Rebased to latest trunk

13 files changed, 563 insertions, 89 deletions

diff --git a/doc/SetOptions.3 b/doc/SetOptions.3
index ebd6f6a..b5f0782 100644
--- a/doc/SetOptions.3
+++ b/doc/SetOptions.3
@@ -129,19 +129,21 @@ option table is no longer needed \fBTk_DeleteOptionTable\fR should be
 called to free all of its resources.  All of the option tables
 for a Tcl interpreter are freed automatically if the interpreter is deleted.
 .PP
-\fBTk_InitOptions\fR is invoked when a new widget is created to set
-the default values for all of the widget's configuration options.
-\fBTk_InitOptions\fR is passed a token for an option table (\fIoptionTable\fR)
-and a pointer to a widget record (\fIrecordPtr\fR), which is the C
-structure that holds information about this widget. \fBTk_InitOptions\fR
-uses the information in the option table to
-choose an appropriate default for each option, then it stores the default
-value directly into the widget record, overwriting any information that
-was already present in the widget record.  \fBTk_InitOptions\fR normally
-returns \fBTCL_OK\fR.  If an error occurred while setting the default values
-(e.g., because a default value was erroneous) then \fBTCL_ERROR\fR is returned
-and an error message is left in \fIinterp\fR's result if \fIinterp\fR
-is not NULL.
+\fBTk_InitOptions\fR is invoked when a new widget is created to set the
+default values for all of the widget's configuration options that do not
+have \fBTK_OPTION_DONT_SET_DEFAULT\fR set in their \fIflags\fR field.
+\fBTk_InitOptions\fR is passed a token for an option table
+(\fIoptionTable\fR) and a pointer to a widget record (\fIrecordPtr\fR),
+which is the C structure that holds information about this widget.
+\fBTk_InitOptions\fR uses the information in the option table to choose an
+appropriate default for each option, except those having
+\fBTK_OPTION_DONT_SET_DEFAULT\fR set, then it stores the default value
+directly into the widget record, overwriting any information that was
+already present in the widget record.  \fBTk_InitOptions\fR normally
+returns \fBTCL_OK\fR.  If an error occurred while setting the default
+values (e.g., because a default value was erroneous) then \fBTCL_ERROR\fR
+is returned and an error message is left in \fIinterp\fR's result if
+\fIinterp\fR is not NULL.
 .PP
 \fBTk_SetOptions\fR is invoked to modify configuration options based
 on information specified in a Tcl command.  The command might be one that
@@ -306,19 +308,27 @@ given by \fIinternalOffset\fR.  For example, if the option's type is
 value is not stored in that form.  At least one of the offsets must be
 greater than or equal to zero.
 .PP
-The \fIflags\fR field consists of one or more bits ORed together.  At
-present only a single flag is supported: \fBTK_OPTION_NULL_OK\fR.  If
-this bit is set for an option then an empty string will be accepted as
-the value for the option and the resulting internal form will be a
-NULL pointer, a zero value, or \fBNone\fR, depending on the type of
-the option.  If the flag is not set then empty strings will result
-in errors.
+The \fIflags\fR field consists of one or more bits ORed together. The
+following flags are supported:
+.TP
+\fBTK_OPTION_NULL_OK\fR
+If this bit is set for an option then an empty string will be accepted as
+the value for the option and the resulting internal form will be a NULL
+pointer, a zero value, or \fBNone\fR, depending on the type of the option.
+If the flag is not set then empty strings will result in errors.
 \fBTK_OPTION_NULL_OK\fR is typically used to allow a
 feature to be turned off entirely, e.g. set a cursor value to
 \fBNone\fR so that a window simply inherits its parent's cursor.
 Not all option types support the \fBTK_OPTION_NULL_OK\fR
 flag; for those that do, there is an explicit indication of that fact
 in the descriptions below.
+.TP
+\fBTK_OPTION_DONT_SET_DEFAULT\fR
+If this bit is set for an option then no default value will be set in
+\fBTk_InitOptions\fR for this option. Neither the option database, nor any
+system default value, nor \fIoptionTable\fR are used to give a default
+value to this option. Instead it is assumed that the caller has already
+supplied a default value in the widget code.
 .PP
 The \fItype\fR field of each Tk_OptionSpec structure determines
 how to parse the value of that configuration option. The
diff --git a/doc/text.n b/doc/text.n
index 976503b..ac7803c 100644
--- a/doc/text.n
+++ b/doc/text.n
@@ -917,6 +917,83 @@ affected.
 .PP
 See below for the \fIpathName \fBpeer\fR widget command that controls the
 creation of peer widgets.
+.SH "ASYNCHRONOUS UPDATE OF LINE HEIGHTS"
+.PP
+In order to maintain a responsive user-experience, the text widget calculates
+lines metrics (line heights in pixels) asynchronously. Because of this, some
+commands of the text widget may return wrong results if the asynchronous
+calculations are not finished at the time of calling. This applies to
+\fIpathName \fBcount -ypixels\fR and \fIpathName \fByview\fR.
+.PP
+Again for performance reasons, it would not be appropriate to let these
+commands always wait for the end of the update calculation each time they are
+called. In most use cases of these commands a more or less inaccurate result
+does not really matter compared to execution speed.
+.PP
+In case accurate result is needed (and if the text widget is managed by a
+geometry manager), one can resort to \fIpathName \fBsync\fR and \fIpathName
+\fBpendingsync\fR to control the synchronization of the view of text widgets.
+.PP
+The \fB<<WidgetViewSync>>\fR virtual event fires when the line heights of the
+text widget becomes obsolete (due to some editing command or configuration
+change), and again when the internal data of the text widget are back in sync
+with the widget view. The detail field (%d substitution) is either true (when
+the widget is in sync) or false (when it is not).
+.PP
+\fIpathName \fBsync\fR, \fIpathName \fBpendingsync\fR and
+\fB<<WidgetViewSync>>\fR apply to each text widget independently of its peers.
+.PP
+Examples of use:
+.CS
+## Example 1:
+# immediately complete line metrics at any cost (GUI unresponsive)
+$w sync
+$w yview moveto $fraction
+
+## Example 2:
+# synchronously wait for up-to-date line metrics (GUI responsive)
+# before executing the scheduled command, but don't block execution flow
+$w sync -command [list $w yview moveto $fraction]
+
+## Example 3:
+# init
