### C++ API Example with User Patterns

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample-user_patterns.md

This C++ code demonstrates how to initialize Tesseract with a user patterns config file and process an image. Ensure Tesseract and Leptonica are correctly installed and linked.

```cpp
#include <tesseract/baseapi.h>
#include <leptonica/allheaders.h>

int main()
{
    Pix *image;
    char *outText;
    char *configs[]={\"path/to/my.patterns.config\"};
    int configs_size = 1;
    tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
    if (api->Init(NULL, \"eng\", tesseract::OEM_LSTM_ONLY, configs, configs_size, NULL, NULL, false)) {
      fprintf(stderr, \"Could not initialize tesseract.\\n\");
      exit(1);
    }
    image = pixRead(\"Arial.png\");
    api->SetImage(image);
    outText = api->GetUTF8Text();
    printf(outText);
    api->End();
    delete api;
    delete [] outText;
    pixDestroy(&image);
    return 0;
}

```

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

### Install Training Dependencies (Ubuntu/Debian)

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/tess5/TrainingTesseract-5.md

Installs essential libraries required for building Tesseract training tools. Ensure these are installed before compiling.

```bash
sudo apt-get install libicu-dev libpango1.0-dev libcairo2-dev
```

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

### Get Tesseract Command Line Help

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/FAQ.md

Run `tesseract --help` to display the most recent command-line usage information for your installed version.

```bash
tesseract --help
```

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

### Build and Install Tesseract with Training Tools

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Compiles and installs Tesseract along with its training tools from source.

```bash
git clone https://github.com/tesseract-ocr/tesseract/
cd tesseract
./autogen.sh
./configure
make training
sudo make install training-install
```

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

### Install Tesseract on Fedora 31

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Install Tesseract and the German language pack on Fedora 31. Execute as root.

```bash
dnf config-manager --add-repo https://download.opensuse.org/repositories/home:Alexander_Pozdnyakov/Fedora_31/home:Alexander_Pozdnyakov.repo
dnf install tesseract
dnf install tesseract-langpack-deu
```

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

### Configure Tesseract Installation to a Custom Prefix

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Configures Tesseract to install into a specified directory, useful for installing without root privileges. This example installs to `$HOME/local/`.

```bash
./autogen.sh
./configure --prefix=$HOME/local/
make
make install
```

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

### Build and Install Tesseract Training Tools

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/tess5/TrainingTesseract-5.md

Commands to build and install the Tesseract training tools after configuring the build. This is necessary for training new models.

```bash
make
make training
sudo make training-install
```

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

### Install Tesseract on RHEL 7

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Install Tesseract and the German language pack on RHEL 7. Execute as root.

```bash
yum-config-manager --add-repo https://download.opensuse.org/repositories/home:/Alexander_Pozdnyakov/RHEL_7/
yum update
yum install tesseract 
yum install tesseract-langpack-deu
```

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

### Install Tesseract on openSUSE Leap 15.0

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Install Tesseract OCR and the German trained data on openSUSE Leap 15.0. Execute as root.

```bash
zypper addrepo https://download.opensuse.org/repositories/home:Alexander_Pozdnyakov/openSUSE_Leap_15.0/home:Alexander_Pozdnyakov.repo
zypper refresh
zypper install tesseract-ocr
zypper install tesseract-ocr-traineddata-german
```

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

### Install Cygwin Packages for Tesseract

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

List of Tesseract-specific packages to install for building on Cygwin. Ensure these are installed before proceeding with compilation.

```bash
Tesseract specific packages to be installed:

tesseract-ocr                           3.04.01-1
tesseract-ocr-eng                       3.04-1
tesseract-training-core                 3.04-1
tesseract-training-eng                  3.04-1
tesseract-training-util                 3.04.01-1
```

