package jnpf.fileStorage.dms;
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import jnpf.dmsEntity.preview.model.DmsWatermarkSnapshot;
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import jnpf.exception.DataException;
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import lombok.RequiredArgsConstructor;
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import org.apache.pdfbox.Loader;
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import org.apache.pdfbox.pdmodel.PDDocument;
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import org.apache.pdfbox.pdmodel.PDPage;
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import org.apache.pdfbox.pdmodel.PDPageContentStream;
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import org.apache.pdfbox.pdmodel.common.PDRectangle;
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import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
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import org.apache.pdfbox.util.Matrix;
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import org.springframework.beans.BeanUtils;
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import org.springframework.stereotype.Service;
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import java.io.ByteArrayOutputStream;
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import java.util.ArrayList;
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import java.util.List;
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@Service
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@RequiredArgsConstructor
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public class DmsPdfWatermarkService {
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private static final double POINTS_PER_MM = 72D / 25.4D;
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private static final int MAX_PAGES = 1000;
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private static final int MAX_OUTPUT_BYTES = 200 * 1024 * 1024;
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private final DmsDocxWatermarkService rasterizer;
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public byte[] apply(byte[] source, List<DmsWatermarkSnapshot> watermarks) {
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if (watermarks == null || watermarks.isEmpty()) return source;
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if (source == null || source.length == 0) throw new DataException("PDF 内容为空，不能生成水印");
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try (PDDocument document = Loader.loadPDF(source);
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ByteArrayOutputStream output = new ByteArrayOutputStream()) {
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int totalPages = document.getNumberOfPages();
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if (totalPages < 1 || totalPages > MAX_PAGES) {
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throw new DataException("PDF 页数超出动态水印处理范围（1-1000 页）");
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}
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for (DmsWatermarkSnapshot watermark : watermarks) {
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if (watermark == null) throw new DataException("PDF 水印配置无效");
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if (watermark.getRenderPages() != null && watermark.getRenderPages().stream()
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.anyMatch(page -> page == null || page < 1 || page > totalPages)) {
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throw new DataException("PDF 水印指定页码超出文件页数");
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}
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}
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for (int pageIndex = 0; pageIndex < totalPages; pageIndex++) {
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int pageNumber = pageIndex + 1;
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List<DmsWatermarkSnapshot> selected = forPage(watermarks, pageNumber, totalPages);
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if (selected.isEmpty()) continue;
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PDPage page = document.getPage(pageIndex);
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PDRectangle box = page.getCropBox();
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if (box == null || box.getWidth() <= 0 || box.getHeight() <= 0) {
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throw new DataException("PDF 页面尺寸无效，不能生成水印");
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}
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int rotation = Math.floorMod(page.getRotation(), 360);
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boolean quarterTurn = rotation == 90 || rotation == 270;
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float visualWidth = quarterTurn ? box.getHeight() : box.getWidth();
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float visualHeight = quarterTurn ? box.getWidth() : box.getHeight();
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byte[] overlay = rasterizer.renderPdfOverlay(visualWidth / POINTS_PER_MM,
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visualHeight / POINTS_PER_MM, selected);
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PDImageXObject image = PDImageXObject.createFromByteArray(document, overlay,
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"dms-watermark-page-" + pageNumber);
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try (PDPageContentStream stream = new PDPageContentStream(document, page,
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PDPageContentStream.AppendMode.APPEND, true, true)) {
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stream.transform(pageTransform(box, rotation));
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stream.drawImage(image, 0, 0, visualWidth, visualHeight);
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}
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}
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document.save(output);
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if (output.size() > MAX_OUTPUT_BYTES) {
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throw new DataException("PDF 水印输出超过处理上限（200 MB）");
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}
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return output.toByteArray();
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} catch (DataException exception) {
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throw exception;
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} catch (Exception exception) {
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throw new DataException("生成 PDF 水印失败：" + exception.getMessage());
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}
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}
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private Matrix pageTransform(PDRectangle box, int rotation) {
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// PDF /Rotate changes the displayed page, while CropBox keeps its unrotated dimensions.
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float x = box.getLowerLeftX();
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float y = box.getLowerLeftY();
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float width = box.getWidth();
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float height = box.getHeight();
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switch (rotation) {
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case 0: return new Matrix(1, 0, 0, 1, x, y);
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case 90: return new Matrix(0, 1, -1, 0, x + width, y);
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case 180: return new Matrix(-1, 0, 0, -1, x + width, y + height);
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case 270: return new Matrix(0, -1, 1, 0, x, y + height);
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default: throw new DataException("PDF 页面旋转角度无效");
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}
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}
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private List<DmsWatermarkSnapshot> forPage(List<DmsWatermarkSnapshot> watermarks,
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int pageNumber, int totalPages) {
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List<DmsWatermarkSnapshot> selected = new ArrayList<>();
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for (DmsWatermarkSnapshot watermark : watermarks) {
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if (watermark.getRenderPages() != null
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&& !watermark.getRenderPages().contains(pageNumber)) continue;
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DmsWatermarkSnapshot copy = new DmsWatermarkSnapshot();
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BeanUtils.copyProperties(watermark, copy);
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if ("TEXT".equalsIgnoreCase(copy.getWatermarkType()) && copy.getContent() != null) {
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copy.setContent(copy.getContent().replace("{/CurrPage}", String.valueOf(pageNumber))
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.replace("{/TotalPage}", String.valueOf(totalPages)));
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}
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selected.add(copy);
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}
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return selected;
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}
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}
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