+set yud($w) 0
+proc updateaction w {
+\&set ::yud($w) 1
+\&# any other update action here...
+}
+# runtime, synchronously wait for up-to-date line metrics (GUI responsive)
+$w sync -command [list updateaction $w]
+vwait yud($w)
+$w yview moveto $fraction
+
+## Example 4:
+# init
+set todo($w) {}
+proc updateaction w {
+\&foreach cmd $::todo($w) {uplevel #0 $cmd}
+\&set todo($w) {}
+}
+# runtime
+lappend todo($w) [list $w yview moveto $fraction]
+$w sync -command [list updateaction $w]
+
+## Example 5:
+# init
+set todo($w) {}
+bind $w <<WidgetViewSync>> {
+\&if {%d} {
+\&\&foreach cmd $todo(%W) {eval $cmd}
+\&\&set todo(%W) {}
+\&}
+}
+# runtime
+if {![$w pendingsync]} {
+\&$w yview moveto $fraction
+} else {
+\&lappend todo($w) [list $w yview moveto $fraction]
+}
+.CE
 .SH "WIDGET COMMAND"
 .PP
 The \fBtext\fR command creates a new Tcl command whose name is the same as the
@@ -981,7 +1058,9 @@ if the text widget is managed by a geometry manager), then all subsequent
 options ensure that any possible out of date information is recalculated.
 This currently only has any effect for the \fB\-ypixels\fR count (which, if
 \fB\-update\fR is not given, will use the text widget's current cached value
-for each line). The count options are interpreted as follows:
+for each line). This \fB\-update\fR option is obsoleted by \fIpathName
+\fBsync\fR, \fIpathName \fBpendingsync\fR and \fB<<WidgetViewSync>>\fR.  The
+count options are interpreted as follows:
 .RS
 .IP \fB\-chars\fR
 count all characters, whether elided or not. Do not count embedded windows or
@@ -1344,13 +1423,16 @@ Returns a list of peers of this widget (this does not include the widget
 itself). The order within this list is undefined.
 .RE
 .TP
-\fIpathName \fBreplace \fIindex1 index2 chars\fR ?\fItagList chars tagList ...\fR?
-.
-Replaces the range of characters between \fIindex1\fR and \fIindex2\fR with
-the given characters and tags. See the section on \fIpathName \fBinsert\fR for
-an explanation of the handling of the \fItagList...\fR arguments, and the
-section on \fIpathName \fBdelete\fR for an explanation of the handling of the
-indices. If \fIindex2\fR corresponds to an index earlier in the text than
+\fIpathName \fBpendingsync\fR
+Returns 1 if the line heights calculations are not up-to-date, 0 otherwise.
+.TP
+\fIpathName \fBreplace\fR \fIindex1 index2 chars\fR ?\fItagList chars tagList ...\fR?
+Replaces the range of characters between \fIindex1\fR and \fIindex2\fR
+with the given characters and tags.  See the section on \fIpathName
+\fBinsert\fR for an explanation of the handling of the \fItagList...\fR
+arguments, and the section on \fIpathName
+\fBdelete\fR for an explanation of the handling of the indices.  If
+\fIindex2\fR corresponds to an index earlier in the text than
 \fIindex1\fR, an error will be generated.
 .RS
 .PP
@@ -1523,6 +1605,23 @@ the view just enough to make \fIindex\fR visible at the edge of the window.
 If \fIindex\fR is far out of view, then the command centers \fIindex\fR in the
 window.
 .TP
+\fIpathName \fBsync\fR ?\fB-command \fIcommand\fR?
+Controls the synchronization of the view of the text widget.
+.RS
+.TP
+\fIpathName \fBsync\fR
+Immediately brings the line metrics up-to-date by forcing computation of any
+outdated line heights. The command returns immediately if there is no such
+outdated line heights, otherwise it returns only at the end of the computation.
+The command returns an empty string.
+.TP
+\fIpathName \fBsync -command \fIcommand\fR
+Schedules \fIcommand\fR to be executed (by the event loop) exactly once as soon
+as all line heights are up-to-date. If there are no pending line metrics
+calculations, the scheduling is immediate. The command returns the empty
+string. \fBbgerror\fR is called on \fIcommand\fR failure.
+.RE
+.TP
 \fIpathName \fBtag \fIoption \fR?\fIarg arg ...\fR?
 .
 This command is used to manipulate tags. The exact behavior of the command
diff --git a/generic/tkEntry.c b/generic/tkEntry.c
index 36798a2..ea8d7f1 100644
--- a/generic/tkEntry.c
+++ b/generic/tkEntry.c
@@ -133,7 +133,7 @@ static const Tk_OptionSpec entryOptSpec[] = {
 	0, DEF_ENTRY_SELECT_BD_MONO, 0},
     {TK_OPTION_COLOR, "-selectforeground", "selectForeground", "Background",
 	DEF_ENTRY_SELECT_FG_COLOR, -1, Tk_Offset(Entry, selFgColorPtr),
-	TK_CONFIG_NULL_OK, DEF_ENTRY_SELECT_FG_MONO, 0},
+	TK_OPTION_NULL_OK, DEF_ENTRY_SELECT_FG_MONO, 0},
     {TK_OPTION_STRING, "-show", "show", "Show",
 	DEF_ENTRY_SHOW, -1, Tk_Offset(Entry, showChar),
 	TK_OPTION_NULL_OK, 0, 0},
@@ -279,23 +279,23 @@ static const Tk_OptionSpec sbOptSpec[] = {
 	0, DEF_ENTRY_SELECT_BD_MONO, 0},
     {TK_OPTION_COLOR, "-selectforeground", "selectForeground", "Background",
 	DEF_ENTRY_SELECT_FG_COLOR, -1, Tk_Offset(Entry, selFgColorPtr),
-	TK_CONFIG_NULL_OK, DEF_ENTRY_SELECT_FG_MONO, 0},
+	TK_OPTION_NULL_OK, DEF_ENTRY_SELECT_FG_MONO, 0},
     {TK_OPTION_STRING_TABLE, "-state", "state", "State",
 	DEF_ENTRY_STATE, -1, Tk_Offset(Entry, state),
 	0, stateStrings, 0},
     {TK_OPTION_STRING, "-takefocus", "takeFocus", "TakeFocus",
 	DEF_ENTRY_TAKE_FOCUS, -1, Tk_Offset(Entry, takeFocus),
-	TK_CONFIG_NULL_OK, 0, 0},
+	TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_STRING, "-textvariable", "textVariable", "Variable",
 	DEF_ENTRY_TEXT_VARIABLE, -1, Tk_Offset(Entry, textVarName),
-	TK_CONFIG_NULL_OK, 0, 0},
+	TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_DOUBLE, "-to", "to", "To",
 	DEF_SPINBOX_TO, -1, Tk_Offset(Spinbox, toValue), 0, 0, 0},
     {TK_OPTION_STRING_TABLE, "-validate", "validate", "Validate",
 	DEF_ENTRY_VALIDATE, -1, Tk_Offset(Entry, validate),
 	0, validateStrings, 0},
     {TK_OPTION_STRING, "-validatecommand", "validateCommand","ValidateCommand",
-	NULL, -1, Tk_Offset(Entry, validateCmd), TK_CONFIG_NULL_OK, 0, 0},
+	NULL, -1, Tk_Offset(Entry, validateCmd), TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_STRING, "-values", "values", "Values",
 	DEF_SPINBOX_VALUES, -1, Tk_Offset(Spinbox, valueStr),
 	TK_OPTION_NULL_OK, 0, 0},
@@ -307,7 +307,7 @@ static const Tk_OptionSpec sbOptSpec[] = {
 	DEF_SPINBOX_WRAP, -1, Tk_Offset(Spinbox, wrap), 0, 0, 0},
     {TK_OPTION_STRING, "-xscrollcommand", "xScrollCommand", "ScrollCommand",
 	DEF_ENTRY_SCROLL_COMMAND, -1, Tk_Offset(Entry, scrollCmd),
-	TK_CONFIG_NULL_OK, 0, 0},
+	TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_END, NULL, NULL, NULL, NULL, 0, -1, 0, 0, 0}
 };
 
