### Create PDF with Page Labels Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This example demonstrates how to create a PDF document with custom page labels.

```java
Create example of PDF creation with page labels
```

--------------------------------

### Add Example to Jump to Local Page in AddAnnotations

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Includes an example demonstrating how to add annotations that jump to a local page within the PDF document.

```java
PDDocument document = new PDDocument();
PDPage page1 = new PDPage();
document.addPage(page1);
PDPage page2 = new PDPage();
document.addPage(page2);

// Create a destination on page2
PDPageXYZDestination dest = new PDPageXYZDestination(page2);
dest.setZoom(1.0f);

// Create an action to go to the destination
PDActionGoTo action = new PDActionGoTo();
action.setDestination(dest);

// Create an annotation (e.g., a link) that triggers the action
PDAnnotationLink link = new PDAnnotationLink();
link.setRectangle(new PDRectangle(50, 50, 100, 100)); // Annotation position
link.setAction(action);
page1.addAnnotation(link);

document.save("document_with_link.pdf");
document.close();
```

--------------------------------

### Get Async Profiler Help

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Display help information and available options for configuring the async-profiler within JMH.

```bash
java -jar target/benchmarks.jar -prof async:help
```

--------------------------------

### Create Flexible CheckBox and RadioButtons Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This example showcases the creation of flexible CheckBox and RadioButtons in PDF documents.

```java
Create flexible CheckBox and RadioButtons example
```

--------------------------------

### CreateVisibleSignature Example with Correct Alias

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Corrects the CreateVisibleSignature example to use the proper alias for keystore access, ensuring signatures are created with the intended credentials.

```java
KeyStore ks = KeyStore.getInstance("PKCS12");
ks.load(new FileInputStream(keyStorePath), keyStorePassword.toCharArray());
String alias = "my-alias"; // Correct alias for the certificate
// ... rest of the signing process ...
```

--------------------------------

### Create PDF with Patterns Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Sample code for creating a PDF with patterns. This demonstrates how to use patterns for graphical elements within a PDF document.

```java
PDPageContentStream contentStream = new PDPageContentStream(document, page);
// ... pattern setup code ...
contentStream.fillPatten(pattern, rect);
contentStream.close();
```

--------------------------------

### Create PDFMergerUtility Example with Metadata Handling

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Provides an example of using PDFMergerUtility with improved metadata handling, ensuring metadata is correctly preserved during merging.

```java
PDFMergerUtility merger = new PDFMergerUtility();
merger.addSource("source1.pdf");
merger.addSource("source2.pdf");
merger.setDestinationFileName("merged.pdf");
merger.mergeDocuments(MemoryUsageSetting.setupMainMemoryOnly());
```

--------------------------------

### Create AcroForm Example with Two Widgets

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Provides an example of creating an AcroForm field that has two associated widgets, demonstrating complex form field configurations.

```java
PDAcroForm acroForm = new PDAcroForm(document);
document.getDocumentCatalog().setAcroForm(acroForm);

PDTextField textField = new PDTextField(acroForm);
textField.setPartialName("MyTextField");

// Create first widget
PDRectangle rect1 = new PDRectangle(50, 700, 100, 20);
PDAnnotationWidget widget1 = new PDAnnotationWidget();
widget1.setRectangle(rect1);
widget1.setFieldType(PDAnnotationWidget.FIELD_TYPE_TEXT);
textField.add(widget1);

// Create second widget
PDRectangle rect2 = new PDRectangle(50, 680, 100, 20);
PDAnnotationWidget widget2 = new PDAnnotationWidget();
widget2.setRectangle(rect2);
widget2.setFieldType(PDAnnotationWidget.FIELD_TYPE_TEXT);
textField.add(widget2);

acroForm.addFields(textField);

document.save("form_with_two_widgets.pdf");
document.close();
```

--------------------------------

### Build Apache PDFBox

Source: https://github.com/apache/pdfbox/blob/trunk/AGENTS.md

Standard Maven command to clean and install the entire project. Ensure the correct Java version for the target branch is set.

```bash
mvn clean install
```

--------------------------------

### Run Apache PDFBox Tests

Source: https://github.com/apache/pdfbox/blob/trunk/AGENTS.md

Maven command to execute all tests without performing a full installation. Use this for quick validation of changes.

```bash
mvn test
```

--------------------------------

### Add Watermark Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This snippet provides an example of how to add a watermark to a PDF document.

```java
Add watermark example
```

--------------------------------

### Add Text to AcroForm Examples

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This example shows how to add text to AcroForm fields within a PDF document.

```java
Add text to AcroForm examples
```

--------------------------------

### Add Polygon Annotation Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This snippet demonstrates how to add a polygon annotation to a PDF document using the AddAnnotations.java example.

```java
AddAnnotations.java
```

--------------------------------

### CWEAVE Parsing Example

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Demonstrates the output of CWEAVE when run in debugging mode ('@ @c @2') on a simple C function. The output shows grammar rules being applied during parsing.

```text
main (argc,argv)
char **argv;
{ for (;argc>0;argc--) printf("%s\n",argv[argc-1]); }
```

```text
4:*exp ( +exp+ )...
11:*exp +exp+ int...
5:*+exp+ int +unorbinop+...
...
60: +fn_decl+*+{+ -stmt- +}-
55:*+fn_decl+ -stmt-
52:*+function-...
```

--------------------------------

### CWEAVE Peeping Mode Example Output

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Illustrates the output generated by CWEAVE when its 'peeping' mode is active, showing grammar rule applications and parsing states. This helps in understanding CWEAVE's internal processing.

```text
4:*exp ( +exp+ )...
11:*exp +exp+ int...
5:*+exp+ int +unorbinop+...
...
60: +fn_decl+*+{+ -stmt- +}- 
55:*+fn_decl+ -stmt-
52:*+function-...
```

--------------------------------

### Usage of Separation Color (Spot Color) Example

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This snippet illustrates the usage of separation color, also known as spot color, in PDF documents.

```java
Add example of usage of separation color (spot color)
```

--------------------------------

### CWEAVE Formatting Example with Brackets

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Example of C code formatted by CWEAVE with the '-e' option enabled, which encloses C material in \PB{...} for special hooks. This option has no effect on CTANGLE.

```c
\PB{main (argc,argv)
char **argv;
{
 for (;argc>0;argc--)
 printf("%s\n",argv[argc-1]);
}}
```

--------------------------------

### Index Entry with Custom Sort Key

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Example of using the '@:' feature to create an index entry for 'TeX' with a custom sort key. The \9 macro ensures the sort key is not printed.

```tex
@:TeX}{\TeX@>
```

--------------------------------

### Define Custom Sanitization with \def and \ifheader

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

This example demonstrates how to define a macro \klujj that conditionally formats text based on whether it's intended for a header. It also shows how to create a custom table of contents entry and bookmark text.

```tex
\def\klujj#1\{\ifheader FOO\else foo\fi}
@*Chinese \klujj bar\.

```

```tex
\ZZ {Chinese \klujj bar\}{1}{1}{1}{Chinese bar}
```

--------------------------------

### List All Available Benchmarks

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Display a list of all benchmarks that can be run. This is useful for identifying specific tests.

```bash
java -jar target/benchmarks.jar -l
```

--------------------------------

### Run Benchmark with GC Profiler

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute benchmarks and measure allocation rates using the GC profiler. Focus on 'norm' allocation rates for per-operation measurements.

```bash
java -jar target/benchmarks.jar -prof gc
```

--------------------------------

### Run Benchmark with Async Profiler

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute benchmarks using the async-profiler. Specify the library path to the async profiler shared object.

```bash
java -jar target/benchmarks.jar -prof async:libPath=/path/to/libasyncProfiler.so
```

--------------------------------

### CWEB Translation of Embedded C Code

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

This is how CWEB translates the example of embedded C code into TEX, demonstrating the handling of special characters and formatting.

```tex
If \\{pa} is declared as ‘&{int} ${}{*}\\\{pa}$’,
the assignment $\\\{pa}\K{\AND}\|a[\T{0}]$
makes \\{pa} point to the zeroth element of \|a.
```

--------------------------------

### Run Benchmark with Async Profiler and Flame Graph Output

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute benchmarks using the async-profiler and generate a flame graph. The semicolon is escaped to prevent command separation.

```bash
java -jar target/benchmarks.jar -prof async:libPath=/path/to/libasyncProfiler.so\;output=flamegraph
```

--------------------------------

### Run All Benchmarks

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute all available benchmarks in the module. Ensure the JMH JAR is in the current directory or specify its path.

```bash
java -jar target/benchmarks.jar
```

--------------------------------

### Table of Contents Data Entry - TEX

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Example format for data entries in a table of contents file. Each line represents a section with its title, and numerical identifiers.

```tex
\ZZ {Introduction}{0}{1}{28}{}
\ZZ {The character set}{2}{5}{29}{}
```

--------------------------------

### Implement GoToE Action Type

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Implementation of the GoToE action type for PDF navigation. This allows for creating links that navigate to specific destinations within a PDF.

```java
PDActionGoTo action = new PDActionGoTo();
action.setDestination(destination);
currentPage.addPDAction(action);
```

--------------------------------

### CWEB Logic for Skipping Comment Lines

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

This CWEB code snippet demonstrates how to skip over comment lines in a change file, allowing lines starting with '@@' but not '@@y', '@@z', or '@@i'.

```c
while(1) {
change_line++;

```

--------------------------------

### Skip Comment Lines in Change File (TeX)

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Skips over comment lines in the change file, identified by lines starting with '@'. Returns if the end of the file is reached.

```tex
\X13:Skip over comment lines in the change file; \PB{\&{return}} if end
of file\X${}
\&{while} (\T{1})\5
${}\{}
${}\{change\_line}\PP;{}
\&{if} ${}(\R\{input\_ln}(\{change\_file})){}$\1
\&{return};\2
\&{if} ${}(\{limit}<\{buffer}+\T{2}){}$\1
\&{continue};\2
\&{if} ${}(\{buffer}[\T{0}]\I\.{'@'}){}$\1
\&{continue};\2
\&{if} (\\{xisupper}(\{buffer}[\T{1}]))\1
${}\{buffer}[\T{1}]\K\\{tolower}(\{buffer}[\T{1}]);{}
\&{if} ${}(\{buffer}[\T{1}]\E\.{'x'}){}$\1
\&{break};\2
\&{if} ${}(\{buffer}[\T{1}]\E\.{'y'}\V\{buffer}[\T{1}]\E\.{'z'}\V\{buffer}[%
\T{1}]\E\.{'i'}){}$\5
${}\{}
${}\{loc}\K\{buffer}+\T{2};{}
\\{err\_print}(\.{"!\ Missing\ @x\ in\ cha}\)\,.{nge\ file");{}
\4${}\{}
\4${}\{}
\par
\U12.\fi
```

--------------------------------

### List Available Profilers

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Display a list of all available profilers that can be used with JMH benchmarks.

```bash
java -jar target/benchmarks.jar -lprof
```

--------------------------------

### CWEAVE Command Line Usage

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Details the command-line syntax for the CWEAVE program, mirroring CTANGLE's conventions for file handling and options. Output extensions include .tex and .idx/.scn for index files.

```bash
cweave [options] web_file[.w] [{change_file[.ch]|−} [out_file]]
```

--------------------------------

### Skip Comment Lines in Change File (C)

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Skips over comment lines in the change file, identified by lines starting with '@'. Returns if the end of the file is reached.

```c
while(1){
change_line++;
if(!input_ln(change_file))return;
if(limit<buffer+2)continue;
if(buffer[0]!='@')continue;
if(xisupper(buffer[1]))buffer[1]= tolower(buffer[1]);
if(buffer[1]=='x')break;
if(buffer[1]=='y'||buffer[1]=='z'||buffer[1]=='i'){
loc= buffer+2;
err_print("! Missing @x in change file");
}
}
```

--------------------------------

### Run Specific Benchmark with Custom Iterations

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute a specific benchmark while overriding the number of forks, iterations, and warm-up iterations to a custom value (e.g., 2).

```bash
java -jar target/benchmarks.jar -f 2 -i 2 -wi 2 LoadAndSave.loadMediumFile
```

--------------------------------

### Build Specific Apache PDFBox Module

Source: https://github.com/apache/pdfbox/blob/trunk/AGENTS.md

Maven command to build or test a specific module using the -pl flag. Replace 'pdfbox' with the desired module name.

```bash
mvn -pl pdfbox test
```

--------------------------------

### Skip Comment Lines in Change File

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Skips over comment lines in a change file. Returns if the end of the file is reached. This logic is used when searching for lines starting with '@x'.

```C
while (1) {
change line ++;
if (¬input ln (change file )) return;
if (limit < buffer + 2) continue;
if (buffer [0] 6= ’@’) continue;
if (xisupper (buffer [1])) buffer [1] = tolower (buffer [1]);
if (buffer [1] ≡ ’x’) break;
if (buffer [1] ≡ ’y’ ∨ buffer [1] ≡ ’z’ ∨ buffer [1] ≡ ’i’) {
loc = buffer + 2;
err print ("! Missing @x in change file");
}
}
```

--------------------------------

### Customizing TEX Code Sanitization

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Define TEX macros to control how code is sanitized. In this example, '\\kluj bar\\\' prints as 'foo' but sanitizes to 'bar' because '\\kluj' and '\\' are removed during sanitization.

```tex
\def\kluj#1\\{foo}
```

