Java：部分填充圓並放入其中的百分比數

Question

我們怎樣才能部分地填充繪製的圓（或任何其他形狀）（例如從底部到頂部）？

如何將百分比的數字放在這個圓圈內？

這裏有一個預覽，但針對Android環境：Draw a circle partially filled dynamically

Answer 1

畫出輪廓，然後加入裁剪並繪製在它上面填充版本，然後繪製最重要的是百分比的字符串。

import java.text.NumberFormat; 
import java.util.Objects; 

import java.awt.EventQueue; 

import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.Paint; 
import java.awt.FontMetrics; 

import java.awt.Dimension; 
import java.awt.Shape; 
import java.awt.Rectangle; 

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.font.TextLayout; 

import java.awt.geom.AffineTransform; 
import java.awt.geom.Ellipse2D; 

import javax.swing.JOptionPane; 
import javax.swing.JPanel; 
import javax.swing.SwingConstants; 
import javax.swing.SwingUtilities; 
import javax.swing.Timer; 

public class ShapeFiller 
extends JPanel { 
    private static final long serialVersionUID = 1; 

    private final Shape shape; 

    private final Timer fillTimer; 

    private float percentageFilled; 

    private final NumberFormat percentageFormat; 

    private final Rectangle textBounds = new Rectangle(); 
    private final Rectangle iconBounds = new Rectangle(); 

    public ShapeFiller(Shape shape) { 
     this(shape, 250); 
    } 

    public ShapeFiller(Shape shape, 
         int fillDelayMillis) { 
     this.shape = Objects.requireNonNull(shape, "Shape cannot be null"); 
     this.percentageFormat = NumberFormat.getPercentInstance(); 
     this.fillTimer = new Timer(Math.max(50, fillDelayMillis), 
      new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent event) { 
        incrementPercentage(); 
       } 
      }); 

     setFont(getFont().deriveFont(getFont().getSize2D() * 4)); 
    } 

    @Override 
    public Dimension getPreferredSize() { 
     Rectangle bounds = shape.getBounds(); 
     bounds.add(0, 0); 
     return bounds.getSize(); 
    } 

    @Override 
    protected void paintComponent(Graphics graphics) { 
     super.paintComponent(graphics); 

     Graphics2D g = (Graphics2D) graphics; 
     g.draw(shape); 

     // Fill shape 

     Shape originalClip = g.getClip(); 

     Rectangle bounds = shape.getBounds(); 
     int clipHeight = (int) (bounds.height * percentageFilled); 
     g.clip(new Rectangle(0, bounds.y + bounds.height - clipHeight, 
      getWidth(), clipHeight)); 
     g.fill(shape); 

     g.setClip(originalClip); 

     // Draw percentage 

     String text = percentageFormat.format(percentageFilled); 
     TextLayout layout = 
      new TextLayout(text, g.getFont(), g.getFontRenderContext()); 

     FontMetrics metrics = g.getFontMetrics(); 
     iconBounds.setBounds(0, 0, 0, 0); 
     textBounds.setBounds(0, 0, 0, 0); 
     SwingUtilities.layoutCompoundLabel(this, 
      metrics, text, null, 
      SwingConstants.CENTER, SwingConstants.CENTER, 
      SwingConstants.CENTER, SwingConstants.CENTER, 
      bounds, iconBounds, textBounds, 0); 
     int textX = textBounds.x; 
     int textY = textBounds.y + metrics.getAscent(); 

     Paint originalPaint = g.getPaint(); 
     g.setPaint(getBackground()); 
     layout.draw(g, textX, textY); 
     g.setPaint(originalPaint); 

     // Draw percentage outline 

     AffineTransform textPos = 
      AffineTransform.getTranslateInstance(textX, textY); 
     g.draw(layout.getOutline(textPos)); 
    } 

    public void setPercentageDone(float percentage) { 
     if (Float.isNaN(percentage) || Float.isInfinite(percentage)) { 
      throw new IllegalArgumentException("Percentage must be finite"); 
     } 
     percentageFilled = Math.max(0, Math.min(1, percentage)); 
     repaint(); 
    } 

    public void startFilling() { 
     percentageFilled = 0; 
     fillTimer.restart(); 
    } 

    private void incrementPercentage() { 
     setPercentageDone(percentageFilled + 0.01f); 
     if (percentageFilled >= 1) { 
      fillTimer.stop(); 
     } 
    } 

    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       Shape shape = new Ellipse2D.Float(50, 50, 200, 200); 
       ShapeFiller shapeFiller = new ShapeFiller(shape); 
       shapeFiller.startFilling(); 
       JOptionPane.showMessageDialog(null, shapeFiller); 
       System.exit(0); 
      } 
     }); 
    } 
}