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       hovercraft - Hovercraft! Documentation



   GUI tools are limiting
       I used to do presentations with typical slideshow software, such as OpenOffice/LibreOffice
       Impress, but these tools felt restricted and limiting.  I need to do a lot of reorganizing
       and  moving  around,  and that might mean changing things from bullet lists to headings to
       text to pictures and back to bullet lists over  again.  This  happens  through  the  whole
       process.  I  might  realize something that was just a bullet point needs to be a slide, or
       that a set of slides for time reasons need to be shortened down to bullet points.  Much of
       the  reorganization  comes from seeing what fits on one slide and what does not, and how I
       need to pace the presentation, and to some extent even what kinda of pictures I  can  find
       to illustrate what I try to say, and if the pictures are funny or not.

       Presentation  software should give you complete freedom to reorganize your presentation on
       every level, not only by reorganizing slides.

       The  solution  for  me  and  many  others,  is  to  use  a  text-markup   language,   like
       reStructuredText,  Markdown  or  similar, and then use a tool that generates an HTML slide
       show from that.

       Text-markup gives you the convenience and freedom to quickly  move  parts  around  as  you

       I chose reStructuredText, because I know it and because it has a massive feature set. When
       I read the documentations of other text-markup langages it was not obvious if they has the
       features I needed or not.

   Pan, rotate and zoom
       The  tools that exist to make presentations from text-markup will make slideshows that has
       a sequence of slides from left to right. But the fashion now is to have presentations that
       rotate and zoom in and out. One open source solution for that is impress.js.

       With impress.js you can make modern cool presentations.

       But impress.js requires you to write your presentation as HTML, which is annoying, and the
       markup isn't flexible enough to let you quickly reorganize things from  bullet  points  to
       headings etc.

       You  also  have  to  position  each slide separately, and if you insert a new slide in the
       middle, you have to reposition all the slides that follow.

       So what  I  want  is  a  tool  that  takes  the  power,  flexibility  and  convenience  of
       reStructuredText  and  allows  me  to  generate  pan,  rotate  and zoom presentations with
       impress.js, without having to manually reposition each slide if I reorganize a little  bit
       of the presentation. I couldn't find one, so I made Hovercraft.

       Hovercraft’s  power  comes from the combination of reStructuredText’s convenience with the
       cool of impress.js, together with a flexible and powerful solution to position the slides.

       There are four ways to position slides:

          1. Absolute positioning: You simply add X and Y coordinates  to  a  slide,  in  pixels.
             Doing only this will not be fun, but someone might need it.

          2. Relative  positioning  to  last slide: By specifying x and/or y with with a starting
             r,you specify  the  distance  from  the  previous  slide.  By  using  this  form  of
             positioning  you  can  insert  a  slide, and the other slides will just move to make
             space for the new slide.

          3. Relative positiong to any slide: You can reference any previous slide by its id  and
             specify  the  position  relative  to  it. This will work for all positioning fields.
             However, you should not use r as a slide id since the positioning might  not  behave
             as you expect.

          4. Automatically:  If  you  don’t  specify  any  position  the slide will have the same
             settings as the previous slide. With a relative positioning, this  means  the  slide
             will move as long as the previous slide moved. This defaults to moving 1600px to the
             right, which means  that  if  you  supply  no  positions  at  all  anywhere  in  the
             presentation, you get the standard slide-to-the-left presentation.

          5. With  an SVG path: In this last way of positioning, you can take an SVG path from an
             SVG document and stick it into  the  presentation,  and  that  slide  +  all  slides
             following that has no explicit positioning will be positioned on that path. This can
             be a bit fiddly to use, but can create awesome  results,  such  as  positioning  the
             slides as snaking Python or similar.

       Hovercraft!  also  includes  impress-console,  a presenter console that will show you your
       notes, slide previews and the time, essential tools for any presentation.

   Shortcut/Navigation Keys:
       A help popup appears upon launching a presentation; it shows the following shortcuts.

       · Space -> Forward

       · Left, Down, Page Down -> Next slide

       · Right, Up, Page Up    -> Previous slide

       · P     -> Open presenter console

       · H     -> Toggle the help popup


       You can either use Hovercraft! to generate the presentation as HTML in a target directory,
       or you can let Hovercraft! serve the presentation from its builtin webserver.

       The  latter  have several benefits. One is that most webbrowsers will be very reluctant to
       open popup-windows from pages served from the file system.  This  is  a  security  measure
       which  can  be changed, but it's easier to just point the browser to http://localhost:8000

       The second benefit is that Hovercraft! will monitor the source files for the presentation,
       and  if  they are modified Hovercraft! will generate the presentation again automatically.
       That way you don't have to run Hovercraft!  everytime you save a file, you  only  need  to
       refresh the browser.

       hovercraft  [-h]  [-t  TEMPLATE]  [-c CSS] [-j JS] [-a] [-s] [-n] [-p PORT] <presentation>

       Positional arguments:

                 The path to the reStructuredText presentation file.

                 The directory where the presentation is saved. Will be created if  it  does  not
                 exist.  If  you  do  not  specify  a  targetdir Hovercraft! will instead start a
                 webserver and serve the presentation from that server.

       Optional arguments:

          -h, --help
                 Show this help.

