mirror of
https://github.com/Frooodle/Stirling-PDF.git
synced 2026-04-16 23:08:38 +02:00
qr split fixes (#6043)
This commit is contained in:
Anthony Stirling
GitHub
@@ -1,19 +1,22 @@
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package stirling.software.SPDF.controller.api.misc;
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import java.awt.Graphics2D;
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import java.awt.image.BufferedImage;
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import java.awt.image.DataBufferByte;
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import java.awt.image.DataBufferInt;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.nio.file.Files;
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import java.util.ArrayList;
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import java.util.HashSet;
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import java.util.EnumMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Set;
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import java.util.zip.ZipEntry;
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import java.util.zip.ZipOutputStream;
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import org.apache.pdfbox.cos.COSName;
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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.graphics.image.PDImageXObject;
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import org.apache.pdfbox.rendering.PDFRenderer;
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import org.springframework.http.MediaType;
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import org.springframework.http.ResponseEntity;
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@@ -21,6 +24,7 @@ import org.springframework.web.bind.annotation.ModelAttribute;
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import org.springframework.web.multipart.MultipartFile;
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import com.google.zxing.*;
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import com.google.zxing.common.GlobalHistogramBinarizer;
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import com.google.zxing.common.HybridBinarizer;
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import io.github.pixee.security.Filenames;
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@@ -35,7 +39,6 @@ import stirling.software.common.annotations.AutoJobPostMapping;
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import stirling.software.common.annotations.api.MiscApi;
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import stirling.software.common.model.ApplicationProperties;
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import stirling.software.common.service.CustomPDFDocumentFactory;
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import stirling.software.common.util.ApplicationContextProvider;
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import stirling.software.common.util.ExceptionUtils;
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import stirling.software.common.util.GeneralUtils;
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import stirling.software.common.util.TempFile;
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@@ -48,61 +51,219 @@ import stirling.software.common.util.WebResponseUtils;
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public class AutoSplitPdfController {
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private static final Set<String> VALID_QR_CONTENTS =
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new HashSet<>(
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Set.of(
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"https://github.com/Stirling-Tools/Stirling-PDF",
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"https://github.com/Frooodle/Stirling-PDF",
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"https://stirlingpdf.com"));
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Set.of(
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"https://github.com/Stirling-Tools/Stirling-PDF",
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"https://github.com/Frooodle/Stirling-PDF",
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"https://stirlingpdf.com");
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private static final int MAX_IMAGES_FOR_DIRECT_EXTRACTION = 3;
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// 150 DPI is sufficient for QR code detection — higher wastes memory and CPU
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private static final int QR_DETECTION_DPI = 150;
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// Max total pixels before we downscale to avoid OOM on getRGB() allocation
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private static final long MAX_IMAGE_PIXELS = 100_000_000L; // ~10000x10000
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// Number of evenly-spaced pixel samples used for the blank image check
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private static final int BLANK_CHECK_SAMPLES = 20;
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private static final Map<DecodeHintType, Object> DECODE_HINTS;
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static {
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DECODE_HINTS = new EnumMap<>(DecodeHintType.class);
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DECODE_HINTS.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
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DECODE_HINTS.put(DecodeHintType.ALSO_INVERTED, Boolean.TRUE);
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DECODE_HINTS.put(DecodeHintType.POSSIBLE_FORMATS, List.of(BarcodeFormat.QR_CODE));
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}
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private final CustomPDFDocumentFactory pdfDocumentFactory;
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private final TempFileManager tempFileManager;
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private final ApplicationProperties applicationProperties;
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private static String decodeQRCode(BufferedImage bufferedImage) {
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LuminanceSource source;
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if (bufferedImage.getRaster().getDataBuffer() instanceof DataBufferByte dataBufferByte) {
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byte[] pixels = dataBufferByte.getData();
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source =
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new PlanarYUVLuminanceSource(
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pixels,
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bufferedImage.getWidth(),
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bufferedImage.getHeight(),
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0,
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0,
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bufferedImage.getWidth(),
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bufferedImage.getHeight(),
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false);
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} else if (bufferedImage.getRaster().getDataBuffer()
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instanceof DataBufferInt dataBufferInt) {
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int[] pixels = dataBufferInt.getData();
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byte[] newPixels = new byte[pixels.length];
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for (int i = 0; i < pixels.length; i++) {
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newPixels[i] = (byte) (pixels[i] & 0xff);
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}
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source =
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new PlanarYUVLuminanceSource(
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newPixels,
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bufferedImage.getWidth(),
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bufferedImage.getHeight(),
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0,
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0,
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bufferedImage.getWidth(),
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bufferedImage.getHeight(),
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false);
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} else {
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throw new IllegalArgumentException(
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"BufferedImage must have 8-bit gray scale, 24-bit RGB, 32-bit ARGB (packed"
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+ " int), byte gray, or 3-byte/4-byte RGB image data");
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/**
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* Downscale an image if it exceeds the maximum pixel count. Scales uniformly based on the
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* pixel-count ratio so both portrait and landscape images are handled correctly.
