With this tutorial we shall show you how to draw simple shapes in a Java Desktop Application. This is a very important step when designing your own graphics for your App.
Basically, all you have to do in order to draw shapes in a Java application is:
- Create a new
Frame. - Create a class that extends the
Componentclass and override thepaintmethod. - Use
Graphics2D.drawLineto draw a simple line. - Use
Graphics2D.drawOvalto draw an oval shape in the screen. - Use
Graphics2D.drawRectto draw a rectangle on the screen. - Use
Graphics2D.drawArcto draw an arch. - Create a new
Polygonto add a polygon to your drawing, and useaddPointto add more points to the polygon.
Let’s see the code snippet that follows:
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 | package com.javacodegeeks.snippets.desktop;import java.awt.Component;import java.awt.Frame;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Polygon;public class DrawShapesExample { public static void main(String[] args) {// Create a frameFrame frame = new Frame();// Add a component with a custom paint methodframe.add(new CustomPaintComponent());// Display the frameint frameWidth = 300;int frameHeight = 300;frame.setSize(frameWidth, frameHeight);frame.setVisible(true); } /** * To draw on the screen, it is first necessary to subclass a Component * and override its paint() method. The paint() method is automatically called * by the windowing system whenever component's area needs to be repainted. */ static class CustomPaintComponent extends Component {public void paint(Graphics g) { // Retrieve the graphics context; this object is used to paint shapes Graphics2D g2d = (Graphics2D)g; // Draw an oval that fills the window int x = 0; int y = 0; int w = getSize().width-1; int h = getSize().height-1; /** * The coordinate system of a graphics context is such that the origin is at the * northwest corner and x-axis increases toward the right while the y-axis increases * toward the bottom. */ g2d.drawLine(x, y, w, h); // to draw a filled oval use : g2d.fillOval(x, y, w, h) instead g2d.drawOval(x, y, w, h); // to draw a filled rectangle use : g2d.fillRect(x, y, w, h) instead g2d.drawRect(x, y, w, h); // A start angle of 0 represents a 3 o'clock position, 90 represents a 12 o'clock position, // and -90 (or 270) represents a 6 o'clock position int startAngle = 45; int arcAngle = -60; // to draw a filled arc use : g2d.fillArc(x, y, w, h, startAngle, arcAngle) instead g2d.drawArc(x, y, w/2, h/2, startAngle, arcAngle); // to draw a filled round rectangle use : g2d.fillRoundRect(x, y, w, h, arcWidth, arcHeight) instead g2d.drawRoundRect(x, y, w, h, w/2, h/2); Polygon polygon = new Polygon(); polygon.addPoint(w/4, h/2); polygon.addPoint(0, h/2); polygon.addPoint(w/4, 3*h/4); polygon.addPoint(w/2, 3*h/4); // Add more points... // to draw a filled round rectangle use : g2d.fillPolygon(polygon) instead g2d.drawPolygon(polygon);} }} |
This was an example on how to draw shapes in a Java Desktop Application.