--------------------------------

### Initialize Change Buffer in C

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Initializes the change buffer and limit for processing change files. Handles various conditions for reading and processing lines from the change file.

```c
void
prime_the_change_buffer()
{
change_limit= change_buffer;
/*13:*/
#line 261 "common.w"
while(1){
change_line++;
if(!input_ln(change_file))return;
if(limit<buffer+2)continue;
if(buffer[0]!=’@’)continue;
if(xisupper(buffer[1]))buffer[1]= tolower(buffer[1]);
if(buffer[1]==’x’)break;
if(buffer[1]==’y’||buffer[1]==’z’||buffer[1]==’i’){
loc= buffer+2;
err_print("! Missing @x in change file");
}
}
/*:13*/
#line 252 "common.w"
;
/*14:*/
#line 278 "common.w"
do{
change_line++;
if(!input_ln(change_file)){
err_print("! Change file ended after @x");
return;
}
}while(limit==buffer);
/*:14*/
#line 253 "common.w"
;
/*15:*/
#line 288 "common.w"
{
change_limit= change_buffer-buffer+limit;
strncpy(change_buffer,buffer,limit-buffer+1);
}
/*:15*/
#line 254 "common.w"
;
}
```

--------------------------------

### CWEB Option Syntax

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Illustrates how to enable or disable options for CWEB tools using '+' for enabling and '-' for disabling. Options can be placed before or after file names.

```bash
+s
```

```bash
−fb
```

--------------------------------

### Cancel Line Break with @+

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Use '@+' to cancel a potential line break, for instance, before 'else' to keep a short if-else on one line. It can also affect indentation at the start of a compound statement.

```cweb
@+ [MC] This control code cancels a line break that might otherwise be inserted by CWEAVE, e.g., before
the word ‘else’, if you want to put a short if–else construction on a single line. If you say ‘{@+’ at the
beginning of a compound statement that is the body of a function, the first declaration or statement of
the function will appear on the same line as the left brace, and it will be indented by the same amount
as the second declaration or statement on the next line.
```

--------------------------------

### Consistently Use Download Maven Plugin Version

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This task ensures consistent usage of the download-maven-plugin version across the project.

```xml
Consistently using the same version of the download-maven-plugin
```

--------------------------------

### Run a Specific Benchmark

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Execute a single benchmark by its name. This is useful for targeted testing.

```bash
java -jar target/benchmarks.jar LoadAndSave.loadMediumFile
```

--------------------------------

### Skip Comment Lines in Change File (C)

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Skips over comment lines in the change file, identified by lines starting with '@'. Returns if the end of the file is reached. Handles specific cases like '@x', '@y', '@z', and '@i'.

```c
while(1){
change_line++;
if(!input_ln(change_file))return;
if(limit<buffer+2)continue;
if(buffer[0]!=’@’)continue;
if(xisupper(buffer[1]))buffer[1]= tolower(buffer[1]);
if(buffer[1]==’x’)break;
if(buffer[1]==’y’||buffer[1]==’z’||buffer[1]==’i’){
loc= buffer+2;
err_print("! Missing @x in change file");
}
}
```

--------------------------------

### List Benchmarks Matching a Pattern

Source: https://github.com/apache/pdfbox/blob/trunk/benchmark/README.md

Filter and display benchmarks that match a given pattern or name. This helps in selecting specific tests to run.

```bash
java -jar target/benchmarks.jar -l LoadAndSave
```

--------------------------------

### CTANGLE Command Line Usage

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Specifies the command-line syntax for the CTANGLE program, including input files, change files, and output files. Extensions like .w, .ch, and .c are handled automatically.

```bash
ctangle [options] web_file[.w] [{change_file[.ch]|−} [out_file]]
```

--------------------------------

### ImageToPDF Command Line Tool

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This snippet refers to the ImageToPDF command line tool, likely used for converting images to PDF format.

```java
ImageToPDF as Command Line
```

--------------------------------

### Insert Thin Space with @,

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Use '@,' to insert a thin space in CWEAVE's output, useful when two identifiers are adjacent due to macro usage.

```cweb
@, [MCc] This control code inserts a thin space in CWEAVE’s output. Sometimes you need this extra space
if you are using macros in an unusual way, e.g., if two identifiers are adjacent.
```

--------------------------------

### PDFToImage Command Line Tool Support for Subsampling

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This enhancement adds support for subsampling in the PDFToImage command line tool, potentially improving performance or reducing output size.

```java
Support subsampling in PDFToImage command line tool
```

