windows-nt/Source/XPSP1/NT/multimedia/media/avi/vidcap32/help.c
2020-09-26 16:20:57 +08:00

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/**************************************************************************
*
* THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
* KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
* PURPOSE.
*
* Copyright (c) 1992 - 1995 Microsoft Corporation. All Rights Reserved.
*
**************************************************************************/
/****************************************************************************
*
* help.c: Help system interface
*
* Vidcap32 Source code
*
***************************************************************************/
/*
* supports F1 key help in app and in dialog by installing a hook,
*
* Keep track of which dialog is currently displayed in a global:
* dialog ids are also topic ids in the help file.
*/
#include <windows.h>
#include <windowsx.h>
#include <string.h>
#include "help.h"
int CurrentDialogID = 0;
// app info passed to helpinit
HINSTANCE hInstance;
TCHAR HelpFile[MAX_PATH];
HWND hwndApp;
//hook proc and old msg filter
#ifdef _WIN32
HHOOK hOurHook;
#else
FARPROC fnOldMsgFilter = NULL;
FARPROC fnMsgHook = NULL;
#endif
// call DialogBoxParam, but ensuring correct help processing:
// assumes that each Dialog Box ID is a context number in the help file.
// calls MakeProcInstance as necessary. Uses instance data passed to
// HelpInit().
INT_PTR
DoDialog(
HWND hwndParent, // parent window
int DialogID, // dialog resource id
DLGPROC fnDialog, // dialog proc
LPARAM lParam // passed as lparam in WM_INITDIALOG
)
{
int olddialog;
DLGPROC fn;
INT_PTR result;
// remember current id (for nested dialogs)
olddialog = CurrentDialogID;
// save the current id so the hook proc knows what help to display
CurrentDialogID = DialogID;
fn = (DLGPROC) MakeProcInstance(fnDialog, hInstance);
result = DialogBoxParam(
hInstance,
MAKEINTRESOURCE(CurrentDialogID),
hwndParent,
fn,
lParam);
FreeProcInstance(fn);
CurrentDialogID = olddialog;
return result;
}
// set the help context id for a dialog displayed other than by DoDialog
// (eg by GetOpenFileName). Returns the old help context that you must
// restore by a further call to this function
int
SetCurrentHelpContext(int DialogID)
{
int oldid = CurrentDialogID;
CurrentDialogID = DialogID;
return(oldid);
}
// return TRUE if lpMsg is a non-repeat F1 key message
BOOL
IsHelpKey(LPMSG lpMsg)
{
return lpMsg->message == WM_KEYDOWN &&
lpMsg->wParam == VK_F1 &&
!(HIWORD(lpMsg->lParam) & KF_REPEAT) &&
GetKeyState(VK_SHIFT) >= 0 &&
GetKeyState(VK_CONTROL) >= 0 &&
GetKeyState(VK_MENU) >= 0;
}
LRESULT CALLBACK
HelpMsgHook(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode >= 0) {
if (IsHelpKey((LPMSG)lParam)) {
if (CurrentDialogID != 0) {
WinHelp(hwndApp, HelpFile, HELP_CONTEXT, CurrentDialogID);
} else {
WinHelp(hwndApp, HelpFile, HELP_CONTENTS, 0);
}
}
}
#ifdef _WIN32
return CallNextHookEx(hOurHook, nCode, wParam, lParam);
#else
return DefHookProc(nCode, wParam, lParam, fnOldMsgFilter);
#endif
}
// help init - initialise the support for the F1 key help
BOOL
HelpInit(HINSTANCE hinstance, LPSTR helpfilepath, HWND hwnd)
{
LPSTR pch;
// save app details
hwndApp = hwnd;
hInstance = hinstance;
// assume that the help file is in the same directory as the executable-
// get the executable path, and replace the filename with the help
// file name.
GetModuleFileName(hinstance, HelpFile, sizeof(HelpFile));
// find the final backslash, and append the help file name there
pch = _fstrrchr(HelpFile, '\\');
pch++;
lstrcpy(pch, helpfilepath);
// install a hook for msgs and save old one
#ifdef _WIN32
hOurHook = SetWindowsHookEx(
WH_MSGFILTER,
(HOOKPROC) HelpMsgHook,
NULL, GetCurrentThreadId());
#else
fnMsgHook = (FARPROC) MakeProcInstance(HelpMsgHook, hInstance);
fnOldMsgFilter = SetWindowsHook(WH_MSGFILTER, (HOOKPROC) fnMsgHook);
#endif
return(TRUE);
}
// shutdown the help system
void
HelpShutdown(void)
{
#ifdef _WIN32
UnhookWindowsHookEx(hOurHook);
#else
if (fnOldMsgFilter) {
UnhookWindowsHook(WH_MSGFILTER, fnMsgHook);
FreeProcInstance(fnMsgHook);
}
#endif
WinHelp(hwndApp, HelpFile, HELP_QUIT, 0);
}
// start help at the contents page
void
HelpContents(void)
{
WinHelp(hwndApp, HelpFile, HELP_CONTENTS, 0);
}