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

### Extract Orientation and Script with cffi in Python

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample.md

Python example using cffi to interact with Tesseract's C-API for detecting page orientation and script. Requires 'pip install cffi'.

```python
# /usr/bin/env python3
# coding: utf-8

PATH_TO_LIBTESS = '/path/to/development/libtesseract.so'

import cffi  # requires "pip install cffi"

ffi = cffi.FFI()
ffi.cdef(""
struct Pix;
typedef struct Pix PIX;
PIX * pixRead ( const char *filename );
char * getLeptonicaVersion (  );

typedef struct TessBaseAPI TessBaseAPI;
typedef int BOOL;

const char* TessVersion();

TessBaseAPI* TessBaseAPICreate();
int TessBaseAPIInit3(TessBaseAPI* handle, const char* datapath, const char* language);

void TessBaseAPISetImage2(TessBaseAPI* handle, struct Pix* pix);

BOOL   TessBaseAPIDetectOrientationScript(TessBaseAPI* handle, char** best_script_name,
                                                            int* best_orientation_deg, float* script_confidence,
                                                            float* orientation_confidence);
""")

libtess = ffi.dlopen(PATH_TO_LIBTESS)
from ctypes.util import find_library
liblept = ffi.dlopen(find_library('lept'))

ffi.string(libtess.TessVersion())

ffi.string(liblept.getLeptonicaVersion())

api = libtess.TessBaseAPICreate()

libtess.TessBaseAPIInit3(api, ffi.NULL, ffi.NULL)

pix = liblept.pixRead('mono.png'.encode())

libtess.TessBaseAPISetImage2(api, pix)

script_name = ffi.new('char **')
orient_deg = ffi.new('int *')
script_conf = ffi.new('float *')
orient_conf = ffi.new('float *')
libtess.TessBaseAPIDetectOrientationScript(api, script_name, orient_deg, script_conf, orient_conf)

print(ffi.string(script_name).decode('utf-8'))
print(orient_deg[0])
print(script_conf[0])
print(orient_conf[0])

```

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

### Extracting Textline Components with Bounding Boxes

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample.md

This example demonstrates how to get bounding boxes for text lines in an image and then perform OCR on each identified component. It iterates through components, extracts text, and prints confidence.

```c++
  Pix *image = pixRead("/usr/src/tesseract/testing/phototest.tif");
  tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
  api->Init(NULL, "eng");
  api->SetImage(image);
  Boxa* boxes = api->GetComponentImages(tesseract::RIL_TEXTLINE, true, NULL, NULL);
  printf("Found %d textline image components.\n", boxes->n);
  for (int i = 0; i < boxes->n; i++) {
    BOX* box = boxaGetBox(boxes, i, L_CLONE);
    api->SetRectangle(box->x, box->y, box->w, box->h);
    char* ocrResult = api->GetUTF8Text();
    int conf = api->MeanTextConf();
    fprintf(stdout, "Box[%d]: x=%d, y=%d, w=%d, h=%d, confidence: %d, text: %s",
                    i, box->x, box->y, box->w, box->h, conf, ocrResult);
    boxDestroy(&box);
  }
  delete api;
```

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

### Tesseract Training: Install Dependencies and Build

Source: https://context7.com/tesseract-ocr/tessdoc/llms.txt

Steps to install necessary dependencies and build Tesseract with training tools. This is a prerequisite for LSTM fine-tuning.

```bash
# Install dependencies
sudo apt-get install libicu-dev libpango1.0-dev libcairo2-dev
```

```bash
# Build Tesseract with training tools
./configure
make && make training && sudo make training-install
```

```bash
# Clone the tesstrain repo for Python training scripts
git clone https://github.com/tesseract-ocr/tesstrain
cd tesstrain
```

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

### Install Core Dependencies for Tesseract on Ubuntu

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs essential development libraries for compiling Tesseract on Ubuntu 16.04/14.04. Ensure these are installed before building Tesseract from source.

```bash
sudo apt-get install g++ # or clang++ (presumably)
sudo apt-get install autoconf automake libtool
sudo apt-get install pkg-config
sudo apt-get install libpng-dev
sudo apt-get install libjpeg8-dev
sudo apt-get install libtiff5-dev
sudo apt-get install zlib1g-dev
sudo apt-get install libwebpdemux2 libwebp-dev
sudo apt-get install libopenjp2-7-dev
sudo apt-get install libgif-dev
sudo apt-get install libarchive-dev libcurl4-openssl-dev
```

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

### Install Tesseract with CMake Build

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Build and install Tesseract from the command line using CMake. This command performs a Release build and installs the necessary files.

```sh
cmake --build . --config Release --target install
```

