CEnumPins Class
`
`Page 3 of7
`
`Return Values
`
`No return value.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 111j Topic Contents
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`CEnumPins: :Clone
`
`CEnumPins Class
`
`Makes a copy of the enumerator. This allows the calling application to retain two positions in
`the list of pins.
`
`HRESULT Clone(
`IEnumPins ** ppEnum
`);
`
`Parameters
`
`ppEnum
`New enumerator that is a copy of this enumerator.
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`This member function implements the IEnumPins: :Clone method.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M 11!.l:.!j Topic Contents
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`CEnumPins::Next
`
`CEnumPins Class
`
`Places pointers to IPin interfaces into the specified array.
`
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`
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`CEnumPins Class
`
`Page 4 of7
`
`HRESULT Next(
`ULONG cPins,
`I Pin * * ppPins,
`ULONG * pcFetched
`);
`
`Parameters
`
`cPins
`
`Number of pins to place.
`ppPins
`Array in which to place the interface pointers.
`pcFetched
`Actual number of pins placed in the array.
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`This member function implements the IEnumPins:: Next method. The derived class is
`responsible for implementing CBaseFilter: :GetPin, which this member function calls to retrieve
`the next pin.
`
`Because this member function returns one or more interfaces that have had their reference
`counts incremented, the caller of this member function must be sure to release the interfaces
`by calling !Unknown: :Release on the interfaces when done with them.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQi@[.jjj,M l!i.! 111j Topic Contents
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`MQi§i[.jjj,M 1 !1·Hj Topic Contents
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`l@IJll!MM
`
`CEnumPins: :Querylnterface
`
`CEnumPins Class
`
`Retrieves a pointer to a specified interface on a component to which a client currently holds an
`interface pointer. This method must call !Unknown: :AddRef on the pointer it returns.
`
`HRESULT Queryinterface(
`REFIID iid,
`void * * ppvObject
`);
`
`1487
`
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`
`CEnumPins Class
`
`Parameters
`
`Page 5 of7
`
`iid
`
`Specifies the IID of the interface being requested.
`ppvObject
`Receives a pointer to an interface pointer to the object on return. If the interface
`specified in iid is not supported by the object, ppvObject is set to NULL.
`
`Return Values
`
`Returns S_OK if the interface is supported, S_FALSE if not.
`
`Remarks
`
`This member function implements the IUnknown: :Queryinterface method and passes out
`references to the IEnumPins interface.
`
`© 1997 Microsoft Corporation . All rights reserved . Terms of Use.
`
`•;<MM+' •11·!:.!¥ Topic Contents lmli§lll¥M
`
`CEnumPins::Release
`
`CEnumPins Class
`
`Decrements the reference count for the calling interface on an object. If the reference count on
`the object falls to zero, the object is freed from memory.
`
`ULONG Release(void);
`
`Return Values
`
`Returns the resulting value of the reference count, which is used for diagnostic/testing
`purposes only. If you need to know that resources have been freed, use an interface with
`higher-level semantics.
`
`Remarks
`
`This member function implements the IUnknown:: Release method.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQi§1[.]+• 1 11·1::'¥ Topic Contents
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`
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`
`CEnumPins Class
`
`Page 6 of7
`
`CEnumPins::Reset
`
`CEnumPins Class
`
`Resets the enumerator to the beginning so that the next call to the IEnumPins: :Next method
`will return, at a minimum, the first pin of the filter.
`
`HRESULT Reset(void);
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`This member function implements the IEnumPins:: Reset method.
`
`© 1997 Microsoft Corporation . All rights reserved. Terms of Use.
`
`•;<MM+' •11·!:.!¥ Topic Contents
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`lmli§lllMM
`
`CEnumPins::Skip
`
`CEnumPins Class
`
`Skips the next specified number of pins.
`
`HRESULT Skip(
`ULONG cPins
`);
`
`Parameters
`
`cPins
`
`Number of pins to skip.
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`This member function implements the IEnumPins:: Skip method. This member function affects
`the next call to the IEnumPins:: Next method.
`
`© 1997 Microsoft Corooratjon . All rights reserved. Terms of Use.
`
`1489
`
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`CEnumPins Class
`
`Page 7 of7
`
`1490
`
`

