UIProgressView custom draw method

Code snippet of a UIProgressView subclass that implements custom draw method.
This example uses four images for the left side, right side and ten sections that can be either on/off or partially filled.
My images included edge and shadow and named: pb_left.png (9x32), pb_right.png (9x32), pb_on.png (28x32). pb_off.png (28x32)

- (void)awakeFromNib
{
 [self setBackgroundColor:[UIColor clearColor]];
}

// allow non-clear background color in Interface Builder, but do not draw it
- (BOOL)getClearsContextBeforeDrawing
{
 return NO;
};

// draw left and right edge of progress bar with filled sections between
- (void)drawRect:(CGRect)rect
{
 const int numParts = 10;
 UIImage *pb_left = [UIImage imageNamed:@"pb_left.png"];  // "["
 UIImage *pb_right = [UIImage imageNamed:@"pb_right.png"]; // "]"
 UIImage *pb_on = [UIImage imageNamed:@"pb_on.png"];   // "X"
 UIImage *pb_off = [UIImage imageNamed:@"pb_off.png"];  // " "
 CGPoint p = {0,0};
 [pb_left drawAtPoint:p];
 p.x = pb_left.size.width;
 int q = (int)(self.progress * numParts);
 for (int i=0; i<numParts; i++)
 {
  if (i == q)  // partial on/off section. works with semi-transparent images too
  {
   float w = truncf(pb_on.size.width * fmodf(self.progress * numParts, 1.0f));
   [pb_on drawInRect:CGRectMake(p.x, p.y, w, pb_on.size.height)];
   [pb_off drawInRect:CGRectMake(p.x + w, p.y, pb_on.size.width - w, pb_on.size.height)];
  }
  else if (i < q)
  {
   [pb_on drawAtPoint:p];
  }
  else // (i > q)
  {
   [pb_off drawAtPoint:p];
  }
  p.x += pb_on.size.width;
 }
 [pb_right drawAtPoint:p];
}