Initial revision

1 files changed, 745 insertions, 0 deletions

diff --git a/win/tkWinScrlbr.c b/win/tkWinScrlbr.c
new file mode 100644
index 0000000..6c1a664
--- /dev/null
+++ b/win/tkWinScrlbr.c
@@ -0,0 +1,745 @@
+/* 
+ * tkWinScrollbar.c --
+ *
+ *	This file implements the Windows specific portion of the scrollbar
+ *	widget.
+ *
+ * Copyright (c) 1996 by Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tkWinScrlbr.c 1.19 97/08/13 17:37:49
+ */
+
+#include "tkWinInt.h"
+#include "tkScrollbar.h"
+
+
+/*
+ * The following constant is used to specify the maximum scroll position.
+ * This value is limited by the Win32 API to either 16-bits or 32-bits,
+ * depending on the context.  For now we'll just use a value small
+ * enough to fit in 16-bits, but which gives us 4-digits of precision.
+ */
+
+#define MAX_SCROLL 10000
+
+/*
+ * Declaration of Windows specific scrollbar structure.
+ */
+
+typedef struct WinScrollbar {
+    TkScrollbar info;		/* Generic scrollbar info. */
+    WNDPROC oldProc;		/* Old window procedure. */
+    int lastVertical;		/* 1 if was vertical at last refresh. */
+    HWND hwnd;			/* Current window handle. */
+    int winFlags;		/* Various flags; see below. */
+} WinScrollbar;
+
+/*
+ * Flag bits for native scrollbars:
+ * 
+ * IN_MODAL_LOOP:		Non-zero means this scrollbar is in the middle
+ *				of a modal loop.
+ * ALREADY_DEAD:		Non-zero means this scrollbar has been
+ *				destroyed, but has not been cleaned up.
+ */
+
+#define IN_MODAL_LOOP	1
+#define ALREADY_DEAD	2
+
+/*
+ * Cached system metrics used to determine scrollbar geometry.
+ */
+
+static int initialized = 0;
+static int hArrowWidth, hThumb; /* Horizontal control metrics. */
+static int vArrowWidth, vArrowHeight, vThumb; /* Vertical control metrics. */
+
+/*
+ * This variable holds the default width for a scrollbar in string
+ * form for use in a Tk_ConfigSpec.
+ */
+
+static char defWidth[8];
+
+/*
+ * Declarations for functions defined in this file.
+ */
+
+static Window		CreateProc _ANSI_ARGS_((Tk_Window tkwin,
+			    Window parent, ClientData instanceData));
+static void		ModalLoopProc _ANSI_ARGS_((Tk_Window tkwin,
+			    XEvent *eventPtr));
+static int		ScrollbarBindProc _ANSI_ARGS_((ClientData clientData,
+			    Tcl_Interp *interp, XEvent *eventPtr,
+			    Tk_Window tkwin, KeySym keySym));
+static LRESULT CALLBACK	ScrollbarProc _ANSI_ARGS_((HWND hwnd, UINT message,
+			    WPARAM wParam, LPARAM lParam));
+static void		UpdateScrollbar _ANSI_ARGS_((
+    			    WinScrollbar *scrollPtr));
+static void		UpdateScrollbarMetrics _ANSI_ARGS_((void));
+
+/*
+ * The class procedure table for the scrollbar widget.
+ */
+
+TkClassProcs tkpScrollbarProcs = {
+    CreateProc,			/* createProc */
+    NULL,			/* geometryProc */
+    ModalLoopProc,		/* modalProc */
+};
+
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpCreateScrollbar --
+ *
+ *	Allocate a new TkScrollbar structure.
+ *
+ * Results:
+ *	Returns a newly allocated TkScrollbar structure.