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*/
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private static BufferedImage downscaleIfNeeded(BufferedImage image) {
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long totalPixels = (long) image.getWidth() * image.getHeight();
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if (totalPixels <= MAX_IMAGE_PIXELS) {
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return image;
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}
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double scale = Math.sqrt((double) MAX_IMAGE_PIXELS / totalPixels);
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int newWidth = Math.max(1, (int) (image.getWidth() * scale));
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int newHeight = Math.max(1, (int) (image.getHeight() * scale));
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log.debug(
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"Downscaling image from {}x{} to {}x{} for QR detection",
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image.getWidth(),
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image.getHeight(),
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newWidth,
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newHeight);
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BufferedImage scaled = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
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Graphics2D g = scaled.createGraphics();
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g.drawImage(image, 0, 0, newWidth, newHeight, null);
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g.dispose();
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return scaled;
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}
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BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
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/**
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* Quick check whether an image appears to be blank (single solid colour). Samples pixels at
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* evenly-spaced positions — if all samples match the first pixel the image is almost certainly
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* blank (e.g. a masked image that returned solid white).
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*/
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private static boolean isBlankImage(int[] pixels) {
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if (pixels.length == 0) return true;
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int first = pixels[0];
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int step = Math.max(1, pixels.length / BLANK_CHECK_SAMPLES);
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for (int i = step; i < pixels.length; i += step) {
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if (pixels[i] != first) {
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return false;
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}
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}
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return true;
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}
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/**
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* Try to decode a QR code from pre-extracted RGB pixel data using multiple binarization
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* strategies. Returns the decoded text or null.
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*
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* <p>Strategy 1: HybridBinarizer — good for variable brightness (digital PDFs).
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*
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* <p>Strategy 2: GlobalHistogramBinarizer — better for scanned/noisy images with uniform
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* lighting, and for QR codes with embedded logos that confuse the hybrid approach.
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*/
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private static String tryDecodeQR(int[] pixels, int width, int height) {
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RGBLuminanceSource source = new RGBLuminanceSource(width, height, pixels);
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MultiFormatReader reader = new MultiFormatReader();
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// Strategy 1: HybridBinarizer — good for variable brightness (digital PDFs)
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try {
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Result result = new MultiFormatReader().decode(bitmap);
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BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
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Result result = reader.decode(bitmap, DECODE_HINTS);
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log.debug("QR detected via HybridBinarizer: '{}'", result.getText());
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return result.getText();
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} catch (NotFoundException e) {
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return null; // there is no QR code in the image
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// continue
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}
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// Strategy 2: GlobalHistogramBinarizer — better for scanned/noisy images
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try {
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BinaryBitmap bitmap = new BinaryBitmap(new GlobalHistogramBinarizer(source));
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Result result = reader.decode(bitmap, DECODE_HINTS);
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log.debug("QR detected via GlobalHistogramBinarizer: '{}'", result.getText());
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return result.getText();
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} catch (NotFoundException e) {
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return null;
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}
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}
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/**
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* Attempt to decode a QR code from a BufferedImage. Handles downscaling for oversized images
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* and skips blank images early.
