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Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
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QPlatformGraphicsBuffer Class Referenceabstract

\inmodule QtGui More...

#include <qplatformgraphicsbuffer.h>

+ Inheritance diagram for QPlatformGraphicsBuffer:
+ Collaboration diagram for QPlatformGraphicsBuffer:

Public Types

enum  AccessType {
  None = 0x00 , SWReadAccess = 0x01 , SWWriteAccess = 0x02 , TextureAccess = 0x04 ,
  HWCompositor = 0x08
}
 This enum describes the access that is desired or granted for the graphics buffer. More...
 
enum  Origin { OriginBottomLeft , OriginTopLeft }
 This enum describes the origin of the content of the buffer. More...
 

Signals

void unlocked (AccessTypes previousAccessTypes)
 Signal that is emitted after unlocked has been called.
 
- Signals inherited from QObject
void destroyed (QObject *=nullptr)
 This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
 
void objectNameChanged (const QString &objectName, QPrivateSignal)
 This signal is emitted after the object's name has been changed.
 

Public Member Functions

 Q_ENUM (AccessType)
 
 Q_DECLARE_FLAGS (AccessTypes, AccessType)
 
 Q_ENUM (Origin)
 
 ~QPlatformGraphicsBuffer ()
 Virtual destructor.
 
AccessTypes isLocked () const
 Function to check if the buffer is locked.
 
bool lock (AccessTypes access, const QRect &rect=QRect())
 Before the data can be retrieved or before a buffer can be bound to a texture it needs to be locked.
 
void unlock ()
 Unlocks the current buffer lock.
 
virtual bool bindToTexture (const QRect &rect=QRect()) const
 Binds the content of this graphics buffer into the currently bound texture.
 
virtual const uchardata () const
 Accessor for the bytes of the buffer.
 
virtual uchardata ()
 Accessor for the bytes of the buffer.
 
virtual int bytesPerLine () const
 Accessor for bytes per line in the graphics buffer.
 
int byteCount () const
 Accessor for the length of the data buffer.
 
virtual Origin origin () const
 In origin of the content of the graphics buffer.
 
QSize size () const
 Accessor for content size.
 
QPixelFormat format () const
 Accessor for the pixel format of the buffer.
 
- Public Member Functions inherited from QObject
Q_INVOKABLE QObject (QObject *parent=nullptr)
 Constructs an object with parent object parent.
 
virtual ~QObject ()
 Destroys the object, deleting all its child objects.
 
virtual bool event (QEvent *event)
 This virtual function receives events to an object and should return true if the event e was recognized and processed.
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 Filters events if this object has been installed as an event filter for the watched object.
 
QString objectName () const
 
Q_WEAK_OVERLOAD void setObjectName (const QString &name)
 Sets the object's name to name.
 
void setObjectName (QAnyStringView name)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
QBindable< QStringbindableObjectName ()
 
bool isWidgetType () const
 Returns true if the object is a widget; otherwise returns false.
 
bool isWindowType () const
 Returns true if the object is a window; otherwise returns false.
 
bool isQuickItemType () const
 Returns true if the object is a QQuickItem; otherwise returns false.
 
bool signalsBlocked () const noexcept
 Returns true if signals are blocked; otherwise returns false.
 
bool blockSignals (bool b) noexcept
 If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
 
QThreadthread () const
 Returns the thread in which the object lives.
 
bool moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
 Changes the thread affinity for this object and its children and returns true on success.
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
 
int startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
 
void killTimer (int id)
 Kills the timer with timer identifier, id.
 
void killTimer (Qt::TimerId id)
 
template<typename T >
findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
 
template<typename T >
QList< T > findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
 
template<typename T >
findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
template<typename T >
QList< T > findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QObjectListchildren () const
 Returns a list of child objects.
 
void setParent (QObject *parent)
 Makes the object a child of parent.
 
void installEventFilter (QObject *filterObj)
 Installs an event filter filterObj on this object.
 
void removeEventFilter (QObject *obj)
 Removes an event filter object obj from this object.
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
 
bool disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
 
bool disconnect (const QObject *receiver, const char *member=nullptr) const
 
void dumpObjectTree () const
 Dumps a tree of children to the debug output.
 
void dumpObjectInfo () const
 Dumps information about signal connections, etc.
 
bool setProperty (const char *name, const QVariant &value)
 Sets the value of the object's name property to value.
 
bool setProperty (const char *name, QVariant &&value)
 
QVariant property (const char *name) const
 Returns the value of the object's name property.
 
QList< QByteArraydynamicPropertyNames () const
 
QBindingStoragebindingStorage ()
 
const QBindingStoragebindingStorage () const
 
QObjectparent () const
 Returns a pointer to the parent object.
 
bool inherits (const char *classname) const
 Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.
 

Protected Member Functions

 QPlatformGraphicsBuffer (const QSize &size, const QPixelFormat &format)
 Protected constructor to initialize the private members.
 
virtual bool doLock (AccessTypes access, const QRect &rect=QRect())=0
 This function should be reimplemented by subclasses.
 
virtual void doUnlock ()=0
 This function should remove all locks set on the buffer.
 
