Re: [TCLCORE] TIPs looking for implementations

[Koen D. <ko...@re...>]

Joe English wrote:
> Kevin Kenny wrote:
>> Donal K. Fellows wrote:
>>>   * TIP#171 should be easy to act on; I've not done it yet because I'm
>>>     not the relevant maintainer.
>> Didn't we do these changes already? Why not? Jeff??
> 
> I (for one) still have unanswered questions about the
> proposed TIP#171 implementation.  Specifically:
> 
> | instead of going through all sorts of rigamarole at
> | the scripting level to redirect MouseWheel events
> | to the widget under the pointer on Windows, wouldn't
> | it make more sense to simply not redirect them to
> | the focus window in the first place (see tkEvent.c,
> | InvokeFocusHandlers)?  That's how it's currently done
> | on OSX.  I suspect it also interferes with some of
> | the ttk::* widgets.
> 
> I agree with the TIP#171 Rationale (paraphrased: "On
> Windows, mouse wheel scrolling should affect the widget
> under the pointer [just like it does on X11 and OSX]
> instead of the widget with keyboard focus.")  But the
> proposed implementation smells really bad to me.
> 
> (The proposed implementation looks like a usable stopgap
> solution for Tk <= 8.5, but long-term it is -- I suspect --
> something we're just going to have to undo later.)

In case anyone is interested in it, I use the C patch below to achieve basically the same as TIP 171, but whithout all the [focus] voodoo going on in that TIP's implementation.


Index: generic/tkEvent.c
===================================================================
RCS file: /cvsroot/tktoolkit/tk/generic/tkEvent.c,v
retrieving revision 1.37
diff -u -r1.37 tkEvent.c
--- generic/tkEvent.c   8 Nov 2008 18:44:39 -0000       1.37
+++ generic/tkEvent.c   25 Nov 2008 11:34:05 -0000
@@ -246,17 +246,7 @@
        return 1;
     }
 
-    /*
-     * MouseWheel events are not focus specific on Mac OS X.
-     */
-
-#ifdef MAC_OSX_TK
-#define FOCUS_DIRECTED_EVENT_MASK (KeyPressMask|KeyReleaseMask)
-#else
-#define        FOCUS_DIRECTED_EVENT_MASK (KeyPressMask|KeyReleaseMask|MouseWheelMask)
-#endif
-
-    if (mask & FOCUS_DIRECTED_EVENT_MASK) {
+    if (mask & (KeyPressMask|KeyReleaseMask)) {
        (*winPtrPtr)->dispPtr->lastEventTime = eventPtr->xkey.time;
        *winPtrPtr = TkFocusKeyEvent(*winPtrPtr, eventPtr);
        if (*winPtrPtr == NULL) {
Index: win/tkWinX.c
===================================================================
RCS file: /cvsroot/tktoolkit/tk/win/tkWinX.c,v
retrieving revision 1.58
diff -u -r1.58 tkWinX.c
--- win/tkWinX.c        27 Apr 2008 22:39:17 -0000      1.58
+++ win/tkWinX.c        25 Nov 2008 11:34:08 -0000
@@ -1006,6 +1006,16 @@
     ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
            Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
 
+    /* Redirect mousewheel events to the window containing the cursor. */
+    if (message == WM_MOUSEWHEEL) {
+        POINTS rootPoint = MAKEPOINTS(lParam);
+        POINT pos;
+        pos.x = rootPoint.x;
+        pos.y = rootPoint.y;
+        hwnd = WindowFromPoint(pos);
+        winPtr = (TkWindow *) Tk_HWNDToWindow(hwnd);
+    }
+
     if (!winPtr || winPtr->window == None) {
        return;
     }
@@ -1103,11 +1113,6 @@
        break;
 
     case WM_MOUSEWHEEL:
-       /*
-        * The mouse wheel event is closer to a key event than a mouse event
-        * in that the message is sent to the window that has focus.
-        */
-
     case WM_CHAR:
     case WM_UNICHAR:
     case WM_SYSKEYDOWN: