|
ACMFORMATCHOOSE
The ACMFORMATCHOOSE structure contains information the ACM uses to initialize the system-defined
waveform-audio format 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;
LPWAVEFORMATEX pwfx;
DWORD cbwfx;
LPCSTR pszTitle;
char szFormatTag[ACMFORMATTAGDETAILS_FORMATTAG_CHARS];
char szFormat[ACMFORMATDETAILS_FORMAT_CHARS];
LPSTR pszName;
DWORD cchName;
DWORD fdwEnum;
LPWAVEFORMATEX pwfxEnum;
HINSTANCE hInstance;
LPCSTR pszTemplateName;
LPARAM lCustData;
ACMFORMATCHOOSEHOOKPROC pfnHook;
} ACMFORMATCHOOSE;
Members
cbStruct
Size, in bytes, of the ACMFORMATCHOOSE structure. This member must be initialized before an application calls the acmFormatChoose function. The size specified in this member must be large enough to contain
the base ACMFORMATCHOOSE structure.
fdwStyle
Optional style flags for the acmFormatChoose function. This member must be initialized to a valid combination of the
following flags before an application calls the acmFormatChoose function:
ACMFORMATCHOOSE_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.
ACMFORMATCHOOSE_STYLEF_ENABLEHOOK
Enables the hook function pointed to by the pfnHook member. An application can use hook functions for a variety of
customizations, including answering the MM_ACM_FORMATCHOOSE message.
ACMFORMATCHOOSE_STYLEF_ENABLETEMPLATE
Causes the ACM to create the dialog box template identified by hInstance and pszTemplateName.
ACMFORMATCHOOSE_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.
ACMFORMATCHOOSE_STYLEF_INITTOWFXSTRUCT
The buffer pointed to by pwfx contains a valid WAVEFORMATEX structure that the dialog box will use as the initial selection.
ACMFORMATCHOOSE_STYLEF_SHOWHELP
A help button will appear in the dialog box. To use a custom Help file, an
application must register the ACMHELPMSGSTRING constant with the RegisterWindowMessage function. When the user presses the help button, the registered message will
be 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 acmFormatChoose function.
pwfx
Address of a WAVEFORMATEX structure. If the ACMFORMATCHOOSE_STYLEF_INITTOWFXSTRUCT flag is specified in
the fdwStyle member, this structure must be initialized to a valid format. When the acmFormatChoose function returns, this buffer contains the selected format. If the user
cancels the dialog box, no changes will be made to this buffer.
cbwfx
Size, in bytes, of the buffer pointed to by pwfx. If the buffer is too small to contain the format information, the acmFormatChoose function returns ACMERR_NOTPOSSIBLE. Also, the ACM copies the required size
into this member. An application can use the acmMetrics and acmFormatTagDetails 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, "Sound Selection").
szFormatTag
Buffer containing a null-terminated string describing the format tag of the
format selection when the acmFormatChoose function returns. This string is equivalent to the szFormatTag member of the ACMFORMATTAGDETAILS structure returned by the acmFormatTagDetails function. If the user cancels the dialog box, this member will contain a
null-terminated string.
szFormat
Buffer containing a null-terminated string describing the format attributes of
the format selection when the acmFormatChoose function returns. This string is equivalent to the szFormat member of the ACMFORMATDETAILS structure returned by the acmFormatDetails function. If the user cancels the dialog box, this member will contain a
null-terminated string.
pszName
Address of a string for a user-defined format name. If this is a
non-null-terminated string, the ACM will attempt to match the name with a previously saved
user-defined format name. If a match is found, the dialog box is initialized to
that format. If a match is not found or this member is a null-terminated
string, this member is ignored on input. When the acmFormatChoose function returns, this buffer contains a null-terminated string describing
the user-defined format. If the format name is untitled (that is, the user has
not given a name for the format), 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 ACMFORMATCHOOSE_STYLEF_INITTOWFXSTRUCT flag is specified in the fdwStyle member, the pszName member is ignored for input.
cchName
Size, in characters, of the buffer identified by the pszName member. This buffer should be at least 128 characters long. If the pszName member is NULL, this member is ignored.
fdwEnum
Optional flags for restricting the type of formats listed in the dialog box.
These flags are identical to the fdwEnum flags for the acmFormatEnum function. If pwfxEnum is NULL, this member should be zero. The following values are defined:
ACM_FORMATENUMF_CONVERT
The WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate only destination formats that
can be converted from the given pwfxEnum format.
ACM_FORMATENUMF_HARDWARE
The enumerator should enumerate only formats that are supported in hardware by
one or more of the installed waveform-audio devices. This flag provides a way
for an application to choose only formats native to an installed waveform-audio
device.
ACM_FORMATENUMF_INPUT
The enumerator should enumerate only formats that are supported for input
(recording).
ACM_FORMATENUMF_NCHANNELS
The nChannels member of the WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate only a format that conforms to
this attribute.
ACM_FORMATENUMF_NSAMPLESPERSEC
The nSamplesPerSec member of the WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate only a format that conforms to
this attribute.
ACM_FORMATENUMF_OUTPUT
The enumerator should enumerate only formats that are supported for output
(playback).
ACM_FORMATENUMF_SUGGEST
The WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate all suggested destination
formats for the given pwfxEnum format.
ACM_FORMATENUMF_WBITSPERSAMPLE
The wBitsPerSample member of the WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate only a format that conforms to
this attribute.
ACM_FORMATENUMF_WFORMATTAG
The wFormatTag member of the WAVEFORMATEX structure pointed to by the pwfxEnum member is valid. The enumerator will enumerate only a format that conforms to
this attribute.
pwfxEnum
Address of a WAVEFORMATEX structure that will be used to restrict the formats listed in the dialog box.
The fdwEnum member defines the members of the structure pointed to by pwfxEnum that should be used for the enumeration restrictions. If no special
restrictions are desired, this member can be NULL. For other requirements associated
with the pwfxEnum member, see the description for the acmFormatEnum function.
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 ACMFORMATCHOOSE_STYLEF_ENABLETEMPLATE or
ACMFORMATCHOOSE_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 ACMFORMATCHOOSE_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 ACMFORMATCHOOSE_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
acmFormatChoose, acmFormatDetails, ACMFORMATDETAILS, acmFormatEnum, acmFormatTagDetails, ACMFORMATTAGDETAILS, acmMetrics, MAKEINTRESOURCE, MM_ACM_FORMATCHOOSE, RegisterWindowMessage, WAVEFORMATEX, 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
|
