Add a checkbox to WatermarkController to convert the pdf to pdf-image (#1633)

* Add a checkbox to WatermarkController to convert the pdf to pdf-image

* 381: Fix messages_en_GB

---------

Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

src/main/java/stirling/software/SPDF/controller/api/security/RedactController.java

@@ -1,21 +1,14 @@
 package stirling.software.SPDF.controller.api.security;
 
 import java.awt.Color;
-import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.List;
 
 import org.apache.pdfbox.Loader;
 import org.apache.pdfbox.pdmodel.PDDocument;
-import org.apache.pdfbox.pdmodel.PDPage;
 import org.apache.pdfbox.pdmodel.PDPageContentStream;
-import org.apache.pdfbox.pdmodel.PDPageContentStream.AppendMode;
 import org.apache.pdfbox.pdmodel.common.PDRectangle;
-import org.apache.pdfbox.pdmodel.graphics.image.LosslessFactory;
-import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
-import org.apache.pdfbox.rendering.ImageType;
-import org.apache.pdfbox.rendering.PDFRenderer;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.http.ResponseEntity;
@@ -32,6 +25,7 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 import stirling.software.SPDF.model.PDFText;
 import stirling.software.SPDF.model.api.security.RedactPdfRequest;
 import stirling.software.SPDF.pdf.TextFinder;
+import stirling.software.SPDF.utils.PdfUtils;
 import stirling.software.SPDF.utils.WebResponseUtils;
 
 @RestController
@@ -81,22 +75,9 @@ public class RedactController {
         }
 
         if (convertPDFToImage) {
-            PDDocument imageDocument = new PDDocument();
+            PDDocument convertedPdf = PdfUtils.convertPdfToPdfImage(document);
-            PDFRenderer pdfRenderer = new PDFRenderer(document);
-            pdfRenderer.setSubsamplingAllowed(true);
-            for (int page = 0; page < document.getNumberOfPages(); ++page) {
-                BufferedImage bim = pdfRenderer.renderImageWithDPI(page, 300, ImageType.RGB);
-                PDPage newPage = new PDPage(new PDRectangle(bim.getWidth(), bim.getHeight()));
-                imageDocument.addPage(newPage);
-                PDImageXObject pdImage = LosslessFactory.createFromImage(imageDocument, bim);
-                PDPageContentStream contentStream =
-                        new PDPageContentStream(
-                                imageDocument, newPage, AppendMode.APPEND, true, true);
-                contentStream.drawImage(pdImage, 0, 0);
-                contentStream.close();
-            }
             document.close();
-            document = imageDocument;
+            document = convertedPdf;
         }
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();

src/main/java/stirling/software/SPDF/controller/api/security/WatermarkController.java

@@ -36,6 +36,7 @@ import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import stirling.software.SPDF.model.api.security.AddWatermarkRequest;
+import stirling.software.SPDF.utils.PdfUtils;
 import stirling.software.SPDF.utils.WebResponseUtils;
 
 @RestController
@@ -60,6 +61,7 @@ public class WatermarkController {
         float opacity = request.getOpacity();
         int widthSpacer = request.getWidthSpacer();
         int heightSpacer = request.getHeightSpacer();
+        boolean convertPdfToImage = request.isConvertPDFToImage();
 
         // Load the input PDF
         PDDocument document = Loader.loadPDF(pdfFile.getBytes());
@@ -104,6 +106,12 @@ public class WatermarkController {
             contentStream.close();
         }
 
+        if (convertPdfToImage) {
+            PDDocument convertedPdf = PdfUtils.convertPdfToPdfImage(document);
+            document.close();
+            document = convertedPdf;
+        }
+
         return WebResponseUtils.pdfDocToWebResponse(
                 document,
                 Filenames.toSimpleFileName(pdfFile.getOriginalFilename())

src/main/java/stirling/software/SPDF/model/api/security/AddWatermarkRequest.java

@@ -44,4 +44,7 @@ public class AddWatermarkRequest extends PDFFile {
 
     @Schema(description = "The height spacer between watermark elements", example = "50")
     private int heightSpacer;
+
+    @Schema(description = "Convert the redacted PDF to an image", defaultValue = "false")
+    private boolean convertPDFToImage;
 }

src/main/java/stirling/software/SPDF/utils/PdfUtils.java

@@ -341,6 +341,30 @@ public class PdfUtils {
         }
     }
 
+    /**
+     * Converts a given Pdf file to PDF-Image.
+     *
+     * @param document to be converted. Note: the caller is responsible for closing the document
+     * @return converted document to PDF-Image
+     * @throws IOException if conversion fails
+     */
+    public static PDDocument convertPdfToPdfImage(PDDocument document) throws IOException {
+        PDDocument imageDocument = new PDDocument();
+        PDFRenderer pdfRenderer = new PDFRenderer(document);
+        pdfRenderer.setSubsamplingAllowed(true);
+        for (int page = 0; page < document.getNumberOfPages(); ++page) {
+            BufferedImage bim = pdfRenderer.renderImageWithDPI(page, 300, ImageType.RGB);
+            PDPage newPage = new PDPage(new PDRectangle(bim.getWidth(), bim.getHeight()));
+            imageDocument.addPage(newPage);
+            PDImageXObject pdImage = LosslessFactory.createFromImage(imageDocument, bim);
+            PDPageContentStream contentStream =
+                    new PDPageContentStream(imageDocument, newPage, AppendMode.APPEND, true, true);
+            contentStream.drawImage(pdImage, 0, 0);
+            contentStream.close();
+        }
+        return imageDocument;
+    }
+
     private static BufferedImage prepareImageForPdfToImage(
             int maxWidth, int height, String imageType) {
         BufferedImage combined;

src/main/resources/messages_en_GB.properties

@@ -945,6 +945,7 @@ watermark.selectText.6=heightSpacer (Space between each watermark vertically):
 watermark.selectText.7=Opacity (0% - 100%):
 watermark.selectText.8=Watermark Type:
 watermark.selectText.9=Watermark Image:
+watermark.selectText.10=Convert PDF to PDF-Image
 watermark.submit=Add Watermark
 watermark.type.1=Text
 watermark.type.2=Image

src/main/resources/messages_en_US.properties

@@ -945,6 +945,7 @@ watermark.selectText.6=heightSpacer (Space between each watermark vertically):
 watermark.selectText.7=Opacity (0% - 100%):
 watermark.selectText.8=Watermark Type:
 watermark.selectText.9=Watermark Image:
+watermark.selectText.10=Convert PDF to PDF-Image
 watermark.submit=Add Watermark
 watermark.type.1=Text
 watermark.type.2=Image

src/main/resources/templates/security/add-watermark.html

@@ -104,6 +104,10 @@
                   <label for="heightSpacer" th:text="#{watermark.selectText.6}"></label>
                   <input type="text" id="heightSpacer" name="heightSpacer" class="form-control" value="50">
                 </div>
+                <div class="mb-3 form-check">
+                  <input type="checkbox" id="convertPDFToImage" name="convertPDFToImage">
+                  <label for="convertPDFToImage" th:text="#{watermark.selectText.10}"></label>
+                </div>
                 <div class="mb-3 text-center">
                   <input type="submit" id="submitBtn" th:value="#{watermark.submit}" class="btn btn-primary">
                 </div>