// fill color
g.setColor(java.awt.Color.WHITE);
int x = Math.min(width-1, (int) (markerPos * width));
int[] xPoints = { x-MARKER_WIDTH, x, x+MARKER_WIDTH };
int[] yPoints = { 0, MARKER_HEIGHT, 0 };
g.fillPolygon(xPoints, yPoints, 3);
g.setColor(java.awt.Color.BLACK);
g.drawLine(x-MARKER_WIDTH, 0, x, MARKER_HEIGHT);
g.drawLine(x, MARKER_HEIGHT, x+MARKER_WIDTH, 0);
g.drawLine(x-MARKER_WIDTH, 0, x+MARKER_WIDTH, 0);