Java 中的 2D 图形-java教程-PHP中文网

Java 2D 渲染

示例#5

结论

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Java 中的 2D 图形

PHPz

Aug 30, 2024 pm 04:06 PM

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借助 Java 2 平台的一些高级功能，可以使用 Java 编程来实现 2D 图形，其中包括用于图像处理、高级图形设计选项、几何变换、Alpha 合成等操作的 Java 内置函数java 2D包下提供了许多包，例如awt、awt.image、awt.color、awt.font、awt.geom、awt.print和awt.image.renderable。 Java 因其高质量的图形结果而成为游戏开发人员社区中著名的首选选项，各种各样的几何设计选项有利于文档的打印，并允许保持所开发产品的性能。

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Java 2D 渲染

Java 2D API 支持跨所有不同设备的统一渲染模型：显示监视器或打印机。在程序开发过程中，无论最终组件是打印机还是显示器，渲染都以相同的方式工作。该包根据最终组件自动检测并更改图形上下文。 Java 2D API 由 java.awt.Graphics2D 组成，它扩展了 Graphics 类以提供对增强图形和渲染功能的支持。

以下是该软件包提供的功能：

支持原始几何形状和图形的渲染。
它提供了使用描边用绘画属性中指定的任何颜色或图案填充任何形状内部的选项。
它可以让您渲染指定的图像。
它可以让您将文本字符串转换为字形，并用绘制属性中指定的颜色填充。

示例#1

让我们看一下同一个 Java 程序，看看它是如何工作的。

代码：

import javax.swing.JFrame;
import java.awt.*;       // AWT package is responsible for creating GUI
import javax.swing.*;    // Java swing package is responsible to provide UI components
// AWT class extents Jframe which is part of Swing package
public class AWTGraphicsSampleProgram extends JFrame {
/**
*
*/
// Defining all the static variables
private static final long serialVersionUID = 1L;
public static final int SAMPLE_CANVAS_WIDTH  = 500;
public static final int SAMPLE_CANVAS_HEIGHT = 500;
// The program enters from the main method
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new AWTGraphicsSampleProgram(); // this run method will create a new object and thus invoke the constructor method.
}
});
}
//Here we are creating an instance of the drawing canvas inner class called DrawCanwas
private DrawCanvas sampleCanvas;
public AWTGraphicsSampleProgram() {
sampleCanvas = new DrawCanvas();
sampleCanvas.setPreferredSize(new Dimension(SAMPLE_CANVAS_WIDTH,            SAMPLE_CANVAS_HEIGHT));
Container containerPane = getContentPane();
containerPane.add(sampleCanvas);
setDefaultCloseOperation(EXIT_ON_CLOSE);   // setting up the default close mechanism
pack();
setTitle("......");  // set the desired title of the JFrame
setVisible(true);    // setVisible method will be set the visibility of the Jframe to true
}
/**
* here drawCanvas is the inner class of the Jpanel which is used for custom drawing
*/
private class DrawCanvas extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
// Overriding paintComponent will let you to design your own painting
@Override
public void paintComponent(Graphics graphics) {
super.paintComponent(graphics);
setBackground(Color.BLACK);  // setting the background color to black
graphics.setColor(Color.GREEN);  // setting up the color to green
graphics.drawLine(30, 40, 100, 200);
graphics.drawOval(150, 180, 10, 10);
graphics.drawRect(200, 210, 20, 30);
graphics.setColor(Color.magenta);
graphics.fillOval(300, 310, 30, 50);
graphics.fillRect(400, 350, 60, 50);
graphics.setColor(Color.WHITE);
graphics.setFont(new Font("Monospaced", Font.PLAIN, 12)); // setting up the font style and font size
graphics.drawString("Java Graphics in 2D ...", 10, 20);
}
}
}

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输出：

Java 中的 2D 图形

Graphics类提供了不同的方法来绘制不同的图形对象。最常见的方法是drawString()、drawImage() 和fillXxx()。这些方法大致可分为两类。第一种类型的 Graphics 方法是，它提供绘制和填充功能，使用户能够渲染基本形状、文本和图像。另一种类型的方法是属性设置，它允许您更改绘图在控制台中的显示效果。 setColor 和 setFont 等方法可让您决定绘制和填充的呈现方式。图形上下文负责维护状态或属性，例如当前字体的当前绘画颜色。