`
`CFactoryTemplate Class
`
`Page I of3
`
`e4140.111,e 1:1.11119 T op1c Contents
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`i@IQilt§jM
`
`CFactoryTemplate Class
`
`( CFactoryTemplate
`
`)
`
`This class provides a template used by the default class factory code.
`
`Create one <::FactoryTemplate object in an array for every object class so that the default
`class factory code can create new instances.
`
`This class holds the name of the object, the object's class identifier (CLSID), and a pointer to
`the creation function for the corresponding object. Initialize one of these in an array called
`g Templates for each CLSID the application's dynamic-link library (DLL) supports. The creation
`function should take an LPUNKNOWN parameter and an HRESULT pointer and return an object
`derived from the CBaseObject class. Set the HRESULT to a failed value if there is any error in
`construction. An example declaration (from the Gargle sample filter) follows:
`
`fl list of class ids and creator functions for class factory
`CFact.oryTerrplat.e g_ Terrplat.es [2] = { { L"Gargle fi lt.er"
`&CLSID Gargle
`03argle::Create!nstance
`
`II CFact.oryTerrplat.e,rr
`II CFact.oryTerrplat.e,rr
`II CFact.oryTerrplat.e,rr
`NULL
`&sudGargle
`
`}
`{ L"Gargle fi lt.er propert.y page"
`&CLSID GargProp
`03argleProperties::Createinstance
`
`};
`int. g_cTerrplat.es = sizeof{g_Terrplat.es) I sizeof{g_Terrplat.es[O]J;
`
`i
`
`Note that the name of the object is strictly necessary only if you are using the
`DURegisterServer setup routine to implement self-registering of your filter. If you are not using
`this feature, you can set the first element of the gTemplates instance (m Name) to NULL or
`L .....
`
`Protecte<I Data Members
`Name
`Description
`m_ClsID
`Pointer to the CLSID of the object class.
`m_lpfnNew
`Pointer to a function that creates an instance of the object class.
`m_lpfnlnlt
`Pointer to a function that initializes a new instance of the object
`class.
`Name of the filter; required when using filter self-registration
`serviees.
`m_pAMovleSetup_Fllter Pointer to an AMOVIESETIJP FI! TER structure; required when
`using filter self-registration services.
`
`m_Name
`
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`
`

`
`CFactoryTemplate Class
`
`Page 2 of3
`
`Member Functions
`Name
`Description
`Createlnstance Calls the object-creation function for the class.
`IsClassID
`Determines whether a CLSID matches this class template.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+;<§1[.]lj,i 111.],.[9 Topic Contents
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`lfflj(§l 1!1¥1M
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`+Qij[.jlj,M 111.11119 Topic Contents
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`l@i§lllMM
`
`CFactoryTemplate: :Createlnsta nee
`
`CFactoryTemplate Class
`
`Calls the object-creation function for the class.
`
`CUnknown *Createlnstance(
`LPUNKNOWN pUnk,
`HRESULT *phr
`);
`
`Parameters
`
`pUnk
`
`phr
`
`Pointer to the IUnknown interface.
`
`Pointer to the HRESULT value into which to place resulting information.
`
`Return Values
`
`Returns an instance of the class object.
`
`Remarks
`
`The implementer of the class code registered using this factory template class is responsible
`for providing the code that creates an instance of the class object and assigning it to the
`m lpfnNew data member. This member function simply calls that function and returns a new
`object of that type.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+Q<@[.jlj,M 111.11119 Topic Contents
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`1492
`
`

`
`CFactoryTemplate Class
`
`Page 3of3
`
`CFactoryTemplate: :lsClasslD
`
`CFactoryTemplate Class
`
`Determines if the class identifier (CLSID) passed matches the CLSID assigned to this class
`template.
`
`BOOL lsClasslD(
`REFCLSID rclsid
`);
`
`Parameters
`
`rclsid
`CLSID being tested.
`
`Return Values
`
`Returns TRUE if the CLSIDs are the same; otherwise, returns FALSE.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`1493
`
`

