Add 'reset' button

It's very tedious to deselect multiple XLFD field names if you want to
start from scratch (it's often easier to relaunch the app). Hence, a
simple reset button can be handy.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

app-defaults/XFontSel

@@ -50,8 +50,13 @@ XFontSel.cursor:	left_ptr
 *quitButton.left:	chainLeft
 *quitButton.right:	chainLeft
 
+*resetButton.Label:	reset
+*resetButton.fromHoriz:	quitButton
+*resetButton.left:	chainLeft
+*resetButton.right:	chainLeft
+
 *ownButton.Label:	select
-*ownButton.fromHoriz:	quitButton
+*ownButton.fromHoriz:	resetButton
 *ownButton.left:	chainLeft
 *ownButton.right:	chainLeft
 

xfontsel.c

@@ -68,6 +68,7 @@ void GetFontNames(XtPointer closure);
 Boolean Matches(String pattern, String fontName, Boolean fields[], int *maxfields);
 Boolean DoWorkPiece(XtPointer closure);
 void Quit(Widget w, XtPointer closure, XtPointer callData) _X_NORETURN;
+void Reset(Widget w, XtPointer closure, XtPointer callData);
 void OwnSelection(Widget w, XtPointer closure, XtPointer callData);
 void SelectField(Widget w, XtPointer closure, XtPointer callData);
 void ParseFontNames(XtPointer closure);
@@ -223,6 +224,7 @@ static void ScheduleWork(XtProc proc, XtPointer closure, int priority);
 static void SetCurrentFontCount(void);
 static void SetNoFonts(void);
 static void SetParsingFontCount(int count);
+static void reset_currentFontNameString(void);
 
 static XtAppContext appCtx;
 static int numFonts;
@@ -234,6 +236,7 @@ static FieldValueList *fieldValues[FIELD_COUNT];
 static FontValues currentFont;
 static int matchingFontCount;
 static Boolean anyDisabled = False;
+static Widget resetButton;
 static Widget ownButton;
 static Widget fieldBox;
 static Widget countLabel;
@@ -283,11 +286,14 @@ see 'xfontsel' manual page."
 
 	commandBox = XtCreateManagedWidget("commandBox",formWidgetClass,pane,NZ);
 	{
-	    Widget quitButton /*, ownButton , countLabel*/;
+	    Widget quitButton /*, resetButton, ownButton , countLabel*/;
 
 	    quitButton =
 		XtCreateManagedWidget("quitButton",commandWidgetClass,commandBox,NZ);
 
+	    resetButton =
+		XtCreateManagedWidget("resetButton",commandWidgetClass,commandBox,NZ);
+
 	    ownButton =
 		XtCreateManagedWidget("ownButton",toggleWidgetClass,commandBox,NZ);
 
@@ -295,6 +301,7 @@ see 'xfontsel' manual page."
 		XtCreateManagedWidget("countLabel",labelWidgetClass,commandBox,NZ);
 
 	    XtAddCallback(quitButton, XtNcallback, Quit, NULL);
+	    XtAddCallback(resetButton, XtNcallback, Reset, NULL);
 	    XtAddCallback(ownButton,XtNcallback,OwnSelection,(XtPointer)True);
 	}
 
@@ -322,10 +329,7 @@ see 'xfontsel' manual page."
 	/* currentFontName = */
 	{
 	    Arg args[1];
-	    currentFontNameSize = strlen(AppRes.pattern);
-	    if (currentFontNameSize < 128) currentFontNameSize = 128;
-	    currentFontNameString = XtMalloc(currentFontNameSize);
-	    strcpy(currentFontNameString, AppRes.pattern);
+	    reset_currentFontNameString();
 	    XtSetArg(args[0], XtNlabel, currentFontNameString);
 	    currentFontName =
 		XtCreateManagedWidget("fontName",labelWidgetClass,pane,args,ONE);
@@ -910,6 +914,7 @@ static void SetNoFonts(void)
     matchingFontCount = 0;
     SetCurrentFontCount();
     XtSetSensitive(fieldBox, False);
+    XtSetSensitive(resetButton, False);
     XtSetSensitive(ownButton, False);
     if (AppRes.app_defaults_version >= MIN_APP_DEFAULTS_VERSION) {
 	XtUnmapWidget(sampleText);
@@ -1398,6 +1403,28 @@ void Quit(Widget w, XtPointer closure, XtPointer callData)
 }
 
 
+void Reset(Widget w, XtPointer closure, XtPointer callData) {
+  Arg args[1];
+  reset_currentFontNameString();
+  XtSetArg(args[0], XtNlabel, currentFontNameString);
+  XtSetValues(currentFontName, args, ONE);
+
+  for (int f = 0; f < FIELD_COUNT; f++)
+    currentFont.value_index[f] = patternFieldSpecified[f] ? 0 : -1;
+
+  SetCurrentFont(NULL);
+  EnableRemainingItems(SkipCurrentField); /* menu */
+}
+
+static void reset_currentFontNameString(void) {
+  currentFontNameSize = strlen(AppRes.pattern);
+  if (currentFontNameSize < 128) currentFontNameSize = 128;
+  XtFree(currentFontNameString);
+  currentFontNameString = XtMalloc(currentFontNameSize);
+  strcpy(currentFontNameString, AppRes.pattern);
+}
+
+
 static Boolean
 ConvertSelection(Widget w, Atom *selection, Atom *target, Atom *type,
 		 XtPointer *value, unsigned long *length, int *format)