我正在尝试使用 Graphics 2D 用 java 制作一个程序，该程序在 3 条边和 8 条边之间绘制多边形，并且我可以使用 slider 调整其大小，但我不知道如何使用 slider 均匀地更改其大小。
这是我绘制的五边形的示例
if (sides == 5){
g.drawLine(110+x,135-y, 10+x,205-y);
g.drawLine(10+x,205-y, 48+x, 320-y);
g.drawLine(48+x,320-y, 170+x,320-y);
g.drawLine(170+x,320-y, 205+x,205-y);
g.drawLine(205+x,205-y, 110+x,135-y);
}
现在我想均匀地改变它的大小。 (我可以在 X 轴和 Y 轴上移动多边形)。
提前致谢。
最佳答案
你可以...
使用 AffineTransformation缩放图形上下文
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
TestPane tp = new TestPane();
JSlider slider = new JSlider(10, 200);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
tp.setScale(slider.getValue());
}
});
slider.setValue(100);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(tp);
frame.add(slider, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private int scale = 100;
public TestPane() {
}
@Override
public Dimension getPreferredSize() {
return new Dimension(250, 350);
}
public void setScale(int value) {
if (value != scale) {
int old = scale;
this.scale = value;
firePropertyChange("scale", old, scale);
repaint();
}
}
public int getScale() {
return scale;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
double scaleValue = getScale() / 100d;
System.out.println(scaleValue);
AffineTransform at = AffineTransform.getScaleInstance(scaleValue, scaleValue);
g2d.setTransform(at);
int x = 10;
int y = 10;
g2d.drawLine(110 + x, 135 - y, 10 + x, 205 - y);
g2d.drawLine(10 + x, 205 - y, 48 + x, 320 - y);
g2d.drawLine(48 + x, 320 - y, 170 + x, 320 - y);
g2d.drawLine(170 + x, 320 - y, 205 + x, 205 - y);
g2d.drawLine(205 + x, 205 - y, 110 + x, 135 - y);
g2d.dispose();
}
}
}
这将同时缩放大小和位置，这可能并不理想......
你可以...
改用 2D 图形形状 API。这将允许您独立定义形状并根据需要简单地绘制它。这样做的好处是可以更好地控制变换，变换尺度而不变换位置
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
TestPane tp = new TestPane();
JSlider slider = new JSlider(10, 200);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
tp.setScale(slider.getValue());
}
});
slider.setValue(100);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(tp);
frame.add(slider, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private int scale = 100;
private PentegonShape pentegonShape;
public TestPane() {
pentegonShape = new PentegonShape(100, 100);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(250, 350);
}
public void setScale(int value) {
if (value != scale) {
int old = scale;
this.scale = value;
firePropertyChange("scale", old, scale);
repaint();
}
}
public int getScale() {
return scale;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int x = 10;
int y = 10;
double scaleValue = getScale() / 100d;
Shape shape = AffineTransform.getScaleInstance(scaleValue, scaleValue).createTransformedShape(pentegonShape);
g2d.setTransform(AffineTransform.getTranslateInstance(x, y));
g2d.draw(shape);
g2d.dispose();
}
}
public class PentegonShape extends Path2D.Double {
public PentegonShape(double width, double height) {
moveTo(width / 2, 0);
lineTo(width, height / 3d);
lineTo((width / 5d) * 4, height);
lineTo((width / 5d), height);
lineTo(0, height / 3d);
closePath();
}
}
}
关于java - 如何使用 slider 更改 Java Graphics2D 中制作的图形的大小？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29067700/