|
ACMFILTERCHOOSE
The ACMFILTERCHOOSE structure contains information the ACM uses to initialize the system-defined
waveform-audio filter selection dialog box. After the user closes the dialog
box, the system returns information about the user's selection in this structure.
typedef struct {
DWORD cbStruct;
DWORD fdwStyle;
HWND hwndOwner;
LPWAVEFILTER pwfltr;
DWORD cbwfltr;
LPCSTR pszTitle;
char szFilterTag[ACMFILTERTAGDETAILS_FILTERTAG_CHARS];
char szFilter[ACMFILTERDETAILS_FILTER_CHARS];
LPSTR pszName;
DWORD cchName;
DWORD fdwEnum;
LPWAVEFILTER pwfltrEnum;
HINSTANCE hInstance;
LPCSTR pszTemplateName;
LPARAM lCustData;
ACMFILTERCHOOSEHOOKPROC pfnHook;
} ACMFILTERCHOOSE;
Members
cbStruct
Size, in bytes, of the ACMFILTERCHOOSE structure. This member must be initialized before an application calls the acmFilterChoose function. The size specified in this member must be large enough to contain
the base ACMFILTERCHOOSE structure.
fdwStyle
Optional style flags for the acmFilterChoose function. This member must be initialized to a valid combination of the
following flags before an application calls the acmFilterChoose function. The following values are defined:
ACMFILTERCHOOSE_STYLEF_CONTEXTHELP
Context-sensitive help will be available in the dialog box. To use this
feature, an application must register the ACMHELPMSGCONTEXTMENU and
ACMHELPMSGCONTEXTHELP constants, using the RegisterWindowMessage function. When the user invokes help, the registered message will be posted
to the owning window. The message will contain the wParam and lParam parameters from the original WM_CONTEXTMENU or WM_CONTEXTHELP message.
ACMFILTERCHOOSE_STYLEF_ENABLEHOOK
Enables the hook function specified in the pfnHook member. An application can use hook functions for a variety of
customizations, including answering the MM_ACM_FILTERCHOOSE message.
ACMFILTERCHOOSE_STYLEF_ENABLETEMPLATE
Causes the ACM to create the dialog box template identified by the hInstance and pszTemplateName members.
ACMFILTERCHOOSE_STYLEF_ENABLETEMPLATEHANDLE
The hInstance member identifies a data block that contains a preloaded dialog box template.
If this flag is specified, the ACM ignores the pszTemplateName member.
ACMFILTERCHOOSE_STYLEF_INITTOFILTERSTRUCT
The buffer pointed to by pwfltr contains a valid WAVEFILTER structure that the dialog box will use as the initial selection.
ACMFILTERCHOOSE_STYLEF_SHOWHELP
A help button will appear in the dialog box. To use a custom Help file, an
application must register the ACMHELPMSGSTRING value with the RegisterWindowMessage function. When the user presses the help button, the registered message is
posted to the owner.
hwndOwner
Handle of the window that owns the dialog box. This member can be any valid
window handle or NULL if the dialog box has no owner. This member must be
initialized before calling the acmFilterChoose function.
pwfltr
Address of a WAVEFILTER structure. If the ACMFILTERCHOOSE_STYLEF_INITTOFILTERSTRUCT flag is specified
in the fdwStyle member, this structure must be initialized to a valid filter. When the acmFilterChoose function returns, this buffer contains the selected filter. If the user
cancels the dialog box, no changes will be made to this buffer.
cbwfltr
Size, in bytes, of the buffer pointed to by the pwfltr member. The acmFilterChoose function returns ACMERR_NOTPOSSIBLE if the buffer is too small to contain the
filter information; the ACM also copies the required size into this member. An
application can use the acmMetrics and acmFilterTagDetails functions to determine the largest size required for this buffer.
pszTitle
Address of a string to be placed in the title bar of the dialog box. If this
member is NULL, the ACM uses the default title (that is, "Filter Selection").
szFilterTag
Buffer containing a null-terminated string describing the filter tag of the
filter selection when the acmFilterChoose function returns. This string is equivalent to the szFilterTag member of the ACMFILTERTAGDETAILS structure returned by acmFilterTagDetails. If the user cancels the dialog box, this member will contain a
null-terminated string.