`
`CGenericList Class
`
`Page 1 of 10
`
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`i@IQilt@M
`
`CGenericList Class
`
`CBaseObject
`
`CGenericlist
`
`CGenerlcllst is a template class that allows for a type-specific implementation of a list. It is
`derived from caase! ist and uses that class's typeless implementation. The constructor creates
`a CBaseUst object, and au CGenericUst member functions ca!! CBasellst member functions
`but provide type-checking dependent on the template.
`
`Member Functions
`Name
`Description
`Add After
`Inserts a node or list of nodes after the specified node.
`Add Before
`Inserts a node or list of nodes before the specified node.
`Add Head
`Inserts a node or list of nodes at the front of the list.
`AddTai!
`Appends a node or list of nodes to the end of the list.
`Constructs a CGenerlcllst object.
`CGenericUst
`Returns the first position that contains the specified object.
`f.iD.!J.
`Returns the object at the specified position.
`~
`GetCount
`Returns the number of objects (object count) in the list.
`GetHead
`Returns the object at the head of the list.
`GetHeadPosition Returns a cursor identifying the first element of the liSt.
`Get Next
`Returns the specified object and update position.
`GetTai!Position Returns a cursor identifying the last element of the list.
`Remove
`Removes the specified node from the list.
`RemoveHead
`Removes the first node in the liSt.
`RemoveTai!
`Removes the last node in the list.
`
`+;•; 11.111,+ 111.1111s T op1c Contents
`Topic Contents '@'!'''""
`
`l@i§Mlt§M
`
`CGenericList: :AddAfter
`
`1494
`
`

`
`CGenericList Class
`
`CGenericlist Class
`
`Inserts a node or list of nodes after the specified node.
`
`Page 2of10
`
`POSITION AddAfter(
`POSITION p,
`OBJECT * pObj
`);
`BOOL AddAfter(
`POSITION pos,
`CGenericlist<OBJECT> *pList
`);
`
`Parameters
`
`pos
`
`pObj
`
`pList
`
`Position after which to add the node or list of nodes.
`
`Pointer to the object to add.
`
`Pointer to the list of objects to add.
`
`Return Values
`
`Returns the position of the inserted object in the case of single-object insertion. For list
`insertion, returns TRUE if successful; otherwise, returns FALSE.
`
`Remarks
`
`This member function calls the CBaselist: :AddAfter member function when passed a list of
`nodes. CGenericlist::AddAfter calls the CBaselist: :AddAfterI member function when passed
`a single node.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 111j
`
`Topic Contents
`
`l@i§il!MM
`
`MQ<§i[.jlj,M lh.l:.!j
`
`Topic Contents
`
`i@faii!MM
`
`CGenericlist: :Add Before
`
`CGenericlist Class
`
`Inserts a node or list of nodes before the specified node.
`
`POSITION AddBefore(
`POSITION p,
`OBJECT * pObj
`
`1495
`
`

`
`CGenericList Class
`
`Page 3of10
`
`);
`BOOL AddBefore(
`POSITION pos,
`CGenericlist<OBJECT> *pList
`);
`
`Parameters
`
`pos
`
`pObj
`
`pList
`
`Position before which to add the node or list of nodes.
`
`Pointer to the object to add.
`
`Pointer to the list of objects to add.
`
`Return Values
`
`Returns the position of the inserted object in the case of single-object insertion. For list
`insertion, returns TRUE if successful; otherwise, returns FALSE.
`
`Remarks
`
`This member function calls the CBaseList: :AddBefore member function when passed a list of
`nodes. CGenericlist::AddBefore calls the CBaseList: :AddBeforeI member function when
`passed a single node.
`
`© 1997 Microsoft Corporation . All rights reserved . Terms of Use.
`
`•;<MM+' 111.],.[9
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`lmli§lllMM
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`8 4'41M+• 111.q9
`
`Topic Contents 1@!§111$8
`
`CGenericlist: :Add Head
`
`CGenericList Class
`
`Inserts a node or list of nodes at the front of the list.
`
`POSITION AddHead(
`OBJECT * pObj
`);
`BOOL Add Head (
`CGenericlist<OBJECT> *pList
`);
`
`Parameters
`
`pObj
`
`1496
`
`

