git.zerfleddert.de Git - micropolis/blob - src/notes/to.ouster

   1 To: ouster@sprite.berkeley.edu
   2 Cc: hopkins
   3 Subject: more multiple display stuff
   4 --text follows this line--
   5 A problem I fixed is that the "focus" command only returns the focus
   6 of the main window's display, and there's no way to find out the focus
   7 on other displays.  I fixed this by adding a "focus -query .window"
   8 form, that returns the focus of the display of the named window.  When
   9 the tcl menu tracking code supports multiple displays, it will need to
  10 use this form to save the focus of the appropriate display before
  11 popping up a menu.
  12
  13 A problem I haven't fixed yet is with the "selection" command, which
  14 right now will only retrieve the selection from the display of the
  15 main window.  Pasting into a text field on another display with ^V
  16 inserts the selection from the main display.  It could be changed to
  17 take a window argument similar to "focus".
  18
  19 I wish I could think of a better flag name than "-query"...
  20
  21 I had a go at hacking the Tk C code to keep track of one focus per
  22 display instead of per main window.  (Should I be using one main
  23 window per display?  I'm not now, I'm just creating remote toplevels
  24 with the -screen argument.)  I moved the "struct TkWindow *focusPtr;"
  25 from the TkMainInfo to the TkDisplay structure, and modified the code
  26 in tkEvent.c that handled it and tkWindow.c that initialized it.
  27
  28 In tkEvent.c, I changed 3 "winPtr->mainPtr->focusPtr"'s to
  29 "winPtr->dispPtr->focusPtr", in Tk_HandleEvent and TkEventDeadWindow.
  30 I worked over Tk_FocusCmd and TkFocusEventProc, included below.
  31 I'm not sure what the "winPtr == winPtr->dispPtr->mouseMainPtr" test
  32 at the end of Tk_FocusCmd really intends, but the transformation was
  33 pretty straightforward, and it seems to work for my cases.
  34
  35 I've looked at the tcl code to try to figure out how to make it track
  36 properly with multiple displays.  I think I'll need a function that
  37 given the name of a window, returns a unique string describing the
  38 display, that I can use to make tk_priv keys that distinguish between
  39 displays.  The tcl functions tk_mbUnpost, tk_nextMenu, and
  40 tk_nextMenuEntry all need to take an argument so they can figure out
  41 which display to work on.
  42
  43 Another unrelated fix I made to Tk and Tcl was to put the TK_LIBRARY
  44 and TCL_LIBRARY strings into global variables, and refer to those
  45 variables instead of embeding strings in the code, so it's possible to
  46 set them up properly before initializing, since I want to be able to
  47 set a couple environment variables and run the application with no
  48 installation.  Is there a more appropriate way to do this?
  49
  50         -Don
  51
  52 Here is the code for Tk_FocusCmd and TkFocusEventProc:
  53
  54 \f
  55 /*
  56  *--------------------------------------------------------------
  57  *
  58  * Tk_FocusCmd --
  59  *
  60  *      This procedure is invoked to process the "focus" Tcl command.
  61  *      See the user documentation for details on what it does.
  62  *
  63  * Results:
  64  *      A standard Tcl result.
  65  *
  66  * Side effects:
  67  *      See the user documentation.
