docs/microwin/readme.txt

   1 wxMicroWindows port
   2 ===================
   3
   4 Julian Smart 2001-12-08
   5
   6 This is a port of wxWindows to MicroWindows, under Linux.
   7 Widgets are supplied by the wxUniversal project, while the
   8 underlying port uses the Windows ports with small modifications
   9 for the MicroWindows API.
  10
  11 === NOTE: ===
  12
  13   Current efforts are being concentrated on a port to Nano-X,
  14   which potentially offers greater flexibility than the WIN32
  15   API of MicroWindows, such as the ability to run multiple
  16   Nano-X processes simultaneously. Please see
  17   ../docs/x11/readme-nanox.txt for information.
  18
  19 There are many things missing from MicroWindows that will
  20 make the port quite limited for the time being.
  21 In particular, only one WIN32 app may be run at a time.
  22
  23 Note that you can gain confidence in the WIN32/wxUniversal
  24 combination by compiling wxUniversal under Windows using VC++,
  25 using src/wxUniv.dsp. You can compile the minimal
  26 and widgets samples in wxUniversal mode using the
  27 UnivDebug and UnivRelease targets. Most of the code is shared
  28 between this combination, and the wxMicroWindows port.
  29
  30 Installation
  31 ============
  32
  33 MicroWindows:
  34
  35 - unarchive MicroWindows 0.89pre8
  36
  37 - change 'config' to use X11 and any other options you feel fit.
  38   Suggestions for changes to the defaults:
  39
  40   ERASEMOVE=N (otherwise moving windows will look messy)
  41   X11=Y
  42   OPTIMIZE=N
  43   DEBUG=Y
  44   VERBOSE=Y
  45
  46   Note: these are already applied by the patch below.
  47
  48 - apply microwindows.patches (from wxWindows:
  49   docs/microwin/microwindows.patches) to fix PeekMessage
  50   and other issues. If the patch doesn't apply automatically,
  51   you may need to apply it by hand, and the relevant changed
  52   functions are given at the end of this file for convenience.
  53
  54   Example patch command:
  55
  56   % cd microwindows-0.89pre8.orig
  57   % patch -p0 < ~/wx2/docs/microwin/microwindows.patches
  58
  59 - compile by typing 'make' from within the MicroWindows src directory
  60
  61 wxMicroWindows:
  62
  63 - Download wxMSW 2.3.4 or greater, or get it from CVS
  64
  65 - Copy include/wx/msw/setup_microwin.h to include/wx/setup.h if
  66   include/wx/setup.h doesn't exist
  67
  68 - EITHER:
  69
  70   o set the MICROWINDOWS environment variable, e.g.:
  71
  72     % export MICROWINDOWS=/home/julians/local/microwindows/microwindows-0.89pre8/src
  73
  74   OR:
  75
  76   o change the TOP variable at the top of src/msw/makefile.mic
  77     to reflect where MicroWindows is installed
  78
  79 - type 'make -f makefile.mic all' from src/msw. To clean, use
  80   cleanwx and NOT clean since that will clean MicroWindows itself
  81
  82 - to make the sample, cd into samples/minimal, edit the TOP variable
  83   (or set MICROWINDOWS) as before, and type 'make -f makefile.mic all'
  84
  85 Running 'minimal' runs the virtual MicroWindows desktop
  86 and the minimal sample, since in a MicroWindows WIN32 application
  87 they are one and the same binary.
  88
  89 Status
  90 ======
  91
  92 The minimal sample is almost fully-functional, apart from some
  93 presentation issues (no menu borders and status bar in the wrong
  94 place.
  95
  96 The widgets sample is crashing in DeleteObject (see notes below).
  97
  98
  99 Implementation Notes
 100 ====================
 101
 102 wxMicroWindows is essentially the wxMSW port + wxUniversal
 103 widgets. Lots of things in include/wx/univ/setup.h are switched
 104 off to allow the port to compile. There are also #ifdefs
 105 switching off further functionality, such as most wxBitmap
 106 functions, pending proper implementation.
 107
 108 There are some WIN32 API functions not implemented by MicroWindows
 109 that are instead stubbed out in include/wx/msw/microwin.c,
 110 and 'implemented' in src/msw/microwin.c. Some of these functions
 111 are important, some less so. They will need to be implemented
 112 in due course. But implementing missing functionality in this way
 113 is preferably to proliferating many #ifdefs in the
 114 wxMSW/wxMicroWindows port itself.
