diff --git a/LICENSE.md b/LICENSE.md new file mode 100644 index 0000000..f74659f --- /dev/null +++ b/LICENSE.md @@ -0,0 +1,651 @@ +GNU Affero General Public License +================================= + +_Version 3, 19 November 2007_ +_Copyright © 2007 Free Software Foundation, Inc. _ + +Everyone is permitted to copy and distribute verbatim copies +of this license document, but changing it is not allowed. + +## Preamble + +The GNU Affero General Public License is a free, copyleft license for +software and other kinds of works, specifically designed to ensure +cooperation with the community in the case of network server software. + +The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +our General Public Licenses are intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. + +When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + +Developers that use our General Public Licenses protect your rights +with two steps: **(1)** assert copyright on the software, and **(2)** offer +you this License which gives you legal permission to copy, distribute +and/or modify the software. + +A secondary benefit of defending all users' freedom is that +improvements made in alternate versions of the program, if they +receive widespread use, become available for other developers to +incorporate. Many developers of free software are heartened and +encouraged by the resulting cooperation. However, in the case of +software used on network servers, this result may fail to come about. +The GNU General Public License permits making a modified version and +letting the public access it on a server without ever releasing its +source code to the public. + +The GNU Affero General Public License is designed specifically to +ensure that, in such cases, the modified source code becomes available +to the community. It requires the operator of a network server to +provide the source code of the modified version running there to the +users of that server. Therefore, public use of a modified version, on +a publicly accessible server, gives the public access to the source +code of the modified version. + +An older license, called the Affero General Public License and +published by Affero, was designed to accomplish similar goals. This is +a different license, not a version of the Affero GPL, but Affero has +released a new version of the Affero GPL which permits relicensing under +this license. + +The precise terms and conditions for copying, distribution and +modification follow. + +## TERMS AND CONDITIONS + +### 0. Definitions + +“This License” refers to version 3 of the GNU Affero General Public License. + +“Copyright” also means copyright-like laws that apply to other kinds of +works, such as semiconductor masks. + +“The Program” refers to any copyrightable work licensed under this +License. Each licensee is addressed as “you”. “Licensees” and +“recipients” may be individuals or organizations. + +To “modify” a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of an +exact copy. The resulting work is called a “modified version” of the +earlier work or a work “based on” the earlier work. + +A “covered work” means either the unmodified Program or a work based +on the Program. + +To “propagate” a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + +To “convey” a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user through +a computer network, with no transfer of a copy, is not conveying. + +An interactive user interface displays “Appropriate Legal Notices” +to the extent that it includes a convenient and prominently visible +feature that **(1)** displays an appropriate copyright notice, and **(2)** +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + +### 1. Source Code + +The “source code” for a work means the preferred form of the work +for making modifications to it. “Object code” means any non-source +form of a work. + +A “Standard Interface” means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + +The “System Libraries” of an executable work include anything, other +than the work as a whole, that **(a)** is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and **(b)** serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +“Major Component”, in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + +The “Corresponding Source” for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + +The Corresponding Source need not include anything that users +can regenerate automatically from other parts of the Corresponding +Source. + +The Corresponding Source for a work in source code form is that +same work. + +### 2. Basic Permissions + +All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + +You may make, run and propagate covered works that you do not +convey, without conditions so long as your license otherwise remains +in force. You may convey covered works to others for the sole purpose +of having them make modifications exclusively for you, or provide you +with facilities for running those works, provided that you comply with +the terms of this License in conveying all material for which you do +not control copyright. Those thus making or running the covered works +for you must do so exclusively on your behalf, under your direction +and control, on terms that prohibit them from making any copies of +your copyrighted material outside their relationship with you. + +Conveying under any other circumstances is permitted solely under +the conditions stated below. Sublicensing is not allowed; section 10 +makes it unnecessary. + +### 3. Protecting Users' Legal Rights From Anti-Circumvention Law + +No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + +When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such circumvention +is effected by exercising