- Protected Member Functions inherited from QObject
QObjectsender () const
 Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
 
int senderSignalIndex () const
 
int receivers (const char *signal) const
 Returns the number of receivers connected to the signal.
 
bool isSignalConnected (const QMetaMethod &signal) const
 
virtual void timerEvent (QTimerEvent *event)
 This event handler can be reimplemented in a subclass to receive timer events for the object.
 
virtual void childEvent (QChildEvent *event)
 This event handler can be reimplemented in a subclass to receive child events.
 
virtual void customEvent (QEvent *event)
 This event handler can be reimplemented in a subclass to receive custom events.
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
 QObject (QObjectPrivate &dd, QObject *parent=nullptr)
 

Additional Inherited Members

- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 
- Static Public Member Functions inherited from QObject
static QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
 \threadsafe
 
static QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
 
static bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
 \threadsafe
 
static bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
 
static bool disconnect (const QMetaObject::Connection &)
 Disconnect a connection.
 
template<typename Func1 , typename Func2 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
 
template<typename Func1 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)
 
- Protected Attributes inherited from QObject
QScopedPointer< QObjectDatad_ptr
 
- Properties inherited from QObject
QString objectName
 the name of this object
 

Detailed Description

\inmodule QtGui

Since
5.5

The QPlatformGraphicsBuffer is a windowsystem abstraction for native graphics buffers

Different platforms have different ways of representing graphics buffers. On some platforms, it is possible to create one graphics buffer that you can bind to a texture and also get main memory access to the image bits. On the other hand, on some platforms all graphics buffer abstraction is completely hidden.

QPlatformGraphicsBuffer is an abstraction of a single Graphics Buffer.

There is no public constructor nor any public factory function.

Definition at line 26 of file qplatformgraphicsbuffer.h.

Member Enumeration Documentation

◆ AccessType

This enum describes the access that is desired or granted for the graphics buffer.

\value None \value SWReadAccess \value SWWriteAccess \value TextureAccess \value HWCompositor

Enumerator
None 
SWReadAccess 
SWWriteAccess 
TextureAccess 
HWCompositor 

Definition at line 30 of file qplatformgraphicsbuffer.h.

◆ Origin

This enum describes the origin of the content of the buffer.

\value OriginTopLeft \value OriginBottomLeft

Enumerator
OriginBottomLeft 
OriginTopLeft 

Definition at line 41 of file qplatformgraphicsbuffer.h.

Constructor & Destructor Documentation

◆ ~QPlatformGraphicsBuffer()

QPlatformGraphicsBuffer::~QPlatformGraphicsBuffer ( )

Virtual destructor.

Definition at line 70 of file qplatformgraphicsbuffer.cpp.

◆ QPlatformGraphicsBuffer()

QPlatformGraphicsBuffer::QPlatformGraphicsBuffer ( const QSize & size,
const QPixelFormat & format )
protected

Protected constructor to initialize the private members.

size is the size of the buffer. format is the format of the buffer.

See also
size() format()

Definition at line 60 of file qplatformgraphicsbuffer.cpp.

Member Function Documentation

◆ bindToTexture()

bool QPlatformGraphicsBuffer::bindToTexture ( const QRect & rect = QRect()) const
virtual

Binds the content of this graphics buffer into the currently bound texture.

This function should fail for buffers not capable of locking to TextureAccess.

rect is the subrect which is desired to be bounded to the texture. This argument has a no less than semantic, meaning more (if not all) of the buffer can be bounded to the texture. An empty QRect is interpreted as entire buffer should be bound.

This function only supports binding buffers to the GL_TEXTURE_2D texture target.

Returns true on success, otherwise false.

Definition at line 89 of file qplatformgraphicsbuffer.cpp.

References Q_UNUSED, and rect.

Referenced by QPlatformGraphicsBufferHelper::lockAndBindToTexture().

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◆ byteCount()

int QPlatformGraphicsBuffer::byteCount ( ) const

Accessor for the length of the data buffer.

This function is a convenience function multiplying height of buffer with bytesPerLine().

See also
data() bytesPerLine() size()

Definition at line 198 of file qplatformgraphicsbuffer.cpp.

References bytesPerLine(), QSize::height(), and size().

Referenced by QIOSurfaceGraphicsBuffer::QIOSurfaceGraphicsBuffer().

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◆ bytesPerLine()

int QPlatformGraphicsBuffer::bytesPerLine ( ) const
virtual

Accessor for bytes per line in the graphics buffer.

Reimplemented in QIOSurfaceGraphicsBuffer, and QXcbGraphicsBuffer.

Definition at line 206 of file qplatformgraphicsbuffer.cpp.

Referenced by QPlatformGraphicsBufferHelper::bindSWToTexture(), and byteCount().

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◆ data() [1/2]

uchar * QPlatformGraphicsBuffer::data ( )
virtual

Accessor for the bytes of the buffer.

