Mirrors/Stirling-PDF
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Remove shitty ai comments :)

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Anthony Stirling 2025-03-20 08:33:12 +00:00
parent 8be11cb3d9
commit f1866eb528
1 changed files with 39 additions and 48 deletions
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87
src/main/java/stirling/software/SPDF/controller/api/misc/CompressController.java
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@ -90,7 +90,7 @@ public class CompressController {
COSName imageName; // Name of the image within the form
}
// Image compression statistics for reporting
// Tracks compression stats for reporting
private static class CompressionStats {
int totalImages = 0;
int nestedImages = 0;
@ -114,7 +114,7 @@ public class CompressController {
GeneralUtils.formatBytes(originalFileSize));
try (PDDocument doc = pdfDocumentFactory.load(pdfFile)) {
// Step 1: Find all unique images in the document
// Find all unique images in the document
Map<String, List<ImageReference>> uniqueImages = findImages(doc);
// Get statistics
@ -122,12 +122,12 @@ public class CompressController {
stats.uniqueImagesCount = uniqueImages.size();
calculateImageStats(uniqueImages, stats);
// Step 2: Create compressed versions of unique images
// Create compressed versions of unique images
Map<String, PDImageXObject> compressedVersions =
createCompressedImages(
doc, uniqueImages, scaleFactor, jpegQuality, convertToGrayscale, stats);
// Step 3: Replace all instances with compressed versions
// Replace all instances with compressed versions
replaceImages(doc, uniqueImages, compressedVersions, stats);
// Log compression statistics
@ -137,7 +137,6 @@ public class CompressController {
compressedVersions.clear();
uniqueImages.clear();
// Save the document
log.info("Saving compressed PDF to {}", newCompressedPDF.toString());
doc.save(newCompressedPDF.toString());
@ -153,7 +152,7 @@ public class CompressController {
}
}
/** Find all images in the document, both direct and nested within forms. */
// Find all images in the document, both direct and nested within forms
private Map<String, List<ImageReference>> findImages(PDDocument doc) throws IOException {
Map<String, List<ImageReference>> uniqueImages = new HashMap<>();
@ -167,7 +166,7 @@ public class CompressController {
for (COSName name : res.getXObjectNames()) {
PDXObject xobj = res.getXObject(name);
// Process direct image
// Direct image
if (isImage(xobj)) {
addDirectImage(pageNum, name, (PDImageXObject) xobj, uniqueImages);
log.info(
@ -177,7 +176,7 @@ public class CompressController {
((PDImageXObject) xobj).getWidth(),
((PDImageXObject) xobj).getHeight());
}
// Process form XObject that may contain nested images
// Form XObject that may contain nested images
else if (isForm(xobj)) {
checkFormForImages(pageNum, name, (PDFormXObject) xobj, uniqueImages);
}
@ -211,7 +210,7 @@ public class CompressController {
return ref;
}
/** Check a form XObject for nested images. */
// Look for images inside form XObjects
private void checkFormForImages(
int pageNum,
COSName formName,
@ -255,7 +254,7 @@ public class CompressController {
}
}
/** Calculate statistics about the images found in the document. */
// Count total images and nested images
private void calculateImageStats(
Map<String, List<ImageReference>> uniqueImages, CompressionStats stats) {
for (List<ImageReference> references : uniqueImages.values()) {
@ -268,7 +267,7 @@ public class CompressController {
}
}
/** Create compressed versions of all unique images. */
// Create compressed versions of all unique images
private Map<String, PDImageXObject> createCompressedImages(
PDDocument doc,
Map<String, List<ImageReference>> uniqueImages,
@ -330,7 +329,7 @@ public class CompressController {
return compressedVersions;
}
/** Get the original image from an image reference. */
// Get original image from a reference
private PDImageXObject getOriginalImage(PDDocument doc, ImageReference ref) throws IOException {
if (ref instanceof NestedImageReference) {
// Get the nested image from within a form XObject
@ -352,7 +351,7 @@ public class CompressController {
}
}
/** Process an individual image and return a compressed version if beneficial. */
// Try to compress an image if it makes sense
private PDImageXObject compressImage(
PDDocument doc,
PDImageXObject originalImage,
@ -384,7 +383,7 @@ public class CompressController {
return null;
}
/** Replace all instances of original images with their compressed versions. */
// Replace all instances of original images with their compressed versions
private void replaceImages(
PDDocument doc,
Map<String, List<ImageReference>> uniqueImages,
@ -407,7 +406,7 @@ public class CompressController {
}
}
/** Replace a specific image reference with a compressed version. */
// Replace a specific image reference with a compressed version
private void replaceImageReference(
PDDocument doc, ImageReference ref, PDImageXObject compressedImage) throws IOException {
if (ref instanceof NestedImageReference) {
@ -438,7 +437,7 @@ public class CompressController {
}
}
/** Log compression statistics. */
// Log final stats about the compression
private void logCompressionStats(CompressionStats stats, long originalFileSize) {
// Calculate image reduction percentage
double overallImageReduction =
@ -474,10 +473,7 @@ public class CompressController {
return grayImage;
}
/**
* Processes and compresses an image if beneficial. Returns the processed image if compression
* is worthwhile, null otherwise.
