Make GenerateWidgetSyncEvent save the sync state whenever it sends an event,

and not send an event unless the requested state differs from the saved state.

3 files changed, 17 insertions, 7 deletions

diff --git a/generic/tkText.c b/generic/tkText.c
index 2dabe4c..5f2abb2 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -533,6 +533,7 @@ CreateWidget(
     textPtr->widgetCmd = Tcl_CreateObjCommand(interp,
 	    Tk_PathName(textPtr->tkwin), TextWidgetObjCmd,
 	    textPtr, TextCmdDeletedProc);
+    textPtr->inSync = 1;
 
     if (sharedPtr == NULL) {
 	sharedPtr = ckalloc(sizeof(TkSharedText));
diff --git a/generic/tkText.h b/generic/tkText.h
index 5d88784..91abb73 100644
--- a/generic/tkText.h
+++ b/generic/tkText.h
@@ -785,7 +785,8 @@ typedef struct TkText {
 				 * refering to us. */
     int insertCursorType;	/* 0 = standard insertion cursor, 1 = block
 				 * cursor. */
-
+    int inSync;                 /* The last value sent as a <<WidgetViewSync>>
+                                   event. Initialized to 1.*/
     /*
      * Copies of information from the shared section relating to the undo/redo
      * functonality
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 03546af..f63cb0c 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -3115,8 +3115,14 @@ AsyncUpdateLineMetrics(
  * GenerateWidgetViewSyncEvent --
  *
  *      Send the <<WidgetViewSync>> event related to the text widget
- *      line metrics asynchronous update.
- *      This is equivalent to:
+ *      line metrics asynchronous update.  These events should only
+ *      be sent when the sync status has changed.  So this function
+ *      compares the requested state with the state saved in the
+ *      TkTest structure, and only generates the event if they are
+ *      different.  This means that it is safe to call this function
+ *      at any time when the state is known.
+ *
+ *      If an event is sent, the effect is equivalent to:
  *         event generate $textWidget <<WidgetViewSync>> -data $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).
@@ -3147,8 +3153,11 @@ GenerateWidgetViewSyncEvent(
 	FORCE_DISPLAY(textPtr->tkwin);
     }
 
-    TkSendVirtualEvent(textPtr->tkwin, "WidgetViewSync",
-        Tcl_NewBooleanObj(InSync));
+    if (InSync != textPtr->inSync) {
+        textPtr->inSync = InSync;
+        TkSendVirtualEvent(textPtr->tkwin, "WidgetViewSync",
+                           Tcl_NewBooleanObj(InSync));
+    }
 }
 
 /*
@@ -3531,9 +3540,8 @@ TextInvalidateLineMetrics(
     /*
      * The widget is now out of sync: send a <<WidgetViewSync>> event.
      */
-    
-    GenerateWidgetViewSyncEvent(textPtr, 0);
 
+    GenerateWidgetViewSyncEvent(textPtr, 0);
 }
 
 /*