digital_filters

TODO: brief description!

Build the project

This project should be built using CMake. Assuming that you are in the root directory of this repository, you can create a build directory (it will not be tracked by git since build has been gitignored 😉) and move in there to compile the sources.

As an example, you could build the project as follows:

mkdir build && cd build
cmake ..
cmake --build .

Build options

You might want to use ccmake .. or cmake-gui to configure the options of the project in a simple way. Otherwise, pass them from the command line in the "usual" CMake way: cmake .. -D<OPTION>=<VALUE>.

The following is a list of possible options (some additional options are discussed in dedicated sections!):

CMAKE_BUILD_TYPE: can be either Debug or Release. It will configure different code optimization levels and different warn levels.

For options related to documentation and tests, please refer to the dedicated sections below.

Install

After a successful build, you might wish to install this project on your machine so that its binaries/libraries can be accessed by other projects. Assuming that you are in the build folder and that you have built the project via cmake --build ., you should be able to simply execute

cmake --install . # might require sudo!

By default, the install location should be /usr/local and you might need root privileges to properly copy the files. If you do not have the rights (or if you prefer to install the project somewhere else for any reason) you can change the install location during the configuration step. As an example:

cmake .. -DCMAKE_INSTALL_PREFIX=~/barbaz

Would install the header and other compiled targets in the barbaz directory in your home.

If at any point you wish to "uninstall" the project, you can do it thanks to a provided CMake script. In particular, after installing the project, move into the build location and run:

cmake -P uninstall.cmake # might require sudo!

⚠️ Beware of the following limitations! The uninstall.cmake script is very simple and limited. It reads the install_manifest.txt that is generated during the install step and attempts to remove, one by one, each copied target. This implies that:

Folders are not removed, but left empty. If you want to remove them, you have to do so manually.
Since the script reads install_manifest.txt, if you remove the build folder and/or change the installed products, the script might not correctly and completely remove all installed targets.

TL;DR: please, always check manually that all installed targets are removed! :sweat_smile:

You are not obliged to install the project if you wish to use it in another CMake-based project. This can be useful, e.g., when you work on multiple inter-dependent projects at once since you do not have to always update the installed targets. If you wish to do so, you simply need to export the environment variable digital_filters_DIR that contains the path to the build location:

# Make the library visible to other CMake-based projects
export digital_filters_DIR="$HOME/path/to/digital_filters/build"

You can add the line above to your .bashrc to "make it permanent".

Using `digital_filters` in your project

If you followed the instructions above to compile the source code and installed it (or opted for the export digital_filters_DIR solution), using digital_filters in your CMake-based project should be rather easy. First of all, locate digital_filters using any of the following:

# choose one ;)
find_package(digital_filters)
find_package(digital_filters QUIET)
find_package(digital_filters REQUIRED)

Then, just link the digital_filters::digital_filters library to your targets, e.g.,

add_executable(your_program your_source.cpp)
target_link_libraries(your_program digital_filters::digital_filters)

Note that headers are "automatically" made visible to your executable, and there is thus no need for any of the following

include_directories(${digital_filters_INCLUDE_DIRS})
target_include_directories(your_program ${digital_filters_INCLUDE_DIRS})

Indeed, when you call find_package, no digital_filters_INCLUDE_DIRS is populated at all!

Documentation

The documentation of this project is available online here.

The same documentation can also be generated locally using Doxygen. On Ubuntu/Debian, it should be possible to install it via:

apt install doxygen graphviz doxygen-latex

Note that the package doxygen-latex is needed only if you want to generate a printable version of the documentation - a sort of reference manual.

⚠️ Please, do not use the doxywizard (aka doxygen-gui) application to edit the Doxygen configuration file doxyfile.in. In fact, it contains some CMake-configurable variables (such as @GENERATE_LATEX@) that would be overridden by doxywizard - it expects them to contain either YES or NO. This would break some of the functionalities described below 😅

If Doxygen is installed on your system, a custom CMake target named doc will be added by default, and the documentation will be re-generated every time you build the project.

Alternatively, to re-build the documentation only, you can call:

cmake --build . --target doc

To disable the generation of the documentation, you can pass the BUILD_DOC=OFF argument during the configuration step:

cmake .. -DBUILD_DOC=OFF

By default, BUILD_DOC will be set to ON if Doxygen is found on your machine and to OFF if the package is not detected.

⛔ If you do not have Doxygen and try to set BUILD_DOC to ON anyway, CMake will send an error and exit.

Configuring the Documentation

While running, Doxygen can be rather verbose, printing on the console every detail about what it is currently doing. While this is a good thing in general, it can become tedious to have to scroll up every time to read errors coming from the compilation of the source code. Therefore, Doxygen is instructed to limit its output to warning messages, e.g., in case you forgot to document a member or if you misspelled a function's parameter. If at any moment you wish to see again the complete output produces by Doxygen, you can re-configure the project via:

cmake .. -DQUIET_DOXYGEN=NO

Similarly, if you wish to switch back to the quiet mode, use:

cmake .. -DQUIET_DOXYGEN=YES

By default, only an HTML version of the documentation is created. However, if you wish to generate a "print-friendly" version of it, you can create it thanks to LaTeX (you must have a valid distribution and pdflatex installed) via:

cmake .. -DDOXYGEN_MAKE_LATEX=YES

Testing

To check code sanity, tests can be run using Google Test. On Ubuntu/Debian, it should be possible to install it via:

cd where/you/want/to/store/gtest/sources
git clone https://github.com/google/googletest.git
mkdir -p googletest/build
cd googletest/build
cmake ..
cmake --build .
cmake --install . # might require sudo!

If a valid GTest distribution is found on your machine, CMake will generate the target test. To build and run the tests, use the following:

cmake ..
cmake --build . # build the project, tests included
cmake --build . --target test # run the tests

As you can see, tests are built altogether with the other "regular" targets. If for any reason you want tests not to be built, use the BUILD_TESTS option:

cmake .. -DBUILD_TESTS=OFF

To re-enable test compilation, you can use

cmake .. -DBUILD_TESTS=ON

Unless specified otherwise, BUILD_TESTS will be set to ON if GTest is found on your machine and to OFF if the package is missing. Also note that if you pass BUILD_TESTS=ON and CMake is not able to find GTest on your machine, an error will be thrown.

francofusco/digital_filters