rights under this License with respect to +the covered work, and you disclaim any intention to limit operation or +modification of the work as a means of enforcing, against the work's +users, your or third parties' legal rights to forbid circumvention of +technological measures. + +### 4. Conveying Verbatim Copies + +You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + +You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + +### 5. Conveying Modified Source Versions + +You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these conditions: + +* **a)** The work must carry prominent notices stating that you modified +it, and giving a relevant date. +* **b)** The work must carry prominent notices stating that it is +released under this License and any conditions added under section 7. +This requirement modifies the requirement in section 4 to +“keep intact all notices”. +* **c)** You must license the entire work, as a whole, under this +License to anyone who comes into possession of a copy. This +License will therefore apply, along with any applicable section 7 +additional terms, to the whole of the work, and all its parts, +regardless of how they are packaged. This License gives no +permission to license the work in any other way, but it does not +invalidate such permission if you have separately received it. +* **d)** If the work has interactive user interfaces, each must display +Appropriate Legal Notices; however, if the Program has interactive +interfaces that do not display Appropriate Legal Notices, your +work need not make them do so. + +A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +“aggregate” if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + +### 6. Conveying Non-Source Forms + +You may convey a covered work in object code form under the terms +of sections 4 and 5, provided that you also convey the +machine-readable Corresponding Source under the terms of this License, +in one of these ways: + +* **a)** Convey the object code in, or embodied in, a physical product +(including a physical distribution medium), accompanied by the +Corresponding Source fixed on a durable physical medium +customarily used for software interchange. +* **b)** Convey the object code in, or embodied in, a physical product +(including a physical distribution medium), accompanied by a +written offer, valid for at least three years and valid for as +long as you offer spare parts or customer support for that product +model, to give anyone who possesses the object code either **(1)** a +copy of the Corresponding Source for all the software in the +product that is covered by this License, on a durable physical +medium customarily used for software interchange, for a price no +more than your reasonable cost of physically performing this +conveying of source, or **(2)** access to copy the +Corresponding Source from a network server at no charge. +* **c)** Convey individual copies of the object code with a copy of the +written offer to provide the Corresponding Source. This +alternative is allowed only occasionally and noncommercially, and +only if you received the object code with such an offer, in accord +with subsection 6b. +* **d)** Convey the object code by offering access from a designated +place (gratis or for a charge), and offer equivalent access to the +Corresponding Source in the same way through the same place at no +further charge. You need not require recipients to copy the +Corresponding Source along with the object code. If the place to +copy the object code is a network server, the Corresponding Source +may be on a different server (operated by you or a third party) +that supports equivalent copying facilities, provided you maintain +clear directions next to the object code saying where to find the +Corresponding Source. Regardless of what server hosts the +Corresponding Source, you remain obligated to ensure that it is +available for as long as needed to satisfy these requirements. +* **e)** Convey the object code using peer-to-peer transmission, provided +you inform other peers where the object code and Corresponding +Source of the work are being offered to the general public at no +charge under subsection 6d. + +A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + +A “User Product” is either **(1)** a “consumer product”, which means any +tangible personal property which is normally used for personal, family, +or household purposes, or **(2)** anything designed or sold for incorporation +into a dwelling. In determining whether a product is a consumer product, +doubtful cases shall be resolved in favor of coverage. For a particular +product received by a particular user, “normally used” refers to a +typical or common use of that class of product, regardless of the status +of the particular user or of the way in which the particular user +actually uses, or expects or is expected to use, the product. A product +is a consumer product regardless of whether the product has substantial +commercial, industrial or non-consumer uses, unless such uses represent +the only significant mode of use of the product. + +“Installation Information” for a User Product means any methods, +procedures, authorization keys, or other information required to install +and execute modified versions of a covered work in that User Product from +a modified version of its Corresponding Source. The information must +suffice to ensure that the continued functioning of the modified object +code is in no case prevented or interfered with solely because +modification has been made. + +If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + +The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or updates +for a work that has been modified or installed