`
`CGenericList Class
`
`Page 4of10
`
`Pointer to the object to add.
`
`pList
`
`Pointer to the list of objects to add.
`
`Return Values
`
`Returns the new head position, or NULL if unsuccessful in the case of single-node additions.
`For list insertions, returns TRUE if successful; otherwise, returns FALSE.
`
`Remarks
`
`This member function calls the CBaseList: :AddHead member function when passed a list of
`nodes. CGenericlist::AddHead calls the CBaseList: :AddHeadI member function when passed
`a single node.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+Qi§1H++ 1 !!·HM
`
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`
`ifflj[§ii!¥M
`
`CGenericlist: :AddTail
`
`CGenericList Class
`
`Appends a node or list of nodes to the end of the list.
`
`POSITION AddTail (
`OBJECT * pObj
`);
`BOOL AddTail(
`CGenericlist<OBJECT> *pList
`);
`
`Parameters
`
`pObj
`
`pList
`
`Pointer to the object to add.
`
`Pointer to the list of objects to add.
`
`Return Values
`
`Returns the new tail position, or NULL if unsuccessful in the case of single-node insertions. For
`list insertions, returns TRUE if successful; otherwise, returns FALSE.
`
`Remarks
`
`This member function calls the CBaseList: :AddTail member function when passed a list of
`nodes. CGenericlist::AddTail calls the CBaseList: :AddTailI member function when passed a
`
`1497
`
`

`
`CGenericList Class
`
`single node.
`
`Page 5of10
`
`© 1997 Microsoft Corporation . All rights reserved . Terms of Use.
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`Topic Contents
`
`lmll§lllMM
`
`CGenericlist: :CGenericlist
`
`CGenericList Class
`
`Constructs a CGenericList object.
`
`CGenericlist(
`TCHAR *pName,
`INT iitems,
`BOOL block,
`BOOL bA/ert
`);
`
`CGenericlist(
`TCHAR *pName
`);
`
`Parameters
`
`pName
`Name of the list.
`iitems
`Number of items in the list.
`block
`TRUE if the list is locked and FALSE otherwise. This parameter defaults to TRUE.
`bAlert
`Not used.
`
`Return Values
`
`No return value.
`
`Remarks
`
`This constructor calls the CBaseList constructor.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQ1§1[.jjj,M '!!·HM Topic Contents
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`l@i§i MUMM
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`•;<@[.]jj,i 1!1.l:.1¥ Topic Contents
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`
`

`
`CGenericList Class
`
`Page 6of10
`
`CGenericlist:: Find
`
`CGenericList Class
`
`Retrieves the first position that contains the specified object.
`
`POSITION Find(
`OBJECT * pObj
`);
`
`Parameters
`
`pObj
`
`Pointer to the object to find.
`
`Return Values
`
`Returns a position cursor.
`
`Remarks
`
`This member function calls the CBaseList:: FindI member function.
`
`© 1997 Microsoft Corooratjon . All rights reserved. Terms of Use.
`
`MQ<§i[.jjj,M MB.HS
`
`Topic Contents
`
`i@faiilMM
`
`CGenericlist: :Get
`
`CGenericList Class
`
`Retrieves the object at the specified position.
`
`OBJECT *Get(
`POSITION pos
`);
`
`Parameters
`
`pos
`
`Position in the list from which to retrieve the object.
`
`Return Values
`
`1499
`
`

`
`CGenericList Class
`
`Page 7of10
`
`Returns a pointer to an object.
`
`Remarks
`
`This member function calls the CBaselist: :Getl member function.
`
`© 1997 Microsoft Corporation . All rights reserved . Terms of Use.
`
`w QIM [.] 11,1 Ill.HM
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`Topic Contents
`
`l@fa* 1gnw
`
`CGenericlist: :GetCou nt
`
`CGenericlist Class
`
`Retrieves the number of objects (object count) in the list.
`
`int GetCount( );
`
`Return Values
`
`Returns the value of m Count.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M 111.11119
`
`Topic Contents
`
`l@fail!MM
`
`CGenericlist: :GetHead
`
`CGenericlist Class
`
`Retrieves the object at the head of the list.
`
`OBJECT Get Head( ) ;
`
`Return Values
`
`Returns the head of the list by calling CGenericlist: :GetHeadPosition.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use .
`
`• QIM [.] +• I !!·HM Topic Contents
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`l@fail!MM
`
`1500
`
`

`
`CGenericList Class
`
`Page 8of10
`
`CGenericlist: :GetHead Position
`
`CGenericList Class
`
`Retrieves a cursor identifying the first element of the list.
`
`POSITION GetHeadPosition( );
`
`Return Values
`
`Returns the position cursor held by m pFirst.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 11ij
`
`Topic Contents
`
`l@i§il!MM
`
`CGenericlist: :GetNext
`
`CGenericList Class
`
`Retrieves the specified object and update position.
`
`OBJECT *GetNext(
`POSITION& rp
`);
`
`Parameters
`
`rp
`
`Returned pointer to the next object.
`
`Return Values
`
`Returns a pointer to an object at the next position.
`
`Remarks
`
`This member function calls the CBaseList: :GetNextI member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 11ij Topic Contents
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`l@i§il!MM
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`1501
`
`