+ *
+ * Side effects:
+ *	Registers an event handler for the widget.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TkScrollbar *
+TkpCreateScrollbar(tkwin)
+    Tk_Window tkwin;
+{
+    WinScrollbar *scrollPtr;
+    TkWindow *winPtr = (TkWindow *)tkwin;
+    
+    if (!initialized) {
+	UpdateScrollbarMetrics();
+	initialized = 1;
+    }
+
+    scrollPtr = (WinScrollbar *) ckalloc(sizeof(WinScrollbar));
+    scrollPtr->winFlags = 0;
+    scrollPtr->hwnd = NULL;
+
+    Tk_CreateEventHandler(tkwin,
+	    ExposureMask|StructureNotifyMask|FocusChangeMask,
+	    TkScrollbarEventProc, (ClientData) scrollPtr);
+
+    if (!Tcl_GetAssocData(winPtr->mainPtr->interp, "TkScrollbar", NULL)) {
+	Tcl_SetAssocData(winPtr->mainPtr->interp, "TkScrollbar", NULL,
+		(ClientData)1);
+	TkCreateBindingProcedure(winPtr->mainPtr->interp,
+		winPtr->mainPtr->bindingTable,
+		(ClientData)Tk_GetUid("Scrollbar"), "<ButtonPress>",
+		ScrollbarBindProc, NULL, NULL);
+    }
+
+    return (TkScrollbar*) scrollPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * UpdateScrollbar --
+ *
+ *	This function updates the position and size of the scrollbar
+ *	thumb based on the current settings.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Moves the thumb.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+UpdateScrollbar(scrollPtr)
+    WinScrollbar *scrollPtr;
+{
+    SCROLLINFO scrollInfo;
+    double thumbSize;
+
+    /*
+     * Update the current scrollbar position and shape.
+     */
+
+    scrollInfo.fMask = SIF_PAGE | SIF_POS | SIF_RANGE;
+    scrollInfo.cbSize = sizeof(scrollInfo);
+    scrollInfo.nMin = 0;
+    scrollInfo.nMax = MAX_SCROLL;
+    thumbSize = (scrollPtr->info.lastFraction - scrollPtr->info.firstFraction);
+    if (tkpIsWin32s) {
+	scrollInfo.nPage = 0;
+    } else {
+	scrollInfo.nPage = ((UINT) (thumbSize * (double) MAX_SCROLL)) + 1;
+    } 
+    if (thumbSize < 1.0) {
+	scrollInfo.nPos = (int)
+	    ((scrollPtr->info.firstFraction / (1.0-thumbSize))
+		    * (MAX_SCROLL - (scrollInfo.nPage - 1)));
+    } else {
+	scrollInfo.nPos = 0;
+    }
+    SetScrollInfo(scrollPtr->hwnd, SB_CTL, &scrollInfo, TRUE);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CreateProc --
+ *
+ *	This function creates a new Scrollbar control, subclasses
+ *	the instance, and generates a new Window object.
+ *
+ * Results:
+ *	Returns the newly allocated Window object, or None on failure.
+ *
+ * Side effects:
+ *	Causes a new Scrollbar control to come into existence.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Window
+CreateProc(tkwin, parentWin, instanceData)
+    Tk_Window tkwin;		/* Token for window. */
+    Window parentWin;		/* Parent of new window. */
+    ClientData instanceData;	/* Scrollbar instance data. */
+{
+    DWORD style;
+    Window window;
+    HWND parent;
+    TkWindow *winPtr;
+    WinScrollbar *scrollPtr = (WinScrollbar *)instanceData;
+
+    parent = Tk_GetHWND(parentWin);
+
+    if (scrollPtr->info.vertical) {
+	style = WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS
+	    | SBS_VERT | SBS_RIGHTALIGN;
+    } else {
+	style = WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS
+	    | SBS_HORZ | SBS_BOTTOMALIGN;
+    }
+
+    scrollPtr->hwnd = CreateWindow("SCROLLBAR", NULL, style,
+	    Tk_X(tkwin), Tk_Y(tkwin), Tk_Width(tkwin), Tk_Height(tkwin),
+	    parent, NULL, Tk_GetHINSTANCE(), NULL);
+
+    /*
+     * Ensure new window is inserted into the stacking order at the correct
+     * place. 
