16.18.6 渐变方框与文字 Cyclic GradientPaint

 

import java.awt.Color;import java.awt.Font;import java.awt.FontMetrics;import java.awt.GradientPaint;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.geom.Line2D;import java.awt.geom.Point2D;import java.awt.geom.Point2D.Float;import java.awt.geom.Rectangle2D;import javax.swing.JComponent;import javax.swing.JFrame;public class GradientPane extends JComponent{public void paint(Graphics g){Graphics2D g2d = (Graphics2D) g;Point2D.Float p1 = new Point2D.Float(150.f,75.f);//起点坐标Point2D.Float p2 = new Point2D.Float(250.f,75.f);float width = 300;float height = 50;GradientPaint g1 = new GradientPaint(p1,Color.green,p2,Color.black,true);Rectangle2D.Float rect1 = new Rectangle2D.Float(p1.x - 100,p1.y -25,width,height);g2d.setPaint(g1);//它是从150处开始绿色，正好是窗口的x/2:中心g2d.fill(rect1);//画方：从150-100=50处开始,宽300，高50g2d.setPaint(Color.PINK);g2d.draw(rect1);g2d.draw(new Line2D.Float(p1,p2));//p1 - 此线段的起始 Point2D   p2 - 此线段的结束 Point2DFont font = new Font("Dialog", Font.BOLD ,40);//FontMetrics 类定义字体规格对象，该对象封装将在特定屏幕上呈现特定字体的有关信息。FontMetrics fontMetrics = getFontMetrics(font);//metrics:度量、指标GradientPaint g2 = new GradientPaint(150.f,280.f,Color.blue,fontMetrics.stringWidth("Hello"),fontMetrics.getHeight(),Color.red);// 创建一个新 FontMetrics 对象，用于查找该 Font 中关于指定 Font 和特定字符字形的 height 和 width 信息。g2d.setFont(font);g2d.setPaint(g2);g2d.drawString("Hello", 150, 150);}public static void main(String[] args) {JFrame window = new JFrame("Cyclic Gradient Paint");    window.setBounds(30, 30, 300, 300);    window.getContentPane().add(new GradientPane());    window.setVisible(true);}}