*/
// Resize and optionally convert to grayscale
private BufferedImage processAndCompressImage(
PDImageXObject image, double scaleFactor, float jpegQuality, boolean convertToGrayscale)
throws IOException {
@ -559,10 +555,7 @@ public class CompressController {
return scaledImage;
}
/**
* Converts a BufferedImage to a byte array with specified JPEG quality. Checks if compression
* is beneficial compared to original.
*/
// Convert image to byte array with quality settings
private byte[] convertToBytes(BufferedImage scaledImage, float jpegQuality) throws IOException {
String format = scaledImage.getColorModel().hasAlpha() ? "png" : "jpeg";
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
@ -593,7 +586,7 @@ public class CompressController {
return outputStream.toByteArray();
}
/** Modified hash function to consistently identify identical image content */
// Hash function to identify identical images
private String generateImageHash(PDImageXObject image) {
try {
// Create a stream for the raw stream data
@ -631,26 +624,26 @@ public class CompressController {
}
}
// Updated scale factor method for levels 4-9
// Scale factors for different optimization levels
private double getScaleFactorForLevel(int optimizeLevel) {
return switch (optimizeLevel) {
case 4 -> 0.9; // 90% of original size - lite image compression
case 5 -> 0.8; // 80% of original size - lite image compression
case 6 -> 0.7; // 70% of original size - lite image compression
case 7 -> 0.6; // 60% of original size - intense image compression
case 8 -> 0.5; // 50% of original size - intense image compression
case 9, 10 -> 0.4; // 40% of original size - intense image compression
default -> 1.0; // No image scaling for levels 1-3
case 4 -> 0.9; // 90% - lite compression
case 5 -> 0.8; // 80% - lite compression
case 6 -> 0.7; // 70% - lite compression
case 7 -> 0.6; // 60% - intense compression
case 8 -> 0.5; // 50% - intense compression
case 9, 10 -> 0.4; // 40% - intense compression
default -> 1.0; // No scaling for levels 1-3
};
}
// New method for JPEG quality based on optimization level
// JPEG quality for different optimization levels
private float getJpegQualityForLevel(int optimizeLevel) {
return switch (optimizeLevel) {
case 7 -> 0.8f; // 80% quality - intense compression
case 8 -> 0.6f; // 60% quality - more intense compression
case 9, 10 -> 0.4f; // 40% quality - most intense compression
default -> 0.7f; // 70% quality for levels 1-6 (higher quality)
case 7 -> 0.8f; // 80% quality
case 8 -> 0.6f; // 60% quality
case 9, 10 -> 0.4f; // 40% quality
default -> 0.7f; // 70% quality for levels 1-6
};
}
@ -710,7 +703,7 @@ public class CompressController {
double scaleFactor = getScaleFactorForLevel(optimizeLevel);
float jpegQuality = getJpegQualityForLevel(optimizeLevel);
// Use the returned path from compressImagesInPDF
// Compress images
Path compressedImageFile =
compressImagesInPDF(
currentFile,
@ -718,7 +711,6 @@ public class CompressController {
jpegQuality,
Boolean.TRUE.equals(convertToGrayscale));
// Add to temp files list and update current file
tempFiles.add(compressedImageFile);
currentFile = compressedImageFile;
imageCompressionApplied = true;
@ -736,7 +728,7 @@ public class CompressController {
qpdfCompressionApplied = true;
}
// Check if file size is within expected size or not auto mode
// Check if target size reached or not in auto mode
long outputFileSize = Files.size(currentFile);
if (outputFileSize <= expectedOutputSize || !autoMode) {
sizeMet = true;
@ -761,12 +753,11 @@ public class CompressController {
}
}
// Check if optimized file is larger than the original
// Use original if optimized file is somehow larger
long finalFileSize = Files.size(currentFile);
if (finalFileSize >= inputFileSize) {
log.warn(
"Optimized file is larger than the original. Using the original file instead.");
// Use the stored reference to the original file
currentFile = originalFile;
}
@ -790,7 +781,7 @@ public class CompressController {
}
}
/** Apply QPDF compression to a PDF file */
// Run QPDF compression
private void applyQpdfCompression(
OptimizePdfRequest request, int optimizeLevel, Path currentFile, List<Path> tempFiles)
throws IOException {
@ -808,7 +799,7 @@ public class CompressController {
Path qpdfOutputFile = Files.createTempFile("qpdf_output_", ".pdf");
tempFiles.add(qpdfOutputFile);
// Run QPDF optimization
// Build QPDF command
List<String> command = new ArrayList<>();
command.add("qpdf");
if (request.getNormalize()) {
@ -848,7 +839,7 @@ public class CompressController {
}
}
/** Determine the appropriate optimization level based on the desired size reduction ratio */
// Pick optimization level based on target size
private int determineOptimizeLevel(double sizeReductionRatio) {
if (sizeReductionRatio > 0.9) return 1;
if (sizeReductionRatio > 0.8) return 2;
@ -861,7 +852,7 @@ public class CompressController {
return 9;
}
/** Increment optimization level based on current size vs target size */
// Increment optimization level if we need more compression
private int incrementOptimizeLevel(int currentLevel, long currentSize, long targetSize) {
double currentRatio = currentSize / (double) targetSize;
log.info("Current compression ratio: {}", String.format("%.2f", currentRatio));
@ -873,4 +864,4 @@ public class CompressController {
}
return Math.min(9, currentLevel + 1);
}
}
}