@@ -390,7 +390,7 @@ static const char *const selElementNames[] = {
  */
 
 static int		ConfigureEntry(Tcl_Interp *interp, Entry *entryPtr,
-			    int objc, Tcl_Obj *const objv[], int flags);
+			    int objc, Tcl_Obj *const objv[]);
 static int		DeleteChars(Entry *entryPtr, int index, int count);
 static void		DestroyEntry(void *memPtr);
 static void		DisplayEntry(ClientData clientData);
@@ -554,7 +554,7 @@ Tk_EntryObjCmd(
 
     if ((Tk_InitOptions(interp, (char *) entryPtr, optionTable, tkwin)
 	    != TCL_OK) ||
-	    (ConfigureEntry(interp, entryPtr, objc-2, objv+2, 0) != TCL_OK)) {
+	    (ConfigureEntry(interp, entryPtr, objc-2, objv+2) != TCL_OK)) {
 	Tk_DestroyWindow(entryPtr->tkwin);
 	return TCL_ERROR;
     }
@@ -659,7 +659,7 @@ EntryWidgetObjCmd(
 	    }
 	    Tcl_SetObjResult(interp, objPtr);
 	} else {
-	    result = ConfigureEntry(interp, entryPtr, objc-2, objv+2, 0);
+	    result = ConfigureEntry(interp, entryPtr, objc-2, objv+2);
 	}
 	break;
 
@@ -1088,8 +1088,7 @@ ConfigureEntry(
     Entry *entryPtr,		/* Information about widget; may or may not
 				 * already have values for some fields. */
     int objc,			/* Number of valid entries in argv. */
-    Tcl_Obj *const objv[],	/* Argument objects. */
-    int flags)			/* Flags to pass to Tk_ConfigureWidget. */
+    Tcl_Obj *const objv[])	/* Argument objects. */
 {
     Tk_SavedOptions savedOptions;
     Tk_3DBorder border;
@@ -3660,7 +3659,7 @@ Tk_SpinboxObjCmd(
 	Tk_DestroyWindow(entryPtr->tkwin);
 	return TCL_ERROR;
     }
-    if (ConfigureEntry(interp, entryPtr, objc-2, objv+2, 0) != TCL_OK) {
+    if (ConfigureEntry(interp, entryPtr, objc-2, objv+2) != TCL_OK) {
 	goto error;
     }
 
@@ -3768,7 +3767,7 @@ SpinboxWidgetObjCmd(
 	    }
 	    Tcl_SetObjResult(interp, objPtr);
 	} else {
-	    result = ConfigureEntry(interp, entryPtr, objc-2, objv+2, 0);
+	    result = ConfigureEntry(interp, entryPtr, objc-2, objv+2);
 	}
 	break;
 
diff --git a/generic/tkListbox.c b/generic/tkListbox.c
index 50f1717..490f795 100644
--- a/generic/tkListbox.c
+++ b/generic/tkListbox.c
@@ -290,7 +290,7 @@ static const Tk_OptionSpec optionSpecs[] = {
 	 Tk_Offset(Listbox, selBorderWidth), 0, 0, 0},
     {TK_OPTION_COLOR, "-selectforeground", "selectForeground", "Background",
 	 DEF_LISTBOX_SELECT_FG_COLOR, -1, Tk_Offset(Listbox, selFgColorPtr),
-	 TK_CONFIG_NULL_OK, DEF_LISTBOX_SELECT_FG_MONO, 0},
+	 TK_OPTION_NULL_OK, DEF_LISTBOX_SELECT_FG_MONO, 0},
     {TK_OPTION_STRING, "-selectmode", "selectMode", "SelectMode",
 	 DEF_LISTBOX_SELECT_MODE, -1, Tk_Offset(Listbox, selectMode),
 	 TK_OPTION_NULL_OK, 0, 0},
@@ -391,7 +391,7 @@ enum indices {
 static void		ChangeListboxOffset(Listbox *listPtr, int offset);
 static void		ChangeListboxView(Listbox *listPtr, int index);
 static int		ConfigureListbox(Tcl_Interp *interp, Listbox *listPtr,
-			    int objc, Tcl_Obj *const objv[], int flags);
+			    int objc, Tcl_Obj *const objv[]);
 static int		ConfigureListboxItem(Tcl_Interp *interp,
 			    Listbox *listPtr, ItemAttr *attrs, int objc,
 			    Tcl_Obj *const objv[], int index);
@@ -575,7 +575,7 @@ Tk_ListboxObjCmd(
 	return TCL_ERROR;
     }
 
-    if (ConfigureListbox(interp, listPtr, objc-2, objv+2, 0) != TCL_OK) {
+    if (ConfigureListbox(interp, listPtr, objc-2, objv+2) != TCL_OK) {
 	Tk_DestroyWindow(listPtr->tkwin);
 	return TCL_ERROR;
     }
@@ -713,7 +713,7 @@ ListboxWidgetObjCmd(
 	    Tcl_SetObjResult(interp, objPtr);
 	    result = TCL_OK;
 	} else {
-	    result = ConfigureListbox(interp, listPtr, objc-2, objv+2, 0);
+	    result = ConfigureListbox(interp, listPtr, objc-2, objv+2);
 	}
 	break;
 