--------------------------------

### Move Buffer and Limit to Change Buffer (TeX)

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Copies the current buffer and limit pointers to the change buffer and change limit variables.

```tex
\X15:Move \PB{\{buffer}} and \PB{\{limit}} to \PB{\{change\_buffer}}
and \PB{\{change\_limit}}\X${}
${}\{}
${}\{change\_limit}\K\{change\_buffer}-\{buffer}+\{limit};{}
${}\{strncpy}(\{change\_buffer},\39\{buffer},\39\{limit}-\{buffer}+%
\T{1});{}
\4${}\{}
\Us12\ET16.\fi
```

--------------------------------

### Support Simple Lossless Compression of 16-bit RGB Images

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

This enhancement adds support for simple lossless compression of 16-bit RGB images, improving efficiency.

```java
[PATCH]: Support simple lossless compression of 16 bit RGB images
```

--------------------------------

### Initialize Change Buffer in PDFBox

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Initializes the change buffer for subsequent matching operations. This function is called when 'changing' is active.

```c
void
prime_the_change_buffer()
{
change_limit= change_buffer;
/*13:*/
#line 261 "common.w"
while(1){
change_line++;
if(!input_ln(change_file))return;
if(limit<buffer+2)continue;
if(buffer[0]!='@')continue;
if(xisupper(buffer[1]))buffer[1]= tolower(buffer[1]);
if(buffer[1]=='x')break;
if(buffer[1]=='y'||buffer[1]=='z'||buffer[1]=='i'){
loc= buffer+2;
err_print("! Missing @x in change file");
}
}
/*:13*/
#line 252 "common.w"
;
/*14:*/
#line 278 "common.w"
do{
change_line++;
if(!input_ln(change_file)){
err_print("! Change file ended after @x");
return;
}
}while(limit==buffer);
/*:14*/
#line 253 "common.w"
;
/*15:*/
#line 288 "common.w"
{
change_limit= change_buffer-buffer+limit;
strncpy(change_buffer,buffer,limit-buffer+1);
}
/*:15*/
#line 254 "common.w"
;
}
```

--------------------------------

### Inserting Custom Spacing in CWEB

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf.txt

Illustrates the use of the '@t' feature in CWEB to insert custom spacing or perform actions like backspacing within formatted C code. '
@t\hskip 1in@>' inserts one inch of space, and '@t\4@>' backspaces by one indentation unit.

```cweb
@t\hskip 1in@>
```

```cweb
@t\4@>
```

```cweb
@t}\3{−5@>}
```

--------------------------------

### CWEB Function to Initialize Change Buffer

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

The `prime_the_change_buffer` function initializes the `change_buffer` for the next matching operation. It is called when `changing` is 1 and handles end-of-file conditions.

```c
void
prime_the_change_buffer()
{
change_limit=change_buffer;
@<Skip over comment lines in the change file; |return| if end of file@>;
@<Skip to the next nonblank line; |return| if end of file@>;
@<Move |buffer| and |limit| to |change_buffer| and |change_limit|@>;
}

```

--------------------------------

### Referencing Sections in C and TEX

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Demonstrates how to reference C code sections within both C text and TEX text using the '@<section name@>' construct. Note the use of '|...|' when citing a section in TEX text.

```c
if (x==0) @<Empty the |buffer| array@>
... using the algorithm in |@<Empty the |buffer| array@>|.
```

--------------------------------

### Create Clickable URLs with \pdfURL

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Use the \pdfURL macro to create clickable links in PDF documents. The first argument is the displayed text, and the second is the URL. Special characters in URLs like '@' and '~' should be escaped using '@@' and '\\TILDE/' respectively.

```tex
You can send email to \pdfURL{the author}{mailto:andreas.scherer@@pobox.com}
or visit \pdfURL{his home page}{http://www.pobox.com/\TILDE/scherer}.
```

--------------------------------

### Move Buffer and Limit to Change Buffer (C)

Source: https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/test/resources/input/cweb.pdf-sorted.txt

Copies the content from the current buffer and limit to the change buffer and change limit. This is used to store the current line for later comparison or processing.

```c
{
change_limit= change_buffer-buffer+limit;
strncpy(change_buffer,buffer,limit-buffer+1);
}
```

--------------------------------

### Using RenderingMode with PDPageContentStream

Source: https://github.com/apache/pdfbox/blob/trunk/RELEASE-NOTES.txt

Demonstrates how to use the RenderingMode with PDPageContentStream for controlling text rendering behavior, such as showing text as filled or stroked.

```java
PDPageContentStream contentStream = new PDPageContentStream(document, page);
contentStream.setTextRenderingMode(RenderingMode.FILL_STROKE);
contentStream.showText("Sample Text");
contentStream.close();
```