{
* This Source Code Form is subject to the terms of the Mozilla Public License,
* v. 2.0. If a copy of the MPL was not distributed with this file, You can
* obtain one at http://mozilla.org/MPL/2.0/
*
* Copyright (C) 2005-2012, Peter Johnson (www.delphidabbler.com).
*
* $Rev$
* $Date$
*
* Provides a partial translation of HTMLHelp header files. Dynamically imports
* HTMLHelp function from hhctrl.ocx.
}
unit UHTMLHelp;
interface
uses
// Delphi
Windows;
function HtmlHelp(hwndCaller: HWND; pszFile: LPCTSTR; uCommand: UINT;
dwData: DWORD): HWND; stdcall;
{Single function used to control HTML Help. Action varies according to the
specified command.
@param hwndCaller [in] Handle of window calling HtmlHelp. HtmlHelp returns
focus to this window when closed, unless window is desktop. If
notifcations are enabled HtmlHelp sends notification messages to this
window.
@param pszFile [in] Depending on uCommand specifies either a .chm file or a
topic file within a help file. May also specify a window.
@param uCommand [in] Specifies command to be executed.
@param dwData [in] Specifies any data that may be required, based on the
value of the uCommand parameter.
@return Depending on uCommand and the result, either the handle of the help
window or 0 are returned. Zero can indicate either failure or that the
help window has not yet been created.
@except ECodeSnip raised if hhctrl.ocx library not available.
}
const
//
// Commands for HtmlHelp API function
//
HH_DISPLAY_TOPIC = $0000;
{Opens a help topic in a specified help window}
HH_HELP_FINDER = $0000;
{Alias for HH_DISPLAY_TOPIC}
HH_DISPLAY_TOC = $0001;
{Selects the Contents tab in the Navigation pane of the HTML Help Viewer}
HH_DISPLAY_INDEX = $0002;
{Selects the Index tab in the Navigation pane of the HTML Help Viewer and
searches for the keyword specified in the dwData parameter}
HH_DISPLAY_SEARCH = $0003;
{Selects the Search tab in the Navigation pane of the HTML Help Viewer}
HH_SET_WIN_TYPE = $0004;
{Creates a new help window or modifies an existing help window at run time}
HH_GET_WIN_TYPE = $0005;
{Retrieves a pointer to the HH_WINTYPE structure associated with a specified
window type}
HH_GET_WIN_HANDLE = $0006;
{Returns the handle of a specified window type}
HH_ENUM_INFO_TYPE = $0007;
{No documentation in htmlhelp.chm}
HH_SET_INFO_TYPE = $0008;
{No documentation in htmlhelp.chm}
HH_SYNC = $0009;
{Locates and selects the contents entry for the help topic that is open in
the Topic pane of the HTML Help Viewer}
HH_RESERVED1 = $000A;
{Reserved for future use}
HH_RESERVED2 = $000B;
{Reserved for future use}
HH_RESERVED3 = $000C;
{Reserved for future use}
HH_KEYWORD_LOOKUP = $000D;
{Looks up one or more keywords in a compiled help file}
HH_DISPLAY_TEXT_POPUP = $000E;
{Opens a pop-up window that displays the contents of one of the following:
an explicit text string; a text string based on a resource ID; a text string
ID based on a text file contained in a compiled help file}
HH_HELP_CONTEXT = $000F;
{Displays a help topic based on a mapped topic ID}
HH_TP_HELP_CONTEXTMENU = $0010;
{Opens a pop-up context menu. Generally used in response to the Windows
WM_CONTEXTMENU message. For example, this message is sent when a user
right-clicks a dialog box control}
HH_TP_HELP_WM_HELP = $0011;
{Opens a pop-up help topic. Generally used in response to the Windows
WM_HELP message. For example, this message is sent when a user presses F1}
HH_CLOSE_ALL = $0012;
{Closes all windows opened directly or indirectly by the calling program}
HH_ALINK_LOOKUP = $0013;
{Looks up one or more Associative Link (ALink) names in compiled help file}
HH_GET_LAST_ERROR = $0014;
{Returns information about the last error that occurred in hhctrl.ocx}
HH_ENUM_CATEGORY = $0015;
{No documentation in htmlhelp.chm}
HH_ENUM_CATEGORY_IT = $0016;
{No documentation in htmlhelp.chm}
HH_RESET_IT_FILTER = $0017;
{No documentation in htmlhelp.chm}
HH_SET_INCLUSIVE_FILTER = $0018;
{No documentation in htmlhelp.chm}
HH_SET_EXCLUSIVE_FILTER = $0019;
{No documentation in htmlhelp.chm}
HH_INITIALIZE = $001C;
{Initializes the help system for use and must be the first HTML Help command
called. It returns a cookie which must be used in the HH_UNINITIALIZE call}
HH_UNINITIALIZE = $001D;
{Called to properly shut down HTML Help. This function should be the last
help command the application calls. HH_UNINITIALIZE should not be called
during DLL process detach, but during the normal application shutdown
process}
HH_PRETRANSLATEMESSAGE = $00FD;
{Called in a Window application's message loop to ensure proper handling of
Windows messages, especially keyboard messages when running HTML Help single
thread}
HH_SET_GLOBAL_PROPERTY = $00FC;
{No documentation in htmlhelp.chm}
type
{
THHAKLink:
Structure used to specify one or more ALink names or KLink keywords to be
searched for.