+     */
+
+    SetWindowPos(scrollPtr->hwnd, HWND_TOP, 0, 0, 0, 0,
+		    SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOSIZE);
+
+    for (winPtr = ((TkWindow*)tkwin)->nextPtr; winPtr != NULL;
+	 winPtr = winPtr->nextPtr) {
+	if ((winPtr->window != None) && !(winPtr->flags & TK_TOP_LEVEL)) {
+	    TkWinSetWindowPos(scrollPtr->hwnd, Tk_GetHWND(winPtr->window),
+		    Below);
+	    break;
+	}
+    }
+
+    scrollPtr->lastVertical = scrollPtr->info.vertical;
+    scrollPtr->oldProc = (WNDPROC)SetWindowLong(scrollPtr->hwnd, GWL_WNDPROC,
+	    (DWORD) ScrollbarProc);
+    window = Tk_AttachHWND(tkwin, scrollPtr->hwnd);
+
+    UpdateScrollbar(scrollPtr);
+    return window;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkpDisplayScrollbar --
+ *
+ *	This procedure redraws the contents of a scrollbar window.
+ *	It is invoked as a do-when-idle handler, so it only runs
+ *	when there's nothing else for the application to do.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information appears on the screen.
+ *
+ *--------------------------------------------------------------
+ */
+
+void
+TkpDisplayScrollbar(clientData)
+    ClientData clientData;	/* Information about window. */
+{
+    WinScrollbar *scrollPtr = (WinScrollbar *) clientData;
+    Tk_Window tkwin = scrollPtr->info.tkwin;
+
+    scrollPtr->info.flags &= ~REDRAW_PENDING;
+    if ((tkwin == NULL) || !Tk_IsMapped(tkwin)) {
+	return;
+    }
+
+    /*
+     * Destroy and recreate the scrollbar control if the orientation
+     * has changed.
+     */
+
+    if (scrollPtr->lastVertical != scrollPtr->info.vertical) {
+	HWND hwnd = Tk_GetHWND(Tk_WindowId(tkwin));
+
+	SetWindowLong(hwnd, GWL_WNDPROC, (DWORD) scrollPtr->oldProc);
+	DestroyWindow(hwnd);
+
+	CreateProc(tkwin, Tk_WindowId(Tk_Parent(tkwin)),
+		(ClientData) scrollPtr);
+    } else {
+	UpdateScrollbar(scrollPtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpDestroyScrollbar --
+ *
+ *	Free data structures associated with the scrollbar control.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Restores the default control state.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkpDestroyScrollbar(scrollPtr)
+    TkScrollbar *scrollPtr;
+{
+    WinScrollbar *winScrollPtr = (WinScrollbar *)scrollPtr;
+    HWND hwnd = winScrollPtr->hwnd;
+    if (hwnd) {
+	SetWindowLong(hwnd, GWL_WNDPROC, (DWORD) winScrollPtr->oldProc);
+	if (winScrollPtr->winFlags & IN_MODAL_LOOP) {
+	    ((TkWindow *)scrollPtr->tkwin)->flags |= TK_DONT_DESTROY_WINDOW;
+	    SetParent(hwnd, NULL);
+	}
+    }
+    winScrollPtr->winFlags |= ALREADY_DEAD;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * UpdateScrollbarMetrics --
+ *
+ *	This function retrieves the current system metrics for a
+ *	scrollbar.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Updates the geometry cache info for all scrollbars.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+UpdateScrollbarMetrics()
+{
+    Tk_ConfigSpec *specPtr;
+
+    hArrowWidth = GetSystemMetrics(SM_CXHSCROLL);
+    hThumb = GetSystemMetrics(SM_CXHTHUMB);
+    vArrowWidth = GetSystemMetrics(SM_CXVSCROLL);
+    vArrowHeight = GetSystemMetrics(SM_CYVSCROLL);
+    vThumb = GetSystemMetrics(SM_CYVTHUMB);
+
+    sprintf(defWidth, "%d", vArrowWidth);
+    for (specPtr = tkpScrollbarConfigSpecs; specPtr->type != TK_CONFIG_END;
+	    specPtr++) {
+	if (specPtr->offset == Tk_Offset(TkScrollbar, width)) {
+	    specPtr->defValue = defWidth;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpComputeScrollbarGeometry --
+ *
+ *	After changes in a scrollbar's size or configuration, this
+ *	procedure recomputes various geometry information used in
+ *	displaying the scrollbar.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The scrollbar will be displayed differently.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkpComputeScrollbarGeometry(scrollPtr)
+    register TkScrollbar *scrollPtr;	/* Scrollbar whose geometry may
+					 * have changed. */
+{
+    int fieldLength, minThumbSize;
+
+    /*
+     * Windows doesn't use focus rings on scrollbars, but we still
+     * perform basic sanity checks to appease backwards compatibility.
