fir

.gitignore

@@ -0,0 +1,3 @@
+out/*
+.idea/*
+note.iml

src/top/dreamcenter/note/Main.java

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+package top.dreamcenter.note;
+
+import javax.swing.*;
+import javax.swing.text.BadLocationException;
+import java.awt.*;
+import java.awt.event.KeyAdapter;
+import java.awt.event.KeyEvent;
+import java.net.URL;
+
+public class Main {
+    public static void main(String[] args) {
+        JFrame jf = new JFrame("日记本");
+
+        jf.setSize(800, 1020);
+        jf.setResizable(false);
+        jf.setLocationRelativeTo(null);
+        jf.getContentPane().setLayout(null);
+        jf.setBackground(Color.WHITE);
+        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+
+        // 内容面板穿透
+        JPanel imPanel=(JPanel) jf.getContentPane();
+        imPanel.setOpaque(false);
+
+        // 设置背景图片
+        URL bkPath = Main.class.getClassLoader().getResource("note.png");
+        assert bkPath != null;
+        ImageIcon backgroundImage = new ImageIcon(bkPath);
+        Image image = backgroundImage.getImage();
+        Image newimg = image.getScaledInstance(jf.getWidth() - 50, jf.getHeight(),  java.awt.Image.SCALE_SMOOTH);
+        JLabel backgroundLabel = new JLabel(new ImageIcon(newimg));
+        backgroundLabel.setBounds(0, 0, jf.getWidth() , jf.getHeight());
+
+
+        // 文本行
+        JTextArea textArea = new JTextArea();
+        textArea.setFont(new Font(null, Font.PLAIN, 36));
+        textArea.setOpaque(false); // 透明背景
+        textArea.setLineWrap(true); // 自动换行
+        textArea.setTabSize(2);
+        textArea.setBounds(20, 90, jf.getWidth() - 40, jf.getHeight() - 140);
+
+        int maxRows = 19;
+        textArea.addKeyListener(new KeyAdapter() {
+            @Override
+            public void keyReleased(KeyEvent e) {
+                try {
+                    int len = textArea.getText().length();
+                    Rectangle rec = textArea.modelToView(len);
+                    // 最大行数
+                    int line = rec.y / rec.height + 1;
+
+                    // 超出部分逻辑判断
+                    if (line > maxRows) {
+                        int i = len - 1;
+                        for (; i >= 0; i--) {
+                            Rectangle rec0 = textArea.modelToView(i);
+
+                            int tmpLine = rec0.y / rec0.height + 1;
+                            if (tmpLine <= maxRows){
+                                i++;
+                                break;
+                            }
+                        }
+
+                        System.out.println("超出行数字符串内容：" + textArea.getText(i, len - i));
+                        textArea.setText(textArea.getText(i, len - i));
+                    }
+
+
+                } catch (BadLocationException badLocationException) {
+                    badLocationException.printStackTrace();
+                }
+
+            }
+        });
+
+
+        // 添加组件
+        jf.getLayeredPane().add(backgroundLabel, Integer.valueOf(Integer.MIN_VALUE));
+        jf.getContentPane().add(textArea);
+
+        jf.setVisible(true);
+    }
+}