示例#2

让我们看看另一个例子，看看我们还可以使用 Java 2D 类实现什么。

代码：

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
public class GeometricShapes extends JFrame
{
/**
*
*/
private static final long serialVersionUID = 1L;
@SuppressWarnings("deprecation")
public GeometricShapes()
{
super( "Geometric shapes" );
setSize( 425, 160 );
show();
}
public static void main( String args[] )
{
GeometricShapes figure = new GeometricShapes();
figure.addWindowListener( new WindowAdapter()
{
public void windowclosing( WindowEvent e )
{
System.exit( 0 );
}
});
}
public void paint( Graphics graphics )
{
// Instantiating Graphics 2D class
Graphics2D graphics2D = ( Graphics2D ) graphics;
graphics2D.setPaint( new GradientPaint( 16, 30,
Color.red,
45, 105,
Color.green,
true ) );
graphics2D.fill( new Ellipse2D.Double( 6, 31, 61, 105 ) );
graphics2D.setPaint( Color.black );
graphics2D.setStroke(new BasicStroke( 9.0f ) );
graphics2D.draw( new Rectangle2D.Double( 82, 32, 67, 102 ) );
// This will create a black colored rounded rectangle
BufferedImage bufferedImage = new BufferedImage( 10, 10,                                  BufferedImage.TYPE_INT_RGB );
Graphics2D design = bufferedImage.createGraphics();
design.setColor( Color.blue );
design.fillRect( 0, 0, 9, 9 );
design.setColor( Color.orange );
design.drawRect( 2, 2, 7, 7 );
design.setColor( Color.black );
design.fillRect( 2, 2, 4, 4 );
design.setColor( Color.pink );
design.fillRect( 5, 5, 2, 2 );
graphics2D.setPaint( new TexturePaint( bufferedImage, new Rectangle( 9, 9 ) ) );
graphics2D.fill( new RoundRectangle2D.Double( 156, 31, 76, 101, 51, 51 ) );
graphics2D.setPaint( Color.CYAN );
graphics2D.setStroke(new BasicStroke( 7.0f ) );
graphics2D.draw( new Arc2D.Double( 240, 30, 75, 100, 0, 270, Arc2D.PIE ) );
// this will create line in red and black color
graphics2D.setPaint( Color.red );
graphics2D.draw( new Line2D.Double( 400, 40, 350, 180 ) );
float dashesArray[] = { 20 };
graphics2D.setPaint( Color.black );
graphics2D.setStroke( new BasicStroke( 4, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND, 10, dashesArray, 0 ) );
graphics2D.draw( new Line2D.Double( 320, 30, 395, 150 ) );
}
}

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输出：

Java 中的 2D 图形

示例 #3

让我们在下面的程序中应用 2D java。

代码：

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.geom.*;
public class GeometricShapes2 extends JFrame
{
/**
*
*/
private static final long <em>serialVersionUID</em> = 1L;
public static void main( String args[] )
{
GeometricShapes2 design = new GeometricShapes2();
design.addWindowListener(new WindowAdapter()
{
});
}
@SuppressWarnings("deprecation")
public GeometricShapes2()
{
super( "A circle made up of stars by joining them at certain position filled with random colors" );
setBackground( Color.<em>green</em> );
setSize( 450, 450 );
show();
}
public void paint( Graphics graphics )
{
int xCoordinates[] = { 57, 69, 111, 75, 85, 57, 29, 39, 3, 45 };
int yCoordinates[] = { 2, 38, 38, 56, 98, 74, 98, 56, 38, 38 };
Graphics2D graphics2D = ( Graphics2D ) graphics;
GeneralPath starFigure = new GeneralPath();
starFigure.moveTo( xCoordinates[ 0 ], yCoordinates[ 0 ] );
for ( int j = 1; j < xCoordinates.length; j++ )
starFigure.lineTo( xCoordinates[ j ], yCoordinates[ j ] );
starFigure.closePath();
graphics2D.translate( 200, 200 );
for ( int i = 1; i <= 10; i++ )
{
graphics2D.rotate( Math.<em>PI</em> / 9.0 );
graphics2D.setColor(new Color( ( int ) ( Math.<em>random</em>() * 128 ),( int ) ( Math.<em>random</em>() * 128 ),
( int ) ( Math.<em>random</em>() * 128 ) ) );
graphics2D.fill( starFigure );
}
}
}