+     */
+
+    if (scrollPtr->highlightWidth < 0) {
+	scrollPtr->highlightWidth = 0;
+    }
+
+    if (scrollPtr->vertical) {
+	scrollPtr->arrowLength = vArrowHeight;
+	fieldLength = Tk_Height(scrollPtr->tkwin);
+	minThumbSize = vThumb;
+    } else {
+	scrollPtr->arrowLength = hArrowWidth;
+	fieldLength = Tk_Width(scrollPtr->tkwin);
+	minThumbSize = hThumb;
+    }
+    fieldLength -= 2*scrollPtr->arrowLength;
+    if (fieldLength < 0) {
+	fieldLength = 0;
+    }
+    scrollPtr->sliderFirst = (int) ((double)fieldLength
+	    * scrollPtr->firstFraction);
+    scrollPtr->sliderLast = (int) ((double)fieldLength
+	    * scrollPtr->lastFraction);
+
+    /*
+     * Adjust the slider so that some piece of it is always
+     * displayed in the scrollbar and so that it has at least
+     * a minimal width (so it can be grabbed with the mouse).
+     */
+
+    if (scrollPtr->sliderFirst > fieldLength) {
+	scrollPtr->sliderFirst = fieldLength;
+    }
+    if (scrollPtr->sliderFirst < 0) {
+	scrollPtr->sliderFirst = 0;
+    }
+    if (scrollPtr->sliderLast < (scrollPtr->sliderFirst
+	    + minThumbSize)) {
+	scrollPtr->sliderLast = scrollPtr->sliderFirst + minThumbSize;
+    }
+    if (scrollPtr->sliderLast > fieldLength) {
+	scrollPtr->sliderLast = fieldLength;
+    }
+    scrollPtr->sliderFirst += scrollPtr->arrowLength;
+    scrollPtr->sliderLast += scrollPtr->arrowLength;
+
+    /*
+     * Register the desired geometry for the window (leave enough space
+     * for the two arrows plus a minimum-size slider, plus border around
+     * the whole window, if any).  Then arrange for the window to be
+     * redisplayed.
+     */
+
+    if (scrollPtr->vertical) {
+	Tk_GeometryRequest(scrollPtr->tkwin,
+		scrollPtr->width, 2*scrollPtr->arrowLength + minThumbSize);
+    } else {
+	Tk_GeometryRequest(scrollPtr->tkwin,
+		2*scrollPtr->arrowLength + minThumbSize, scrollPtr->width);
+    }
+    Tk_SetInternalBorder(scrollPtr->tkwin, 0);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ScrollbarProc --
+ *
+ *	This function is call by Windows whenever an event occurs on
+ *	a scrollbar control created by Tk.
+ *
+ * Results:
+ *	Standard Windows return value.
