package stirling.software.SPDF.controller.api; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Set; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.http.HttpHeaders; import org.springframework.http.MediaType; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.multipart.MultipartFile; import com.itextpdf.kernel.geom.PageSize; import com.itextpdf.kernel.geom.Rectangle; import com.itextpdf.kernel.pdf.PdfDocument; import com.itextpdf.kernel.pdf.PdfPage; import com.itextpdf.kernel.pdf.PdfReader; import com.itextpdf.kernel.pdf.PdfWriter; import com.itextpdf.kernel.pdf.canvas.PdfCanvas; 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.TextRenderInfo; import com.itextpdf.kernel.pdf.canvas.parser.listener.IEventListener; import com.itextpdf.kernel.pdf.xobject.PdfFormXObject; import io.swagger.v3.oas.annotations.Operation; import io.swagger.v3.oas.annotations.Parameter; import io.swagger.v3.oas.annotations.media.Schema; import stirling.software.SPDF.utils.WebResponseUtils; @RestController public class ScalePagesController { private static final Logger logger = LoggerFactory.getLogger(ScalePagesController.class); @PostMapping(value = "/scale-pages", consumes = "multipart/form-data") @Operation(summary = "Change the size of a PDF page/document", description = "This operation takes an input PDF file and the size to scale the pages to in the output PDF file.") public ResponseEntity scalePages( @Parameter(description = "The input PDF file", required = true) @RequestParam("fileInput") MultipartFile file, @Parameter(description = "The scale of pages in the output PDF. Acceptable values are A0-A10, B0-B9, LETTER, TABLOID, LEDGER, LEGAL, EXECUTIVE.", required = true, schema = @Schema(type = "String", allowableValues = { "A0", "A1", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", "A10", "B0", "B1", "B2", "B3", "B4", "B5", "B6", "B7", "B8", "B9", "LETTER", "TABLOID", "LEDGER", "LEGAL", "EXECUTIVE" })) @RequestParam("pageSize") String targetPageSize, @Parameter(description = "The scale of the content on the pages of the output PDF. Acceptable values are floats.", required = true, schema = @Schema(type = "float")) @RequestParam("scaleFactor") float scaleFactor) throws IOException { Map sizeMap = new HashMap<>(); // Add A0 - A10 sizeMap.put("A0", PageSize.A0); sizeMap.put("A1", PageSize.A1); sizeMap.put("A2", PageSize.A2); sizeMap.put("A3", PageSize.A3); sizeMap.put("A4", PageSize.A4); sizeMap.put("A5", PageSize.A5); sizeMap.put("A6", PageSize.A6); sizeMap.put("A7", PageSize.A7); sizeMap.put("A8", PageSize.A8); sizeMap.put("A9", PageSize.A9); sizeMap.put("A10", PageSize.A10); // Add B0 - B9 sizeMap.put("B0", PageSize.B0); sizeMap.put("B1", PageSize.B1); sizeMap.put("B2", PageSize.B2); sizeMap.put("B3", PageSize.B3); sizeMap.put("B4", PageSize.B4); sizeMap.put("B5", PageSize.B5); sizeMap.put("B6", PageSize.B6); sizeMap.put("B7", PageSize.B7); sizeMap.put("B8", PageSize.B8); sizeMap.put("B9", PageSize.B9); // Add other sizes sizeMap.put("LETTER", PageSize.LETTER); sizeMap.put("TABLOID", PageSize.TABLOID); sizeMap.put("LEDGER", PageSize.LEDGER); sizeMap.put("LEGAL", PageSize.LEGAL); sizeMap.put("EXECUTIVE", PageSize.EXECUTIVE); if (!sizeMap.containsKey(targetPageSize)) { throw new IllegalArgumentException("Invalid pageSize. It must be one of the following: A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10"); } PageSize pageSize = sizeMap.get(targetPageSize); byte[] bytes = file.getBytes(); PdfReader reader = new PdfReader(new ByteArrayInputStream(bytes)); PdfDocument pdfDoc = new PdfDocument(reader); ByteArrayOutputStream baos = new ByteArrayOutputStream(); PdfWriter writer = new PdfWriter(baos); PdfDocument outputPdf = new PdfDocument(writer); int totalPages = pdfDoc.getNumberOfPages(); for (int i = 1; i <= totalPages; i++) { PdfPage page = outputPdf.addNewPage(pageSize); PdfCanvas pdfCanvas = new PdfCanvas(page); // Get the page and calculate scaling factors Rectangle rect = pdfDoc.getPage(i).getPageSize(); float scaleWidth = pageSize.getWidth() / rect.getWidth(); float scaleHeight = pageSize.getHeight() / rect.getHeight(); float scale = Math.min(scaleWidth, scaleHeight) * scaleFactor; System.out.println("Scale: " + scale); PdfFormXObject formXObject = pdfDoc.getPage(i).copyAsFormXObject(outputPdf); float x = (pageSize.getWidth() - rect.getWidth() * scale) / 2; // Center Page float y = (pageSize.getHeight() - rect.getHeight() * scale) / 2; // Save the graphics state, apply the transformations, add the object, and then // restore the graphics state pdfCanvas.saveState(); pdfCanvas.concatMatrix(scale, 0, 0, scale, x, y); pdfCanvas.addXObject(formXObject, 0, 0); pdfCanvas.restoreState(); } outputPdf.close(); byte[] pdfContent = baos.toByteArray(); pdfDoc.close(); return WebResponseUtils.bytesToWebResponse(pdfContent, file.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_scaled.pdf"); } @PostMapping(value = "/auto-crop", consumes = "multipart/form-data") public ResponseEntity cropPdf(@RequestParam("fileInput") MultipartFile file) throws IOException { byte[] bytes = file.getBytes(); PdfReader reader = new PdfReader(new ByteArrayInputStream(bytes)); PdfDocument pdfDoc = new PdfDocument(reader); ByteArrayOutputStream baos = new ByteArrayOutputStream(); PdfWriter writer = new PdfWriter(baos); PdfDocument outputPdf = new PdfDocument(writer); int totalPages = pdfDoc.getNumberOfPages(); for (int i = 1; i <= totalPages; i++) { PdfPage page = pdfDoc.getPage(i); Rectangle originalMediaBox = page.getMediaBox(); Rectangle contentBox = determineContentBox(page); // Make sure we don't go outside the original media box. Rectangle intersection = originalMediaBox.getIntersection(contentBox); page.setCropBox(intersection); // Copy page to the new document outputPdf.addPage(page.copyTo(outputPdf)); } outputPdf.close(); byte[] pdfContent = baos.toByteArray(); pdfDoc.close(); return ResponseEntity.ok() .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_cropped.pdf\"") .contentType(MediaType.APPLICATION_PDF) .body(pdfContent); } private Rectangle determineContentBox(PdfPage page) { // Extract the text from the page and find the bounding box. TextBoundingRectangleFinder finder = new TextBoundingRectangleFinder(); PdfCanvasProcessor processor = new PdfCanvasProcessor(finder); processor.processPageContent(page); return finder.getBoundingBox(); } private static class TextBoundingRectangleFinder implements IEventListener { private List allTextBoxes = new ArrayList<>(); public Rectangle getBoundingBox() { // Sort the text boxes based on their vertical position allTextBoxes.sort(Comparator.comparingDouble(Rectangle::getTop)); // Consider a box an outlier if its top is more than 1.5 times the IQR above the third quartile. int q1Index = allTextBoxes.size() / 4; int q3Index = 3 * allTextBoxes.size() / 4; double iqr = allTextBoxes.get(q3Index).getTop() - allTextBoxes.get(q1Index).getTop(); double threshold = allTextBoxes.get(q3Index).getTop() + 1.5 * iqr; // Initialize boundingBox to the first non-outlier box int i = 0; while (i < allTextBoxes.size() && allTextBoxes.get(i).getTop() > threshold) { i++; } if (i == allTextBoxes.size()) { // If all boxes are outliers, just return the first one return allTextBoxes.get(0); } Rectangle boundingBox = allTextBoxes.get(i); // Extend the bounding box to include all non-outlier boxes for (; i < allTextBoxes.size(); i++) { Rectangle textBoundingBox = allTextBoxes.get(i); if (textBoundingBox.getTop() > threshold) { // This box is an outlier, skip it continue; } float left = Math.min(boundingBox.getLeft(), textBoundingBox.getLeft()); float bottom = Math.min(boundingBox.getBottom(), textBoundingBox.getBottom()); float right = Math.max(boundingBox.getRight(), textBoundingBox.getRight()); float top = Math.max(boundingBox.getTop(), textBoundingBox.getTop()); // Add a small padding around the bounding box float padding = 10; boundingBox = new Rectangle(left - padding, bottom - padding, right - left + 2 * padding, top - bottom + 2 * padding); } return boundingBox; } @Override public void eventOccurred(IEventData data, EventType type) { if (type == EventType.RENDER_TEXT) { TextRenderInfo renderInfo = (TextRenderInfo) data; allTextBoxes.add(renderInfo.getBaseline().getBoundingRectangle()); } } @Override public Set getSupportedEvents() { return Collections.singleton(EventType.RENDER_TEXT); } } }