}
THHAKLink = packed record
cbStruct: Integer; // sizeof this structure
fReserved: BOOL; // must be FALSE (really!)
pszKeywords: LPCTSTR; // semi-colon separated keywords
pszUrl: LPCTSTR; // URL to jump to if no keywords found (may be nil)
pszMsgText: LPCTSTR; // MessageBox text on failure (used if pszUrl nil)
pszMsgTitle: LPCTSTR; // Title of any failure MessageBox
pszWindow: LPCTSTR; // Window to display pszURL in
fIndexOnFail: BOOL; // Displays index if keyword lookup fails.
end;
{
PHHAKLink:
Pointer to THHAKLink structure.
}
PHHAKLink = ^THHAKLink;
implementation
uses
// Delphi
SysUtils,
// Project
UConsts, UExceptions;
type
{
THtmlHelp:
Prototype for HtmlHelpA API function.
@param hwndCaller [in] Handle of window calling HtmlHelp. HtmlHelp returns
focus to this window when closed, unless window is desktop. If
notifcations are enabled HtmlHelp sends notification messages to this
window.
@param pszFile [in] Depending on uCommand specifies either a .chm file or
a topic file within a help file. May also specify a window.
@param uCommand [in] Specifies command to be executed.
@param dwData [in] Specifies any data that may be required, based on the
value of the uCommand parameter.
@return Depending on uCommand and the result, either the handle of the
help window or 0 are returned. Zero can indicate either failure or that
the help window has not yet been created.
}
THtmlHelp = function (hwndCaller: HWND; pszFile: LPCTSTR; uCommand: UINT;
dwData: DWORD): HWND; stdcall;
var
pvtHHCtrl: THandle = 0; // handle to hhctrl.ocx library
pvtHtmlHelp: THtmlHelp = nil; // pointer to HtmlHelpA API function
resourcestring
// Error message used for exception raised when hhctrl.ocx not found
sNoHelp = 'Sorry, help is not available. ' + EOL2
+ 'This is because the HTML Help library (hhctrl.ocx) cannot be found.';
function HtmlHelp(hwndCaller: HWND; pszFile: LPCTSTR; uCommand: UINT;
dwData: DWORD): HWND; stdcall;
{Single function used to control HTML Help. Action varies according to the
specified command.
@param hwndCaller [in] Handle of window calling HtmlHelp. HtmlHelp returns
focus to this window when closed, unless window is desktop. If
notifcations are enabled HtmlHelp sends notification messages to this
window.
@param pszFile [in] Depending on uCommand specifies either a .chm file or a
topic file within a help file. May also specify a window.
@param uCommand [in] Specifies command to be executed.
@param dwData [in] Specifies any data that may be required, based on the
value of the uCommand parameter.
@return Depending on uCommand and the result, either the handle of the help
window or 0 are returned. Zero can indicate either failure or that the
help window has not yet been created.
@except ECodeSnip raised if hhctrl.ocx library not available.
}
begin
if not Assigned(pvtHtmlHelp) then
raise ECodeSnip.Create(sNoHelp);
Result := pvtHtmlHelp(hwndCaller, pszFile, uCommand, dwData);
end;
procedure LoadHtmlHelp;
{Attempt to load HtmlHelpA function from hhctrl.ocx.
}
const
cHTMLHelp = 'HtmlHelpW';
begin
pvtHHCtrl := SafeLoadLibrary('hhctrl.ocx');
if pvtHHCtrl <> 0 then
pvtHtmlHelp := GetProcAddress(pvtHHCtrl, cHTMLHelp);
end;
initialization
LoadHtmlHelp;
finalization
// Free hhctrl.ocx
if pvtHHCtrl <> 0 then
FreeLibrary(pvtHHCtrl);
end.
