fix the old code for dlerror() returning const char as well (why was it changed?)

[wxWidgets.git] / docs / microwin / readme.txt

wxMicroWindows port
===================

Julian Smart 2001-12-08

This is a port of wxWindows to MicroWindows, under Linux.
Widgets are supplied by the wxUniversal project, while the
underlying port uses the Windows ports with small modifications
for the MicroWindows API.

There are many things missing from MicroWindows that will
make the port quite limited for the time being. I haven't
worked out how to create bitmaps, though there is a BMP to C
converter. There are no common dialogs (we will use generic ones),
and only one WIN32 app may be run at a time.

Note that you can gain confidence in the WIN32/wxUniversal
combination by compiling wxUniversal under Windows using VC++,
using src/wxvc_universal.dsp. You can compile the minimal
and widgets samples in wxUniversal mode using the
UnivDebug and UnivRelease targets. Most of the code is shared
between this combination, and the wxMicroWindows port.

Installation
============

MicroWindows:

- unarchive MicroWindows 0.89pre8

- change 'config' to use X11 and any other options you feel fit.
  Suggestions for changes to the defaults:

  ERASEMOVE=N (otherwise moving windows will look messy)
  X11=Y
  OPTIMIZE=N
  DEBUG=Y
  VERBOSE=Y

  Note: these are already applied by the patch below.

- apply microwindows.patches (from wxWindows:
  docs/microwin/microwindows.patches) to fix PeekMessage
  and other issues. If the patch doesn't apply automatically,
  you may need to apply it by hand, and the relevant changed
  functions are given at the end of this file for convenience.

  Example patch command:

  % cd microwindows-0.89pre8.orig
  % patch -p0 < ~/wx2/docs/microwin/microwindows.patches

- compile by typing 'make' from within the MicroWindows src directory

wxMicroWindows:

- Download wxMSW 2.3.2 or greater, or get it from CVS

- Copy include/wx/msw/setup_microwin.h to include/wx/setup.h if
  include/wx/setup.h doesn't exist

- change the TOP variable at the top of src/msw/makefile.mic
  to reflect where MicroWindows is installed

- type 'make -f makefile.mic all' from src/msw. To clean, use
  cleanwx and NOT clean since that will clean MicroWindows itself

- to make the sample, cd into samples/minimal, edit the TOP variable,
  and type 'make -f makefile.mic all'

Running 'minimal' runs the virtual MicroWindows desktop
and the minimal sample, since in a MicroWindows WIN32 application
they are one and the same binary.

Status
======

The minimal sample is almost fully-functional, apart from minor
menu presentation issues (no borders, for example).

Implementation Notes
====================

wxMicroWindows is essentially the wxMSW port + wxUniversal
widgets. Lots of things in include/wx/univ/setup.h are switched
off to allow the port to compile. There are also #ifdefs
switching off further functionality, such as most wxBitmap
functions, pending proper implementation.

There are some WIN32 API functions not implemented by MicroWindows
that are instead stubbed out in include/wx/msw/microwin.c,
and 'implemented' in src/msw/microwin.c. Some of these functions
are important, some less so. They will need to be implemented
in due course. But implementing missing functionality in this way
is preferably to proliferating many #ifdefs in the
wxMSW/wxMicroWindows port itself.

Things missing from MicroWindows that need to be worked around
==============================================================

No ::GetKeyState (see include/wx/msw/private.h). Should probably use
GdOpenKeyboard/GdCloseKeyboard/GdReadKeyboard. Could perhaps emulate
GetKeyState this way.

No ::CreateBitmap or BITMAPINFO. But BMPs can be converted
to C using convbmp, then need to use Gr... functions.
We MUST implement creation from XPMs, since wxUniversal
makes use of XPMs, or else create our own bitmaps for
drawing radioboxes, checkboxes etc.: see renderers
in src/univ.

No ::DestroyIcon, ::DestroyCursor - use ::DestroyObject instead?
Also no LoadCursor, LoadImage. So how do we make cursors? No ::SetCursor.

wxDC: no ::GetTextColor, ::GetBkColor, ::IntersectClipRect,
::GetClipBox

No ::SetMenu, so no menus or menubars (now implemented by
wxUniversal).

No ::GetObject so we can't get LOGFONT from an HFONT
in wxSystemSettings (worked around by passing HFONT to
the wxFont constructor).


Applying patches by hand
========================

The full altered functions are given below in case you have
to apply them by hand.

src/mwin/winevent.c
-------------------

A second test has been added to this line:

	if(hittest == HTCLIENT || hwnd == GetCapture()) {

in MwTranslateMouseMessage below. This corrects a mouse message
bug.