@@ -1558,8 +1558,7 @@ ConfigureListbox(
     register Listbox *listPtr,	/* Information about widget; may or may not
 				 * already have values for some fields. */
     int objc,			/* Number of valid entries in argv. */
-    Tcl_Obj *const objv[],	/* Arguments. */
-    int flags)			/* Flags to pass to Tk_ConfigureWidget. */
+    Tcl_Obj *const objv[])	/* Arguments. */
 {
     Tk_SavedOptions savedOptions;
     Tcl_Obj *oldListObj = NULL;
diff --git a/generic/tkText.c b/generic/tkText.c
index 4edf652..3079417 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -211,18 +211,18 @@ static const Tk_OptionSpec optionSpecs[] = {
 	TK_OPTION_NULL_OK, DEF_TEXT_SELECT_BD_MONO, 0},
     {TK_OPTION_COLOR, "-selectforeground", "selectForeground", "Background",
 	DEF_TEXT_SELECT_FG_COLOR, -1, Tk_Offset(TkText, selFgColorPtr),
-	TK_CONFIG_NULL_OK, DEF_TEXT_SELECT_FG_MONO, 0},
+	TK_OPTION_NULL_OK, DEF_TEXT_SELECT_FG_MONO, 0},
     {TK_OPTION_BOOLEAN, "-setgrid", "setGrid", "SetGrid",
 	DEF_TEXT_SET_GRID, -1, Tk_Offset(TkText, setGrid), 0, 0, 0},
     {TK_OPTION_PIXELS, "-spacing1", "spacing1", "Spacing",
 	DEF_TEXT_SPACING1, -1, Tk_Offset(TkText, spacing1),
-	TK_OPTION_DONT_SET_DEFAULT, 0 , TK_TEXT_LINE_GEOMETRY },
+	0, 0 , TK_TEXT_LINE_GEOMETRY },
     {TK_OPTION_PIXELS, "-spacing2", "spacing2", "Spacing",
 	DEF_TEXT_SPACING2, -1, Tk_Offset(TkText, spacing2),
-	TK_OPTION_DONT_SET_DEFAULT, 0 , TK_TEXT_LINE_GEOMETRY },
+	0, 0 , TK_TEXT_LINE_GEOMETRY },
     {TK_OPTION_PIXELS, "-spacing3", "spacing3", "Spacing",
 	DEF_TEXT_SPACING3, -1, Tk_Offset(TkText, spacing3),
-	TK_OPTION_DONT_SET_DEFAULT, 0 , TK_TEXT_LINE_GEOMETRY },
+	0, 0 , TK_TEXT_LINE_GEOMETRY },
     {TK_OPTION_CUSTOM, "-startline", NULL, NULL,
 	 NULL, -1, Tk_Offset(TkText, start), TK_OPTION_NULL_OK,
 	 &lineOption, TK_TEXT_LINE_RANGE},
@@ -402,6 +402,7 @@ static Tcl_Obj *	TextGetText(const TkText *textPtr,
 			    const TkTextIndex *index2, int visibleOnly);
 static void		GenerateModifiedEvent(TkText *textPtr);
 static void		UpdateDirtyFlag(TkSharedText *sharedPtr);
+static void		RunAfterSyncCmd(ClientData clientData);
 static void		TextPushUndoAction(TkText *textPtr,
 			    Tcl_Obj *undoString, int insert,
 			    const TkTextIndex *index1Ptr,
@@ -702,15 +703,16 @@ TextWidgetObjCmd(
     static const char *const optionStrings[] = {
 	"bbox", "cget", "compare", "configure", "count", "debug", "delete",
 	"dlineinfo", "dump", "edit", "get", "image", "index", "insert",
-	"mark", "peer", "replace", "scan", "search", "see", "tag", "window",
-	"xview", "yview", NULL
+	"mark", "peer", "pendingsync", "replace", "scan", "search",
+	"see", "sync", "tag", "window", "xview", "yview", NULL
     };
     enum options {
 	TEXT_BBOX, TEXT_CGET, TEXT_COMPARE, TEXT_CONFIGURE, TEXT_COUNT,
 	TEXT_DEBUG, TEXT_DELETE, TEXT_DLINEINFO, TEXT_DUMP, TEXT_EDIT,
 	TEXT_GET, TEXT_IMAGE, TEXT_INDEX, TEXT_INSERT, TEXT_MARK,
-	TEXT_PEER, TEXT_REPLACE, TEXT_SCAN, TEXT_SEARCH, TEXT_SEE,
-	TEXT_TAG, TEXT_WINDOW, TEXT_XVIEW, TEXT_YVIEW
+	TEXT_PEER, TEXT_PENDINGSYNC, TEXT_REPLACE, TEXT_SCAN,
+	TEXT_SEARCH, TEXT_SEE, TEXT_SYNC, TEXT_TAG, TEXT_WINDOW,
+	TEXT_XVIEW, TEXT_YVIEW
     };
 
     if (objc < 2) {
@@ -1392,6 +1394,16 @@ TextWidgetObjCmd(
     case TEXT_PEER:
 	result = TextPeerCmd(textPtr, interp, objc, objv);
 	break;
+    case TEXT_PENDINGSYNC: {
+        if (objc != 2) {
+            Tcl_WrongNumArgs(interp, 2, objv, NULL);
+            result = TCL_ERROR;
+            goto done;
+        }
+        Tcl_SetObjResult(interp,
+                Tcl_NewBooleanObj(TkTextPendingsync(textPtr)));
+        break;
+    }
     case TEXT_REPLACE: {
 	const TkTextIndex *indexFromPtr, *indexToPtr;
 