`
`CGenericList Class
`
`Page 9of10
`
`CGenericlist: :GetTa i I Position
`
`CGenericList Class
`
`Retrieves a cursor identifying the last element of the list.
`
`POSITION GetTailPosition( );
`
`Return Values
`
`Returns the position cursor held by m plast.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 11ij
`
`Topic Contents
`
`l@i§il!MM
`
`CGenericlist:: Remove
`
`CGenericList Class
`
`Removes the specified node from the list.
`
`OBJECT *Remove(
`POSITION pos
`);
`
`Parameters
`
`pos
`
`Position in the list of nodes to remove.
`
`Return Values
`
`Returns the pointer to the object that was removed.
`
`Remarks
`
`This member function calls the CBaseList:: RemoveI member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQij[.jlj,M l!i.! 11ij Topic Contents
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`l@i§il!MM
`
`1502
`
`

`
`CGenericList Class
`
`Page 10of10
`
`CGenericlist:: RemoveHead
`
`CGenericList Class
`
`Removes the first node in the list.
`
`OBJECT *RemoveHead( );
`
`Return Values
`
`Returns the pointer to the object that was removed.
`
`Remarks
`
`This member function calls the CBaseList:: RemoveHeadI member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+Q'41!.l+' +11.q9
`
`Topic Contents
`
`l@!§il!MM
`
`CGenericlist:: Remove Tai I
`
`CGenericList Class
`
`Removes the last node in the list.
`
`OBJECT *RemoveTail( );
`
`Return Values
`
`Returns the pointer to the object that was removed.
`
`Remarks
`
`This member function calls the CBaseList:: RemoveTailI member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`1503
`
`

`
`CGuidNameList Class
`
`Page 1 of2
`
`w4140.111,e 1:1.11119 T op1c Contents
`
`i@IQilt@M
`
`CGuidNameList Class
`
`( CGuidNamelist
`
`)
`
`This class implements an array of globally unique identifier (m) names base<J on the
`predefined names of GUIDs that come with Microsoft® DirectShow"'. (This might or might not
`inclu<Je user-defined GUIDs.) To get the name used for a GUID, look it up in the GuidNames
`array:
`
`int MyFunc {AM MEDIA TYPE mt)
`-
`-
`{
`DbgLog{{I..CG TRACE, 2, TEXT{"MyFunc: Type :\"s, Subtype :\"s"),
`GuidNames[mt,majortypeJ,
`GuidNames [mt, subtype]
`JJ;
`
`Operators
`Description
`Name
`operatorr J Allows access to the m
`
`name for a given GUID.
`
`Global Data
`Description
`Name
`GuldNaniesArray of CGuidNameList objects describing the predefined names of~ that
`come with DirectShow. (This might or might not include user-defined GUIDs.)
`
`+;14 "·II' a e11.1::•S
`
`Topic Contents i@i§i+t§M
`
`CGuidNameList::operator[ ]
`
`CG11idName! ist C!as.s
`
`Allows access to them name for a given GUID.
`
`TCHAR •operator( j(
`Const GUID& gui<f
`);
`
`1504
`
`

`
`CGuidNameList Class
`
`Page 2 of2
`
`Parameters
`
`guid
`
`Globally unique identifier.
`
`Return Values
`
`Returns the GUID name for the given entry in a GUID name list.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`1505
`
`

