形状和填充
最后修改于 2023 年 7 月 17 日
在本部分 Java 2D 教程中，我们将创建一些基本和更高级的形状。我们将使用纯色、渐变和纹理填充形状。
基本形状
首先，我们绘制一些基本的 Java 2D 形状。
com/zetcode/BasicShapes.java
package com.zetcode;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setPaint(new Color(150, 150, 150));
RenderingHints rh = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
rh.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHints(rh);
g2d.fillRect(30, 20, 50, 50);
g2d.fillRect(120, 20, 90, 60);
g2d.fillRoundRect(250, 20, 70, 60, 25, 25);
g2d.fill(new Ellipse2D.Double(10, 100, 80, 100));
g2d.fillArc(120, 130, 110, 100, 5, 150);
g2d.fillOval(270, 130, 50, 50);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class BasicShapesEx extends JFrame {
public BasicShapesEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Basic shapes");
setSize(350, 250);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
BasicShapesEx ex = new BasicShapesEx();
ex.setVisible(true);
}
});
}
}
在此示例中，我们在面板上绘制六个基本形状：正方形、矩形、圆角矩形、椭圆、弧形和圆形。
g2d.setPaint(new Color(150, 150, 150));
形状将以灰色背景绘制。
g2d.fillRect(20, 20, 50, 50); g2d.fillRect(120, 20, 90, 60);
fillRect 方法用于绘制矩形和正方形。前两个参数是形状的 x、y 坐标。最后两个参数是形状的宽度和高度。
g2d.fillRoundRect(250, 20, 70, 60, 25, 25);
在这里，我们创建了一个圆角矩形。最后两个参数是四个角的圆角的水平和垂直直径。
g2d.fill(new Ellipse2D.Double(10, 100, 80, 100));
fill 方法绘制给定形状（椭圆）的内部。
g2d.fillArc(120, 130, 110, 100, 5, 150);
fillArc 方法填充覆盖指定矩形的圆形或椭圆形弧。弧是圆周的一部分。
g2d.fillOval(270, 130, 50, 50);
使用 fillOval 方法绘制圆形。
通用路径
更复杂的形状可以使用 GeneralPath 构建。它表示由直线、二次和三次贝塞尔曲线构成的几何路径。
以下示例使用此类创建星形。
com/zetcode/StarEx.java
package com.zetcode;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.GeneralPath;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
private final double points[][] = {
{ 0, 85 }, { 75, 75 }, { 100, 10 }, { 125, 75 },
{ 200, 85 }, { 150, 125 }, { 160, 190 }, { 100, 150 },
{ 40, 190 }, { 50, 125 }, { 0, 85 }
};
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g2d.setPaint(Color.gray);
g2d.translate(25, 5);
GeneralPath star = new GeneralPath();
star.moveTo(points[0][0], points[0][1]);
for (int k = 1; k < points.length; k++)
star.lineTo(points[k][0], points[k][1]);
star.closePath();
g2d.fill(star);
g2d.dispose();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class StarEx extends JFrame {
public StarEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Star");
setSize(350, 250);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
StarEx ex = new StarEx();
ex.setVisible(true);
}
});
}
}
我们从一系列点创建星形。
private final double points[][] = {
{ 0, 85 }, { 75, 75 }, { 100, 10 }, { 125, 75 },
{ 200, 85 }, { 150, 125 }, { 160, 190 }, { 100, 150 },
{ 40, 190 }, { 50, 125 }, { 0, 85 }
};
这些是星形的坐标。
GeneralPath star = new GeneralPath();
在这里，我们实例化 GeneralPath 类。
star.moveTo(points[0][0], points[0][1]);
我们将 GeneralPath 移动到初始坐标。
for (int k = 1; k < points.length; k++)
star.lineTo(points[k][0], points[k][1]);
在这里，我们连接星形的所有坐标。
star.closePath(); g2d.fill(star);
我们关闭路径并填充星形的内部。
区域
创建复杂形状的另一种方法是组合区域。Area 存储和操作二维空间封闭区域的分辨率无关的描述。它可以被加法、减法、交集和异或运算操作。
com/zetcode/AreasEx.java