 115
 116
 117 Errors/warnings
 118 ===============
 119
 120 In file ../../src/msw/window.cpp at line 1294: 'UpdateWindow' failed with error 0x00000000 (Success).
 121
 122   - caused because there are no paint messages pending. Presumed
 123     harmless.
 124
 125 In file ../../src/msw/dc.cpp at line 1838: 'BitBlt' failed with error 0x00000000 (Success).
 126
 127   - caused because the window isn't mapped, and MwPrepareDC in wingdi.c
 128     fails (hwnd->unmapcount is non-zero). Presumed harmless.
 129
 130 Recursive paint problem, e.g. when clicking the 'Press Me!'
 131 button in the widgets sample a few times, until the text control
 132 is full.
 133
 134   - possibly the scrollbar is causing the text control to be
 135     updated, which somehow effects the scrollbar, which causes
 136     a window update, etc.
 137
 138 Sluggish updates.
 139
 140   - probably because many image to bitmap conversions are being
 141     done on update, and bitmaps should probably be cached.
 142
 143
 144 Things missing from MicroWindows that need to be worked around
 145 ==============================================================
 146
 147 wxImage/inline XPM/::CreateBitmap support
 148 -----------------------------------------
 149
 150 This is the main obstacle to getting a good range
 151 of widgets working, since wxUniversal uses inline XPMs
 152 to implement most of the widgets.
 153
 154 See src/engine/devimage.c for routines for loading JPEGs,
 155 XPMs etc. Unfortunately the XPM routines are also #ifdefed
 156 for FILE_IO, even though for inline XPMs we don't need file I/O.
 157 (Embedded systems tend not to have file I/O, anyway.)
 158
 159 Now, wxWindows has its own XPM decoder, src/common/xpmdecod.cpp,
 160 so in theory we don't need to use MicroWindows' code there.
 161 wxImage can load an inline XPM, _but_ we need to convert to
 162 a wxBitmap since this is what the widgets need.
 163
 164 There is no ::CreateBitmap or BITMAPINFO. (BMPs can be converted
 165 to C using convbmp, then need to use Gr... functions.)
 166
 167 So how can we convert from wxImage to wxBitmap in MicroWindows?
 168
 169 Well, a simple-minded way would be to use CreateCompatibleBitmap
 170 which returns an HBITMAP, select it into an HDC, and draw
 171 the pixels from the wxImage to the HDC one by one with SetPixel.
 172 This is now implemented, but there are problems with masks.
 173 (a) masks have to be created at screen depth because BitBlt/GrDraw
 174 can't cope with differing depths, and (b) masked blitting
 175 is still not working (try enabling mask creation in
 176 wxBitmap::CreateFromImage by setting USE_MASKS to 1).
 177
 178
 179 Other missing features
 180 ----------------------
 181
 182 No ::GetKeyState (see include/wx/msw/private.h). Should probably use
 183 GdOpenKeyboard/GdCloseKeyboard/GdReadKeyboard. Could perhaps emulate
 184 GetKeyState this way.
 185
 186 No ::DestroyIcon, ::DestroyCursor - use ::DestroyObject instead?
 187 Also no LoadCursor, LoadImage. So how do we make cursors? No ::SetCursor.
 188
 189 wxDC: no ::GetTextColor, ::GetBkColor, ::IntersectClipRect,
 190 ::GetClipBox
 191
 192 No ::SetMenu, so no menus or menubars (now implemented by
 193 wxUniversal).
 194
 195 No ::GetObject so we can't get LOGFONT from an HFONT
 196 in wxSystemSettings (worked around by passing HFONT to
 197 the wxFont constructor).
 198
 199
 200 Applying patches by hand
 201 ========================
 202
 203 The full altered functions are given below in case you have
 204 to apply them by hand.
 205
 206 src/mwin/winevent.c
 207 -------------------
 208
 209 A second test has been added to this line:
 210
 211         if(hittest == HTCLIENT || hwnd == GetCapture()) {
 212
 213 in MwTranslateMouseMessage below. This corrects a mouse message
 214 bug.
 215
 216 /*
 217  * Translate and deliver hardware mouse message to proper window.