by the recipient, or for +the User Product in which it has been modified or installed. Access to a +network may be denied when the modification itself materially and +adversely affects the operation of the network or violates the rules and +protocols for communication across the network. + +Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + +### 7. Additional Terms + +“Additional permissions” are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + +When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + +Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders of +that material) supplement the terms of this License with terms: + +* **a)** Disclaiming warranty or limiting liability differently from the +terms of sections 15 and 16 of this License; or +* **b)** Requiring preservation of specified reasonable legal notices or +author attributions in that material or in the Appropriate Legal +Notices displayed by works containing it; or +* **c)** Prohibiting misrepresentation of the origin of that material, or +requiring that modified versions of such material be marked in +reasonable ways as different from the original version; or +* **d)** Limiting the use for publicity purposes of names of licensors or +authors of the material; or +* **e)** Declining to grant rights under trademark law for use of some +trade names, trademarks, or service marks; or +* **f)** Requiring indemnification of licensors and authors of that +material by anyone who conveys the material (or modified versions of +it) with contractual assumptions of liability to the recipient, for +any liability that these contractual assumptions directly impose on +those licensors and authors. + +All other non-permissive additional terms are considered “further +restrictions” within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + +If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + +Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; +the above requirements apply either way. + +### 8. Termination + +You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + +However, if you cease all violation of this License, then your +license from a particular copyright holder is reinstated **(a)** +provisionally, unless and until the copyright holder explicitly and +finally terminates your license, and **(b)** permanently, if the copyright +holder fails to notify you of the violation by some reasonable means +prior to 60 days after the cessation. + +Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + +Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + +### 9. Acceptance Not Required for Having Copies + +You are not required to accept this License in order to receive or +run a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + +### 10. Automatic Licensing of Downstream Recipients + +Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + +An “entity transaction” is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + +You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + +### 11. Patents + +A “contributor” is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's “contributor version”. + +A contributor's “essential patent claims” are all patent claims +owned or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, “control” includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + +Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + +In the following three paragraphs, a “patent license” is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To “grant” such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + +If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either **(1)** cause the Corresponding Source to be so +available, or **(2)** arrange to deprive yourself of the benefit of the +patent license for this particular work, or **(3)** arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. “Knowingly relying” means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + +If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + +A patent license is “discriminatory” if it does not include within +the scope of its coverage, prohibits the exercise of, or is +conditioned on the non-exercise of one or more of the rights that are +specifically granted under this License. You may not convey a covered +work if you are a party to an arrangement with a third party that is +in the business of distributing software, under which you make payment +to the third party based on the extent of your activity of conveying +the work, and under which the third party grants, to any of the +parties who would receive the covered work from you, a discriminatory +patent license **(a)** in connection with copies of the covered work +conveyed by you (or copies made from those copies), or **(b)** primarily +for and in connection with specific products or compilations that +contain the covered work, unless you entered into that arrangement, +or that patent license was granted, prior to 28 March 2007. + +Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + +### 12. No Surrender of Others' Freedom + +If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you may +not convey it at all. For example, if you agree to terms that obligate you +to collect a royalty for further conveying from those to whom you convey +the Program, the only way you could satisfy both those terms and this +License would be to refrain entirely from conveying the Program. + +### 13. Remote Network Interaction; Use with the GNU General Public License + +Notwithstanding any other provision of this License, if you modify the +Program, your modified version must prominently offer all users +interacting with it remotely through a computer network (if your version +supports such interaction) an opportunity to