`
`CimageAllocator Class
`
`Page 1 of9
`
`e4140.111,e 1:1.11119 T op1c Contents
`
`i@IQilt§jM
`
`CimageAllocator Class
`
`CBaseObject
`
`CCritSec
`
`CBaseAllocator
`
`ClmageAllocator
`
`The (;ImageAllo<:atot class is inherited from the CBaseAllocator class, which allocates sample
`buffers in shared memory. The number, size, and alignment of blocks are determined when the
`connected output pin calls ClmageAllocator::SetProperties (which implements
`lMemAllocator: :SetProperties}. The shared memory blocks are used in subsequent calls to the
`Microsoft® Win32® CreateDIBSectjon function. The output pin can then fill these buffers with
`data, and the buffers wm be handed to GDI using BitBlt.
`
`Protected Data Members
`Name
`Description
`m_pFiltet
`Owning filter of this object.
`m_pMediaType Current media type format.
`
`Membet Functions
`Name
`Description
`~ Allocates the samples through CreateDIBSection.
`CheckSi:zes
`Checks the allocator requirements.
`ClmageAllocator Constructs a ClmageAllocator object.
`CreateDIB
`Creates a device-independent bitmap (DIB).
`~ Releases and deletes the resources for any samples allocated.
`NotifVMediaTupe Notifies the allocator of the agreed media type.
`
`Ovettidable Member Functions
`Name
`Desctiption
`CreatelmageSample Creates a sample.
`
`Implemented INonDelegatingUnknown Methods
`
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`
`CimageAllocator Class
`
`Page 2 of9
`
`Description
`Name
`NonDelegatingAddRef Increments the reference count for an interface.
`NonDelegatingRelease Decrements the reference count for an interface.
`
`Implemented IMemAllocator Methods
`Name
`Description
`SetProoerties Specifies the buffering requirements for the allocator.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
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`MQl@[.jjj,M 111.l:.!9 Topic Contents
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`CimageAllocator: :Alloc
`
`ClmageAllocator Class
`
`Creates image samples based around CreateDIBSection.
`
`HRESULT Alloc( );
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`A filter defines the size and number of buffers required through the
`ClmageAllocator: :SetProperties member function. The base allocator class that this allocator
`derives from calls this internal virtual member function when it wants the memory actually
`committed. For each sample it wants to create, this allocator will create a DIBSECTION object
`for it (through the Microsoft Win32 CreateDIBSection function). With the information it gets
`from that call, it will call the virtual CreatelmageSample member function, passing in the
`buffer pointer and length. After successfully creating an image sample, it will then initialize it
`with the DIBSECTION structure, among other information.
`
`This is a protected member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+Qi§1H+1 1 11·1::'¥ Topic Contents
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`1507
`
`

`
`CimageAllocator Class
`
`Page 3 of9
`
`CimageAllocator: :CheckSizes
`
`ClmageAllocator Class
`
`Internal member function that checks the required buffering properties.
`
`HRESULT CheckSizes(
`ALLOCATOR_PROPE RTIES *pRequest
`);
`
`Parameters
`
`pRequest
`Requested a I locator properties.
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`The image allocator uses the Microsoft Win32 CreateDIBSection function to allocate its
`samples. That function accepts as input a pointer to a BITMAPINFO structure that describes the
`bitmap required. Because the size of the bitmap is therefore fixed according to the
`BITMAPINFO structure for the video, requests to the allocator for a buffer larger than that
`will not be granted. This member function, therefore, adjusts the requested size so that it is no
`larger than the size of the bitmap. If the requested size is smaller than the bitmap size, it
`returns E_INVALIDARG.
`
`This is a protected member function.
`
`© 1997 Microsoft Corooratjon . All rights reserved. Terms of Use.
`
`MQ<§i[.jjj,M MB.HS Topic Contents
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`i@faiilMM
`
`CimageAI locator: :CimageAI locator
`
`CimageAllocator Class
`
`Constructs a CimageAllocator object.
`
`CimageAllocator(
`CBaseFilter *pFilter,
`TCHAR *pName,
`HRESULT *phr
`);
`
`1508
`
`

`
`CimageAllocator Class
`
`Page 4 of9
`
`Parameters
`
`pFilter
`Owning filter object.
`pName
`Debug-only string description.
`
`phr
`
`COM return code.
`
`Return Values
`
`No return value.
`
`Remarks
`
`The ClmageAllocator, CimageSample, and CDrawimage classes are all tightly associated. The
`buffers that the image allocator creates are made using the Microsoft Win32 CreateDIBSection
`function. The allocator then creates its own samples (based on the CimageSample class). The
`image samples are initialized with the buffer pointer and its length. The sample is also passed
`in a structure (a DIBDATA structure) that holds a number of pieces of information obtained
`from the CreateDIBSection call.
`
`These samples can then be passed to the draw object. The draw object knows the private
`format of the samples and how to get back the DIBDATA structure from them. Once it has
`obtained that information, it can pass a bitmap handle that is stored in the DIBDATA
`structure down into GDI when it draws the image that the sample contains. By using the
`bitmap handle from the sample in the drawing, rather than just the buffer pointer (which is the
`alternative if the sample is not a CimageSample), it gets a modest performance improvement.
`
`This is a protected member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`MQl@[.jlj,M l!i.! 111j Topic Contents
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`M QiM [.] ij,+ I !I.HJ Topic Contents
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`'®'*' 1gnw
`
`ClmageAllocator: :CreateDIB
`
`CimageAllocator Class
`
`Calls the Win32 CreateDIBSection function to create a device-independent bitmap (DIB).
`
`HRESULT CreateDIB(
`LONG InSize,
`DIBDATA &DibData
`);
`
`1509
`
`