+ *
+ * Side effects:
+ *	May generate events.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static LRESULT CALLBACK
+ScrollbarProc(hwnd, message, wParam, lParam)
+    HWND hwnd;
+    UINT message;
+    WPARAM wParam;
+    LPARAM lParam;
+{
+    LRESULT result;
+    POINT point;
+    WinScrollbar *scrollPtr;
+    Tk_Window tkwin = Tk_HWNDToWindow(hwnd);
+
+    if (tkwin == NULL) {
+	panic("ScrollbarProc called on an invalid HWND");
+    }
+    scrollPtr = (WinScrollbar *)((TkWindow*)tkwin)->instanceData;
+
+    switch(message) {
+	case WM_HSCROLL:
+	case WM_VSCROLL: {
+	    Tcl_Interp *interp;
+	    Tcl_DString cmdString;
+	    int command = LOWORD(wParam);
+	    int code;
+
+	    GetCursorPos(&point);
+	    Tk_TranslateWinEvent(NULL, WM_MOUSEMOVE, 0,
+		    MAKELPARAM(point.x, point.y), &result);
+
+	    if (command == SB_ENDSCROLL) {
+		return 0;
+	    }
+
+	    /*
+	     * Bail out immediately if there isn't a command to invoke.
+	     */
+
+	    if (scrollPtr->info.commandSize == 0) {
+		Tcl_ServiceAll();
+		return 0;
+	    }
+		
+	    Tcl_DStringInit(&cmdString);
+	    Tcl_DStringAppend(&cmdString, scrollPtr->info.command,
+		    scrollPtr->info.commandSize);
+		
+	    if (command == SB_LINELEFT || command == SB_LINERIGHT) {
+		Tcl_DStringAppendElement(&cmdString, "scroll");
+		Tcl_DStringAppendElement(&cmdString,
+			(command == SB_LINELEFT ) ? "-1" : "1");
+		Tcl_DStringAppendElement(&cmdString, "units");
+	    } else if (command == SB_PAGELEFT || command == SB_PAGERIGHT) {
+		Tcl_DStringAppendElement(&cmdString, "scroll");
+		Tcl_DStringAppendElement(&cmdString,
+			(command == SB_PAGELEFT ) ? "-1" : "1");
+		Tcl_DStringAppendElement(&cmdString, "pages");
+	    } else {
+		char valueString[TCL_DOUBLE_SPACE];
+		double pos = 0.0;
+		switch (command) {
+		    case SB_THUMBPOSITION:
+			pos = ((double)HIWORD(wParam)) / MAX_SCROLL;
+			break;
+
+		    case SB_THUMBTRACK:
+			pos = ((double)HIWORD(wParam)) / MAX_SCROLL;
+			break;
+
+		    case SB_TOP:
+			pos = 0.0;
+			break;
+
+		    case SB_BOTTOM:
+			pos = 1.0;
+			break;
+		}
+		sprintf(valueString, "%g", pos);
+		Tcl_DStringAppendElement(&cmdString, "moveto");
+		Tcl_DStringAppendElement(&cmdString, valueString);
+	    }
+
+	    interp = scrollPtr->info.interp;
+	    code = Tcl_GlobalEval(interp, cmdString.string);
+	    if (code != TCL_OK && code != TCL_CONTINUE && code != TCL_BREAK) {
+		Tcl_AddErrorInfo(interp, "\n    (scrollbar command)");
+		Tcl_BackgroundError(interp);
+	    }		
+	    Tcl_DStringFree(&cmdString);		
+
+	    Tcl_ServiceAll();
+	    return 0;
+	}
+
+	default:
+	    if (Tk_TranslateWinEvent(hwnd, message, wParam, lParam, &result)) {
+		return result;
+	    }
+    }
+    return CallWindowProc(scrollPtr->oldProc, hwnd, message, wParam, lParam);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpConfigureScrollbar --
+ *
+ *	This procedure is called after the generic code has finished
+ *	processing configuration options, in order to configure
+ *	platform specific options.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkpConfigureScrollbar(scrollPtr)
+    register TkScrollbar *scrollPtr;	/* Information about widget;  may or
+					 * may not already have values for
+					 * some fields. */
+{
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * ScrollbarBindProc --
+ *
+ *	This procedure is invoked when the default <ButtonPress>
+ *	binding on the Scrollbar bind tag fires.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The event enters a modal loop.