receive the Corresponding +Source of your version by providing access to the Corresponding Source +from a network server at no charge, through some standard or customary +means of facilitating copying of software. This Corresponding Source +shall include the Corresponding Source for any work covered by version 3 +of the GNU General Public License that is incorporated pursuant to the +following paragraph. + +Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the work with which it is combined will remain governed by version +3 of the GNU General Public License. + +### 14. Revised Versions of this License + +The Free Software Foundation may publish revised and/or new versions of +the GNU Affero General Public License from time to time. Such new versions +will be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the +Program specifies that a certain numbered version of the GNU Affero General +Public License “or any later version” applies to it, you have the +option of following the terms and conditions either of that numbered +version or of any later version published by the Free Software +Foundation. If the Program does not specify a version number of the +GNU Affero General Public License, you may choose any version ever published +by the Free Software Foundation. + +If the Program specifies that a proxy can decide which future +versions of the GNU Affero General Public License can be used, that proxy's +public statement of acceptance of a version permanently authorizes you +to choose that version for the Program. + +Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + +### 15. Disclaimer of Warranty + +THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF +ALL NECESSARY SERVICING, REPAIR OR CORRECTION. + +### 16. Limitation of Liability + +IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGES. + +### 17. Interpretation of Sections 15 and 16 + +If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + +_END OF TERMS AND CONDITIONS_ + +## How to Apply These Terms to Your New Programs + +If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + +To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the “copyright” line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper mail. + +If your software can interact with users remotely through a computer +network, you should also make sure that it provides a way for users to +get its source. For example, if your program is a web application, its +interface could display a “Source” link that leads users to an archive +of the code. There are many ways you could offer source, and different +solutions will be better for different programs; see section 13 for the +specific requirements. + +You should also get your employer (if you work as a programmer) or school, +if any, to sign a “copyright disclaimer” for the program, if necessary. +For more information on this, and how to apply and follow the GNU AGPL, see + diff --git a/readme.nml b/readme.nml index 55190a3..916a4d4 100644 --- a/readme.nml +++ b/readme.nml @@ -81,6 +81,48 @@ Evaluating `!` from a kernel: `\%\%` # Latex -# Support for inline maths: +## Support for inline maths: * $\sum^{\infty}_{k=1} \frac{1}{k^2} = \frac{\pi^2}{6}$ * $n! = \int_0^\infty t^n e^{-t} \text{ d}t$ + +# Graphs + +NML adds support for *Graphviz* graphs. + +[graph][ + width=600px, + layout=neato +] +digraph g { + bgcolor="transparent" + fontname="Helvetica,Arial,sans-serif" + node [fontname="Helvetica,Arial,sans-serif"] + edge [fontname="Helvetica,Arial,sans-serif"] + graph [fontsize=30 labelloc="t" label="" splines=true overlap=false rankdir = "LR"]; + "state0" [ style = "filled, bold" penwidth = 5 fillcolor = "white" fontname = "Courier New" shape = "Mrecord" label =<
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The SVG will have (pseudo-)unique +IDs in case more than one is used on the same HTML page. + +Based on [original work](https://github.com/tuxu/latex2svg) by Tino Wagner. +""" +__version__ = '0.2.1' +__author__ = 'Matthias C. Hormann' +__email__ = 'mhormann@gmx.de' +__license__ = 'MIT' +__copyright__ = 'Copyright (c) 2022, Matthias C. Hormann' + +import os +import sys +import subprocess +import shlex +import re +from tempfile import TemporaryDirectory +from ctypes.util import find_library + +default_template = r""" +\documentclass[{{ fontsize }}pt,preview]{standalone} +{{ preamble }} +\begin{document} +\begin{preview} +{{ code }} +\end{preview} +\end{document} +""" + +default_preamble = r""" +\usepackage[utf8x]{inputenc} +\usepackage{amsmath} +\usepackage{amsfonts} +\usepackage{amssymb} +\usepackage{amstext} +\usepackage{newtxtext} +\usepackage[libertine]{newtxmath} +% prevent errors from old font commands +\DeclareOldFontCommand{\rm}{\normalfont\rmfamily}{\mathrm} +\DeclareOldFontCommand{\sf}{\normalfont\sffamily}{\mathsf} +\DeclareOldFontCommand{\tt}{\normalfont\ttfamily}{\mathtt} +\DeclareOldFontCommand{\bf}{\normalfont\bfseries}{\mathbf} +\DeclareOldFontCommand{\it}{\normalfont\itshape}{\mathit} +\DeclareOldFontCommand{\sl}{\normalfont\slshape}{\@nomath\sl} +\DeclareOldFontCommand{\sc}{\normalfont\scshape}{\@nomath\sc} +% prevent errors from undefined shortcuts +\newcommand{\N}{\mathbb{N}} +\newcommand{\R}{\mathbb{R}} +\newcommand{\Z}{\mathbb{Z}} +""" + +default_svgo_config = r""" +module.exports = { + plugins: [ + { + // use default preset (almost) + name: 'preset-default', + params: { + overrides: { + // viewbox required to resize SVGs with CSS, disable removal + removeViewBox: false, + }, + }, + // enable prefixIds + name: 'prefixIds', + params: { + prefix: '{{ prefix }}', + delim: '_', + }, + }, + ], +}; +""" + +latex_cmd = 'latex -interaction nonstopmode -halt-on-error' +dvisvgm_cmd = 'dvisvgm --no-fonts' +svgo_cmd = 