`
`CimageAllocator Class
`
`Page 5of9
`
`Parameters
`
`In Size
`Size of the bitmap required.
`DibData
`Structure to fill out with details.
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`This is a protected member function.
`
`© 1997 Microsoft Corooratjon . All rights reserved. Terms of Use.
`
`MQ<§i[.jjj,M MB.HS Topic Contents
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`i@faiilMM
`
`ClmageAllocator: :CreatelmageSa m pie
`
`ClmaqeAllocator Class
`
`Creates a ClmaqeSample object.
`
`virtual CimageSample *CreateimageSample(
`LPBYTE pData,
`LONG Length
`);
`
`Parameters
`
`pData
`Pointer to the data buffer the sample looks after.
`Length
`Associated length of the buffer.
`
`Return Values
`
`Returns a new ClmaqeSamole sample object.
`
`Remarks
`
`This virtual member function creates the actual sample for the allocator. It is passed the data
`buffer and its length to store. When the sample is subsequently asked for the buffer (through
`IMediaSample: :GetPointer), this is the pointer it will return. The primary reason for having this
`split out into a separate virtual member function is so that derived classes from
`
`1510
`
`

`
`CimageAllocator Class
`
`Page 6 of9
`
`ClmageAllocator can also derive classes from ClmageSample and have a place to create them.
`
`This is a protected member function.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
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`+;<§1[.]lj,i 111.],.[9 Topic Contents
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`ClmageAllocator::Free
`
`ClmageAllocator Class
`
`Deletes the samples and frees their resources.
`
`void Free( );
`
`Return Values
`
`No return value.
`
`Remarks
`
`The base allocator calls this internal virtual member function when it wants to decommit the
`allocator.
`
`This is a protected member function.
`
`© 1997 Microsoft Corporation . All rights reserved. Terms of Use.
`
`+Qi§i!.l+1 1 !1·HM Topic Contents
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`l@i§lllMM
`
`ClmageAllocator::NonDelegatingAddRef
`
`ClmageAllocator Class
`
`Increments the reference count for the owning filter.
`
`HRESULT NonDelegatingAddRef( );
`
`Return Values
`
`Returns an HRESULT value.
`
`1511
`
`

`
`CimageAllocator Class
`
`Page 7 of9
`
`Remarks
`
`An allocator is conceptually a separate object from the filter that creates it. However, the
`image allocator is dependent on the filter that created it to supply it with additional information
`(such as the media type that it connected with). Therefore, although the allocator looks after
`its own NonDelegatingQueryinterface function, it delegates all reference counting to the
`owning filter. So, when the allocator is subject to its NonDelegatingAddRef function, for
`example, it is the filter that owns the allocator that will actually be reference counted.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
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`MQi@[.jlj,M M!i.!111j Topic Contents
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`l@i§il!MM
`
`ClmageAllocator::NonDelegatingRelease
`
`ClmageAllocator Class
`
`Decrements the reference count for the owning filter.
`
`HRESULT NonDelegatingRelease( );
`
`Return Values
`
`Returns an HRESULT value.
`
`Remarks
`
`An allocator is conceptually a separate object from the filter that creates it. However, the
`image allocator is dependent on the filter that created it to supply it with additional information
`(such as the media type that it connected with). Therefore, although the allocator looks after
`its own NonDelegatingQueryinterface function, it delegates all reference counting to the
`owning filter. So when the allocator is released, for example, it is the filter that owns the
`allocator that will actually be released by the NonDelegatingRelease function.
`
`© 1997 Microsoft Corporation . All rights reserved. Terms of Use.
`
`MQi§i[.jlj,M 1 !1·Hj Topic Contents •@m•11mw
`
`ClmageAllocator:: NotifyMediaType
`
`ClmageAllocator Class
`
`Passes the media type from a filter to the allocator.
`
`1512
`
`