package com.zetcode;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
public void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
RenderingHints rh = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
rh.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHints(rh);
g2d.setPaint(Color.gray);
Area a1 = new Area(new Rectangle2D.Double(20, 20, 100, 100));
Area a2 = new Area(new Ellipse2D.Double(50, 50, 100, 100));
a1.subtract(a2);
g2d.fill(a1);
Area a3 = new Area(new Rectangle2D.Double(150, 20, 100, 100));
Area a4 = new Area(new Ellipse2D.Double(150, 20, 100, 100));
a3.subtract(a4);
g2d.fill(a3);
Area a5 = new Area(new Rectangle2D.Double(280, 20, 100, 100));
Area a6 = new Area(new Ellipse2D.Double(320, 40, 100, 100));
a5.add(a6);
g2d.fill(a5);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class AreasEx extends JFrame {
public AreasEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Areas");
setSize(450, 200);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
AreasEx ex = new AreasEx();
ex.setVisible(true);
}
});
}
}
该示例通过操作区域创建了三个不同的形状。
Area a1 = new Area(new Rectangle2D.Double(20, 20, 100, 100)); Area a2 = new Area(new Ellipse2D.Double(50, 50, 100, 100)); a1.subtract(a2); g2d.fill(a1);
此代码通过从矩形中减去椭圆来构造形状。
Area a5 = new Area(new Rectangle2D.Double(280, 20, 100, 100)); Area a6 = new Area(new Ellipse2D.Double(320, 40, 100, 100)); a5.add(a6); g2d.fill(a5);
这些线条通过将矩形添加到椭圆来构造形状。
颜色
Color 类用于处理 Java 2D 中的颜色。要用当前颜色填充矩形，我们使用 fillRect 方法。
com/zetcode/ColoursEx.java
package com.zetcode;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
public void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(new Color(125, 167, 116));
g2d.fillRect(10, 10, 90, 60);
g2d.setColor(new Color(42, 179, 231));
g2d.fillRect(130, 10, 90, 60);
g2d.setColor(new Color(70, 67, 123));
g2d.fillRect(250, 10, 90, 60);
g2d.setColor(new Color(130, 100, 84));
g2d.fillRect(10, 100, 90, 60);
g2d.setColor(new Color(252, 211, 61));
g2d.fillRect(130, 100, 90, 60);
g2d.setColor(new Color(241, 98, 69));
g2d.fillRect(250, 100, 90, 60);
g2d.setColor(new Color(217, 146, 54));
g2d.fillRect(10, 190, 90, 60);
g2d.setColor(new Color(63, 121, 186));
g2d.fillRect(130, 190, 90, 60);
g2d.setColor(new Color(31, 21, 1));
g2d.fillRect(250, 190, 90, 60);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class ColoursEx extends JFrame {
public ColoursEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Colours");
setSize(360, 300);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
ColoursEx ex = new ColoursEx();
ex.setVisible(true);
}
});
}
}
在示例中，我们绘制了九个彩色的矩形。
Graphics2D g2d = (Graphics2D) g;
当我们更改图形上下文的颜色属性时，无需创建 Graphics2D 类的副本或重置该值。
g2d.setColor(new Color(125, 167, 116));
使用 Color 类创建新颜色。构造函数的参数是新颜色的红色、绿色和蓝色部分。setColor 方法将图形上下文的当前颜色设置为指定的颜色值。所有后续图形操作都使用此颜色值。
g2d.fillRect(10, 15, 90, 60);
要用颜色填充矩形，我们使用 fillRect 方法。
渐变
在计算机图形学中，渐变是指从浅到深或从一种颜色到另一种颜色的平滑混合。在 2D 制图程序和绘画程序中，渐变用于创建丰富多彩的背景和特殊效果，以及模拟光影。（answers.com）
com/zetcode/GradientsEx.java
package com.zetcode;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g.create();
