### Build libkeyfinder with CMake

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/README.md

Standard procedure to configure, build, and install the libkeyfinder library using CMake. Ensure dependencies like FFTW3 and Catch2 are installed.

```sh
cmake -DCMAKE_INSTALL_PREFIX=/where/you/want/to/install/to -S . -B build
cmake --build build --parallel number-of-cpu-cores
cmake --install build
```

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

### Progressive Key Estimation

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/docs/Introduction.txt

This example demonstrates progressive key estimation from an audio stream, suitable for real-time analysis or when processing audio in packets. It involves creating a Workspace for memory allocations and iteratively updating the chromagram.

```cpp
KeyFinder::AudioData a;
a.setFrameRate(yourAudioStream.framerate);
a.setChannels(yourAudioStream.channels);
a.addToSampleCount(yourAudioStream.packetLength);

static KeyFinder::KeyFinder k;

// the workspace holds the memory allocations for analysis of a single track
KeyFinder::Workspace w;

while (someType yourPacket = newAudioPacket()) {

  for (int i = 0; i < yourPacket.length; i++) {
    a.setSample(i, yourPacket[i]);
  }
  k.progressiveChromagram(a, w);

  // if you want to grab progressive key estimates...
  KeyFinder::key_t key = k.keyOfChromagram(w);
  doSomethingWithMostRecentKeyEstimate(key);
}

// if you only want a single key estimate, or to squeeze
// every last bit of audio from the working buffer after
// progressive estimates...
k.finalChromagram(w);

// and finally...
KeyFinder::key key = k.keyOfChromagram(w);

doSomethingWithFinalKeyEstimate(key);

```

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

### Basic Key Estimation

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/docs/Introduction.txt

Use this snippet for a straightforward estimation of the musical key of an entire audio stream. Initialize KeyFinder and AudioData objects, populate AudioData with your audio samples, and then call keyOfAudio.

```cpp
// Static because it retains useful resources for repeat use
static KeyFinder::KeyFinder k;

// Build an empty audio object
KeyFinder::AudioData a;

// Prepare the object for your audio stream
a.setFrameRate(yourAudioStream.framerate);
a.setChannels(yourAudioStream.channels);
a.addToSampleCount(yourAudioStream.length);

// Copy your audio into the object
for (int i = 0; i < yourAudioStream.length; i++) {
  a.setSample(i, yourAudioStream[i]);
}

// Run the analysis
KeyFinder::key_t key = k.keyOfAudio(a);

// And do something with the result
doSomethingWith(key);

```

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

### Run libkeyfinder Tests

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/README.md

Execute the unit tests for libkeyfinder after building the library. Navigate to the build directory and run 'ctest'.

```sh
cd build
ctest --parallel number-of-cpu-cores
```

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

### CMakeLists.txt Configuration

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/examples/CMakeLists.txt

This snippet shows the essential CMake commands to configure a project that uses libkeyfinder. It sets the minimum CMake version, defines the project name, adds a module path, finds the KeyFinder package, and links the executable to the keyfinder library.

```cmake
cmake_minimum_required(VERSION 3.1.0)
project(KeyFinderBasicExample)

list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")

find_package(KeyFinder CONFIG REQUIRED)
add_executable(basic basic.cpp)
target_link_libraries(basic PRIVATE KeyFinder::keyfinder)
```

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

### Find and Fetch Catch2

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/tests/CMakeLists.txt

Attempts to find the Catch2 configuration. If not found, it fetches Catch2 from GitHub using FetchContent and makes it available.

```cmake
find_package(Catch2 CONFIG)
if(NOT TARGET Catch2::Catch2)
    message(STATUS "Fetching Catch2 from GitHub")
    include(FetchContent)
    FetchContent_Declare(
      Catch2
      GIT_REPOSITORY https://github.com/catchorg/Catch2.git
      GIT_TAG        v3.3.2)
    FetchContent_MakeAvailable(Catch2)
    list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/contrib)
endif()
```

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

### Link Libraries

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/tests/CMakeLists.txt

Links the test executable against the main library ('keyfinder') and the Catch2 testing framework. 'Catch2WithMain' includes the necessary main function for running tests.

```cmake
target_link_libraries(keyfinder-tests PRIVATE keyfinder)
```

```cmake
target_link_libraries(keyfinder-tests PRIVATE Catch2::Catch2WithMain)
```

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

### Build libkeyfinder Statically with CMake

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/README.md

Configure libkeyfinder to build as a static library by adding the -DBUILD_SHARED_LIBS=OFF flag during the CMake configuration step.

```sh
cmake -DBUILD_SHARED_LIBS=OFF -DCMAKE_INSTALL_PREFIX=/where/you/want/to/install/to -S . -B build
cmake --build build --parallel number-of-cpu-cores
cmake --install build
```

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

### Discover Tests

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/tests/CMakeLists.txt

Uses the Catch2 module to automatically discover and register tests within the 'keyfinder-tests' executable.

```cmake
include(Catch)
catch_discover_tests(keyfinder-tests)
```

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

### Set Include Directories

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/tests/CMakeLists.txt

Specifies private include directories for the test executable. This allows the test code to find headers from the project's source directory.

```cmake
target_include_directories(keyfinder-tests PRIVATE ../src)
```

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

### Define Test Executable

Source: https://github.com/mixxxdj/libkeyfinder/blob/main/tests/CMakeLists.txt

Defines the main executable for running tests. It lists all source files that will be compiled into the test executable.

```cmake
add_executable(keyfinder-tests
    _testhelpers.cpp
    audiodatatest.cpp
    binodetest.cpp
    chromagramtest.cpp
    chromatransformtest.cpp
    chromatransformfactorytest.cpp
    constantstest.cpp
    downsamplershortcuttest.cpp
    fftadaptertest.cpp
    keyclassifiertest.cpp
    keyfindertest.cpp
    lowpassfiltertest.cpp
    lowpassfilterfactorytest.cpp
    spectrumanalysertest.cpp
    temporalwindowfactorytest.cpp
    toneprofilestest.cpp
    windowfunctiontest.cpp
    workspacetest.cpp)
```

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