  68  *
  69  *--------------------------------------------------------------
  70  */
  71
  72 int
  73 Tk_FocusCmd(clientData, interp, argc, argv)
  74     ClientData clientData;      /* Main window associated with
  75                                  * interpreter. */
  76     Tcl_Interp *interp;         /* Current interpreter. */
  77     int argc;                   /* Number of arguments. */
  78     char **argv;                /* Argument strings. */
  79 {
  80     Tk_Window tkwin = (Tk_Window) clientData;
  81     register TkWindow *winPtr = (TkWindow *) clientData;
  82     register TkWindow *newPtr;
  83
  84     if (argc > 3) {
  85         focusSyntax:
  86         Tcl_AppendResult(interp, "too many args: should be \"",
  87                 argv[0], " ?-query? ?window?\"", (char *) NULL);
  88         return TCL_ERROR;
  89     }
  90
  91     if (argc == 1) {
  92         if (winPtr->dispPtr->focusPtr == NULL) {
  93             interp->result = "none";
  94         } else {
  95             interp->result = winPtr->dispPtr->focusPtr->pathName;
  96         }
  97         return TCL_OK;
  98     }
  99
 100     if (argv[1][0] == '-') {
 101         int switchLength;
 102
 103         switchLength = strlen(argv[1]);
 104         if ((switchLength >= 2)
 105                 && (strncmp(argv[1], "-query", switchLength) == 0)) {
 106
 107             if (argc != 3) {
 108                 goto focusSyntax;
 109             }
 110
 111             newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[2], tkwin);
 112             if (newPtr == NULL) {
 113                 return TCL_ERROR;
 114             }
 115             if (newPtr->dispPtr->focusPtr == NULL) {
 116                 interp->result = "none";
 117             } else {
 118                 interp->result = newPtr->dispPtr->focusPtr->pathName;
 119             }
 120             return TCL_OK;
 121         }
 122     }
 123
 124     if (argc != 2) {
 125         goto focusSyntax;
 126     }
 127
 128     if (strcmp(argv[1], "none") == 0) {
 129         newPtr = NULL;
 130     } else {
 131         newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[1], tkwin);
 132         if (newPtr == NULL) {
 133             return TCL_ERROR;
 134         }
 135     }
 136     if (newPtr->dispPtr->focusPtr == newPtr) {
 137         return TCL_OK;
 138     }
 139     if (winPtr == newPtr->dispPtr->mouseMainPtr) { /* XXX: ??? presumably */
 140         if ((newPtr->dispPtr->focusPtr != NULL)
 141                 && (newPtr->dispPtr->focusPtr->focusProc != NULL)) {
 142             (*newPtr->dispPtr->focusPtr->focusProc)(
 143                     newPtr->dispPtr->focusPtr->focusData, 0);
 144         }
 145         newPtr->dispPtr->focusPtr = newPtr;
 146         if ((newPtr != NULL) && (newPtr->focusProc != NULL)) {
 147             (*newPtr->focusProc)(newPtr->focusData, 1);
 148         }
 149     } else {
 150         newPtr->dispPtr->focusPtr = newPtr;
 151     }
 152     return TCL_OK;
 153 }
 154 \f
 155 /*
 156  *--------------------------------------------------------------
 157  *
 158  * TkFocusEventProc --
 159  *
 160  *      This procedure is invoked whenever the pointer enters
 161  *      or leaves a top-level window.  It notifies the current
 162  *      owner of the focus, if any.
 163  *
 164  * Results:
 165  *      None.
 166  *
 167  * Side effects:
 168  *      None.
 169  *
 170  *--------------------------------------------------------------
 171  */
 172
 173 void
 174 TkFocusEventProc(winPtr, eventPtr)
 175     register TkWindow *winPtr;  /* Top-level window just entered or left. */
 176     XEvent *eventPtr;           /* EnterWindow or LeaveWindow event. */
 177 {
 178     register TkWindow *focusPtr;
 179     TkWindow *newMouseMainPtr = NULL;
 180
 181     if (eventPtr->type == EnterNotify) {
 182         newMouseMainPtr = winPtr->mainPtr->winPtr;
 183     }
 184     if (winPtr->dispPtr->mouseMainPtr == newMouseMainPtr) {
 185         return;
 186     }
 187     if (winPtr->dispPtr->mouseMainPtr != NULL) {
 188         focusPtr = winPtr->dispPtr->focusPtr;
 189         if ((focusPtr != NULL)
 190                 && (focusPtr->focusProc != NULL)) {
 191             (*focusPtr->focusProc)(focusPtr->focusData, 0);
 192         }
 193     }
 194     winPtr->dispPtr->mouseMainPtr = newMouseMainPtr;
 195     if (newMouseMainPtr != NULL) {
 196         focusPtr = newMouseMainPtr->dispPtr->focusPtr;
 197         if ((focusPtr != NULL)
 198                 && (focusPtr->focusProc != NULL)) {
 199             (*focusPtr->focusProc)(focusPtr->focusData, 1);
 200         }
 201     }
 202 }