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Anthony Stirling
2023-05-19 23:58:54 +01:00
parent 87cd6dfb54
commit 9d80458250
7 changed files with 145 additions and 83 deletions
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124
src/main/java/stirling/software/SPDF/controller/api/other/CompressController.java
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@@ -5,8 +5,8 @@ import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
@@ -45,55 +45,98 @@ public class CompressController {
@PostMapping(consumes = "multipart/form-data", value = "/compress-pdf")
@Operation(summary = "Optimize PDF file", description = "This endpoint accepts a PDF file and optimizes it based on the provided parameters.")
public ResponseEntity<byte[]> optimizePdf(
@RequestPart(required = true, value = "fileInput") @Parameter(description = "The input PDF file to be optimized.", required = true) MultipartFile inputFile,
@RequestParam("optimizeLevel") @Parameter(description = "The level of optimization to apply to the PDF file. Higher values indicate greater compression but may reduce quality.", schema = @Schema(allowableValues = {
"0", "1", "2", "3" }), example = "1") int optimizeLevel,
@RequestParam("expectedOutputSize") @Parameter(description = "The expected output size in bytes.", required = false) Long expectedOutputSize)
throws IOException, InterruptedException {
@RequestPart(value = "fileInput") @Parameter(description = "The input PDF file to be optimized.", required = true) MultipartFile inputFile,
@RequestParam(required = false, value = "optimizeLevel") @Parameter(description = "The level of optimization to apply to the PDF file. Higher values indicate greater compression but may reduce quality.", schema = @Schema(allowableValues = {
"1", "2", "3", "4", "5" })) Integer optimizeLevel,
@RequestParam(value = "expectedOutputSize", required = false) @Parameter(description = "The expected output size, e.g. '100MB', '25KB', etc.", required = false) String expectedOutputSizeString)
throws Exception {
if(expectedOutputSizeString == null && optimizeLevel == null) {
throw new Exception("Both expected output size and optimize level are not specified");
}
Long expectedOutputSize = 0L;
if (expectedOutputSizeString != null) {
expectedOutputSize = PdfUtils.convertSizeToBytes(expectedOutputSizeString);
}
// Save the uploaded file to a temporary location
Path tempInputFile = Files.createTempFile("input_", ".pdf");
inputFile.transferTo(tempInputFile.toFile());
long inputFileSize = Files.size(tempInputFile);
// Prepare the output file path
Path tempOutputFile = Files.createTempFile("output_", ".pdf");
// Prepare the Ghostscript command
List<String> command = new ArrayList<>();
command.add("gs");
command.add("-sDEVICE=pdfwrite");
command.add("-dCompatibilityLevel=1.4");
switch (optimizeLevel) {
case 0:
command.add("-dPDFSETTINGS=/default");
break;
case 1:
command.add("-dPDFSETTINGS=/ebook");
break;
case 2:
command.add("-dPDFSETTINGS=/printer");
break;
case 3:
command.add("-dPDFSETTINGS=/prepress");
break;
default:
command.add("-dPDFSETTINGS=/default");
// Determine initial optimization level based on expected size reduction, only if optimizeLevel is not provided
if(optimizeLevel == null) {
double sizeReductionRatio = expectedOutputSize / (double) inputFileSize;
if (sizeReductionRatio > 0.7) {
optimizeLevel = 1;
} else if (sizeReductionRatio > 0.5) {
optimizeLevel = 2;
} else if (sizeReductionRatio > 0.35) {
optimizeLevel = 3;
} else {
optimizeLevel = 4;
}
}
command.add("-dNOPAUSE");
command.add("-dQUIET");
command.add("-dBATCH");
command.add("-sOutputFile=" + tempOutputFile.toString());
command.add(tempInputFile.toString());
boolean sizeMet = expectedOutputSize == 0L;
while (!sizeMet && optimizeLevel <= 5) {
// Prepare the Ghostscript command
List<String> command = new ArrayList<>();
command.add("gs");
command.add("-sDEVICE=pdfwrite");
command.add("-dCompatibilityLevel=1.4");
int returnCode = ProcessExecutor.getInstance(ProcessExecutor.Processes.GHOSTSCRIPT).runCommandWithOutputHandling(command);
switch (optimizeLevel) {
case 1:
command.add("-dPDFSETTINGS=/prepress");
break;
case 2:
command.add("-dPDFSETTINGS=/printer");
break;
case 3:
command.add("-dPDFSETTINGS=/default");
break;
case 4:
command.add("-dPDFSETTINGS=/ebook");
break;
case 5:
command.add("-dPDFSETTINGS=/screen");
break;
default:
command.add("-dPDFSETTINGS=/default");
}
command.add("-dNOPAUSE");
command.add("-dQUIET");
command.add("-dBATCH");
command.add("-sOutputFile=" + tempOutputFile.toString());
command.add(tempInputFile.toString());
int returnCode = ProcessExecutor.getInstance(ProcessExecutor.Processes.GHOSTSCRIPT).runCommandWithOutputHandling(command);
// Check if file size is within expected size
long outputFileSize = Files.size(tempOutputFile);
if (outputFileSize <= expectedOutputSize) {
sizeMet = true;
} else {
// Increase optimization level for next iteration
optimizeLevel++;
System.out.println("Increasing ghostscript optimisation level to " + optimizeLevel);
}
}
if (expectedOutputSize != null) {
long outputFileSize = Files.size(tempOutputFile);
if (outputFileSize > expectedOutputSize) {
try (PDDocument doc = PDDocument.load(new File(tempOutputFile.toString()))) {
long previousFileSize = 0;
double scaleFactor = 1.0;
while (true) {
for (PDPage page : doc.getPages()) {
@@ -142,14 +185,21 @@ public class CompressController {
// save the document to tempOutputFile again
doc.save(tempOutputFile.toString());
long currentSize = Files.size(tempOutputFile);
// Check if the overall PDF size is still larger than expectedOutputSize
if (Files.size(tempOutputFile) > expectedOutputSize) {
if (currentSize > expectedOutputSize) {
// Log the current file size and scaleFactor
System.out.println("Current file size: " + FileUtils.byteCountToDisplaySize(currentSize));
System.out.println("Current scale factor: " + scaleFactor);
// The file is still too large, reduce scaleFactor and try again
scaleFactor *= 0.9; // reduce scaleFactor by 10%
// Avoid scaleFactor being too small, causing the image to shrink to 0
if(scaleFactor < 0.1){
throw new RuntimeException("Could not reach the desired size without excessively degrading image quality");
if(scaleFactor < 0.2 || previousFileSize == currentSize){
throw new RuntimeException("Could not reach the desired size without excessively degrading image quality, lowest size recommended is " + FileUtils.byteCountToDisplaySize(currentSize) + ", " + currentSize + " bytes");
}
previousFileSize = currentSize;
} else {
// The file is small enough, break the loop
break;

27
src/main/java/stirling/software/SPDF/utils/PdfUtils.java
View File

@@ -22,6 +22,7 @@ import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
@@ -287,4 +288,30 @@ public class PdfUtils {
return PdfUtils.boasToWebResponse(baos, docName);
}
public static Long convertSizeToBytes(String sizeStr) {
if (sizeStr == null) {
return null;
}
sizeStr = sizeStr.trim().toUpperCase();
try {
if (sizeStr.endsWith("KB")) {
return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 2)) * 1024;
} else if (sizeStr.endsWith("MB")) {
return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 2)) * 1024 * 1024;
} else if (sizeStr.endsWith("GB")) {
return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 2)) * 1024 * 1024 * 1024;
} else if (sizeStr.endsWith("B")) {
return Long.parseLong(sizeStr.substring(0, sizeStr.length() - 1));
} else {
// Input string does not have a valid format, handle this case
}
} catch (NumberFormatException e) {
// The numeric part of the input string cannot be parsed, handle this case
}
return null;
}
}