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

### Build Tesseract from Source

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling-–-GitInstallation.md

Compiles and installs Tesseract after cloning the repository. This sequence includes autogen, configure, make, and install steps.

```bash
cd tesseract
./autogen.sh
./configure
make
sudo make install
sudo ldconfig
```

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

### Install Tesseract on Scientific Linux 7

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Install Tesseract and the German language pack on Scientific Linux 7. Execute as root.

```bash
yum-config-manager --add-repo https://download.opensuse.org/repositories/home:/Alexander_Pozdnyakov/ScientificLinux_7/
yum update
yum install tesseract 
yum install tesseract-langpack-deu
```

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

### Install Training Dependencies for Tesseract on Ubuntu

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs additional libraries required for Tesseract training tools on Ubuntu. Include these if you are building the training components.

```bash
sudo apt-get install libicu-dev
sudo apt-get install libpango1.0-dev
sudo apt-get install libcairo2-dev
```

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

### Install Packages for Tesseract Training Tools

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs additional packages required for building Tesseract's training tools using MacPorts.

```bash
sudo port install cairo pango
sudo port install icu +devel
```

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

### Install Tesseract via Snap

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Installation.md

Use this command to install the Tesseract snap package on systems with snapd. The --channel=edge flag installs the latest development version.

```bash
sudo snap install --channel=edge tesseract
```

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

### Install Optional Manpage Dependencies

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling-–-GitInstallation.md

Installs packages required for building manpages using asciidoc. Use this if you need documentation generated from source.

```bash
apt-get install --no-install-recommends asciidoc docbook-xsl xsltproc
```

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

### Install Tesseract OCR Developer Tools on Ubuntu

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs the Tesseract OCR developer tools, which are necessary for training Tesseract. Use this if you plan to train Tesseract.

```bash
sudo apt install libtesseract-dev
```

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

### Install Debian/Ubuntu Dependencies

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling-–-GitInstallation.md

Installs essential packages for building Tesseract on Debian/Ubuntu systems. Includes automake, git, and development libraries.

```bash
apt-get install automake ca-certificates g++ git libtool libleptonica-dev make pkg-config
```

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

### Install Tesseract on Fedora 32

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Commands to install Tesseract and the German language pack on Fedora 32. Run as root.

```bash
dnf config-manager --add-repo https://download.opensuse.org/repositories/home:Alexander_Pozdnyakov/Fedora_32/home:Alexander_Pozdnyakov.repo
dnf install tesseract
dnf install tesseract-langpack-deu
```

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

### Install Tesseract on openSUSE Tumbleweed

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/InstallationOpenSuse.md

Commands to install Tesseract OCR and the German trained data on openSUSE Tumbleweed. Run as root.

```bash
zypper addrepo https://download.opensuse.org/repositories/home:Alexander_Pozdnyakov/openSUSE_Tumbleweed/home:Alexander_Pozdnyakov.repo
zypper refresh
zypper install tesseract-ocr
zypper install tesseract-ocr-traineddata-german
```

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

### Install Mingw-w64 Cross-Compilation Tools on Debian/Ubuntu

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Install the necessary Mingw-w64 cross-compilation tools for targeting 32-bit and 64-bit Windows executables on Debian-based systems.

```bash
# Development environment targeting 32- and 64-bit Windows (required)
apt-get install mingw-w64
# Development tools for 32- and 64-bit Windows (optional)
apt-get install mingw-w64-tools
```

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

### Iterating Through Words with Confidence and Bounding Boxes

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample.md

This example shows how to use a ResultIterator to get the text, confidence value, and bounding box for each word in the OCR result. It supports various iterator levels like block, line, and word.

```c++
  Pix *image = pixRead("/usr/src/tesseract/testing/phototest.tif");
  tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
  api->Init(NULL, "eng");
  api->SetImage(image);
  api->Recognize(0);
  tesseract::ResultIterator* ri = api->GetIterator();
  tesseract::PageIteratorLevel level = tesseract::RIL_WORD;
  if (ri != 0) {
    do {
      const char* word = ri->GetUTF8Text(level);
      float conf = ri->Confidence(level);
      int x1, y1, x2, y2;
      ri->BoundingBox(level, &x1, &y1, &x2, &y2);
      printf("word: '%s';  \tconf: %.2f; BoundingBox: %d,%d,%d,%d;\n",
               word, conf, x1, y1, x2, y2);
      delete[] word;
    } while (ri->Next(level));
  }
  delete api;
```

