clip

clip

clip (the command line illustration processor) is an open-source command line program and software library for creating charts and other data-driven illustrations.

Getting Started · Examples · Documentation

Introduction

In essence, clip is an automated drawing program; it reads a text file containing a description of the chart or diagram and produces an image from it. This is best explained by example, so here is how to draw a simple line chart using clip:

class: plot;

limit-x: 0 7200;
limit-y: 0 100;

axes {
  font: "Roboto";
  position: left bottom;
  label-placement-x: linear-interval(900 900 7000);
  label-format-x: datetime("%H:%M:%S");
}

lines {
  data: "test/testdata/timeseries.csv";
  stroke-width: 0.8pt;
  color: #06c;
}

The input file from above (example.clp) can be processed with clip using the following command:

$ clip --export output.svg example.clp

This is the resulting SVG file (output.svg):

Note that this example is only intended to give you an idea of what the syntax looks like; for an in-depth description of all parameters, please refer to the documentation. More examples can be found on the examples page.

Documentation

You can find the full documentation and more examples at clip-lang.org.

Installation

Compile from source

To build clip, you need an up-to-date C++ compiler, cmake, fmtlib, libharfbuzz, libfreetype and cairo. Then run:

$ cmake .
$ make

To install the clip binary into your system, run make install:

$ make install

To run the test suite, run make test:

$ make test

For detailed installation instructions, have a look at the Installation page.

FAQ

I’m getting build errors when compiling the code

clip is written in C++17 and requires a reasonably modern C++ compiler and standard library. In most cases where the code doesn’t build it’s due to some problem with the local build environment. Still, we always appreciate bug reports via Github Issues so that we can improve our build system.

The test suite fails on my machine because text placement is slightly offset

The test suite requires that you have the original Microsoft Arial TTF files installed on your machine. To verify that this is the case, run fc-match 'Arial,Helvetica,Helvetica Neue:style=Regular,Roman' and check that it returns the correct ‘arial.ttf’ file.

What happened to the project name?

The project was started in 2011 and was initially called “FnordMetric”. The first version from 8 years ago also included facilities for storing and transforming data in addition to the charting code. Over time, the data processing parts were removed, leaving only the plotting code. However, as a consequence, most of the search queries for the project name would return outdated information, resulting in a generally confusing and stale-feeling situation. The best solution seemed to be to rename the project and so it was renamed to “clip”.

Acknowledgements

• Text rendering is based on the libre freetype and harfbuzz stack.

• The structure of the plot elements is based on ideas from The Grammar of Graphics and the ggplot2 library.

• A number of concepts in clip are modelled after the CSS specification

License

clip -- The command line illustration processor
https://clip-lang.org

Copyright (c) 2020, Paul Asmuth, Laura Schlimmer
All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.