@@ -1506,6 +1518,39 @@ TextWidgetObjCmd(
     case TEXT_SEE:
 	result = TkTextSeeCmd(textPtr, interp, objc, objv);
 	break;
+    case TEXT_SYNC: {
+	if (objc == 4) {
+	    Tcl_Obj *cmd = objv[3];
+	    const char *option = Tcl_GetString(objv[2]);
+	    if (strncmp(option, "-command", objv[2]->length)) {
+		Tcl_AppendResult(interp, "wrong option \"", option, "\": should be \"-command\"", NULL);
+		result = TCL_ERROR;
+		goto done;
+	    }
+	    Tcl_IncrRefCount(cmd);
+	    if (TkTextPendingsync(textPtr)) {
+		if (textPtr->afterSyncCmd) {
+		    Tcl_DecrRefCount(textPtr->afterSyncCmd);
+		}
+		textPtr->afterSyncCmd = cmd;
+	    } else {
+		textPtr->afterSyncCmd = cmd;
+                Tcl_DoWhenIdle(RunAfterSyncCmd, (ClientData) textPtr);
+	    }
+	    break;
+	} else if (objc != 2) {
+	    Tcl_WrongNumArgs(interp, 2, objv, "?-command command?");
+	    result = TCL_ERROR;
+	    goto done;
+	}
+	if (textPtr->afterSyncCmd) {
+	    Tcl_DecrRefCount(textPtr->afterSyncCmd);
+	}
+	textPtr->afterSyncCmd = NULL;
+	TkTextUpdateLineMetrics(textPtr, 1,
+		TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr), -1);
+	break;
+    }
     case TEXT_TAG:
 	result = TkTextTagCmd(textPtr, interp, objc, objv);
 	break;
@@ -1995,6 +2040,10 @@ DestroyText(
     textPtr->tkwin = NULL;
     textPtr->refCount--;
     Tcl_DeleteCommandFromToken(textPtr->interp, textPtr->widgetCmd);
+    if (textPtr->afterSyncCmd){
+	Tcl_DecrRefCount(textPtr->afterSyncCmd);
+	textPtr->afterSyncCmd = NULL;
+    }
     if (textPtr->refCount == 0) {
 	ckfree(textPtr);
     }
@@ -5368,6 +5417,52 @@ UpdateDirtyFlag(
 /*
  *----------------------------------------------------------------------
  *
+ * RunAfterSyncCmd --
+ *
+ *	This function is called by the event loop and executes the command
+ *      scheduled by [.text sync -command $cmd].
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Anything may happen, depending on $cmd contents.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+RunAfterSyncCmd(
+    ClientData clientData)		/* Information about text widget. */
+{
+    register TkText *textPtr = (TkText *) clientData;
+    int code;
+
+    if ((textPtr->tkwin == NULL) || (textPtr->flags & DESTROYED)) {
+        /*
+        * The widget has been deleted. Don't do anything.
+        */
+
+        if (--textPtr->refCount == 0) {
+            ckfree((char *) textPtr);
+        }
+        return;
+    }
+
+    Tcl_Preserve((ClientData) textPtr->interp);
+    code = Tcl_EvalObjEx(textPtr->interp, textPtr->afterSyncCmd, TCL_EVAL_GLOBAL);
+    if (code == TCL_ERROR) {
+        Tcl_AddErrorInfo(textPtr->interp, "\n    (text sync)");
+        Tcl_BackgroundError(textPtr->interp);
+    }
+    Tcl_Release((ClientData) textPtr->interp);
+    Tcl_DecrRefCount(textPtr->afterSyncCmd);
+    textPtr->afterSyncCmd = NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * SearchPerform --
  *
  *	Overall control of search process. Is given a pattern, a starting
diff --git a/generic/tkText.h b/generic/tkText.h
index 78a99a9..fc92644 100644
--- a/generic/tkText.h
+++ b/generic/tkText.h
@@ -785,6 +785,8 @@ typedef struct TkText {
 				 * statements. */
     int autoSeparators;		/* Non-zero means the separators will be
 				 * inserted automatically. */
+    Tcl_Obj *afterSyncCmd;	/* Command to be executed when lines are up to
+                                 * date */
 } TkText;
 
 /*
@@ -1109,6 +1111,7 @@ MODULE_SCOPE int	TkTextMarkNameToIndex(TkText *textPtr,
 MODULE_SCOPE void	TkTextMarkSegToIndex(TkText *textPtr,
 			    TkTextSegment *markPtr, TkTextIndex *indexPtr);
 MODULE_SCOPE void	TkTextEventuallyRepick(TkText *textPtr);
+MODULE_SCOPE Bool	TkTextPendingsync(TkText *textPtr);
 MODULE_SCOPE void	TkTextPickCurrent(TkText *textPtr, XEvent *eventPtr);
 MODULE_SCOPE void	TkTextPixelIndex(TkText *textPtr, int x, int y,
 			    TkTextIndex *indexPtr, int *nearest);
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index a57c24b..18b373f 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -591,6 +591,7 @@ static int		TextGetScrollInfoObj(Tcl_Interp *interp,
 			    Tcl_Obj *const objv[], double *dblPtr,
 			    int *intPtr);
 static void		AsyncUpdateLineMetrics(ClientData clientData);
+static void		GenerateWidgetViewSyncEvent(TkText *textPtr, Bool InSync);
 static void		AsyncUpdateYScrollbar(ClientData clientData);
 static int              IsStartOfNotMergedLine(TkText *textPtr,
                             CONST TkTextIndex *indexPtr);
@@ -2941,6 +2942,8 @@ AsyncUpdateLineMetrics(
     lineNum = TkTextUpdateLineMetrics(textPtr, lineNum,
 	    dInfoPtr->lastMetricUpdateLine, 256);
 
+    dInfoPtr->currentMetricUpdateLine = lineNum;
+
     if (tkTextDebug) {
 	char buffer[2 * TCL_INTEGER_SPACE + 1];
 
@@ -2958,16 +2961,37 @@ AsyncUpdateLineMetrics(
 	/*
 	 * We have looped over all lines, so we're done. We must release our
 	 * refCount on the widget (the timer token was already set to NULL
-	 * above).
+	 * above). If there is a registered aftersync command, run that first.
 	 */
 
+        if (textPtr->afterSyncCmd) {
+            int code;
+            Tcl_Preserve((ClientData) textPtr->interp);
+            code = Tcl_EvalObjEx(textPtr->interp, textPtr->afterSyncCmd,
+                    TCL_EVAL_GLOBAL);
+	    if (code == TCL_ERROR) {
+                Tcl_AddErrorInfo(textPtr->interp, "\n    (text sync)");
+                Tcl_BackgroundError(textPtr->interp);
+	    }
+            Tcl_Release((ClientData) textPtr->interp);
+            Tcl_DecrRefCount(textPtr->afterSyncCmd);
+            textPtr->afterSyncCmd = NULL;
+	}
+
+        /*
+         * Fire the <<WidgetViewSync>> event since the widget view is in sync
+         * with its internal data (actually it will be after the next trip
+         * through the event loop, because the widget redraws at idle-time).
+         */
+
+        GenerateWidgetViewSyncEvent(textPtr, 1);
+
 	textPtr->refCount--;
 	if (textPtr->refCount == 0) {
 	    ckfree(textPtr);
 	}
 	return;
     }
-    dInfoPtr->currentMetricUpdateLine = lineNum;
 
