Eclipse Plug-in Development Beginner's Guide - Second Edition

Time for action – drawing a seconds hand

A clock with no hands and no numbers is just a circle. To change this, a second hand will be drawn using a filled arc.

Since arcs are drawn anticlockwise from 0 (on the right, or 3 o'clock) through 90 degrees (12 o'clock), then 180 degrees (9 o'clock), then 270 degrees (6 o'clock), and finally back to 360 degrees (3 o'clock), it is possible to calculate the arc's position for the second hand using the expression (15 – seconds) * 6 % 360.

1. Go to the drawClock method of the ClockView class.
2. Add a variable called seconds that is initialized to LocalTime.now().getSecond().
3. Get the SWT.COLOR_BLUE via the display, and store it in a local variable, blue.
4. Set the background color of the graphics context to blue.
5. Draw ...