Draw a Circle Programatically Java

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Details: Written past; Last Updated on x August 2019 | Print Email

In Java, to draw a rectangle (outlines) onto the current graphics context, we tin use the post-obit methods provided by the Graphics/Graphics2D class:

drawRect(int x, int y, int width, int height)
draw3DRect(int x, int y, int width, int top, boolean raised)
draw(Rectangle2D)
drawRoundRect(int ten, int y, int width, int acme, int arcWidth, int arcHeight)

With:

(x, y) is the upper left corner of the rectangle.
width and acme: specify dimension of the rectangle.
raised: specifies whether the rectangle edges are raised or sunk when drawing a 3D rectangle.
Rectangle2D is the base class of Rectangle (for integer coordinates) Rectangle2D.Double (for double coordinates) and Rectangle2D.Float (for float coordinates).
arcWidth and arcHeight: specify the horizontal and vertical diameters of the arcs at the four corners when drawing a rectangle with rounded corners.

To demonstrate the examples, we create the following Swing programme:

/**  * This program demonstrates how to rectangles using Graphics2D object.  * @writer world wide web.codejava.net  *  */ public class RectanglesDrawingExample extends JFrame {  	public RectanglesDrawingExample() { 		super("Rectangles Drawing Demo");  		getContentPane().setBackground(Color.WHITE); 		setSize(480, 200); 		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 		setLocationRelativeTo(null); 	}  	void drawRectangles(Graphics m) { 		Graphics2D g2d = (Graphics2D) k;  		// code to draw rectangles goes hither...  	}  	public void paint(Graphics thousand) { 		super.paint(g); 		drawRectangles(m); 	}  	public static void main(Cord[] args) throws Exception {  		SwingUtilities.invokeLater(new Runnable() { 			@Override 			public void run() { 				new RectanglesDrawingExample().setVisible(true); 			} 		}); 	} }

The code examples volition go into the drawRectangles() method which obtains graphics context of the JFrame window:

void drawRectangles(Graphics g) { 	Graphics2D g2d = (Graphics2D) g;  	// code to draw rectangles goes here...  }

Now, allow's see the examples in details.

1. Drawing Rectangles in integer coordinates

Using the drawRect() method:

g2d.drawRect(30, fifty, 420, 120);

Using the draw(Rectangle) method:

g2d.describe(new Rectangle(30, l, 420, 120));

Result:

rectangle demo 1

2. Cartoon Rectangles in double coordinates

To draw a rectangle in double coordinates, create a new example of the Rectangle2D.Double course. For example:

double x = 29.5d; double y = 48.8d; double width = 413.2d; double height = 118.6d;  Rectangle2D.Double rect = new Rectangle2D.Double(10, y, width, superlative); g2d.draw(rect);

Or like this for brusk:

g2d.describe(new Rectangle2D.Double(29.5d, 48.8d, 413.second, 118.6d));

three. Drawing Rectangles in float coordinates

Like to double coordinates, we use the Rectangle2D.Float class to depict rectangles in bladder coordinates. For case:

float x = 29.5f; float y = 48.8f; float width = 413.2f; float height = 118.6f;  Rectangle2D.Float rect = new Rectangle2D.Float(10, y, width, acme); g2d.draw(rect);

Or like this for short:

g2d.draw(new Rectangle2D.Float(29.5f, 48.8f, 413.2f, 118.6f));

four. Drawing Rectangles with Rounded-Corners

To depict a rectangle with four rounded corners, use the drawRoundRect() method and pass values for the horizontal diameter (arcWidth) and vertical diameter (arcHeight) of the corners. Here's an example:

int x = 30; int y = 50; int width = 420; int height = 120; int arcWidth = 20; int arcHeight = 20;  g2d.drawRoundRect(x, y, width, acme, arcWidth, arcHeight);

