Quick and Dirty Tickmarks

Quick and Dirty Tickmarks

The JSlider component can be customized so that its labels, track, and tickmarks (or any combination of the three) are hidden. Unfortunately, there’s no way to turn off the slider itself. This would be useful in situations where you want to display a scale next to some sort of ruler, thermometer, or other graphical measurement.

You can modify the JSlider’s paint routine to shift the painting area so that only the tickmarks and the labels are visible, while the slider and the track are painted invisibly offscreen. The secret is in the Graphics.translate() method, which modifies the coordinate space of all subsequent drawing operations. Override JSlider’s paint() method and call translate() to shift the slider and track up and off the screen.

Note that this example is hard-coded for horizontal sliders. For vertical sliders change the call to translate so that the x coordinate is altered instead of the y. Also, the code has been designed only for the Metal look-and-feel. Other look-and-feels may use different sizes for the slider track, in which case the track will be partially visible or the tickmarks will be partially hidden. I know of no way around this problem, since the sizes of internal slider components are not accessible outside the look-and-feel classes themselves.

 import java.awt.*;import javax.swing.*;public class TickMarks{	public static void main(String[] args)	{		JFrame frame = new JFrame();		JSlider tickMarks = 			new JSlider(JSlider.HORIZONTAL)		{			public void paint(Graphics g)			{				Rectangle clip = g.getClipBounds();				g.setColor(getBackground());				g.fillRect(clip.x, clip.y, 					clip.width, clip.height);				g.translate(clip.x, clip.y - 19);				super.paint(g);			}		};		tickMarks.setPaintLabels(true);		tickMarks.setPaintTicks(true);		tickMarks.setMajorTickSpacing(10);		tickMarks.setMinorTickSpacing(1);		frame.getContentPane().add(tickMarks);		frame.setSize(600, 100);;	}}


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