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*/
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private static String decodeQRCode(BufferedImage bufferedImage) {
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bufferedImage = downscaleIfNeeded(bufferedImage);
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int width = bufferedImage.getWidth();
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int height = bufferedImage.getHeight();
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int[] pixels = new int[width * height];
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bufferedImage.getRGB(0, 0, width, height, pixels, 0, width);
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// Skip blank images early (e.g. masked images that decode to solid white)
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if (isBlankImage(pixels)) {
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log.debug("Skipping blank {}x{} image", width, height);
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return null;
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}
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return tryDecodeQR(pixels, width, height);
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}
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/** Count the number of images embedded in a page's resources. */
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private static int countPageImages(PDPage page) {
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if (page.getResources() == null || page.getResources().getXObjectNames() == null) {
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return 0;
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}
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int count = 0;
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for (COSName name : page.getResources().getXObjectNames()) {
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if (page.getResources().isImageXObject(name)) {
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count++;
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}
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}
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return count;
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}
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/**
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* Extract images directly from a page's resources and check each for a QR code. Returns the QR
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* code text if found, null otherwise.
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*/
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private static String checkPageImagesDirect(PDPage page) throws IOException {
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if (page.getResources() == null || page.getResources().getXObjectNames() == null) {
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return null;
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}
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for (COSName name : page.getResources().getXObjectNames()) {
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if (!page.getResources().isImageXObject(name)) {
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continue;
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}
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PDImageXObject imageObject = (PDImageXObject) page.getResources().getXObject(name);
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BufferedImage image;
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try {
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image = imageObject.getImage();
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} catch (OutOfMemoryError e) {
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log.warn(
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"Skipping oversized embedded image '{}' ({}x{}) - out of memory",
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name.getName(),
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imageObject.getWidth(),
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imageObject.getHeight());
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continue;
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}
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String result = decodeQRCode(image);
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if (result != null) {
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return result;
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}
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}
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return null;
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}
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/**
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* Render the full page to an image and scan it for a QR code. Tries a low DPI first (fast, low
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* memory) and only retries at the system's maxDPI if detection fails. The first rendered image
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* is released before the retry to allow GC to reclaim it.
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*/
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private String checkPageByRendering(PDFRenderer pdfRenderer, int pageNum) throws IOException {
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log.debug("Rendering page {} at {} DPI for QR detection", pageNum + 1, QR_DETECTION_DPI);
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BufferedImage bim =
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ExceptionUtils.handleOomRendering(
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pageNum + 1,
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QR_DETECTION_DPI,
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() -> pdfRenderer.renderImageWithDPI(pageNum, QR_DETECTION_DPI));
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String result = decodeQRCode(bim);
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bim = null; // allow GC before potential high-DPI retry
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if (result == null) {
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int maxDpi = getSystemMaxDpi();
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if (maxDpi > QR_DETECTION_DPI) {
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log.debug(
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"Retrying page {} at {} DPI (low-DPI detection failed)",
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pageNum + 1,
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maxDpi);
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BufferedImage highRes =
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ExceptionUtils.handleOomRendering(
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pageNum + 1,
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maxDpi,
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() -> pdfRenderer.renderImageWithDPI(pageNum, maxDpi));
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result = decodeQRCode(highRes);
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}
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}
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return result;
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}
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private int getSystemMaxDpi() {
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if (applicationProperties != null && applicationProperties.getSystem() != null) {
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return applicationProperties.getSystem().getMaxDPI();
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}
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return QR_DETECTION_DPI;
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}
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@AutoJobPostMapping(value = "/auto-split-pdf", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
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@@ -111,42 +272,56 @@ public class AutoSplitPdfController {
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summary = "Auto split PDF pages into separate documents",
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description =
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"This endpoint accepts a PDF file, scans each page for a specific QR code, and"
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+ " splits the document at the QR code boundaries. The output is a zip file"
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+ " containing each separate PDF document. Input:PDF Output:ZIP-PDF"
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+ " splits the document at the QR code boundaries. The output is a zip"
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+ " file containing each separate PDF document. Input:PDF Output:ZIP-PDF"
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+ " Type:SISO")
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public ResponseEntity<byte[]> autoSplitPdf(@ModelAttribute AutoSplitPdfRequest request)