`
`CimageAllocator Class
`
`Page 8 of9
`
`void NotifyMediaType(
`CMediaType *pMediaType
`);
`
`Parameters
`
`pMediaType
`Media type the filter established.
`
`Return Values
`
`No return value.
`
`Remarks
`
`The buffers that the image allocator creates are based around CreateDIBSection, which must
`be told what sort of bitmap the filter requires it to create. The filter does this by calling this
`member function on the allocator. A filter will usually call this member function after agreeing
`on a media type during a pin connection. The media type passed to this member function is a
`pointer; the allocator stores this pointer (not a copy) of the media type it points to (for
`performance reasons, copying media types is relatively slow). Therefore, the filter that calls
`this member function should ensure that the media type is always valid until the media type is
`next set on the allocator (or is called with a NULL type).
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`+Q'41!.l+' +11.q9
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`Topic Contents
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`l@!§il!MM
`
`ClmageAllocator: :SetProperties
`
`ClmageAllocator Class
`
`Determines the size, number, and alignment of blocks.
`
`HRESULT SetProperties(
`ALLOCATOR_PROPERTIES * pRequest,
`ALLOCATOR_PROPERTIES * pActual
`);
`
`Parameters
`
`pRequest
`Requested a I locator properties.
`pActual
`Allocator properties actually set.
`
`Return Values
`
`1513
`
`

`
`CimageAllocator Class
`
`Page 9 of9
`
`Returns an HRESULT value.
`
`Remarks
`
`The pRequest parameter is filled in by the caller with the requested values for the count,
`number, and alignment as specified by the ALLOCATOR PROPERTIES structure. The pActual
`parameter is filled in by the allocator with the closest values that it can provide for the
`request. This member function cannot be called unless the allocator has been decommitted by
`using the !MemAllocator:: Decommit method.
`
`© 1997 Microsoft Corporation. All rights reserved. Terms of Use.
`
`1514
`
`

`
`CimageDisplay Class
`
`Page 1of11
`
`e4140.111,e 1:1.11119 T op1c Contents
`
`i@IQilt§jM
`
`CimageDisplay Class
`
`CCritSec
`
`ClmageDisplay
`
`This class initializes itself with a display format so that other objects can query or reset the
`display type. It also provides member functions to check display formats and accept only those
`video formats that can be efficiently rendered by using GDI calls.
`
`Protected Data Members
`Name
`Des<:riptlon
`m_DisplayVIDEOINFOHEADER structure corresponding to the current device display type.
`
`CimageDisplay
`Co1 mt Prefix Bits
`Co! mt Set Bits
`GetBitMasks
`
`Member Functions
`Des<:riptlon
`Name
`Checks that the bit fields on a VIDEOINFOHEADER structure are correct.
`CheckBitfields
`CheckHeaderValidity Determines if a BITMAPINFOH EADER structure is valid.
`CheckMediaTupe
`Determines if the filter can support the media type proposed by the
`output pin.
`Checi.:pa!etteHeader Determines if the palette on a VIDEOINEOHEADER structure is correct.
`CheckVideoTyoo
`Compares a video type to determine if it is compatible with the current
`display mode.
`Constructs a CimageDisplay object.
`Counts the number of prefix bits.
`Counts the total number of bits set in a field.
`Retrieves a set of color element bitmasks for the supplied
`VIDEOINFOHEADER structure.
`Retrieves a set of individual color element masks.
`Retrieves the bit depth of the current display mode.
`Retrieves a VIDEOINFOHEADER structure representing the current
`display mode.
`Determines if the display uses a palette.
`Updates the CimageDisplay object with the current display type.
`Updates the VIDEOINFOHEADER structure to remove implicit
`assumptions.
`
`GetColourMask
`Get Display Depth
`Get Display format
`
`IsPa!ettized
`RefreshDisplayTupe
`UOOateformat
`
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`1515
`
`

`
`CimageDisplay Class
`
`Page 2of11
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`
`ClmageDisplay: :CheckBitFields
`
`ClmageDisplay Class
`
`Checks that the bit fields in the VIDEOINFOHEADER structure are correct.
`
`BOOL CheckBitFields