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

### Install Tesseract OCR and Dev Tools on Ubuntu

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Installation.md

Use apt to install the Tesseract OCR engine and its development libraries. Ensure the 'universe' repository is enabled if packages are not found.

```bash
sudo apt install tesseract-ocr
sudo apt install libtesseract-dev
```

```bash
deb http://archive.ubuntu.com/ubuntu bionic universe
```

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

### Build Tesseract with Training Tools

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling-–-GitInstallation.md

Compiles and installs Tesseract along with its training tools. This requires additional dependencies and a separate 'make training' step.

```bash
cd tesseract
./autogen.sh
./configure
make
sudo make install
sudo ldconfig
make training
sudo make training-install
```

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

### Get Confidence for Alternative LSTM Symbol Choices

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample.md

This C++ example shows how to retrieve confidence levels for alternative symbol choices per character using the LSTM engine. It involves setting 'lstm_choice_mode' to '2' and iterating through the results obtained from GetBestLSTMSymbolChoices.

```C++
#include <tesseract/baseapi.h>
#include <leptonica/allheaders.h>
int main()
{
    tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
// Initialize tesseract-ocr with English, without specifying tessdata path
    if (api->Init(NULL, "eng")) {
        fprintf(stderr, "Could not initialize tesseract.\n");
        exit(1);
    }
// Open input image with leptonica library
  Pix *image = pixRead("/home/ubuntu/tesseract/test/testing/trainingital.tif");
  api->SetImage(image);
// Set lstm_choice_mode to alternative symbol choices per character, bbox is at word level.
  api->SetVariable("lstm_choice_mode", "2");
  api->Recognize(0);
  tesseract::PageIteratorLevel level = tesseract::RIL_WORD;
  tesseract::ResultIterator* res_it = api->GetIterator();
// Get confidence level for alternative symbol choices. Code is based on
// https://github.com/tesseract-ocr/tesseract/blob/a7a729f6c315e751764b72ea945da961638effc5/src/api/hocrrenderer.cpp#L325-L344
  std::vector<std::vector<std::pair<const char*, float>>>* choiceMap = nullptr;
  if (res_it != 0) {
    do {
      const char* word;
      float conf;
      int x1, y1, x2, y2, tcnt = 1, gcnt = 1, wcnt = 0;
     res_it->BoundingBox(level, &x1, &y1, &x2, &y2);
     choiceMap = res_it->GetBestLSTMSymbolChoices();
      for (auto timestep : *choiceMap) {
        if (timestep.size() > 0) {
          for (auto & j : timestep) {
            conf = int(j.second * 100);
            word =  j.first;
            printf("%d  symbol: '%s';  \tconf: %.2f; BoundingBox: %d,%d,%d,%d;\n",
                        wcnt, word, conf, x1, y1, x2, y2);
           gcnt++;
          }
          tcnt++;
        }
      wcnt++;
      printf("\n");
      }
    } while (res_it->Next(level));
  }
  // Destroy used object and release memory
  api->End();
  delete api;
  pixDestroy(&image);
  return 0;
}
```

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

### Get HOCR Output with Alternative LSTM Symbol Choices

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample.md

This C++ example demonstrates how to obtain HOCR output that includes alternative symbol choices per character from the LSTM engine. It is equivalent to running Tesseract from the command line with '-c lstm_choice_mode=2 hocr'.

```C++
#include <tesseract/baseapi.h>
#include <leptonica/allheaders.h>

int main()
{
    char *outText;

    tesseract::TessBaseAPI *api = new tesseract::TessBaseAPI();
// Initialize tesseract-ocr with English, without specifying tessdata path
    if (api->Init(NULL, "eng")) {
        fprintf(stderr, "Could not initialize tesseract.\n");
        exit(1);
    }

// Open input image with leptonica library
    Pix *image = pixRead("/tesseract/test/testing/trainingital.tif");
    api->SetImage(image);
    api->SetVariable("lstm_choice_mode", "2");
// Get HOCR result
    outText = api->GetHOCRText(0);
    printf("HOCR alternative symbol choices  per character :\n%s", outText);

// Destroy used object and release memory
    api->End();
    delete api;
    delete [] outText;
    pixDestroy(&image);

    return 0;
}
```

