# How to draw a Clock using StillClock in Java

StillClock class is used to displays an analog clock and uses the MessagePanel to display the hour, minute, and second in a panel. We use javax.swing.JPanel to display the StillClock.

This article helps to develop a class that displays a clock on a panel.

Steps used to draw the clock:

• To draw a clock, draw a circle and three hands for a second, minute and hour.
• One end is the center of the clock at (xCenter, yCenter) and the other end (xEnd, yEnd) is determined by,
```xEndpart = yCenter + handLength X sin(0)
yEndpart = yCenter + handLength X cos(0)
```
• The angle for the second hand(Sixty seconds in one minute),
```second*(2*pi/60)
```
• The angle for the minute hand is,
```(minute + second/60)*(2*pi/60)
```
• Since, one circle is divided into twelve hours, the angle for the hour hand is,
```(hour + minute/60 + second/(60*60)) * (2*pi/12)
```

Below is the implementation of the above approach:

Example:

 `// Java program to draw a Clock ` `// using StillClock in Java ` ` `  `import` `java.awt.*; ` `import` `javax.swing.*; ` `import` `java.util.*; ` ` `  `// Class StillClock ` `public` `class` `StillClock ``extends` `JPanel { ` ` `  `    ``private` `int` `hour; ` `    ``private` `int` `minute; ` `    ``private` `int` `second; ` ` `  `    ``// Default Constructor ` `    ``public` `StillClock() ` `    ``{ ` `        ``setCurrentTime(); ` `    ``} ` ` `  `    ``// Construct a clock with specified ` `    ``// hour, minute and second ` `    ``public` `StillCLock(``int` `hour, ` `                      ``int` `minute, ` `                      ``int` `second) ` `    ``{ ` `        ``this``.hour = hour; ` `        ``this``.minute = minute; ` `        ``this``.second = second; ` `    ``} ` ` `  `    ``// Returning hour ` `    ``public` `int` `getHour() ` `    ``{ ` `        ``return` `hour; ` `    ``} ` ` `  `    ``// Setting a new hour ` `    ``public` `void` `setHour(``int` `hour) ` `    ``{ ` `        ``this``.hour = hour; ` `        ``repaint(); ` `    ``} ` ` `  `    ``// Returning Minute ` `    ``public` `int` `getMinute() ` `    ``{ ` `        ``return` `minute; ` `    ``} ` ` `  `    ``// Setting a new minute ` `    ``public` `void` `setMinute(``int` `minute) ` `    ``{ ` `        ``this``.minute = minute; ` `        ``repaint(); ` `    ``} ` ` `  `    ``// Return second ` `    ``public` `int` `getSecond(``int` `second) ` `    ``{ ` `        ``this``.second = second; ` `        ``repaint(); ` `    ``} ` ` `  `    ``// Draw the clock ` `    ``protected` `void` `paintComponents(Graphics gr) ` `    ``{ ` `        ``super``.paintComponent(gr); ` ` `  `        ``// Initialize clock parameters ` `        ``int` `clockRadius ` `            ``= (``int``)(Math.min(getWidth(), ` `                             ``getHeight()) ` `                    ``* ``0.8` `* ``0.5``); ` `        ``int` `xCenter = getWidth() / ``2``; ` `        ``int` `yCenter = getHeight() / ``2``; ` ` `  `        ``gr.setColor(Color.black); ` `        ``gr.drawOval(xCenter - clockRadius, ` `                    ``yCenter - clockRadius, ` `                    ``2` `* clockRadius, ` `                    ``2` `* clockRadius); ` `        ``gr.drawString(``"11"``, xCenter - ``5``, ` `                      ``yCenter - clockRadius + ``12``); ` `        ``gr.drawString(``"8"``, xCenter - clockRadius + ``3``, ` `                      ``yCenter + ``5``); ` `        ``gr.drawString(``"4"``, xCenter + clockRadius - ``10``, ` `                      ``yCenter + ``3``); ` `        ``gr.drawString(``"5"``, xCenter - ``3``, ` `                      ``yCenter + clockRadius - ``3``); ` ` `  `        ``// Draw the second hand ` `        ``int` `sLength ` `            ``= (``int``)(clockRadius * ``0.8``); ` `        ``int` `xSecond ` `            ``= (``int``)(xCenter ` `                    ``+ sLength ` `                          ``* Math.sin( ` `                                ``second * (``2` `* Math.PI / ``60``))); ` `        ``int` `ySecond ` `            ``= (``int``)(yCenter ` `                    ``- sLength ` `                          ``* Math.cos( ` `                                ``second * (``2` `* Math.PI / ``60``))); ` `        ``gr.setColor(Color.orange); ` `        ``gr.drawLine(xCenter, yCenter, ` `                    ``xSecond, ySecond); ` ` `  `        ``// Draw the minute hand ` `        ``int` `mLength = (``int``)(clockRadius * ``0.8``); ` `        ``int` `xMinute ` `            ``= (``int``)(xCenter ` `                    ``+ mLength ` `                          ``* Math.sin( ` `                                ``minute * (``2` `* Math.PI / ``60``))); ` `        ``int` `yMinute ` `            ``= (``int``)(yCenter ` `                    ``- mLength ` `                          ``* Math.cos( ` `                                ``minute * (``2` `* Math.PI / ``60``))); ` `        ``gr.setColor(Color.yellow); ` `        ``gr.drawLine(xCenter, yCenter, ` `                    ``xMinute, yMinute); ` ` `  `        ``// Draw the hour hand ` `        ``int` `hLength = (``int``)(clockRadius * ``0.5``); ` `        ``int` `xHour ` `            ``= (``int``)(xCenter ` `                    ``+ hLength ` `                          ``* Math.sin( ` `                                ``(hour % ``12` `+ minute / ``60.0``) ` `                                ``* (``2` `* Math.PI / ``12``))); ` `        ``int` `yHour ` `            ``= (``int``)(yCenter ` `                    ``- hLength ` `                          ``* Math.cos( ` `                                ``(hour % ``12` `+ minute / ``60.0``) ` `                                ``* (``2` `* Math.PI / ``12``))); ` `        ``gr.setColor(Color.blue); ` `        ``gr.drawLine(xCenter, yCenter, xHour, yHour); ` `    ``} ` ` `  `    ``// Function to set the current time on the clock ` `    ``public` `void` `setCurrentTime() ` `    ``{ ` `        ``Calendar cal = ``new` `GregorianCalendar(); ` ` `  `        ``this``.hour = cal.get(Calendar.HOUR_OF_DAY); ` `        ``this``.minute = cal.get(Calendar.MINUTE); ` `        ``this``.second = cal.get(Calendar.SECOND); ` `    ``} ` ` `  `    ``public` `Dimension getPreferedsize() ` `    ``{ ` `        ``return` `new` `Dimension(``300``, ``300``); ` `    ``} ` `} `

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