Java How to add String below an image and resizing

I am trying to add a title string below a png image. The problem is that there is no space for the text and I have to add some white space. Im not sure how to do this. This is what I have done so far:

        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"));

回答1:

Why not simply add the spacing you need to the new BufferedImages height?

Here is an example I made:

The real magic happens here:

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;
}

The above method will allow you to pass in text, a reference to the image and the amount of spacing you want to add. It will than draw the string to the image within the specified space. The image is resized before passing it to the above method (drawTextOnImage(..)) via:

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;
}

Test.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;
    }
}

回答2:

To add white space to the bottom of a BufferedImage, you have to create a new BufferedImage and copy the image.

The 30 on the 3rd line is 30 pixels of white space. Substitute any number you wish to get the amount of white space you want.

        BufferedImage image = ImageIO.read(new File("output.png"));
        BufferedImage newImage = new BufferedImage(image.getWidth(), 
            image.getHeight() + 30, BufferedImage.TYPE_INT_ARGB);
        Graphics g1 = image.getGraphics();
        Graphics g2 = newImage.getGraphics();
        g2.setColor(Color.WHITE);
        g2.fillRect(0, 0, newImage.getWidth(), newImage.getHeight());
        g2.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);