Result:

rectangle rounded corners demo 1

The post-obit instance plays around with various values for the arcWidth and arcHeight:

g2d.drawRoundRect(10, y, width, height, arcWidth, arcHeight); g2d.drawRoundRect(x + 10, y + 10, width - 20, height - 20, arcWidth + 10, arcHeight + 10); g2d.drawRoundRect(x + twenty, y + 20, width - forty, height - 40, arcWidth + xx, arcHeight + 10); g2d.drawRoundRect(x + 30, y + 30, width - 60, height - 60, arcWidth + 40, arcHeight + twenty);

Result:

rectangle rounded corners demo 2

5. Drawing 3D Rectangles

The draw3DRect() method draws a rectangle with edges appear to exist raised or sunk, specified by the raised boolean flag. Here's an case:

int x = 30; int y = 50; int width = 420; int height = 120; boolean raised = true;  g2d.setColor(Color.LIGHT_GRAY);  g2d.draw3DRect(x, y, width, height, raised);

Result (a actually elementary 3D consequence):

rectangle 3D demo 2

The following example draws ii rectangles - one with raised edges and one with sunk edges:

g2d.setColor(Color.LIGHT_GRAY); g2d.draw3DRect(thirty, l, 200, 120, true); g2d.draw3DRect(250, 50, 200, 120, false);

Result:

rectangle 3D demo

NOTE: The draw3DRect() method uses only the current color and ignores the current pigment, such every bit line strokes.

half dozen. Drawing Rectangles with Custom Strokes

Rather than using the default style (sparse and solid line, black colour), we can brand some attractive decorations for the outlines of the rectangles using Strokesouth. For example:

Stroke stroke1 = new BasicStroke(6f);  g2d.setColor(Colour.Black); g2d.setStroke(stroke1);  g2d.drawRect(30, l, 420, 120);

That draws a rectangle with outlines in blue colour and thickness of 6 pixels width. Hither'southward the result:

rectangle stroke demo 1

To understand more than well-nigh using strokes, see the tutorial: Drawing lines examples with Graphics2D. The following code snippet plays effectually with various strokes:

int 10 = 20; int y = 40; int width = 440; int peak = 140;  Stroke stroke1 = new BasicStroke(6f);  g2d.setColor(Color.Blue); g2d.setStroke(stroke1); g2d.drawRect(x, y, width, meridian);  float[] dashingPattern1 = {2f, 2f}; Stroke stroke2 = new BasicStroke(2f, BasicStroke.CAP_BUTT, 		BasicStroke.JOIN_MITER, 1.0f, dashingPattern1, 2.0f);  g2d.setColor(Color.RED); g2d.setStroke(stroke2); g2d.drawRect(10 + 20, y + 20, width - 40, height - 40);  float[] dashingPattern2 = {10f, 4f}; Stroke stroke3 = new BasicStroke(4f, BasicStroke.CAP_BUTT, 		BasicStroke.JOIN_MITER, 1.0f, dashingPattern2, 0.0f);  g2d.setColor(Color.GREEN); g2d.setStroke(stroke3); g2d.drawRect(x + 40, y + 40, width - 80, top - lxxx);   float[] dashingPattern3 = {10f, 10f, 1f, 10f}; Stroke stroke4 = new BasicStroke(4f, BasicStroke.CAP_SQUARE, 		BasicStroke.JOIN_MITER, i.0f, dashingPattern3, 0.0f);  g2d.setColor(Color.BLUE); g2d.setStroke(stroke4); g2d.drawRect(10 + 60, y + 60, width - 120, height - 120);

Result:

rectangle stroke demo 2

API References:

drawRect() method Javadoc
draw3DRect() method Javadoc
describe(Shape) method Javadoc
drawRoundRect() method Javadoc
BasicStroke class Javadoc
Rectangle2D form Javadoc
Rectangle class Javadoc
Rectangle2D.Double grade Javadoc
Rectangle2D.Float course Javadoc

Nigh the Writer:

Nam Ha Minh is certified Coffee programmer (SCJP and SCWCD). He started programming with Java in the time of Java one.4 and has been falling in love with Java since then. Make friend with him on Facebook and watch his Coffee videos yous YouTube.