[RELEASE] iText pdfOCR 4.1.0

Author: iText-CI

pdfocr-api/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>com.itextpdf</groupId>
     <artifactId>pdfocr-root</artifactId>
-    <version>4.0.2</version>
+    <version>4.1.0</version>
   </parent>
 
   <artifactId>pdfocr-api</artifactId>
@@ -76,7 +76,7 @@
               </dependency>
             </dependencies>
             <configuration>
-              <projectName>pdfocr</projectName>
+              <projectName>pdfocr-api</projectName>
               <cSharpTargetFolder>./../../../sharp/pdfocr</cSharpTargetFolder>
               <cSharpSourceCodeDestination>itext/itext.pdfocr.api</cSharpSourceCodeDestination>
               <cSharpTestCodeDestination>itext.tests/itext.pdfocr.api.tests</cSharpTestCodeDestination>

pdfocr-api/src/main/java/com/itextpdf/pdfocr/ImageExtraction.java

@@ -0,0 +1,175 @@
+/*
+    This file is part of the iText (R) project.
+    Copyright (c) 1998-2025 Apryse Group NV
+    Authors: Apryse Software.
+
+    This program is offered under a commercial and under the AGPL license.
+    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.
+
+    AGPL licensing:
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.itextpdf.pdfocr;
+
+import com.itextpdf.commons.utils.FileUtil;
+import com.itextpdf.kernel.geom.AffineTransform;
+import com.itextpdf.kernel.geom.Matrix;
+import com.itextpdf.kernel.geom.Point;
+import com.itextpdf.kernel.geom.Rectangle;
+import com.itextpdf.kernel.pdf.PdfPage;
+import com.itextpdf.kernel.pdf.canvas.parser.EventType;
+import com.itextpdf.kernel.pdf.canvas.parser.PdfCanvasProcessor;
+import com.itextpdf.kernel.pdf.canvas.parser.data.IEventData;
+import com.itextpdf.kernel.pdf.canvas.parser.data.ImageRenderInfo;
+import com.itextpdf.kernel.pdf.canvas.parser.listener.IEventListener;
+import com.itextpdf.kernel.pdf.xobject.PdfImageXObject;
+import com.itextpdf.pdfocr.util.PdfOcrFileUtil;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * Class to extract images on page content stream processing, see {@link PdfCanvasProcessor}.
+ */
+final class ImageExtraction {
+
+    private ImageExtraction() {
+        // Empty constructor to forbid instantiation
+    }
+
+    /**
+     * @return map where the key is an image path and the value is a position on the page
+     */
+    static List<PageImageData> extractImagesFromPdfPage(PdfPage pdfPage) throws IOException {
+        CanvasImageExtractor listener = new CanvasImageExtractor();
+        PdfCanvasProcessor processor = new PdfCanvasProcessor(listener);
+        processor.processPageContent(pdfPage);
+        Map<PdfImageXObject, Rectangle> images = listener.getImages();
+
+        // Now output to temp files
+        List<PageImageData> pageImageData = new ArrayList<>(images.size());
+        for (Map.Entry<PdfImageXObject, Rectangle> image : images.entrySet()) {
+            final String extension = image.getKey().identifyImageFileExtension();
+            final String imageFilePath = PdfOcrFileUtil.getTempFilePath(
+                    "pdfocr_img_" + UUID.randomUUID(), "." + extension);
+            try (OutputStream fos = FileUtil.getFileOutputStream(imageFilePath)) {
+                byte[] imageBytes = image.getKey().getImageBytes();
+                fos.write(imageBytes, 0, imageBytes.length);
+                pageImageData.add(new PageImageData(new File(imageFilePath), image.getKey(), image.getValue()));
+            }
+        }
+
+        return pageImageData;
+    }
+
+    static final class PageImageData {
+        private File file;
+        private PdfImageXObject xObject;
+        private Rectangle pagePosition;
+
+        PageImageData(File file, PdfImageXObject xObject, Rectangle pagePosition) {
+            this.file = file;
+            this.xObject = xObject;
+            this.pagePosition = pagePosition;
+        }
+
+        File getPath() {
+            return file;
+        }
+
+        PdfImageXObject getXObject() {
+            return xObject;
+        }
+
+        Rectangle getPagePosition() {
+            return pagePosition;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash((Object) file, xObject, pagePosition);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            PageImageData that = (PageImageData) o;
+            return file == that.file && xObject == that.xObject && pagePosition == that.pagePosition;
+        }
+    }
+
+    // Consider moving to kernel if reused anywhere else
+    private static final class CanvasImageExtractor implements IEventListener {
+        // Image xobject - position on a page
+        private final Map<PdfImageXObject, Rectangle> images = new LinkedHashMap<>();
+
+        CanvasImageExtractor() {
+            // Empty constructor
+        }
+
+        public void eventOccurred(IEventData data, EventType type) {
+            if (type == EventType.RENDER_IMAGE) {
+                ImageRenderInfo renderInfo = (ImageRenderInfo) data;
+                final Matrix imageCtm = renderInfo.getImageCtm();
+                final Rectangle bbox = calcImageRect(imageCtm);
+                images.put(renderInfo.getImage(), bbox);
+            }
+        }
+
+        @Override
+        public Set<EventType> getSupportedEvents() {
+            return new HashSet<>(Collections.singletonList(EventType.RENDER_IMAGE));
+        }
+
+        Map<PdfImageXObject, Rectangle> getImages() {
+            return images;
+        }
+
+        private Rectangle calcImageRect(Matrix ctm) {
+            Point[] points = transformPoints(ctm,
+                    new Point(0, 0), new Point(0, 1),
+                    new Point(1, 0), new Point(1, 1));
+
+            return Rectangle.calculateBBox(Arrays.asList(points));
+        }
+
+        private Point[] transformPoints(Matrix transformationMatrix, Point... points) {
+            AffineTransform t = new AffineTransform(transformationMatrix.get(Matrix.I11),
+                    transformationMatrix.get(Matrix.I12),
+                    transformationMatrix.get(Matrix.I21), transformationMatrix.get(Matrix.I22),
+                    transformationMatrix.get(Matrix.I31), transformationMatrix.get(Matrix.I32));
+            Point[] transformed = new Point[points.length];
+            t.transform(points, 0, transformed, 0, points.length);
+
+            return transformed;
+        }
+    }
+}