     /*
      * Re-arm the timer. We already have a refCount on the text widget so no
@@ -2981,6 +3005,45 @@ AsyncUpdateLineMetrics(
 /*
  *----------------------------------------------------------------------
  *
+ * GenerateWidgetViewSyncEvent --
+ *
+ *      Send the <<WidgetViewSync>> event related to the text widget
+ *      line metrics asynchronous update.
+ *      This is equivalent to:
+ *         event generate $textWidget <<WidgetViewSync>> -detail $s
+ *      where $s is the sync status: true (when the widget view is in
+ *      sync with its internal data) or false (when it is not).
+ *
+ * Results:
+ *      None
+ *
+ * Side effects:
+ *      If corresponding bindings are present, they will trigger.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GenerateWidgetViewSyncEvent(
+    TkText *textPtr,		/* Information about text widget. */
+    Bool InSync)                /* True if in sync, false otherwise */
+{
+    union {XEvent general; XVirtualEvent virtual;} event;
+
+    memset(&event, 0, sizeof(event));
+    event.general.xany.type = VirtualEvent;
+    event.general.xany.serial = NextRequest(Tk_Display(textPtr->tkwin));
+    event.general.xany.send_event = False;
+    event.general.xany.window = Tk_WindowId(textPtr->tkwin);
+    event.general.xany.display = Tk_Display(textPtr->tkwin);
+    event.virtual.name = Tk_GetUid("WidgetViewSync");
+    event.virtual.user_data = Tcl_NewBooleanObj(InSync);
+    Tk_HandleEvent(&event.general);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * TkTextUpdateLineMetrics --
  *
  *	This function updates the pixel height calculations of a range of
@@ -3353,6 +3416,7 @@ TextInvalidateLineMetrics(
 	textPtr->refCount++;
 	dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
 		AsyncUpdateLineMetrics, textPtr);
+        GenerateWidgetViewSyncEvent(textPtr, 0);
     }
 }
 
@@ -5064,6 +5128,7 @@ TkTextRelayoutWindow(
 	    textPtr->refCount++;
 	    dInfoPtr->lineUpdateTimer = Tcl_CreateTimerHandler(1,
 		    AsyncUpdateLineMetrics, textPtr);
+            GenerateWidgetViewSyncEvent(textPtr, 0);
 	}
     }
 }
@@ -6066,6 +6131,35 @@ TkTextYviewCmd(
 /*
  *--------------------------------------------------------------
  *
+ * TkTextPendingsync --
+ *
+ *	This function checks if any line heights are not up-to-date.
+ *
+ * Results:
+ *	Returns a boolean true if it is the case, or false if all line
+ *      heights are up-to-date.
+ *
+ * Side effects:
+ *	None.
+ *
+ *--------------------------------------------------------------
+ */
+
+Bool
+TkTextPendingsync(
+    TkText *textPtr)		/* Information about text widget. */
+{
+    TextDInfo *dInfoPtr = textPtr->dInfoPtr;
+
+    return (
+        ((dInfoPtr->metricEpoch == -1) &&
+         (dInfoPtr->lastMetricUpdateLine == dInfoPtr->currentMetricUpdateLine)) ?
+        0 : 1);
+}
+
+/*
+ *--------------------------------------------------------------
+ *
  * TkTextScanCmd --
  *
  *	This function is invoked to process the "scan" option for the widget
diff --git a/generic/tkTextTag.c b/generic/tkTextTag.c
index af3f235..3363d25 100644
--- a/generic/tkTextTag.c
+++ b/generic/tkTextTag.c
@@ -44,11 +44,11 @@ static const Tk_OptionSpec tagOptionSpecs[] = {
     {TK_OPTION_BITMAP, "-bgstipple", NULL, NULL,
 	NULL, -1, Tk_Offset(TkTextTag, bgStipple), TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_PIXELS, "-borderwidth", NULL, NULL,
-	"0", Tk_Offset(TkTextTag, borderWidthPtr), Tk_Offset(TkTextTag, borderWidth),
-	TK_OPTION_DONT_SET_DEFAULT|TK_OPTION_NULL_OK, 0, 0},
+	NULL, Tk_Offset(TkTextTag, borderWidthPtr), Tk_Offset(TkTextTag, borderWidth),
+	TK_OPTION_NULL_OK|TK_OPTION_DONT_SET_DEFAULT, 0, 0},
     {TK_OPTION_STRING, "-elide", NULL, NULL,
-	"0", -1, Tk_Offset(TkTextTag, elideString),
-	TK_OPTION_DONT_SET_DEFAULT|TK_OPTION_NULL_OK, 0, 0},
+	NULL, -1, Tk_Offset(TkTextTag, elideString),
+	TK_OPTION_NULL_OK|TK_OPTION_DONT_SET_DEFAULT, 0, 0},
     {TK_OPTION_BITMAP, "-fgstipple", NULL, NULL,
 	NULL, -1, Tk_Offset(TkTextTag, fgStipple), TK_OPTION_NULL_OK, 0, 0},
     {TK_OPTION_FONT, "-font", NULL, NULL,
diff --git a/generic/ttk/ttkButton.c b/generic/ttk/ttkButton.c
index 2954184..bc44f25 100644
--- a/generic/ttk/ttkButton.c
+++ b/generic/ttk/ttkButton.c
@@ -413,8 +413,8 @@ typedef struct
 static Tk_OptionSpec CheckbuttonOptionSpecs[] =
 {
     {TK_OPTION_STRING, "-variable", "variable", "Variable",
-	"", Tk_Offset(Checkbutton, checkbutton.variableObj), -1,
-	TK_OPTION_DONT_SET_DEFAULT,0,0},
+	NULL, Tk_Offset(Checkbutton, checkbutton.variableObj), -1,
+	TK_OPTION_NULL_OK,0,0},
     {TK_OPTION_STRING, "-onvalue", "onValue", "OnValue",
 	"1", Tk_Offset(Checkbutton, checkbutton.onValueObj), -1,
 	0,0,0},
diff --git a/macosx/README b/macosx/README
index 202dbbd..b27f9ff 100644
--- a/macosx/README
+++ b/macosx/README
@@ -401,7 +401,7 @@ The main program in a typical OSX application looks like this (see *)
     }
 
