Java Graphic2D自动文本定位生成图像
生成图像时，如何在图像内自动定位文本？例如，我使用此方法生成.png图像：Java Graphic2D自动文本定位生成图像,java,graphics,awt,graphics2d,Java,Graphics,Awt,Graphics2d,生成图像时，如何在图像内自动定位文本？例如，我使用此方法生成.png图像： public static void generatePNG(String message){ try { int width = 400, height = 400; // TYPE_INT_ARGB specifies the image format: 8-bit RGBA packed // into integer pixe
public static void generatePNG(String message){
try {
int width = 400, height = 400;
// TYPE_INT_ARGB specifies the image format: 8-bit RGBA packed
// into integer pixels
BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D ig2 = bi.createGraphics();
Font font = new Font("TimesRoman", Font.BOLD, 15);
ig2.setFont(font);
FontMetrics fontMetrics = ig2.getFontMetrics();
int stringWidth = fontMetrics.stringWidth(message);
int stringHeight = fontMetrics.getAscent();
ig2.setPaint(Color.black);
ig2.drawString(message, (width - stringWidth) / 2, height / 2 + stringHeight / 4);
ImageIO.write(bi, "PNG", new File("myimg.png"));
} catch (IOException ie) {
ie.printStackTrace();
}
}
StringBuilderSystem.lineSeparator（）FontMetricsdrawStringJTextAreacreateTextImageJTextAreacreateHtmlImage<html>
This is <u>underlined</u> <br>
or in <i>italics</i>
</html>
我设法使这个解决方案工作，但由于某种原因，我无法更改字体大小。我不在乎我在createTextImage的字体中为“大小”输入了什么数字，但它不会改变任何东西。我用它直接打印到打印机，打印输出总是一样的。我可以在gui中看到，它发生了变化。@user3029612我不确定我是否正确理解了这一点。您正在更改字体大小（例如，从示例中的
1525PNGimport java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.image.BufferedImage;
import javax.swing.BorderFactory;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class GenerateTextImage {
public static void main(String[] args) {
String text = "This is a text" + "\n"
+ "with one line that is muuuuuuuuuuuuuuuuch longer than the others" + "\n"
+ "and some empty lines" + "\n"
+ "\n"
+ "\n"
+ "as a test.";
SwingUtilities.invokeLater(() -> createAndShowGui(text));
}
private static void createAndShowGui(String initialText) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().setLayout(new BorderLayout());
JPanel controlPanel = new JPanel();
JCheckBox htmlCheckBox = new JCheckBox("HTML", false);
controlPanel.add(htmlCheckBox);
f.getContentPane().add(controlPanel, BorderLayout.NORTH);
JPanel mainPanel = new JPanel(new GridLayout(1, 2));
f.getContentPane().add(mainPanel, BorderLayout.CENTER);
JTextArea inputTextArea = new JTextArea();
JScrollPane sp0 = new JScrollPane(inputTextArea);
sp0.setBorder(BorderFactory.createTitledBorder("Input:"));
mainPanel.add(sp0);
ImagePanel imagePanel = new ImagePanel();
JScrollPane sp1 = new JScrollPane(imagePanel);
sp1.setBorder(BorderFactory.createTitledBorder("Image:"));
mainPanel.add(sp1);
Runnable updateImage = () -> {
if (!htmlCheckBox.isSelected()) {
String text = inputTextArea.getText();
BufferedImage image = createTextImage(text);
imagePanel.setImage(image);
} else {
String text = inputTextArea.getText();
BufferedImage image = createHtmlImage(text);
imagePanel.setImage(image);
}
};
inputTextArea.getDocument().addDocumentListener(new DocumentListener() {
public void changedUpdate(DocumentEvent e) {
updateImage();
}
public void insertUpdate(DocumentEvent e) {
updateImage();
}
public void removeUpdate(DocumentEvent e) {
updateImage();
}
private void updateImage() {
updateImage.run();
}
});
htmlCheckBox.addChangeListener(e -> {
updateImage.run();
});
inputTextArea.setText(initialText);
f.setSize(1200, 600);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static BufferedImage createTextImage(String text) {
return createTextImage(text, -1, new Font("TimesRoman", Font.BOLD, 15), Color.BLACK, Color.WHITE);
}
/**
* Creates an image with the given text, using the given font and foreground- and background color.<br>
* <br>
* If the given width is not positive, then the width of the image will be computed
* to show the longest line that appears in the text. If the given width is positive,
* then the lines of the given text will be wrapped (at word boundaries) if possible,
* so that the whole text can be displayed.
*
* @param text The text
* @param width The image width
* @param font The font
* @param foreground The foreground color
* @param background The background color
* @return The image
*/
private static BufferedImage createTextImage(String text, int width, Font font, Color foreground, Color background) {
JTextArea textArea = new JTextArea(text);
textArea.setFont(font);
textArea.setForeground(foreground);
textArea.setBackground(background);
if (width > 0)
{
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
textArea.setSize(new Dimension(width, Short.MAX_VALUE));
}
Dimension size = textArea.getPreferredSize();
int w = Math.max(1, size.width);
if (width > 0)
{
w = width;
}
int h = Math.max(1, size.height);
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = image.createGraphics();
SwingUtilities.paintComponent(g, textArea, new JPanel(), 0, 0, w, h);
g.dispose();
return image;
}
private static BufferedImage createHtmlImage(String text) {
return createHtmlImage(text, new Font("TimesRoman", Font.BOLD, 15), Color.BLACK, Color.WHITE);
}
/**
* Creates an image with the given HTML string, using the given font and foreground- and background color.<br>
*
* @param html The HTML string
* @param font The font
* @param foreground The foreground color
* @param background The background color
* @return The image
*/
private static BufferedImage createHtmlImage(String html, Font font, Color foreground, Color background) {
JLabel label = new JLabel(html);
label.setOpaque(true);
label.setFont(font);
label.setForeground(foreground);
label.setBackground(background);
Dimension size = label.getPreferredSize();
int w = Math.max(1, size.width);
int h = Math.max(1, size.height);
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = image.createGraphics();
SwingUtilities.paintComponent(g, label, new JPanel(), 0, 0, w, h);
g.dispose();
return image;
}
static class ImagePanel extends JPanel {
private static final long serialVersionUID = 1L;
private BufferedImage image;
public void setImage(BufferedImage image) {
this.image = image;
repaint();
}
@Override
public Dimension getPreferredSize() {
if (image == null || super.isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(image.getWidth(), image.getHeight());
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
g.drawImage(image, 0, 0, null);
}
}
}
}
private static BufferedImage createTextImage(String text, int width, Font font, Color foreground, Color background) {
JTextPane textPane = new JTextPane();
textPane.setText(text);
// See https://stackoverflow.com/a/3213361/3182664
StyledDocument doc = textPane.getStyledDocument();
SimpleAttributeSet center = new SimpleAttributeSet();
StyleConstants.setAlignment(center, StyleConstants.ALIGN_CENTER);
doc.setParagraphAttributes(0, doc.getLength(), center, false);
textPane.setFont(font);
textPane.setForeground(foreground);
textPane.setBackground(background);
if (width > 0)
{
//textPane.setLineWrap(true);
//textPane.setWrapStyleWord(true);
textPane.setSize(new Dimension(width, Short.MAX_VALUE));
}
Dimension size = textPane.getPreferredSize();
int w = Math.max(1, size.width);
if (width > 0)
{
w = width;
}
int h = Math.max(1, size.height);
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = image.createGraphics();
SwingUtilities.paintComponent(g, textPane, new JPanel(), 0, 0, w, h);
g.dispose();
return image;
}