native buffer as no longer in use. handle must correspond to the value returned by a previous call to lockNativeBuffer().

### struct wl_resource *QWaylandBufferRef::wl_buffer() const

Returns the Wayland resource for the buffer.

### bool QWaylandBufferRef::operator!=(const QWaylandBufferRef &ref)

Returns false if this QWaylandBufferRef references the same buffer as ref. Otherwise returns true.

### bool QWaylandBufferRef::operator==(const QWaylandBufferRef &ref)

Returns true if this QWaylandBufferRef references the same buffer as ref. Otherwise returns false.