package com.xindao.ocr.swingui.swing.jpanel;
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import org.apache.pdfbox.pdmodel.PDDocument;
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import org.apache.pdfbox.rendering.PDFRenderer;
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import javax.swing.*;
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import java.awt.*;
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import java.awt.event.MouseAdapter;
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import java.awt.event.MouseEvent;
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import java.awt.event.MouseMotionAdapter;
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import java.awt.geom.AffineTransform;
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import java.awt.geom.Rectangle2D;
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import java.awt.image.BufferedImage;
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import java.io.IOException;
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public class PdfPreviewPanel extends JPanel {
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private PDDocument document;
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private int pageNumber;
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private BufferedImage pageImage;
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private Rectangle2D selection = null;
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private Rectangle2D lastSelection = null; // 上次选择的区域
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private Point startDrag = null;
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private float scale = 1.0f;
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private Point translation = new Point(0, 0); // 平移量
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private Point lastDragPoint = null;
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private float pdfWidth;
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private float pdfHeight;
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private boolean isDraggingPage = false; // 是否正在拖拽页面
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private static final Color SELECTION_COLOR = new Color(255, 193, 7, 100); // 半透明黄色
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private static final Color LAST_SELECTION_COLOR = new Color(76, 175, 80, 100); // 半透明绿色，用于标识上次选择的区域
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public PdfPreviewPanel(PDDocument doc, int pageNum, Rectangle2D lastArea) throws IOException {
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this.document = doc;
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this.pageNumber = pageNum;
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this.lastSelection = lastArea;
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// 渲染PDF页面为图片
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PDFRenderer renderer = new PDFRenderer(doc);
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pageImage = renderer.renderImage(pageNumber);
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// 获取PDF页面尺寸
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pdfWidth = pageImage.getWidth();
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pdfHeight = pageImage.getHeight();
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// 如果有上次选择的区域，默认选中
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if (lastSelection != null) {
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this.selection = lastSelection;
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}
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// 添加鼠标监听器处理选择和拖拽
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addMouseListener(new MouseAdapter() {
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@Override
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public void mousePressed(MouseEvent e) {
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// 检查点击位置是否在PDF页面上
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Rectangle2D pageBounds = getPageBounds();
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if (pageBounds.contains(e.getPoint())) {
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// 检查是否点击在选择区域内
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if (selection != null && selection.contains(e.getPoint())) {
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startDrag = e.getPoint();
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isDraggingPage = false;
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} else {
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// 开始新的选择
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startDrag = e.getPoint();
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selection = null;
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isDraggingPage = false;
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}
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} else {
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// 点击在页面外，准备拖拽整个页面
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lastDragPoint = e.getPoint();
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isDraggingPage = true;
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}
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repaint();
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}
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@Override
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public void mouseReleased(MouseEvent e) {
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startDrag = null;
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lastDragPoint = null;
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isDraggingPage = false;
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repaint();
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}
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});
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addMouseMotionListener(new MouseMotionAdapter() {
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@Override
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public void mouseDragged(MouseEvent e) {
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if (isDraggingPage && lastDragPoint != null) {
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// 拖拽整个页面
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int dx = e.getX() - lastDragPoint.x;
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int dy = e.getY() - lastDragPoint.y;
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translation.x += dx;
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translation.y += dy;
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lastDragPoint = e.getPoint();
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repaint();
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} else if (startDrag != null) {
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// 拖拽选择区域
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Point endDrag = e.getPoint();
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selection = createRectangle(startDrag, endDrag);
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repaint();
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}
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}
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});
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// 设置面板首选大小
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setPreferredSize(new Dimension(pageImage.getWidth(), pageImage.getHeight()));
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}
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// 获取PDF页面在面板中的边界
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private Rectangle2D getPageBounds() {
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return new Rectangle2D.Double(
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translation.getX(),
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translation.getY(),
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pageImage.getWidth() * scale,
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pageImage.getHeight() * scale
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);
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}
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private Rectangle2D createRectangle(Point p1, Point p2) {
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int x = Math.min(p1.x, p2.x);
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int y = Math.min(p1.y, p2.y);
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int width = Math.abs(p1.x - p2.x);
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int height = Math.abs(p1.y - p2.y);
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return new Rectangle2D.Double(x, y, width, height);
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2 = (Graphics2D) g;
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g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
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g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
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// 绘制背景
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g2.setColor(new Color(240, 240, 240));
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g2.fillRect(0, 0, getWidth(), getHeight());
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// 绘制PDF页面
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if (pageImage != null) {
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// 保存当前变换
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AffineTransform originalTransform = g2.getTransform();
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// 应用平移和缩放
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g2.translate(translation.x, translation.y);
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g2.scale(scale, scale);
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// 绘制PDF图像
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g2.drawImage(pageImage, 0, 0, null);
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// 绘制上次选择的区域（如果有）
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if (lastSelection != null && (selection == null || !selection.equals(lastSelection))) {
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g2.setColor(LAST_SELECTION_COLOR);
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g2.fill(lastSelection);
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g2.setColor(new Color(76, 175, 80));
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g2.setStroke(new BasicStroke(1));
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g2.draw(lastSelection);
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}
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// 绘制当前选择区域
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if (selection != null) {
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// 转换选择区域坐标到PDF坐标系统
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Rectangle2D pdfSelection = new Rectangle2D.Double(
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selection.getX() - translation.x,
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selection.getY() - translation.y,
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selection.getWidth(),
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selection.getHeight()
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);
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pdfSelection = new Rectangle2D.Double(
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pdfSelection.getX() / scale,
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pdfSelection.getY() / scale,
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pdfSelection.getWidth() / scale,
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pdfSelection.getHeight() / scale
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);
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g2.setColor(SELECTION_COLOR);
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g2.fill(pdfSelection);
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g2.setColor(Color.ORANGE);
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g2.setStroke(new BasicStroke(2));
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g2.draw(pdfSelection);
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}
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// 恢复变换
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g2.setTransform(originalTransform);
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}
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}
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public Rectangle2D getSelection() {
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return selection;
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}
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public float getScale() {
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return scale;
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}
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public Point getTranslation() {
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return translation;
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}
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public float getPdfHeight() {
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return pdfHeight;
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}
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}
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