 The run method implements the event loop for the application.  There
-are three key steps in the run method.  First it calls 
+are three key steps in the run method.  First it calls
 [NSApp finishLaunching], which creates the bouncing application icon
 and does other mysterious things. Second it creates an
 NSAutoreleasePool.  Third, it starts an event loop which drains the
diff --git a/macosx/tkMacOSXDialog.c b/macosx/tkMacOSXDialog.c
index 257f16d..f6edb6d 100644
--- a/macosx/tkMacOSXDialog.c
+++ b/macosx/tkMacOSXDialog.c
@@ -1030,7 +1030,7 @@ Tk_MessageBoxObjCmd(
     NSAlert *alert = [NSAlert new];
     NSInteger modalReturnCode = 1;
     BOOL parentIsKey = NO;
-    
+
     iconIndex = ICON_INFO;
     typeIndex = TYPE_OK;
     for (i = 1; i < objc; i += 2) {
diff --git a/tests/text.test b/tests/text.test
index 7ade29a..52a21af 100644
--- a/tests/text.test
+++ b/tests/text.test
@@ -925,7 +925,7 @@ test text-3.2 {TextWidgetCmd procedure} -setup {
     .t gorp 1.0 z 1.2
 } -cleanup {
     destroy .t
-} -returnCodes {error} -result {bad option "gorp": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, replace, scan, search, see, tag, window, xview, or yview}
+} -returnCodes {error} -result {bad option "gorp": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, pendingsync, replace, scan, search, see, sync, tag, window, xview, or yview}
 
 test text-4.1 {TextWidgetCmd procedure, "bbox" option} -setup {
     text .t
@@ -1147,7 +1147,7 @@ Line 7"
     .t co 1.0 z 1.2
 } -cleanup {
     destroy .t
-} -returnCodes {error} -result {ambiguous option "co": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, replace, scan, search, see, tag, window, xview, or yview}
+} -returnCodes {error} -result {ambiguous option "co": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, pendingsync, replace, scan, search, see, sync, tag, window, xview, or yview}
 # "configure" option is already covered above
 
 test text-7.1 {TextWidgetCmd procedure, "debug" option} -setup {
@@ -1163,7 +1163,7 @@ test text-7.2 {TextWidgetCmd procedure, "debug" option} -setup {
     .t de 0 1
 } -cleanup {
     destroy .t
-} -returnCodes {error} -result {ambiguous option "de": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, replace, scan, search, see, tag, window, xview, or yview}
+} -returnCodes {error} -result {ambiguous option "de": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, pendingsync, replace, scan, search, see, sync, tag, window, xview, or yview}
 test text-7.3 {TextWidgetCmd procedure, "debug" option} -setup {
     text .t
 } -body {
@@ -2686,7 +2686,7 @@ test text-9.2.47 {TextWidgetCmd procedure, "count" option} -setup {
     # next line to be fully sure that asynchronous line heights calculation is
     # up-to-date otherwise this test may fail (depending on the computer
     # performance), especially when the . toplevel has small height
-    .t count -update -ypixels 1.0 end
+    .t sync
     set y1 [lindex [.t yview] 1]
     .t count -displaylines 5.0 11.0
     set y2 [lindex [.t yview] 1]
@@ -2882,6 +2882,176 @@ test text-11.9 {counting with tag priority eliding} -setup {
     destroy .t
 } -result {1 0 0 1 0 2.0 4.0 4.0 4.0 3.0 3.0 3.0 2.0 1.0 1.0}
 
+test text-11a.1 {TextWidgetCmd procedure, "pendingsync" option} -setup {
+    destroy .yt
+} -body {
+    text .yt
+    list [catch {.yt pendingsync mytext} msg] $msg
+} -cleanup {
+    destroy .yt
+} -result {1 {wrong # args: should be ".yt pendingsync"}}
+test text-11a.2 {TextWidgetCmd procedure, "pendingsync" option} -setup {
+    destroy .top.yt .top
+} -body {
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 300} {incr i} {
+        append content [string repeat "$i " 15] \n
+    }
+    .top.yt insert 1.0 $content
+    # wait for end of line metrics calculation to get correct $fraction1
+    # as a reference
+    while {[.top.yt pendingsync]} {update}
+    .top.yt yview moveto 1
+    set fraction1 [lindex [.top.yt yview] 0]
+    set res [expr {$fraction1 > 0}]
+    .top.yt delete 1.0 end
+    .top.yt insert 1.0 $content
+    # ensure the test is relevant
+    lappend res [.top.yt pendingsync]
+    # asynchronously wait for completion of line metrics calculation
+    while {[.top.yt pendingsync]} {update}
+    .top.yt yview moveto $fraction1
+    set fraction2 [lindex [.top.yt yview] 0]
+    lappend res [expr {$fraction1 == $fraction2}]
+} -cleanup {
+    destroy .top.yt .top
+} -result {1 1 1}
+
+test text-11a.11 {TextWidgetCmd procedure, "sync" option} -setup {
+    destroy .yt
+} -body {
+    text .yt
+    list [catch {.yt sync mytext} msg] $msg
+} -cleanup {
+    destroy .yt
+} -result {1 {wrong # args: should be ".yt sync ?-command command?"}}
+test text-11a.12 {TextWidgetCmd procedure, "sync" option} -setup {
+    destroy .top.yt .top
+} -body {
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 30} {incr i} {
+        append content [string repeat "$i " 15] \n
+    }
+    .top.yt insert 1.0 $content
+    # wait for end of line metrics calculation to get correct $fraction1
+    # as a reference
+    .top.yt sync
+    .top.yt yview moveto 1
+    set fraction1 [lindex [.top.yt yview] 0]
+    set res [expr {$fraction1 > 0}]
+    # first case: do not wait for completion of line metrics calculation
+    .top.yt delete 1.0 end
+    .top.yt insert 1.0 $content
+    .top.yt yview moveto $fraction1
+    set fraction2 [lindex [.top.yt yview] 0]
+    lappend res [expr {$fraction1 == $fraction2}]
+    # second case: wait for completion of line metrics calculation
+    .top.yt delete 1.0 end
+    .top.yt insert 1.0 $content
+    .top.yt sync
+    .top.yt yview moveto $fraction1
+    set fraction2 [lindex [.top.yt yview] 0]
+    lappend res [expr {$fraction1 == $fraction2}]
+} -cleanup {
+    destroy .top.yt .top
+} -result {1 0 1}
+
+test text-11a.21 {TextWidgetCmd procedure, "sync" option with -command} -setup {
+    destroy .yt
+} -body {
+    text .yt
+    list [catch {.yt sync -comx foo} msg] $msg
+} -cleanup {
+    destroy .yt
+} -result {1 {wrong option "-comx": should be "-command"}}
+test text-11a.22 {TextWidgetCmd procedure, "sync" option with -command} -setup {
+    destroy .top.yt .top
+} -body {
+    set res {}
+    set ::x 0
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 30} {incr i} {
+        append content [string repeat "$i " 15] \n
+    }
+    .top.yt insert 1.0 $content
+    # first case: line metrics calculation still running when launching 'sync -command'
+    lappend res [.top.yt pendingsync]
+    .top.yt sync -command [list set ::x 1]
+    lappend res $::x
+    # now finish line metrics calculations
+    while {[.top.yt pendingsync]} {update}
+    lappend res [.top.yt pendingsync] $::x
+    # second case: line metrics calculation completed when launching 'sync -command'
+    .top.yt sync -command [list set ::x 2]
+    lappend res $::x
+    vwait ::x
+    lappend res $::x
+} -cleanup {
+    destroy .top.yt .top
+} -result {1 0 0 1 1 2}
+
+test text-11a.31 {"<<WidgetViewSync>>" event} -setup {
+    destroy .top.yt .top
+} -body {
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 300} {incr i} {
+        append content [string repeat "$i " 15] \n
+    }
+    .top.yt insert 1.0 $content
+    update
+    bind .top.yt <<WidgetViewSync>> { if {%d} {set yud(%W) 1} }
+    # wait for end of line metrics calculation to get correct $fraction1
+    # as a reference
+    if {[.top.yt pendingsync]} {vwait yud(.top.yt)}
+    .top.yt yview moveto 1
+    set fraction1 [lindex [.top.yt yview] 0]
+    set res [expr {$fraction1 > 0}]
+    .top.yt delete 1.0 end
+    .top.yt insert 1.0 $content
+    # synchronously wait for completion of line metrics calculation
+    # and ensure the test is relevant
+    set waited 0
+    if {[.top.yt pendingsync]} {set waited 1 ; vwait yud(.top.yt)}
+    lappend res $waited
+    .top.yt yview moveto $fraction1
+    set fraction2 [lindex [.top.yt yview] 0]
+    lappend res [expr {$fraction1 == $fraction2}]
+} -cleanup {
+    destroy .top.yt .top
+} -result {1 1 1}
+
+test text-11a.41 {"sync" "pendingsync" and <<WidgetViewSync>>} -setup {
+    destroy .top.yt .top
+} -body {
+    set res {}
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 300} {incr i} {
+        append content [string repeat "$i " 50] \n
+    }
+    bind .top.yt <<WidgetViewSync>> {lappend res Sync:%d}
+    .top.yt insert 1.0 $content
+    vwait res  ; # event dealt with by the event loop, with %d==0 i.e. we're out of sync
+    # ensure the test is relevant
+    lappend res "Pending:[.top.yt pendingsync]"
+    # - <<WidgetViewSync>> fires when sync returns if there was pending syncs 
+    # - there is no more any pending sync after running 'sync'
+    .top.yt sync
+    vwait res  ; # event dealt with by the event loop, with %d==1 i.e. we're in sync again
+    lappend res "Pending:[.top.yt pendingsync]"
+    set res
+} -cleanup {
+    destroy .top.yt .top
+} -result {Sync:0 Pending:1 Sync:1 Pending:0}
 
