TIP #438 - <<TextLineHeightsInvalid>> event added, with corresponding new tests

2 files changed, 68 insertions, 0 deletions

diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index d740181..ff90520 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -590,6 +590,7 @@ static int		TextGetScrollInfoObj(Tcl_Interp *interp,
 			    Tcl_Obj *CONST objv[], double *dblPtr,
 			    int *intPtr);
 static void		AsyncUpdateLineMetrics(ClientData clientData);
+static void		GenerateTextLineHeightsInvalidEvent(TkText *textPtr);
 static void		AsyncUpdateYScrollbar(ClientData clientData);
 static int              IsStartOfNotMergedLine(TkText *textPtr,
                             CONST TkTextIndex *indexPtr);
@@ -2929,6 +2930,8 @@ AsyncUpdateLineMetrics(
 	LOG("tk_textInvalidateLine", buffer);
     }
 
+    GenerateTextLineHeightsInvalidEvent(textPtr);
+
     /*
      * If we're not in the middle of a long-line calculation (metricEpoch==-1)
      * and we've reached the last line, then we're done.
@@ -2961,6 +2964,43 @@ AsyncUpdateLineMetrics(
 /*
  *----------------------------------------------------------------------
  *
+ * GenerateTextLineHeightsInvalidEvent --
+ *
+ *      Send the <<TextLineHeightsInvalid>> event related to the text widget
+ *      line metrics asynchronous update.
+ *      This is equivalent to:
+ *         event generate $textWidget <<TextLineHeightsInvalid>> -detail $N
+ *      where $N is the number of lines for which the height is outdated.
+ *
+ * Results:
+ *      None
+ *
+ * Side effects:
+ *      If corresponding bindings are present, they will trigger.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GenerateTextLineHeightsInvalidEvent(
+    TkText *textPtr)		/* Information about text widget. */
+{
+    union {XEvent general; XVirtualEvent virtual;} event;
+
+    memset(&event, 0, sizeof(event));
+    event.general.xany.type = VirtualEvent;
+    event.general.xany.serial = NextRequest(Tk_Display(textPtr->tkwin));
+    event.general.xany.send_event = False;
+    event.general.xany.window = Tk_WindowId(textPtr->tkwin);
+    event.general.xany.display = Tk_Display(textPtr->tkwin);
+    event.virtual.name = Tk_GetUid("TextLineHeightsInvalid");
+    event.virtual.user_data = Tcl_NewIntObj(TkTextPendingyupdate(textPtr));
+    Tk_HandleEvent(&event.general);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * TkTextUpdateLineMetrics --
  *
  *	This function updates the pixel height calculations of a range of
diff --git a/tests/text.test b/tests/text.test
index d8ed533..7e754e2 100644
--- a/tests/text.test
+++ b/tests/text.test
@@ -1025,6 +1025,34 @@ test text-11a.12 {TextWidgetCmd procedure, "pendingyupdate" option} {
     set fraction2 [lindex [.top.yt yview] 0]
     lappend res [expr {$fraction1 == $fraction2}]
 } {1 1 1}
+test text-11a.21 {"<<TextLineHeightsInvalid>>" event} {
+    destroy .top.yt .top
+    toplevel .top
+    pack [text .top.yt]
+    set content {}
+    for {set i 1} {$i < 300} {incr i} {
+        append content [string repeat "$i " 15] \n
+    }
+    .top.yt insert 1.0 $content
+    update
+    bind .top.yt <<TextLineHeightsInvalid>> { if {%d == 0} {set yud(%W) 1} }
+    # wait for end of line metrics calculation to get correct $fraction1
+    # as a reference
+    if {[.top.yt pendingyupdate]} {vwait yud(.top.yt)}
+    .top.yt yview moveto 1
+    set fraction1 [lindex [.top.yt yview] 0]
+    set res [expr {$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 pendingyupdate]} {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}]
+} {1 1 1}
 
 # edit, mark, scan, search, see, tag, window, xview and yview actions are tested elsewhere.