Progress bar programming

typedef struct
{
   RectangleType bounds;
   WinHandle savedbits;
} ProgBar;

void OpenProgressBar (ProgBar *progbar)
{
   UInt16 savebitserror;

   progbar->savedbits = WinSaveBits (& progbar->bounds, & savebitserror);
   WinEraseRectangle (& progbar->bounds, 0);
}

void CloseProgressBar (ProgBar *progbar)
{
   if (progbar->savedbits)
   {
       WinRestoreBits (progbar->savedbits,
               progbar->bounds.topLeft.x, progbar->bounds.topLeft.y);
   }
   else
   {
       /* maybe should enqueue a frmUpdateEvent instead, maybe not */
       WinEraseRectangle (& progbar->bounds, 0);
   }
}

void UpdateProgressBar (ProgBar *progbar, Int32 numerator, Int32 denominator)
{
   RectangleType fillrect;

   RctCopyRectangle (& progbar->bounds, & fillrect);
   fillrect.extent.x = progbar->bounds.extent.x * numerator / denominator;

   WinDrawRectangle (& fillrect, 0);
}

void TestProgressBar ()
{
   Int32 i;
   const Int32 max = 25;
   ProgBar progbar;

   progbar.bounds.topLeft.x = 20;
   progbar.bounds.topLeft.y = 70;
   progbar.bounds.extent.x = 120;
   progbar.bounds.extent.y = 20;

   OpenProgressBar (& progbar);
   for (i = 0; i <= max; i++)
   {
       UpdateProgressBar (& progbar, i, max);
       SysTaskDelay (SysTicksPerSecond() / 5);
   }
   CloseProgressBar (& progbar);
}