 test text-12.1 {TextWidgetCmd procedure, "index" option} -setup {
     text .t
@@ -2903,7 +3073,7 @@ test text-12.3 {TextWidgetCmd procedure, "index" option} -setup {
     .t in a b
 } -cleanup {
     destroy .t
-} -returnCodes {error} -result {ambiguous option "in": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, replace, scan, search, see, tag, window, xview, or yview}
+} -returnCodes {error} -result {ambiguous option "in": must be bbox, cget, compare, configure, count, debug, delete, dlineinfo, dump, edit, get, image, index, insert, mark, peer, pendingsync, replace, scan, search, see, sync, tag, window, xview, or yview}
 test text-12.4 {TextWidgetCmd procedure, "index" option} -setup {
     text .t
 } -body {
@@ -6710,7 +6880,7 @@ test text-33.2 {TextWidgetCmd procedure, "peer" option} -setup {
 test text-33.3 {TextWidgetCmd procedure, "peer" option} -setup {
     text .t
 } -body {
-    .t p names
+    .t pee names
 } -cleanup {
     destroy .t
 } -returnCodes {ok} -result {}
diff --git a/tests/textDisp.test b/tests/textDisp.test
index ac3aee0..caba769 100644
--- a/tests/textDisp.test
+++ b/tests/textDisp.test
@@ -4197,29 +4197,34 @@ test textDisp-33.5 {bold or italic fonts} win {
 } {italic font measurement ok}
 destroy .tt
 
-test textDisp-34.1 {Text widgets multi-scrolling problem: Bug 2677890} -setup {
-    pack [text .t1 -width 10 -yscrollcommand {.sy set}] \
-	[ttk::scrollbar .sy -orient vertical -command {.t1 yview}] \
-	-side left -fill both
-    bindtags .sy {}; # No clicky!
+test textDisp-34.1 {Line heights recalculation problem: bug 2677890} -setup {
+    pack [text .t1] -expand 1 -fill both
     set txt ""
-    for {set i 0} {$i < 99} {incr i} {
-	lappend txt "$i" [list pc $i] "\n" ""
+    for {set i 1} {$i < 100} {incr i} {
+        append txt "Line $i\n"
     }
     set result {}
 } -body {
-    .t1 insert end {*}$txt
-    update
-    lappend result [.sy get]
-    .t1 replace 6.0 6.0+1c "*"
-    lappend result [.sy get]
-    after 0 {lappend result [.sy get]}
-    after 1000 {lappend result [.sy get]}
-    vwait result;vwait result
-    return $result
+    .t1 insert end $txt
+    .t1 debug 1
+    set ge [winfo geometry .]
+    scan $ge "%dx%d+%d+%d" width height left top
+    update
+    .t1 sync
+    set negative 0
+    bind .t1 <<WidgetViewSync>> { if {%d < 0} {set negative 1} }
+    # Without the fix for bug 2677890, changing the width of the toplevel
+    # will launch recomputation of the line heights, but will produce negative
+    # number of still remaining outdated lines, which is obviously wrong.
+    # Thus we use this way to check for regression regarding bug 2677890,
+    # i.e. to check that the fix for this bug really is still in.
+    wm geometry . "[expr {$width * 2}]x$height+$left+$top"
+    update
+    .t1 sync
+    set negative
 } -cleanup {
-    destroy .t1 .sy
-} -result {{0.0 0.24} {0.0 0.24} {0.0 0.24} {0.0 0.24}}
+    destroy .t1
+} -result {0}
 
 test textDisp-35.1 {Init value of charHeight - Dancing scrollbar bug 1499165} -setup {
     pack [text .t1] -fill both -expand y -side left