'svgo' + +default_params = { + 'fontsize': 12, # TeX pt + 'template': default_template, + 'preamble': default_preamble, + 'latex_cmd': latex_cmd, + 'dvisvgm_cmd': dvisvgm_cmd, + 'svgo_cmd': svgo_cmd, + 'svgo_config': default_svgo_config, + 'libgs': None, +} + + +if not hasattr(os.environ, 'LIBGS') and not find_library('gs'): + if sys.platform == 'darwin': + # Fallback to homebrew Ghostscript on macOS + homebrew_libgs = '/usr/local/opt/ghostscript/lib/libgs.dylib' + if os.path.exists(homebrew_libgs): + default_params['libgs'] = homebrew_libgs + if not default_params['libgs']: + print('Warning: libgs not found', file=sys.stderr) + + +def latex2svg(code, params=default_params, working_directory=None): + """Convert LaTeX to SVG using dvisvgm and svgo. + + Parameters + ---------- + code : str + LaTeX code to render. + params : dict + Conversion parameters. + working_directory : str or None + Working directory for external commands and place for temporary files. + + Returns + ------- + dict + Dictionary of SVG output and output information: + + * `svg`: SVG data + * `width`: image width in *em* + * `height`: image height in *em* + * `valign`: baseline offset in *em* + """ + if working_directory is None: + with TemporaryDirectory() as tmpdir: + return latex2svg(code, params, working_directory=tmpdir) + + # Caution: TeX & dvisvgm work with TeX pt (1/72.27"), but we need DTP pt (1/72") + # so we need a scaling factor for correct output sizes + scaling = 1.00375 # (1/72)/(1/72.27) + + fontsize = params['fontsize'] + document = code + + with open(os.path.join(working_directory, 'code.tex'), 'w') as f: + f.write(document) + + # Run LaTeX and create DVI file + try: + ret = subprocess.run(shlex.split(params['latex_cmd']+' code.tex'), + stdout=subprocess.PIPE, stderr=subprocess.PIPE, + cwd=working_directory) + ret.check_returncode() + except FileNotFoundError: + raise RuntimeError('latex not found') + + # Add LIBGS to environment if supplied + env = os.environ.copy() + if params['libgs']: + env['LIBGS'] = params['libgs'] + + # Convert DVI to SVG + try: + ret = subprocess.run(shlex.split(params['dvisvgm_cmd']+' code.dvi'), + stdout=subprocess.PIPE, stderr=subprocess.PIPE, + cwd=working_directory, env=env) + ret.check_returncode() + except FileNotFoundError: + raise RuntimeError('dvisvgm not found') + + # Parse dvisvgm output for size and alignment + def get_size(output): + regex = r'\b([0-9.]+)pt x ([0-9.]+)pt' + match = re.search(regex, output) + if match: + return (float(match.group(1)) / fontsize * scaling, + float(match.group(2)) / fontsize * scaling) + else: + return None, None + + def get_measure(output, name): + regex = r'\b%s=([0-9.e-]+)pt' % name + match = re.search(regex, output) + if match: + return float(match.group(1)) / fontsize * scaling + else: + return None + + output = ret.stderr.decode('utf-8') + width, height = get_size(output) + depth = get_measure(output, 'depth') + + # Modify SVG attributes, to a get a self-contained, scaling SVG + from lxml import etree + # read SVG, discarding all comments ("<-- Generated by… -->") + parser = etree.XMLParser(remove_comments=True) + xml = etree.parse(os.path.join(working_directory, 'code.svg'), parser) + svg = xml.getroot() + svg.set('width', f'{width:.6f}em') + svg.set('height', f'{height:.6f}em') + svg.set('style', f'vertical-align:{-depth:.6f}em') + xml.write(os.path.join(working_directory, 'code.svg')) + + # Run svgo to get a minified oneliner with (pseudo-)unique Ids + # generate random prefix using ASCII letters (ID may not start with a digit) + import random, string + prefix = ''.join(random.choice(string.ascii_letters) for n in range(4)) + svgo_config = (params['svgo_config'] + .replace('{{ prefix }}', prefix)) + + # write svgo params file + with open(os.path.join(working_directory, 'svgo.config.js'), 'w') as f: + f.write(svgo_config) + + try: + ret = subprocess.run(shlex.split(params['svgo_cmd']+' code.svg'), + stdout=subprocess.PIPE, stderr=subprocess.PIPE, + cwd=working_directory, env=env) + ret.check_returncode() + except FileNotFoundError: + raise RuntimeError('svgo not found') + + with open(os.path.join(working_directory, 'code.svg'), 'r') as f: + svg = f.read() + + return {'svg': svg, 'valign': round(-depth,6), + 'width': round(width,6), 'height': round(height,6)} + + +def main(): + """Simple command line interface to latex2svg. + + - Read from `stdin`. + - Write SVG to `stdout`. + - On error: write error messages to `stderr` and return with error code. + """ + import json + import argparse + parser = argparse.ArgumentParser(description=""" + Render LaTeX code from stdin as SVG to stdout. Writes metadata (baseline + offset, width, height in em units) into the SVG attributes. + """) + parser.add_argument('--version', action='version', + version='%(prog)s {version}'.format(version=__version__)) + parser.add_argument('--preamble', + help="LaTeX preamble code to read from file") + parser.add_argument('--fontsize', + help="LaTeX fontsize in pt") + args = parser.parse_args() + preamble = default_preamble + if args.preamble is not None: + with open(args.preamble) as f: + preamble = f.read() + fontsize = 12 + if args.fontsize is not None: + fontsize = int(args.fontsize) + latex = sys.stdin.read() + try: + params = default_params.copy() + params['preamble'] = preamble + params['fontsize'] = fontsize + out = latex2svg(latex, params) + sys.stdout.write(out['svg']) + except subprocess.CalledProcessError as exc: + # LaTeX prints errors on stdout instead of stderr (stderr is empty), + # dvisvgm to stderr, so print both (to stderr) + print(exc.output.decode('utf-8'), file=sys.stderr) + print(exc.stderr.decode('utf-8'), file=sys.stderr) + sys.exit(exc.returncode) + + +if __name__ == '__main__': + main()