szFilter
Buffer containing a null-terminated string describing the filter attributes of
the filter selection when the acmFilterChoose function returns. This string is equivalent to the szFilter member of the ACMFILTERDETAILS structure returned by acmFilterDetails. If the user cancels the dialog box, this member will contain a
null-terminated string.
pszName
Address of a string for a user-defined filter name. If this is a
non-null-terminated string, the ACM attempts to match the name with a previously saved
user-defined filter name. If a match is found, the dialog box is initialized to that
filter. If a match is not found or this member is a null-terminated string,
this member is ignored for input. When the acmFilterChoose function returns, this buffer contains a null-terminated string describing
the user-defined filter. If the filter name is untitled (that is, the user has
not given a name for the filter), this member will be a null-terminated string on
return. If the user cancels the dialog box, no changes will be made to this
buffer.
If the ACMFILTERCHOOSE_STYLEF_INITTOFILTERSTRUCT flag is specified by the fdwStyle member, the pszName member is ignored as an input member.
cchName
Size, in characters, of the buffer identified by the pszName member. This buffer should be at least 128 characters long. If pszName is NULL, this member is ignored.
fdwEnum
Optional flags for restricting the type of filters listed in the dialog box.
These flags are identical to the fdwEnum flags for the acmFilterEnum function. If pwfltrEnum is NULL, this member should be zero.
ACM_FILTERENUMF_DWFILTERTAG
The dwFilterTag member of the WAVEFILTER structure pointed to by the pwfltrEnum member is valid. The enumerator will only enumerate a filter that conforms to
this attribute.
pwfltrEnum
Address of a WAVEFILTER structure that will be used to restrict the filters listed in the dialog box.
The fdwEnum member defines which members of this structure should be used for the
enumeration restrictions. The cbStruct member of this WAVEFILTER structure must be initialized to the size of the WAVEFILTER structure. If no special restrictions are desired, this member can be NULL.
hInstance
Handle of a data block that contains a dialog box template specified by the pszTemplateName member. This member is used only if the fdwStyle member specifies the ACMFILTERCHOOSE_STYLEF_ENABLETEMPLATE or
ACMFILTERCHOOSE_STYLEF_ENABLETEMPLATEHANDLE flag; otherwise, this member should be NULL on
input.
pszTemplateName
Address of a null-terminated string that specifies the name of the resource
file for the dialog box template that is to be substituted for the dialog box
template in the ACM. An application can use the MAKEINTRESOURCE macro for numbered dialog box resources. This member is used only if the fdwStyle member specifies the ACMFILTERCHOOSE_STYLEF_ENABLETEMPLATE flag; otherwise,
this member should be NULL on input.
lCustData
Application-defined data that the ACM passes to the hook function identified
by the pfnHook member. The system passes the data in the lParam parameter of the WM_INITDIALOG message.
pfnHook
Address of a hook function that processes messages intended for the dialog
box. An application must specify the ACMFILTERCHOOSE_STYLEF_ENABLEHOOK flag in the fdwStyle member to enable the hook; otherwise, this member should be NULL. The hook
function should return FALSE to pass a message to the standard dialog box
procedure or TRUE to discard the message.
See Also
acmFilterChoose, acmFilterDetails, acmFilterEnum, ACMFILTERDETAILS, acmFilterTagDetails, ACMFILTERTAGDETAILS, acmMetrics, MAKEINTRESOURCE, MM_ACM_FILTERCHOOSE, RegisterWindowMessage, WAVEFILTER, WM_INITDIALOG
Related Links
Software for Delphi and C++ Builder developers
Software for Visual Studio .NET developers
Software for Visual Basic 6 developers
Delphi Tips&Tricks
MegaDetailed.NET
More Online Helps
Win32 Programmer's Reference (win32.hlp)
OLE Programmer's Reference (ole.hlp)
Microsoft Windows Pen API Programmer's Reference (penapi.hlp)
Microsoft Windows Sockets 2 Reference (sock2.hlp)
Microsoft Windows Telephony API (TAPI) Programmer's Reference (tapi.hlp)
Unix Manual Pages
|