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throws IOException {
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MultipartFile file = request.getFileInput();
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boolean duplexMode = Boolean.TRUE.equals(request.getDuplexMode());
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log.info(
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"Auto-split starting: filename='{}', size={} bytes, duplexMode={}",
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file.getOriginalFilename(),
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file.getSize(),
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duplexMode);
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List<PDDocument> splitDocuments = new ArrayList<>();
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try (TempFile outputTempFile = new TempFile(tempFileManager, ".zip");
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PDDocument document = pdfDocumentFactory.load(file.getInputStream())) {
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int totalPages = document.getNumberOfPages();
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log.info("PDF loaded, totalPages={}", totalPages);
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PDFRenderer pdfRenderer = new PDFRenderer(document);
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pdfRenderer.setSubsamplingAllowed(true);
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for (int page = 0; page < document.getNumberOfPages(); ++page) {
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BufferedImage bim;
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for (int page = 0; page < totalPages; ++page) {
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PDPage pdPage = document.getPage(page);
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int imageCount = countPageImages(pdPage);
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// Use global maximum DPI setting, fallback to 300 if not set
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int renderDpi = 150; // Default fallback
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ApplicationProperties properties =
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ApplicationContextProvider.getBean(ApplicationProperties.class);
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if (properties != null && properties.getSystem() != null) {
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renderDpi = properties.getSystem().getMaxDPI();
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String qrResult;
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if (imageCount > 0 && imageCount <= MAX_IMAGES_FOR_DIRECT_EXTRACTION) {
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// Try extracting images directly from the PDF (faster, avoids rendering)
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qrResult = checkPageImagesDirect(pdPage);
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if (qrResult == null) {
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// Fall back to rendering — the image may use masking/compositing
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// that getImage() doesn't resolve, or the QR may be vector-drawn
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qrResult = checkPageByRendering(pdfRenderer, page);
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}
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} else {
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// Too many images or no images — render the full page
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qrResult = checkPageByRendering(pdfRenderer, page);
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}
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final int dpi = renderDpi;
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final int pageNum = page;
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bim =
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ExceptionUtils.handleOomRendering(
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pageNum + 1,
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dpi,
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() -> pdfRenderer.renderImageWithDPI(pageNum, dpi));
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String result = decodeQRCode(bim);
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boolean isValidQrCode = qrResult != null && VALID_QR_CONTENTS.contains(qrResult);
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if (isValidQrCode) {
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log.info(
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"Page {}/{} contains QR divider ('{}')",
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page + 1,
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totalPages,
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qrResult);
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}
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boolean isValidQrCode = VALID_QR_CONTENTS.contains(result);
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log.debug("detected qr code {}, code is vale={}", result, isValidQrCode);
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if (isValidQrCode && page != 0) {
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splitDocuments.add(new PDDocument());
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}
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@@ -159,32 +334,25 @@ public class AutoSplitPdfController {
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splitDocuments.add(firstDocument);
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}
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// If duplexMode is true and current page is a divider, then skip next page
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if (duplexMode && isValidQrCode) {
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page++;
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page++; // skip back of divider page
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}
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}
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// Remove split documents that have no pages
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splitDocuments.removeIf(pdDocument -> pdDocument.getNumberOfPages() == 0);
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log.info("Split complete, {} output documents", splitDocuments.size());
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String filename =
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GeneralUtils.removeExtension(
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Filenames.toSimpleFileName(file.getOriginalFilename()));
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try (ZipOutputStream zipOut =
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new ZipOutputStream(Files.newOutputStream(outputTempFile.getPath()))) {
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// Stream split documents directly into zip — avoids holding all PDFs in memory
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try (OutputStream fileOut = Files.newOutputStream(outputTempFile.getPath());
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ZipOutputStream zipOut = new ZipOutputStream(fileOut)) {
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for (int i = 0; i < splitDocuments.size(); i++) {
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String fileName = filename + "_" + (i + 1) + ".pdf";
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PDDocument splitDocument = splitDocuments.get(i);
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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splitDocument.save(baos);
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byte[] pdf = baos.toByteArray();
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ZipEntry pdfEntry = new ZipEntry(fileName);
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zipOut.putNextEntry(pdfEntry);
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zipOut.write(pdf);
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zipOut.putNextEntry(new ZipEntry(fileName));
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splitDocuments.get(i).save(zipOut);
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zipOut.closeEntry();
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}
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}
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@@ -197,7 +365,6 @@ public class AutoSplitPdfController {
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log.error("Error in auto split", e);
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throw e;
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} finally {
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// Clean up split documents
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for (PDDocument splitDoc : splitDocuments) {
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try {
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splitDoc.close();
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Reference in New Issue
Block a user