 218  */
 219 void
 220 MwTranslateMouseMessage(HWND hwnd,UINT msg,int hittest)
 221 {
 222         POINT           pt;
 223         DWORD           tick;
 224         static UINT     lastmsg = 0;
 225         static HWND     lasthwnd;
 226         static DWORD    lasttick;
 227         static int      lastx, lasty;
 228
 229         /* determine double click eligibility*/
 230         if(msg == WM_LBUTTONDOWN || msg == WM_RBUTTONDOWN) {
 231                 tick = GetTickCount();
 232                 if((hwnd->pClass->style & CS_DBLCLKS) &&
 233                     msg == lastmsg && hwnd == lasthwnd &&
 234                     tick - lasttick < DBLCLICKSPEED &&
 235                     abs(cursorx-lastx) < mwSYSMETRICS_CXDOUBLECLK &&
 236                     abs(cursory-lasty) < mwSYSMETRICS_CYDOUBLECLK)
 237                         msg += (WM_LBUTTONDBLCLK - WM_LBUTTONDOWN);
 238                 lastmsg = msg;
 239                 lasthwnd = hwnd;
 240                 lasttick = tick;
 241                 lastx = cursorx;
 242                 lasty = cursory;
 243         }
 244
 245         /*
 246          * We always send nc mouse message
 247          * unlike Windows, for HTCLIENT default processing
 248          */
 249         PostMessage(hwnd, msg + (WM_NCMOUSEMOVE-WM_MOUSEMOVE), hittest,
 250                 MAKELONG(cursorx, cursory));
 251
 252         /* then possibly send user mouse message*/
 253         if(hittest == HTCLIENT || hwnd == GetCapture()) {
 254                 pt.x = cursorx;
 255                 pt.y = cursory;
 256                 ScreenToClient(hwnd, &pt);
 257                 PostMessage(hwnd, msg, 0, MAKELONG(pt.x, pt.y));
 258         }
 259 }
 260
 261 winuser.c
 262 ---------
 263
 264 Part of PeekMessage has been factored out into PeekMessageHelper,
 265 and used in PeekMessage and GetMessage. The three relevant functions
 266 are:
 267
 268 /*
 269  * A helper function for sharing code between PeekMessage and GetMessage
 270  */
 271
 272 BOOL WINAPI
 273 PeekMessageHelper(LPMSG lpMsg, HWND hwnd, UINT uMsgFilterMin, UINT uMsgFilterMax,
 274         UINT wRemoveMsg, BOOL returnIfEmptyQueue)
 275 {
 276         HWND    wp;
 277         PMSG    pNxtMsg;
 278
 279         /* check if no messages in queue*/
 280         if(mwMsgHead.head == NULL) {
 281                 /* Added by JACS so it doesn't reach MwSelect */
 282                 if (returnIfEmptyQueue)
 283                     return FALSE;
 284
 285 #if PAINTONCE
 286                 /* check all windows for pending paint messages*/
 287                 for(wp=listwp; wp; wp=wp->next) {
 288                         if(!(wp->style & WS_CHILD)) {
 289                                 if(chkPaintMsg(wp, lpMsg))
 290                                         return TRUE;
 291                         }
 292                 }
 293                 for(wp=listwp; wp; wp=wp->next) {
 294                         if(wp->style & WS_CHILD) {
 295                                 if(chkPaintMsg(wp, lpMsg))
 296                                         return TRUE;
 297                         }
 298                 }
 299 #endif
 300                 MwSelect();
 301         }
 302
 303         if(mwMsgHead.head == NULL)
 304                 return FALSE;
 305
 306         pNxtMsg = (PMSG)mwMsgHead.head;
 307         if(wRemoveMsg & PM_REMOVE)
 308                 GdListRemove(&mwMsgHead, &pNxtMsg->link);
 309         *lpMsg = *pNxtMsg;
 310         if(wRemoveMsg & PM_REMOVE)
 311                 GdItemFree(pNxtMsg);
 312         return TRUE;
 313 }
 314
 315 BOOL WINAPI
 316 PeekMessage(LPMSG lpMsg, HWND hwnd, UINT uMsgFilterMin, UINT uMsgFilterMax,
 317         UINT wRemoveMsg)
 318 {
 319         /* Never wait in MwSelect: pass TRUE */
 320         return PeekMessageHelper(lpMsg, hwnd, uMsgFilterMin, uMsgFilterMax, wRemoveMsg, TRUE);
 321 }
 322
 323 BOOL WINAPI
 324 GetMessage(LPMSG lpMsg,HWND hwnd,UINT wMsgFilterMin,UINT wMsgFilterMax)
 325 {
 326         /*
 327          * currently MwSelect() must poll for VT switch reasons,
 328          * so this code will work
 329          */
 330         /* Always wait in MwSelect if there are messages: pass FALSE */
 331         while(!PeekMessageHelper(lpMsg, hwnd, wMsgFilterMin, wMsgFilterMax,PM_REMOVE, FALSE))
 332                 continue;
 333         return lpMsg->message != WM_QUIT;
 334 }