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输出：

Java 中的 2D 图形

示例#4

在以下程序中应用颜色编码。

代码：

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
public class GeometricShapes3 extends Canvas {
/**
*
*/
private static final long serialVersionUID = 1L;
Frame windowFrame;
TextField sampleText;
Font sampleFont;
Color colorOfText;
Color colorOfCircle;
public static void main(String args[]) {
GeometricShapes3 start;
start = new GeometricShapes3();
}
public GeometricShapes3() {
this("Arial", Font.BOLD, 18, Color.gray, Color.red);
}
public GeometricShapes3(String ff, int fs, int fz, Color bg, Color fg) {
setBackground(bg);
colorOfCircle = Color.green.brighter();
colorOfText = fg;
sampleFont = new Font(ff, fs, fz);
sampleText = new TextField("eduCBA (Corporate Bridge Consultancy Pvt Ltd) ");
windowFrame = new Frame("Demo");
windowFrame.add(sampleText, BorderLayout.NORTH);
windowFrame.add(this, BorderLayout.CENTER);
windowFrame.setSize(new Dimension(300,340));
windowFrame.setLocation(150,140);
windowFrame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
sampleText.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
repaint();
}
});
windowFrame.setVisible(true);
}
public void paint(Graphics graphics) {
String sampleTxt = sampleText.getText();
if (sampleTxt.length() == 0) return;
if (graphics instanceof Graphics2D) {
Dimension dimension = getSize();
Point point = new Point(dimension.width / 2, dimension.height / 2);
int radius = (int)(point.x * 0.84);
graphics.setColor(colorOfCircle);
graphics.drawArc(point.x - radius, point.y - radius,
radius*2-1, radius*2-1,
0, 360);
graphics.setColor(colorOfText);
graphics.setFont(sampleFont);
CircularText((Graphics2D)graphics, sampleTxt, point, radius, -Math.PI/2, 1.0);
}
else {
System.out.println("Some Error Occurred");
}
}
static void CircularText(Graphics2D graphics, String sampleTxt, Point center,
double radius, double length, double height)
{
double circleAngle = length;
Point2D circle = new Point2D.Double(center.x, center.y);
char chArray[] = sampleTxt.toCharArray();
FontMetrics fm = graphics.getFontMetrics();
AffineTransform formx, formy;
formx = AffineTransform.getTranslateInstance(circle.getX(),circle.getY());
for(int i = 0; i < chArray.length; i++) {
double cwid = (double)(getWidth(chArray[i],fm));
if (!(chArray[i] == ' ' || Character.isSpaceChar(chArray[i]))) {
cwid = (double)(fm.charWidth(chArray[i]));
formy = new AffineTransform(formx);
formy.rotate(circleAngle, 0.0, 0.0);
String chstr = new String(chArray, i, 1);
graphics.setTransform(formy);
graphics.drawString(chstr, (float)(-cwid/2), (float)(-radius));
}
if (i < (chArray.length - 1)) {
double adv = cwid/2.0 + fm.getLeading() + getWidth(chArray[i + 1],fm)/2.0;
circleAngle += Math.sin(adv / radius);
}
}
}
static int getWidth(char charText, FontMetrics fontMetrics) {
if (charText == ' ' || Character.isSpaceChar(charText)) {
return fontMetrics.charWidth('n');
}
else {
return fontMetrics.charWidth(charText);
}
}
} <strong> </strong><strong>Output:</strong>

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Java 中的 2D 图形

示例#5

用于文本图形的 2D java。

代码：

import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
public class FontsDemo extends Frame {
/**
*
*/
private static final long <em>serialVersionUID</em> = 1L;
public static void main( String[] argv ) {
FontsDemo myExample = new FontsDemo( "Text Graphics" );
}
public FontsDemo( String title ) {
super( title );
setSize( 450, 180 );
addWindowListener( new WindowAdapter() {
public void windowClosing( WindowEvent we ) {
dispose();
System.<em>exit</em>( 0 );
}
} );
setVisible( true );
}
public void paint( Graphics g ) {
Graphics2D graphics = (Graphics2D) g;
FontRenderContext frc = graphics.getFontRenderContext();
Font font = new Font( "Arial", Font.<em>HANGING_BASELINE</em> | Font.<em>BOLD</em>, 72 );
TextLayout tl = new TextLayout( "eduCBA", font, frc );
Shape myShape = tl.getOutline( AffineTransform.<em>getTranslateInstance</em>( 50, 100 ) );
Paint myPaint = loadTextureResource( "1.gif" );
graphics.setPaint( myPaint );
graphics.fill( myShape );
}
public TexturePaint loadTextureResource( String absfilename ) {
MediaTracker tracker = new MediaTracker( this );
Image imtexture = Toolkit.getDefaultToolkit().getImage( absfilename );
tracker.addImage( imtexture, 0 );
try {
tracker.waitForID( 0 );
int width = imtexture.getWidth( this );
int height = imtexture.getHeight( this );
System.<em>out</em>.println( "width" + width + " height =" + height );
BufferedImage buffImg = new
BufferedImage( width, height, BufferedImage.<em>TYPE_INT_ARGB</em> );
Graphics g = buffImg.getGraphics();
g.drawImage( imtexture, 0, 0, this );
return new TexturePaint( buffImg, new Rectangle2D.Double( 0, 0, width, height ) );
}
catch( Exception e ) {
System.<em>out</em>.println( "Exception on Image-Texture Loading" );
}
return null;
}
}

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输出：

Java 中的 2D 图形