Question

我正在尝试渲染一个大胆和上标的java.text.AttributedString。虽然它可以使某些范围为粗体或上标，但渲染似乎无法处理粗体和上标范围。

以下SSCCE显示使用带有HTML文本的JLabel进行渲染可以正常工作。有没有办法在没有JLabel的情况下获得这种行为？

顺便说一下，我查看了创建的AttributedString属性，看起来它们看起来还不错，所以它确实是一个渲染问题。

package funky.chart;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.font.TextAttribute;
import java.text.AttributedString;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;

public class AttributedStringTest
{
    public static void main(String[] args) {
        // prevent using the default UI manager who renders in bold by default for the HTML label
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception ex) {
            System.err.println("Could not set look and feel: " + ex);
        }

        JFrame frame = new JFrame("AttributedString superscript with font");

        frame.getContentPane().add(new JPanel() {
            @Override
            public void paint(Graphics gfx) {
                super.paint(gfx);

                Font bold = gfx.getFont().deriveFont(Font.BOLD);

                // superscript and bold only works fine
                AttributedString test1 = new AttributedString("test superscript and bold");
                test1.addAttribute(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUPER, 5, 16);
                test1.addAttribute(TextAttribute.FONT, bold, 21, 25);

                // both superscript and bold is only rendered as bold
                AttributedString test2 = new AttributedString("test superscript and bold");
                test2.addAttribute(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUPER, 5, 25);
                test2.addAttribute(TextAttribute.FONT, bold, 5, 25);

                gfx.drawString(test1.getIterator(), 5, 20);
                gfx.drawString(test2.getIterator(), 5, 40);
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(200, 70);
            }
        });

        // HTML label works fine
        frame.getContentPane().add(
                new JLabel("<html>test <b>bold</b>, <sup>super</sup> and <b><sup>both</sup></b>"),
                BorderLayout.SOUTH);

        frame.pack();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.setVisible(true);
    }
}

Answer 1

关于完整示例的一些注释：

使用TextAttribute.WEIGHT指定粗体。
使用TextAttribute.SIZE指定字体大小。
使用TextLayout计算首选尺寸，如here所示。
应在event dispatch thread上仅构建和操作Swing GUI对象。
“Swing程序应该覆盖paintComponent()，而不是覆盖paint()。” - Painting in AWT and Swing: The Paint Methods。

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.font.TextAttribute;
import java.text.AttributedString;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

/** @see https://stackoverflow.com/a/31360762/230513 */
public class AttributedStringTest {

    public static void main(String[] args) {
        EventQueue.invokeLater(new AttributedStringTest()::display);
    }

    private void display() {
        JFrame frame = new JFrame("AttributedString superscript with font");
        frame.getContentPane().add(new JPanel() {
            @Override
            public void paintComponent(Graphics g) {
                super.paintComponent(g);

                // superscript and bold only works fine
                AttributedString test1 = new AttributedString("test superscript and bold");
                test1.addAttribute(TextAttribute.SIZE, 28, 0, 25);
                test1.addAttribute(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUPER, 5, 16);
                test1.addAttribute(TextAttribute.WEIGHT, TextAttribute.WEIGHT_BOLD, 21, 25);

                // both superscript and bold is only rendered as bold
                AttributedString test2 = new AttributedString("test superscript and bold");
                test2.addAttribute(TextAttribute.SIZE, 28, 0, 25);
                test2.addAttribute(TextAttribute.SUPERSCRIPT, TextAttribute.SUPERSCRIPT_SUPER, 5, 25);
                test2.addAttribute(TextAttribute.WEIGHT, TextAttribute.WEIGHT_BOLD, 5, 25);

                g.drawString(test1.getIterator(), 5, 35);
                g.drawString(test2.getIterator(), 5, 70);
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 80);
            }
        });

        // HTML label works fine
        frame.getContentPane().add(new JLabel(
            "<html>test <b>bold</b>, <sup>super</sup> and <b><sup>both</sup></b>", JLabel .CENTER),
            BorderLayout.SOUTH);

        frame.pack();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.setVisible(true);
    }
}

Java AttributedString，粗体和上标

1 个答案: