com.itextpdf.io.util.GhostscriptHelper Maven / Gradle / Ivy
/*
This file is part of the iText (R) project.
Copyright (c) 1998-2023 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
* The Ghostscript needs to be installed independently on the system. This class provides a convenient
* way to run it by passing a terminal command. The command can either be specified explicitly or by a mean
* of environment variable {@link #GHOSTSCRIPT_ENVIRONMENT_VARIABLE}.
*/
public class GhostscriptHelper {
/**
* The name of the environment variable with the command to execute Ghostscript operations.
*/
public static final String GHOSTSCRIPT_ENVIRONMENT_VARIABLE = "ITEXT_GS_EXEC";
@Deprecated
static final String GHOSTSCRIPT_ENVIRONMENT_VARIABLE_LEGACY = "gsExec";
static final String GHOSTSCRIPT_KEYWORD = "GPL Ghostscript";
private static final String TEMP_FILE_PREFIX = "itext_gs_io_temp";
private static final String RENDERED_IMAGE_EXTENSION = "png";
private static final String GHOSTSCRIPT_PARAMS = " -dSAFER -dNOPAUSE -dBATCH -sDEVICE="
+ RENDERED_IMAGE_EXTENSION + "16m -r150 {0} -sOutputFile=\"{1}\" \"{2}\"";
private static final String PAGE_NUMBER_PATTERN = "%03d";
private static final Pattern PAGE_LIST_REGEX = Pattern.compile("^(\\d+,)*\\d+$");
private String gsExec;
/**
* Creates new instance that will rely on Ghostscript execution command defined by {@link
* #GHOSTSCRIPT_ENVIRONMENT_VARIABLE} environment variable.
*/
public GhostscriptHelper() {
this(null);
}
/**
* Creates new instance that will rely on Ghostscript execution command defined as passed argument.
*
* @param newGsExec the Ghostscript execution command; if null - environment variables will be used instead
*/
public GhostscriptHelper(String newGsExec) {
gsExec = newGsExec;
if (gsExec == null) {
gsExec = SystemUtil.getPropertyOrEnvironmentVariable(GHOSTSCRIPT_ENVIRONMENT_VARIABLE);
if (gsExec == null) {
gsExec = SystemUtil.getPropertyOrEnvironmentVariable(GHOSTSCRIPT_ENVIRONMENT_VARIABLE_LEGACY);
}
}
if (!CliCommandUtil.isVersionCommandExecutable(gsExec, GHOSTSCRIPT_KEYWORD)) {
throw new IllegalArgumentException(IoExceptionMessageConstant.GS_ENVIRONMENT_VARIABLE_IS_NOT_SPECIFIED);
}
}
/**
* Returns a command that is used to run the utility.
* This command doesn't contain command parameters. Parameters are added on specific
* methods invocation.
*
* @return a string command
*/
public String getCliExecutionCommand() {
return gsExec;
}
/**
* Runs Ghostscript to render the PDF's pages as PNG images.
*
*
* Note, that this method may create temporary directory and files.
*
* @param pdf Path to the PDF file to be rendered
* @param outDir Path to the output directory, in which the rendered pages will be stored
* @param image String which defines the name of the resultant images. This string will be
* concatenated with the number of the rendered page from the start of the
* PDF in "-%03d" format, e.g. "-011" for the eleventh rendered page and so on.
* This number may not correspond to the actual page number: for example,
* if the passed pageList equals to "5,3", then images with postfixes "-001.png"
* and "-002.png" will be created: the former for the third page, the latter
* for the fifth page. "%" sign in the passed name is prohibited.
*
* @throws IOException if there are file's reading/writing issues
* @throws InterruptedException if there is thread interruption while executing GhostScript.
*/
public void runGhostScriptImageGeneration(String pdf, String outDir, String image)
throws IOException, InterruptedException {
runGhostScriptImageGeneration(pdf, outDir, image, null);
}
/**
* Runs Ghostscript to render the PDF's pages as PNG images.
*
*
* Note, that this method may create temporary directory and files.
*
* @param pdf Path to the PDF file to be rendered
* @param outDir Path to the output directory, in which the rendered pages will be stored
* @param image String which defines the name of the resultant images. This string will be
* concatenated with the number of the rendered page from the start of the
* PDF in "-%03d" format, e.g. "-011" for the eleventh rendered page and so on.
* This number may not correspond to the actual page number: for example,
* if the passed pageList equals to "5,3", then images with postfixes "-001.png"
* and "-002.png" will be created: the former for the third page, the latter
* for the fifth page. "%" sign in the passed name is prohibited.
* @param pageList String with numbers of the required pages to be rendered as images.
* This string should be formatted as a string with numbers, separated by commas,
* without whitespaces. Can be null, if it is required to render all the PDF's pages.
*
* @throws IOException if there are file's reading/writing issues
* @throws InterruptedException if there is thread interruption while executing GhostScript.
*/
public void runGhostScriptImageGeneration(String pdf, String outDir, String image, String pageList)
throws IOException, InterruptedException {
if (!FileUtil.directoryExists(outDir)) {
throw new IllegalArgumentException(
IoExceptionMessageConstant.CANNOT_OPEN_OUTPUT_DIRECTORY.replace("", pdf));
}
if (!validateImageFilePattern(image)) {
throw new IllegalArgumentException("Invalid output image pattern: " + image);
}
if (!validatePageList(pageList)) {
throw new IllegalArgumentException("Invalid page list: " + pageList);
}
String formattedPageList = (pageList == null) ? "" : "-sPageList=".replace("", pageList);
String replacementPdf = null;
String replacementImagesDirectory = null;
String[] temporaryOutputImages = null;
try {
replacementPdf = FileUtil.createTempCopy(pdf, TEMP_FILE_PREFIX, null);
replacementImagesDirectory = FileUtil.createTempDirectory(TEMP_FILE_PREFIX);
String currGsParams = MessageFormatUtil.format(GHOSTSCRIPT_PARAMS, formattedPageList,
Paths.get(replacementImagesDirectory,
TEMP_FILE_PREFIX + PAGE_NUMBER_PATTERN + "." + RENDERED_IMAGE_EXTENSION).toString(),
replacementPdf);
if (!SystemUtil.runProcessAndWait(gsExec, currGsParams)) {
temporaryOutputImages = FileUtil
.listFilesInDirectory(replacementImagesDirectory, false);
throw new GhostscriptExecutionException(
IoExceptionMessageConstant.GHOSTSCRIPT_FAILED.replace("", pdf));
}
temporaryOutputImages = FileUtil
.listFilesInDirectory(replacementImagesDirectory, false);
if (null != temporaryOutputImages) {
for (int i = 0; i < temporaryOutputImages.length; i++) {
FileUtil.copy(temporaryOutputImages[i],
Paths.get(
outDir,
image + "-" + formatImageNumber(i + 1) + "." + RENDERED_IMAGE_EXTENSION
).toString());
}
}
} finally {
if (null != temporaryOutputImages) {
FileUtil.removeFiles(temporaryOutputImages);
}
FileUtil.removeFiles(new String[] {replacementImagesDirectory, replacementPdf});
}
}
/**
* Exceptions thrown when errors occur during generation and comparison of images obtained on the basis of pdf
* files.
*/
public static class GhostscriptExecutionException extends RuntimeException {
/**
* Creates a new {@link GhostscriptExecutionException}.
*
* @param msg the detail message.
*/
public GhostscriptExecutionException(String msg) {
super(msg);
}
}
static boolean validatePageList(String pageList) {
return null == pageList
|| PAGE_LIST_REGEX.matcher(pageList).matches();
}
static boolean validateImageFilePattern(String imageFilePattern) {
return null != imageFilePattern
&& !imageFilePattern.trim().isEmpty()
&& !imageFilePattern.contains("%");
}
static String formatImageNumber(int pageNumber) {
StringBuilder stringBuilder = new StringBuilder();
int zeroFiller = pageNumber;
while (0 == zeroFiller / 100) {
stringBuilder.append('0');
zeroFiller *= 10;
}
stringBuilder.append(pageNumber);
return stringBuilder.toString();
}
}