This function needs to be called on a buffer with SWReadAccess access lock. Behavior is undefined for modifying the memory returned when not having a SWWriteAccess.

Reimplemented in QIOSurfaceGraphicsBuffer, and QXcbGraphicsBuffer.

Definition at line 187 of file qplatformgraphicsbuffer.cpp.

◆ data() [2/2]

const uchar * QPlatformGraphicsBuffer::data ( ) const
virtual

Accessor for the bytes of the buffer.

This function needs to be called on a buffer with SWReadAccess access lock. Behavior is undefined for modifying the memory returned when not having a SWWriteAccess.

Reimplemented in QIOSurfaceGraphicsBuffer, and QXcbGraphicsBuffer.

Definition at line 179 of file qplatformgraphicsbuffer.cpp.

Referenced by QPlatformGraphicsBufferHelper::bindSWToTexture().

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◆ doLock()

QPlatformGraphicsBuffer::doLock ( AccessTypes access,
const QRect & rect = QRect() )
protectedpure virtual

This function should be reimplemented by subclasses.

If one of the access types specified cannot be locked, then all should fail and this function should return false.

rect is the subrect which is desired to be locked. This argument has a no less than semantic, meaning more (if not all) of the buffer can be locked. An empty QRect should be interpreted as the entire buffer should be locked.

It is safe to call isLocked() to verify the current lock state.

Implemented in QIOSurfaceGraphicsBuffer, and QXcbGraphicsBuffer.

Referenced by lock().

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◆ doUnlock()

QPlatformGraphicsBuffer::doUnlock ( )
protectedpure virtual

This function should remove all locks set on the buffer.

It is safe to call isLocked() to verify the current lock state.

Implemented in QIOSurfaceGraphicsBuffer, and QXcbGraphicsBuffer.

Referenced by unlock().

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◆ format()

QPlatformGraphicsBuffer::format ( ) const
inline

Accessor for the pixel format of the buffer.

Definition at line 63 of file qplatformgraphicsbuffer.h.

Referenced by QPlatformGraphicsBufferHelper::bindSWToTexture().

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◆ isLocked()

QPlatformGraphicsBuffer::AccessTypes QPlatformGraphicsBuffer::isLocked ( ) const
inline

Function to check if the buffer is locked.

See also
lock()

Definition at line 49 of file qplatformgraphicsbuffer.h.

Referenced by QPlatformGraphicsBufferHelper::bindSWToTexture(), QIOSurfaceGraphicsBuffer::doLock(), and QIOSurfaceGraphicsBuffer::doUnlock().

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◆ lock()

bool QPlatformGraphicsBuffer::lock ( AccessTypes access,
const QRect & rect = QRect() )

Before the data can be retrieved or before a buffer can be bound to a texture it needs to be locked.

This is a separate function call since this operation might be time consuming, and it would not be satisfactory to do it per function call.

access is the access type wanted.

rect is the subrect which is desired to be locked. This argument has a no less than semantic, meaning more (if not all) of the buffer can be locked. An empty QRect is interpreted as entire buffer should be locked.

Return true on successfully locking all AccessTypes specified access otherwise returns false and no locks have been granted.

Definition at line 117 of file qplatformgraphicsbuffer.cpp.

References doLock(), and rect.

Referenced by QPlatformGraphicsBufferHelper::lockAndBindToTexture().

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◆ origin()

QPlatformGraphicsBuffer::Origin QPlatformGraphicsBuffer::origin ( ) const
virtual

In origin of the content of the graphics buffer.

Default implementation is OriginTopLeft, as this is the coordinate system default for Qt. However, for most regular OpenGL textures this will be OriginBottomLeft.

Reimplemented in QXcbGraphicsBuffer.

Definition at line 219 of file qplatformgraphicsbuffer.cpp.

References OriginTopLeft.

◆ Q_DECLARE_FLAGS()

QPlatformGraphicsBuffer::Q_DECLARE_FLAGS ( AccessTypes ,
AccessType  )

◆ Q_ENUM() [1/2]

QPlatformGraphicsBuffer::Q_ENUM ( AccessType )

◆ Q_ENUM() [2/2]

QPlatformGraphicsBuffer::Q_ENUM ( Origin )

◆ size()

QPlatformGraphicsBuffer::size ( ) const
inline

Accessor for content size.

Definition at line 62 of file qplatformgraphicsbuffer.h.

Referenced by QPlatformGraphicsBufferHelper::bindSWToTexture(), and byteCount().

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◆ unlock()

void QPlatformGraphicsBuffer::unlock ( )

Unlocks the current buffer lock.

This function calls doUnlock, and then emits the unlocked signal with the AccessTypes from before doUnlock was called.

Definition at line 132 of file qplatformgraphicsbuffer.cpp.

References doUnlock(), emit, None, and unlocked().

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◆ unlocked

QPlatformGraphicsBuffer::unlocked ( AccessTypes previousAccessTypes)
signal

Signal that is emitted after unlocked has been called.

previousAccessTypes is the access types locked before unlock was called.

Referenced by unlock().

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The documentation for this class was generated from the following files: