Java 如何在图像下方添加字符串并调整其大小？

Question

我正在尝试在 png 图像下方添加标题字符串。问题是文本没有空间，我必须添加一些空白。我不知道该怎么做。这是我到目前为止所做的:

        BufferedImage image = ImageIO.read(new File("output.png"));
        Graphics g = image.getGraphics();
        g.setFont(g.getFont().deriveFont(30f));
        g.setColor(Color.BLACK);
        g.drawString("Hello World!", 100, 350);
        g.dispose();
        ImageIO.write(image, "png", new File("test.png"));

Answer 1

为什么不简单地将您需要的间距添加到新的 BufferedImage 高度？

这是我做的一个例子:

真正的魔法发生在这里:

private BufferedImage drawTextOnImage(String text, BufferedImage image, int space) {
    BufferedImage bi = new BufferedImage(image.getWidth(), image.getHeight() + space, BufferedImage.TRANSLUCENT);
    Graphics2D g2d = (Graphics2D) bi.createGraphics();
    g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
    g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
    g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON));

    g2d.drawImage(image, 0, 0, null);

    g2d.setColor(Color.BLACK);
    g2d.setFont(new Font("Calibri", Font.BOLD, 20));
    FontMetrics fm = g2d.getFontMetrics();
    int textWidth = fm.stringWidth(text);

    //center text at bottom of image in the new space
    g2d.drawString(text, (bi.getWidth() / 2) - textWidth / 2, bi.getHeight());

    g2d.dispose();
    return bi;
}

上述方法将允许您传入文本、对图像的引用以及您要添加的间距量。它会将字符串绘制到指定空间内的图像中。 在通过以下方式将图像传递给上述方法 (drawTextOnImage(..)) 之前调整图像大小:

public static BufferedImage resize(BufferedImage image, int width, int height) {
    BufferedImage bi = new BufferedImage(width, height, BufferedImage.TRANSLUCENT);
    Graphics2D g2d = (Graphics2D) bi.createGraphics();
    g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
    g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
    g2d.drawImage(image, 0, 0, width, height, null);
    g2d.dispose();
    return bi;
}

测试.java:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test {

    public Test() {
        createAndShowGui();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }

    private void createAndShowGui() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        BufferedImage bi = null;
        try {
            bi = ImageIO.read(new URL("http://cs.anu.edu.au/student/comp6700/icons/DukeWithHelmet.png"));
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        BufferedImage resizedImage = resize(bi, 200, 200);

        final BufferedImage textRenderedImage = drawTextOnImage("Hello", resizedImage, 15);

        JPanel p = new JPanel() {
            @Override
            protected void paintComponent(Graphics grphcs) {
                super.paintComponent(grphcs);
                Graphics2D g2d = (Graphics2D) grphcs;
                g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
                g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
                g2d.drawImage(textRenderedImage, 0, 0, null);
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(textRenderedImage.getWidth(), textRenderedImage.getHeight());
            }
        };

        frame.add(p);
        frame.pack();
        frame.setVisible(true);
    }

    private BufferedImage drawTextOnImage(String text, BufferedImage image, int space) {
        BufferedImage bi = new BufferedImage(image.getWidth(), image.getHeight() + space, BufferedImage.TRANSLUCENT);
        Graphics2D g2d = (Graphics2D) bi.createGraphics();
        g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
        g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
        g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON));

        g2d.drawImage(image, 0, 0, null);

        g2d.setColor(Color.BLACK);
        g2d.setFont(new Font("Calibri", Font.BOLD, 20));
        FontMetrics fm = g2d.getFontMetrics();
        int textWidth = fm.stringWidth(text);

        //center text at bottom of image in the new space
        g2d.drawString(text, (bi.getWidth() / 2) - textWidth / 2, bi.getHeight());

        g2d.dispose();
        return bi;
    }

    public static BufferedImage resize(BufferedImage image, int width, int height) {
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TRANSLUCENT);
        Graphics2D g2d = (Graphics2D) bi.createGraphics();
        g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
        g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
        g2d.drawImage(image, 0, 0, width, height, null);
        g2d.dispose();
        return bi;
    }
}