GradientPaint gp1 = new GradientPaint(5, 5,
Color.red, 20, 20, Color.black, true);
g2d.setPaint(gp1);
g2d.fillRect(20, 20, 300, 40);
GradientPaint gp2 = new GradientPaint(5, 25,
Color.yellow, 20, 2, Color.black, true);
g2d.setPaint(gp2);
g2d.fillRect(20, 80, 300, 40);
GradientPaint gp3 = new GradientPaint(5, 25,
Color.green, 2, 2, Color.black, true);
g2d.setPaint(gp3);
g2d.fillRect(20, 140, 300, 40);
GradientPaint gp4 = new GradientPaint(25, 25,
Color.blue, 15, 25, Color.black, true);
g2d.setPaint(gp4);
g2d.fillRect(20, 200, 300, 40);
GradientPaint gp5 = new GradientPaint(0, 0,
Color.orange, 0, 20, Color.black, true);
g2d.setPaint(gp5);
g2d.fillRect(20, 260, 300, 40);
g2d.dispose();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class GradientsEx extends JFrame {
public GradientsEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Gradients");
setSize(350, 350);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
GradientsEx ex = new GradientsEx();
ex.setVisible(true);
}
});
}
}
我们的代码示例展示了五个带有渐变的矩形。
GradientPaint gp4 = new GradientPaint(25, 25,
Color.blue, 15, 25, Color.black, true);
要使用渐变，我们使用 GradientPaint 类。通过操作颜色值以及起始点和结束点，我们可以获得不同的结果。
g2d.setPaint(gp4);
通过调用 setPaint 方法激活渐变。
纹理
纹理是应用于形状的位图图像。要在 Java 2D 中使用纹理，我们使用 TexturePaint 类。纹理通过 setPaint 方法应用。
com/zetcode/TexturesEx.java
package com.zetcode;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.TexturePaint;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
class Surface extends JPanel {
private BufferedImage slate;
private BufferedImage java;
private BufferedImage pane;
private TexturePaint slatetp;
private TexturePaint javatp;
private TexturePaint panetp;
public Surface() {
loadImages();
}
private void loadImages() {
try {
slate = ImageIO.read(new File("slate.png"));
java = ImageIO.read(new File("java.png"));
pane = ImageIO.read(new File("pane.png"));
} catch (IOException ex) {
Logger.getLogger(Surface.class.getName()).log(
Level.SEVERE, null, ex);
}
}
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g.create();
slatetp = new TexturePaint(slate, new Rectangle(0, 0, 90, 60));
javatp = new TexturePaint(java, new Rectangle(0, 0, 90, 60));
panetp = new TexturePaint(pane, new Rectangle(0, 0, 90, 60));
g2d.setPaint(slatetp);
g2d.fillRect(10, 15, 90, 60);
g2d.setPaint(javatp);
g2d.fillRect(130, 15, 90, 60);
g2d.setPaint(panetp);
g2d.fillRect(250, 15, 90, 60);
g2d.dispose();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class TexturesEx extends JFrame {
public TexturesEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Textures");
setSize(360, 120);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
TexturesEx ex = new TexturesEx();
ex.setVisible(true);
}
});
}
}
在代码示例中，我们使用三种不同的纹理填充了三个矩形。
slate = ImageIO.read(new File("slate.png"));
使用 ImageIO 类，我们将图像读取到缓冲图像中。
slatetp = new TexturePaint(slate, new Rectangle(0, 0, 90, 60));
我们创建一个缓冲图像的 TexturePaint 类。
g2d.setPaint(slatetp); g2d.fillRect(10, 15, 90, 60);
我们用纹理填充矩形。
在本部分 Java 2D 教程中，我们介绍了 Java 2D 库的一些基本和更高级的形状。