trase

Trase is a lightweight scientific plotting library for C++ with animation support. It enables you to construct plots and write them out to animated svg files, or display them in an OpenGL window. The main library and svg backend have no dependencies other than the standard library. The OpenGL backend requires GLFW.

For example, the above svg image was generated with the following code.

  auto fig = figure();
  auto ax = fig->axis();
  const int n = 100;
  const int nframes = 10;
  std::vector<float> x(n);
  std::vector<float> y(n);

  // define x points
  for (int i = 0; i < n; ++i) {
    x[i] = static_cast<float>(i) / n;
  }

  // define y = sin(x) with given amplitude and frequency
  auto get_ysinx = [&](const float amplitude, const float freq) {
    for (int i = 0; i < n; ++i) {
      y[i] = amplitude * std::sin(6.28f * freq * x[i]);
    }
    return create_data().x(x).y(y);
  };

  // create a static sin(x) function
  auto static_plot = ax->line(get_ysinx(1.f, 2.f));
  static_plot->set_label("static");

  // create a moving sin(x) function with varying amplitude
  auto moving_plot = ax->line(get_ysinx(1.f, 5.f));
  moving_plot->set_label("moving");

  for (int i = 1; i <= nframes; ++i) {
    const float nf = static_cast<float>(nframes);
    const float amplitude = 1.f - 0.5f * std::sin(6.28f * i / nf);
    moving_plot->add_frame(get_ysinx(amplitude, 5.f), 3.f * i / nf);
  }

  // set label axes
  ax->xlabel("x");
  ax->ylabel("y");
  ax->title("the svg test");
  ax->legend();

  // output to svg
  std::ofstream out;
  out.open("readme.svg");
  BackendSVG backend(out);
  fig->draw(backend);
  out.close();

Contributing to Trase

We welcome community pull requests for Trase, please see the guidelines here. Potential areas for changes are:

• Bug-fixes. Please add a relevant test in tests/ demonstrating the fixed bug.
• New geometry, aesthetic or transform. The design of Trase roughly follows the Grammer of Graphics, so looking at existing GOG packages such as ggplot could give you some good ideas
• New example showing how to use Trase. All the examples shown in the documentation are in examples/.
• New drawing backend. There are two main types of backend. Classes derived from Backend are "pure" drawing classes in the same vein as NanoVG, while those derived from AnimatedBackend can also draw shapes or paths that have properties which animate over time.
• Or consult the issues for more ideas

Usage

1. Clone this repository

$ git clone https://github.com/martinjrobins/trase
$ cd trase

2. Build and install Trase. This uses an install dir of $HOME/trase, change this to wherever you like. This also builds the OpenGL backend of Trase (requires GLFW installed), switch this to OFF if you only want the svg backend.

$ mkdir build
$ cd build
$ cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME/trase -Dtrase_BUILD_OPENGL=ON ..
$ make install

2. (alternate) If you are using the Xcode or Visual Studio generator, you need to specify the configuration in build time

$ mkdir build
$ cd build
$ cmake -DCMAKE_INSTALL_PREFIX=$HOME/trase -Dtrase_BUILD_OPENGL=ON ..
$ cmake --build . --target install --config Release

3. In your C++ project, you might link against Trase with a CMakeLists.txt file like so:

cmake_minimum_required(VERSION 2.8.12)
project(test)

find_package(trase REQUIRED)

add_executable(myexe test.cpp)
target_link_libraries(myexe trase)

4. When you build your project, you can tell CMake where you installed Trase using the CMAKE_PREFIX_PATH variable

$ cmake -DCMAKE_PREFIX_PATH=$HOME/trase ..
$ make

Acknowledgments

Trase uses NanoVG for the OpenGL backend. The Dirent port for Windows is used for finding local font files.