buffer.g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);
buffer.g2.setFont(G4P.numericLabelFont);
buffer.imageMode(PApplet.CENTER);
hotspots = new HotSpot[]{
new HSalpha(THUMB_SPOT, width/2 + (parametricPos - 0.5f) * trackLength, height/2, thumb, PApplet.CENTER), // thumb
new HSrect(TRACK_SPOT, (width-trackLength)/2, (height-trackWidth)/2, trackLength, trackWidth), // track
};
opaque = false;
z = Z_SLIPPY;