The PlotUtils.jl package is licensed under the MIT "Expat" License:

> Copyright (c) 2016: Thomas Breloff*.
>
> Permission is hereby granted, free of charge, to any person obtaining
> a copy of this software and associated documentation files (the
> "Software"), to deal in the Software without restriction, including
> without limitation the rights to use, copy, modify, merge, publish,
> distribute, sublicense, and/or sell copies of the Software, and to
> permit persons to whom the Software is furnished to do so, subject to
> the following conditions:
>
> The above copyright notice and this permission notice shall be
> included in all copies or substantial portions of the Software.
>
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
> IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
> CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
> TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
> SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


Some color gradients are released under individual licenses. The licenses for
each of these follow below:

# matplotlib

> The matplotlib gradients were taken from https://github.com/BIDS/colormap/blob/master/colormaps.py
> Here is the licensing note which accompanied this:

>     New Plots colormaps by Nathaniel J. Smith, Stefan van der Walt,
>     and (in the case of viridis) Eric Firing.
>    
>     This file and the colormaps in it are released under the CC0 license /
>     public domain dedication. We would appreciate credit if you use or
>     redistribute these colormaps, but do not impose any legal restrictions.
>    
>     To the extent possible under law, the persons who associated CC0 with
>     mpl-colormaps have waived all copyright and related or neighboring rights
>     to mpl-colormaps.
>    
>     You should have received a copy of the CC0 legalcode along with this
>     work.  If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.


# cmocean

> The MIT License (MIT)
> Copyright (c) 2015 Kristen M. Thyng
> RGB values were taken from https://github.com/matplotlib/cmocean/tree/master/cmocean/rgb

# colorbrewer

> Apache-Style Software License for ColorBrewer software and ColorBrewer Color Schemes
>
> Copyright (c) 2002 Cynthia Brewer, Mark Harrower, and The Pennsylvania State University.
>
> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
> You may obtain a copy of the License at
>
> http://www.apache.org/licenses/LICENSE-2.0
>
> 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.
>
> This text from my earlier Apache License Version 1.1 also remains in place for guidance on attribution and permissions:
> Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
> 1. Redistributions as source code must retain the above copyright notice, this list of conditions and the following disclaimer.
> 2. The end-user documentation included with the redistribution, if any, must include the following acknowledgment:
> "This product includes color specifications and designs developed by Cynthia Brewer (http://colorbrewer.org/)."
> Alternately, this acknowledgment may appear in the software itself, if and wherever such third-party acknowledgments normally appear.
> 4. The name "ColorBrewer" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact Cynthia Brewer at cbrewer@psu.edu.
> 5. Products derived from this software may not be called "ColorBrewer", nor may "ColorBrewer" appear in their name, without prior written permission of Cynthia Brewer.
>
> RGB values were taken from http://www.colorbrewer2.org

# colorcet

> The MIT License (MIT)
> Copyright (c) 2015 Peter Kovesi
> These are the perceptually correct color maps designed by Peter Kovesi and
> described in
> Peter Kovesi. Good Colour Maps: How to Design Them. arXiv:1509.03700 [cs.GR] 2015


The file "ticks.jl" was moved from Gadfly.jl, and the original author is Daniel Jones (@dcjones)
