我要怎麼讓旋鈕數值不要從最小值直接跳到最大值?

接下來的旋鈕回呼函式程式碼適用於整數型的旋鈕。如果要用在浮點數或倍精數型態的旋鈕，就要更改程式碼因為浮點數需要fudge factor 來做浮點數準確度的補償。

int CVICALLBACK KnobCallback (int panel, int control, int event,
void *callbackData, int eventData1, int eventData2)
{
static int previousValue = 0;
int currentValue;
int max, min, inc;

switch (event)
{
case EVENT_COMMIT:
Beep();
break;

case EVENT_VAL_CHANGED:
GetCtrlVal(panel, control, ¤tValue);
GetCtrlAttribute (panel, control, ATTR_MIN_VALUE, &min);
GetCtrlAttribute (panel, control, ATTR_MAX_VALUE, &max);
GetCtrlAttribute (panel, control, ATTR_INCR_VALUE, &inc);

if (((previousValue == min) && ( abs(currentValue-min) != inc) ) ||
((previousValue == max) && ( abs(max-currentValue) != inc) ))
{
SetCtrlVal (panel, control, previousValue);
return 1; // Swallow event to prevent from updating UIR
}
else
previousValue = currentValue;
break;
}
return 0;
}