boolean setScrollBarVisible(ScrollBar bar, boolean visible) {
if (scrolledHandle == 0) return false;
int barHandle = bar.handle;
boolean managed = OS.XtIsManaged(barHandle);
if (managed == visible) return false;
/*
* Feature in Motif. Hiding or showing a scroll bar
* can cause the widget to automatically resize in
* the OS. This behavior is unwanted. The fix is
* to force the widget to resize to original size.
*/
int[] argList = {OS.XmNwidth, 0, OS.XmNheight, 0, OS.XmNborderWidth, 0};
OS.XtGetValues(scrolledHandle, argList, argList.length / 2);
int[] argList1 = {OS.XmNwidth, 0, OS.XmNheight, 0};
OS.XtGetValues(handle, argList1, argList1.length / 2);
/* Hide or show the scroll bar */
if (visible) {
OS.XtManageChild(barHandle);
} else {
OS.XtUnmanageChild(barHandle);
}
if ((state & CANVAS) != 0) {
if (formHandle != 0) {
boolean showBorder = (style & SWT.BORDER) != 0;
int margin = showBorder || visible ? 3 : 0;
if ((bar.style & SWT.V_SCROLL) != 0) {
int[] argList2 = new int[] {OS.XmNmarginWidth, margin};
OS.XtSetValues(formHandle, argList2, argList2.length / 2);
}
if ((bar.style & SWT.H_SCROLL) != 0) {
int[] argList2 = new int[] {OS.XmNmarginHeight, margin};
OS.XtSetValues(formHandle, argList2, argList2.length / 2);
}
}
}
/*
* Feature in Motif. When XtSetValues() is used to restore the width and
* height of the widget, the new width and height are sometimes ignored.
* The fix is to use XtResizeWidget().
*/
OS.XtResizeWidget(scrolledHandle, argList[1], argList[3], argList[5]);
bar.sendEvent(visible ? SWT.Show : SWT.Hide);
int[] argList3 = {OS.XmNwidth, 0, OS.XmNheight, 0};
OS.XtGetValues(handle, argList3, argList3.length / 2);
return argList1[1] != argList3[1] || argList1[3] != argList3[3];
}
