XmSpinBoxValidatePosition(UNIX SysteXmSpinBoxValidatePosition(3X)
NAME
XmSpinBoxValidatePosition - translate the current value of
the specified XmSpinBox child into a valid position
SYNOPSIS
#include <Xm/SpinBox.h>
int XmSpinBoxValidatePosition(
Widget textfield,
int *position);
VERSION
This page documents Motif 2.1.
DESCRIPTION
The XmSpinBoxValidatePosition function is a utility that can
be used by applications wanting to implement a policy for
tracking user modifications to editable XmSpinBox children
of type XmNUMERIC. The specifics of when and how the user's
modifications take effect is left up to the application.
text_field
The text_field argument specifies the widget ID of
the child of the XmSpinBox that is being modified.
The requirement on text_fieldis that it holds the
accessTextual trait (already a requirement for
children of XmSpinBox). This way, XmSpinBox can
extract the string out of the text_field widget
(even if it is not an XmTextField).
position The location pointed to by the position argument
is assigned the result of the translation done by
XmSpinBoxValidatePosition.
XmSpinBoxValidatePosition first checks to make
sure this is an XmNUMERIC XmSpinBox child. If it
is not, XSmpinBoxValidatePosition sets position to
the current position and returns XmCURRENT_VALUE.
XmSpinBoxValidatePositionattempts to translate the input
string to a floating point number. If this translation
fails, XmSpinBoxValidatePosition sets position to the
current position and returns XmCURRENT_VALUE.
XmSpinBoxValidatePosition converts the floating point number
to an integer using the XmNdecimalPoints resource. Extra
decimal places are truncated. The resulting integer is range
checked to make sure it falls within the valid range defined
by XmNminimumValue and XmNmaximumValue inclusive. If the
input falls outside this range, XmSpinBoxValidatePosition
sets position to the nearest limit and returns either
XmMINIMUM_VALUE or XmMAXIMUM_VALUE.
Finally, XmSpinBoxValidatePosition checks the integer to
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XmSpinBoxValidatePosition(UNIX SysteXmSpinBoxValidatePosition(3X)
make sure it belongs to the series defined by
XmNminimumValue ... XmNminumumValue + ((n - 1) *
XmNincrementlValue). If the integer does not belong to this
series, XmSpinBoxValidatePosition sets position to the
nearest element which is less than or equal to the integer
and returns XmINCREMENT_VALUE.
Otherwise, XmSpinBoxValidatePosition assigns the integer to
position and returns XmVALID_VALUE.
RETURN VALUE
The XmSpinBoxValidatePosition function returns the status of
the validation. The set of possible values returned is as
follows:
XmCURRENT_VALUE
Cannot convert, returning current position_value.
XmMINIMUM_VALUE
Less than min.
XmMAXIMUM_VALUE
More than max.
XmINCREMENT_VALUE
Not on increment.
XmVALID_VALUE
Okay.
EXAMPLES
This first example demonstrates how the
XmSpinBoxValidatePositionfunction could be used from inside
an XmNmodifyVerifyCallback callback installed on the
XmSpinBox or the XmSimpleSpinBox:
/*
* Install a callback on a spin box arrow press.
*/
XtAddCallback(sb, XmNmodifyVerifyCallback, ModifyVerifyCB, NULL);
XtAddCallback(simple_sb, XmNmodifyVerifyCallback, ModifyVerifyCB, NULL);
with the callback doing:
void ModifyVerifyCB(widget, call_data, client_data) {
XmSpinBoxCallbackStruct *cbs = (XmSpinBoxCallbackStruct*) call_data;
int position;
Widget textual = NULL;
if (XtIsSubclass(w, xmSimpleSpinBoxWidgetClass))
{
Arg args[1];
XtSetArg(args[0], XmNtextField, &textual);
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XmSpinBoxValidatePosition(UNIX SysteXmSpinBoxValidatePosition(3X)
XtGetValues(w, args, 1);
}
else if (XtIsSubclass(w, xmSpinBoxWidgetClass))
textual = cbs->widget;
else
textual = (Widget) NULL;
...
if (XmSpinBoxValidatePosition(textual, &position) == XmCURRENT_VALUE)
XBell(XtDisplay(w), 0);
else
cbs->position = position;
}
This second example demonstrates how the
XmSpinBoxValidatePositionfunction could be used from inside
an XmNactivateCallback callback installed on the TextField
child of the XmSpinBox:
/*
* Install a callback on a spin box arrow press.
*/
XtAddCallback(tf, XmNactivateCallback, ModifyVerifyChildCB, NULL);
with the callback doing:
void ModifyVerifyChildCB(widget, call_data, client_data) {
int position;
Widget textual = widget;
Arg args[1];
if (XmSpinBoxValidatePosition (textual, &position) == XmCURRENT_VALUE)
XBell(XtDisplay(widget), 0);
/* Set the position constraint resource of the textfield */
XtSetArg(args[0], XmNposition, position);
XtSetValues(textual, args, 1);
}
SEE ALSO
XmSpinBox(3), XmCreateSpinBox(3)
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