+ *
+ *--------------------------------------------------------------
+ */
+
+static int
+ScrollbarBindProc(clientData, interp, eventPtr, tkwin, keySym)
+    ClientData clientData;
+    Tcl_Interp *interp;
+    XEvent *eventPtr;
+    Tk_Window tkwin;
+    KeySym keySym;
+{
+    TkWindow *winPtr = (TkWindow*)tkwin;
+    if (eventPtr->type == ButtonPress) {
+	winPtr->flags |= TK_DEFER_MODAL;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ModalLoopProc --
+ *
+ *	This function is invoked at the end of the event processing
+ *	whenever the ScrollbarBindProc has been invoked for a ButtonPress
+ *	event. 
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Enters a modal loop.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ModalLoopProc(tkwin, eventPtr)
+    Tk_Window tkwin;
+    XEvent *eventPtr;
+{
+    TkWindow *winPtr = (TkWindow*)tkwin;
+    WinScrollbar *scrollPtr = (WinScrollbar *) winPtr->instanceData;
+    int oldMode;
+
+    Tcl_Preserve((ClientData)scrollPtr);
+    scrollPtr->winFlags |= IN_MODAL_LOOP;
+    oldMode = Tcl_SetServiceMode(TCL_SERVICE_ALL);
+    TkWinResendEvent(scrollPtr->oldProc, scrollPtr->hwnd, eventPtr);
+    (void) Tcl_SetServiceMode(oldMode);
+    scrollPtr->winFlags &= ~IN_MODAL_LOOP;
+    if (scrollPtr->hwnd && scrollPtr->winFlags & ALREADY_DEAD) {
+	DestroyWindow(scrollPtr->hwnd);
+    }
+    Tcl_Release((ClientData)scrollPtr);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkpScrollbarPosition --
+ *
+ *	Determine the scrollbar element corresponding to a
+ *	given position.
+ *
+ * Results:
+ *	One of TOP_ARROW, TOP_GAP, etc., indicating which element
+ *	of the scrollbar covers the position given by (x, y).  If
+ *	(x,y) is outside the scrollbar entirely, then OUTSIDE is
+ *	returned.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkpScrollbarPosition(scrollPtr, x, y)
+    register TkScrollbar *scrollPtr;	/* Scrollbar widget record. */
+    int x, y;				/* Coordinates within scrollPtr's
+					 * window. */
+{
+    int length, width, tmp;
+
+    if (scrollPtr->vertical) {
+	length = Tk_Height(scrollPtr->tkwin);
+	width = Tk_Width(scrollPtr->tkwin);
+    } else {
+	tmp = x;
+	x = y;
+	y = tmp;
+	length = Tk_Width(scrollPtr->tkwin);
+	width = Tk_Height(scrollPtr->tkwin);
+    }
+
+    if ((x < scrollPtr->inset) || (x >= (width - scrollPtr->inset))
+	    || (y < scrollPtr->inset) || (y >= (length - scrollPtr->inset))) {
+	return OUTSIDE;
+    }
+
+    /*
+     * All of the calculations in this procedure mirror those in
+     * TkpDisplayScrollbar.  Be sure to keep the two consistent.
+     */
+
+    if (y < (scrollPtr->inset + scrollPtr->arrowLength)) {
+	return TOP_ARROW;
+    }
+    if (y < scrollPtr->sliderFirst) {
+	return TOP_GAP;
+    }
+    if (y < scrollPtr->sliderLast) {
+	return SLIDER;
+    }
+    if (y >= (length - (scrollPtr->arrowLength + scrollPtr->inset))) {
+	return BOTTOM_ARROW;
+    }
+    return BOTTOM_GAP;
+}