/*
 * Translate and deliver hardware mouse message to proper window.
 */
void
MwTranslateMouseMessage(HWND hwnd,UINT msg,int hittest)
{
	POINT		pt;
	DWORD		tick;
	static UINT	lastmsg = 0;
	static HWND	lasthwnd;
	static DWORD	lasttick;
	static int	lastx, lasty;

	/* determine double click eligibility*/
	if(msg == WM_LBUTTONDOWN || msg == WM_RBUTTONDOWN) {
		tick = GetTickCount();
		if((hwnd->pClass->style & CS_DBLCLKS) &&
		    msg == lastmsg && hwnd == lasthwnd &&
		    tick - lasttick < DBLCLICKSPEED &&
		    abs(cursorx-lastx) < mwSYSMETRICS_CXDOUBLECLK &&
		    abs(cursory-lasty) < mwSYSMETRICS_CYDOUBLECLK)
			msg += (WM_LBUTTONDBLCLK - WM_LBUTTONDOWN);
		lastmsg = msg;
		lasthwnd = hwnd;
		lasttick = tick;
		lastx = cursorx;
		lasty = cursory;
	}

	/*
	 * We always send nc mouse message
	 * unlike Windows, for HTCLIENT default processing
	 */
	PostMessage(hwnd, msg + (WM_NCMOUSEMOVE-WM_MOUSEMOVE), hittest,
		MAKELONG(cursorx, cursory));

	/* then possibly send user mouse message*/
	if(hittest == HTCLIENT || hwnd == GetCapture()) {
		pt.x = cursorx;
		pt.y = cursory;
		ScreenToClient(hwnd, &pt);
		PostMessage(hwnd, msg, 0, MAKELONG(pt.x, pt.y));
	}
}

winuser.c
---------

Part of PeekMessage has been factored out into PeekMessageHelper,
and used in PeekMessage and GetMessage. The three relevant functions
are:

/*
 * A helper function for sharing code between PeekMessage and GetMessage
 */

BOOL WINAPI
PeekMessageHelper(LPMSG lpMsg, HWND hwnd, UINT uMsgFilterMin, UINT uMsgFilterMax,
	UINT wRemoveMsg, BOOL returnIfEmptyQueue)
{
	HWND	wp;
	PMSG	pNxtMsg;

	/* check if no messages in queue*/
	if(mwMsgHead.head == NULL) {
                /* Added by JACS so it doesn't reach MwSelect */
                if (returnIfEmptyQueue)
                    return FALSE;

#if PAINTONCE
		/* check all windows for pending paint messages*/
		for(wp=listwp; wp; wp=wp->next) {
			if(!(wp->style & WS_CHILD)) {
				if(chkPaintMsg(wp, lpMsg))
					return TRUE;
			}
		}
		for(wp=listwp; wp; wp=wp->next) {
			if(wp->style & WS_CHILD) {
				if(chkPaintMsg(wp, lpMsg))
					return TRUE;
			}
		}
#endif
		MwSelect();
	}

	if(mwMsgHead.head == NULL)
		return FALSE;

	pNxtMsg = (PMSG)mwMsgHead.head;
	if(wRemoveMsg & PM_REMOVE)
		GdListRemove(&mwMsgHead, &pNxtMsg->link);
	*lpMsg = *pNxtMsg;
	if(wRemoveMsg & PM_REMOVE)
		GdItemFree(pNxtMsg);
	return TRUE;
}

BOOL WINAPI
PeekMessage(LPMSG lpMsg, HWND hwnd, UINT uMsgFilterMin, UINT uMsgFilterMax,
	UINT wRemoveMsg)
{
        /* Never wait in MwSelect: pass TRUE */
        return PeekMessageHelper(lpMsg, hwnd, uMsgFilterMin, uMsgFilterMax, wRemoveMsg, TRUE);
}

BOOL WINAPI
GetMessage(LPMSG lpMsg,HWND hwnd,UINT wMsgFilterMin,UINT wMsgFilterMax)
{
	/*
	 * currently MwSelect() must poll for VT switch reasons,
	 * so this code will work
	 */
        /* Always wait in MwSelect if there are messages: pass FALSE */
	while(!PeekMessageHelper(lpMsg, hwnd, wMsgFilterMin, wMsgFilterMax,PM_REMOVE, FALSE))
		continue;
	return lpMsg->message != WM_QUIT;
}