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

### Build and Run Script for C++ API Example

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample-user_patterns.md

This script sets environment variables for include and library paths, compiles the C++ code, and runs the executable. It also includes a diff command to compare the output with a ground truth file.

```sh
#!/bin/bash

export CPLUS_INCLUDE_PATH=$CPLUS_INCLUDE_PATH:/usr/local/include
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

g++ -std=c++17  -o my.patterns.api my.patterns.api.cpp   -llept -ltesseract

export TESSDATA_PREFIX=~/tessdata_best

./my.patterns.api > Arial-patterns.txt

diff -u  Arial-patterns.txt  Arial-gt.txt

```

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

### Install Tesseract via MacPorts

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Installation.md

Installs Tesseract using the MacPorts package manager. Ensure MacPorts is installed and configured on your macOS system.

```bash
sudo port install tesseract
```

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

### Install Training Tools Dependencies

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling-–-GitInstallation.md

Installs additional libraries needed to build Tesseract's training tools. This includes ICU, Pango, and Cairo development packages.

```bash
apt-get install libicu-dev
apt-get install libpango1.0-dev
apt-get install libcairo2-dev
```

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

### Install Devanagari Fonts on Debian

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Fonts.md

Installs Devanagari fonts on Debian-based systems using apt-get.

```bash
apt-get install fonts-deva
```

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

### CLI Example for User Patterns

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample-user_patterns.md

User patterns can be invoked directly from the command line using the --user-patterns option.

```sh
tesseract input.tif output --user-patterns path/to/my.patterns
```

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

### Install Required Packages with MacPorts

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs essential development packages for Tesseract compilation using MacPorts.

```bash
sudo port install autoconf \
                  automake \
                  libtool \
                  pkgconfig \
                  leptonica
```

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

### Install Neo-Latin Fonts on Debian

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Fonts.md

Installs specific Neo-Latin fonts on Debian-based systems using apt-get.

```bash
apt-get install fonts-ebgaramond fonts-gfs-didot fonts-gfs-didot-classic fonts-junicode
```

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

### Install Japanese Fonts on Debian

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Fonts.md

Installs various Japanese fonts on Debian-based systems using apt-get.

```bash
apt-get install fonts-noto-cjk fonts-japanese-mincho.ttf fonts-takao-gothic fonts-vlgothic
```

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

### Fix autoconf syntax error

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

This error typically occurs when `autoconf-archive` is not installed. Ensure it is installed and then rerun `./autogen.sh`.

```bash
./configure: line 4237: syntax error near unexpected token `-mavx,'
./configure: line 4237: `AX_CHECK_COMPILE_FLAG(-mavx, avx=1, avx=0)'
```

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

### Config File Example for User Patterns

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/APIExample-user_patterns.md

The config file specifies the path to the user patterns file. Use UNIX line endings and a blank line at the end.

```plaintext
user_patterns_file path/to/my.patterns


```

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

### Install Tesseract Dependencies with Homebrew

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs core and optional dependencies for Tesseract compilation using Homebrew on macOS.

```bash
# Packages which are always needed.
brew install automake autoconf libtool
brew install pkgconfig
brew install icu4c
brew install leptonica
# Packages required for training tools.
brew install pango
# Optional packages for extra features.
brew install libarchive
# Optional package for builds using g++.
brew install gcc
```

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

### Make AppImage Executable and Run

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Installation.md

After downloading an AppImage, make it executable using chmod and then run it to perform OCR. This example demonstrates running OCR on 'page.tif' and saving output to 'page.txt' using the English language model.

```bash
$ chmod a+x tesseract*.AppImage
```

```bash
./tesseract*.AppImage -l eng page.tif page.txt
```

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

### Install OpenMP with MacPorts

Source: https://github.com/tesseract-ocr/tessdoc/blob/main/Compiling.md

Installs OpenMP using the MacPorts package manager. This is an optional step for enabling multithreading.

```bash
sudo port install libomp
```