setLogScaleX method
Implementation
void setLogScaleX( double base ){
if( base <= 1.0 ){
_info[_curIndex]._isLogScaleX = false;
} else {
_info[_curIndex]._isLogScaleX = true;
_info[_curIndex]._baseX = base;
_info[_curIndex]._logBaseX = 1.0 / ClipMath.log( base );
}
}