          -t TEMPLATE, --template TEMPLATE
                 Specify a template. Must be a .cfg file, or  a  directory  with  a  template.cfg
                 file. If not given it will use a default template.

          -c CSS, --css CSS
                 An additional CSS file for the presentation to use.  See also the :css: settings
                 of the presentation.

          -j JS, --js JS
                 An additional Javascript file for the presentation to use. Added  as  a  js-body
                 script.  See also the :js-body: settings of the presentation.

          -a, --auto-console
                 Open the presenter console automatically. This is useful when you are rehearsing
                 and making sure the presenter notes are correct.   You  can  also  set  this  by
                 having :auto-console: true first in the presentation.

          -s, --skip-help Do not show the initial help popup. You can also set
                 this by having :skip-help: true first in the presentation.

          -n, --skip-notes
                 Do not include presenter notes in the output.

          -N, --slide-numbers
                 Show  the current slide number on the slide itself and in the presenter console.
                 You can also  set  this  by  having  slide-numbers:  true  in  the  presentation

          -p PORT, --port PORT
                 The  address  and port that the server uses. Ex 8080 or Defaults

   Built in templates
       There are two templates that come with Hovercraft! One is called default and will be  used
       unless you specify a template. This is the template you will use most of the time.

       The  second  is  called  simple  and it doesn't have a presenter console. This template is
       especially useful if you combine it with the --skip-notes parameter to prepare  a  version
       of your presentation to be put online.


   A note on terminology
       Traditionally  a  presentation  is  made up of slides. Calling them "slides" is not really
       relevant in an impress.js context, as they can overlap and doesn't necessarily slide.  The
       name  "steps"  is  better,  but it's also more ambiguous.  Hence impress.js uses the terms
       "slide" and "step" as meaning the same thing, and so does Hovercraft!

   Hovercraft! syntax
       Presentations are reStructuredText files. If you are reading this documentation  from  the
       source code, then you are looking at a reStructuredText document already.

       It's fairly simple, you underline headings to mark them as headings:

          This becomes a h1

          And this a h2

       The different ways of underlining them doesn't mean anything, instead the order of them is
       relevant, so the first type of underline encountered in the  file  will  make  a  level  1
       heading,  the second type a level 2 heading and so on. In this file = is used for level 1,
       and - for level 2.

       You can also mark text as italic or bold, with *single asterixes* or **double  asterixes**

       You can also have bullet lists:

          * Bullet 1

            * Bullet 1.1

          * Bullet 2

          * Bullet 3

       And numbered lists:

          1. Item 1

              1.1. Item 1.1

          2. Item 2

          3. Item 3

       You can include images:

          .. image:: path/to/image.png
              :height: 600px
              :width: 800px

       As  you  see you can also specify height and width and loads of other parameters, but they
       are all optional.

       And you can mark text as being preformatted. You do that by ending the previous  row  with
       double colons, or have a row of double colons by itself:


              This code here will be preformatted
               and shown with a  monospaced font
              and    all    spaces     preserved.

       If  you  want  to  add  source  code,  you  can  use  the  code  directive, and get syntax

          .. code:: python

              def some_example_code(foo):
                  return foo * foo

       The syntax highlighting is done by Pygments and supports lots and lots of languages.

       You are also likely to want to put a title on the presentation. You do that by having a ..
       title:: statement before the first slide:

          .. title:: This is the presentation title

       That  is  the  most important things you'll need to know about reStructuredText for making
       presentations. There is a lot more to know, and a lot of  advanced  features  like  links,
       footnotes,  and  more.  It is in fact advanced enough so you can write a whole book in it,
       but for all that you need to read the documentation.

       If you add a math directive then hovercraft! will add a link to the MathJax  CDN  so  that

          .. math:: e^{i \pi} + 1 = 0

       will be rendered by the MathJax javascript library. The math directive can also be used as
       a "role" with the equations inlined with the text flow. Note that  if  you  use  the  math
       statement,  by  default the MathJax library will be loaded from the internet, meaning that
       your presentation will need network connectivity to work, which  can  be  a  problem  when
       presenting and conferences, which often have bad network connectivity.

       This can be solved by specifying a local copy of mathjax with the --mathjax command line.

   Presenter notes
       To add presenter notes, that will be displayed in the presenter console, use the following

          .. note::

              Here goes the presenter note.

   External files
       Any image file referenced in the presentation by a relative path will  be  copied  to  the
       target directory, keeping it's relative path to the presentation. The same goes for images
       or fonts referenced in any CSS files used by the presentation or the template.

       Images or fonts referenced by absolute paths or URI's will not be copied.

   Styling your Presentation
       The css that is included by the default template are three files.

       · impressConsole.css contains the CSS needed for the presenter console to work,

       · highlight.css contains a default style for code syntax highlighting, as  that  otherwise
         would  be  a  lot  of  work.  If  you  don't  like  the  default colors or styles in the
         highlighting, this is the file you should copy and modify.

       · hovercraft.css, which only includes the bare minimum: It hides the  impress.js  fallback
         message,  the  presenter  notes,  and sets up a useful default of having a step width be
         1000 pixels wide.

       For this reason you want to include your own CSS to style your slides. To  include  a  CSS
       file you add a :css:-field at the top of the presentation:

          :css: css/presentation.css

       You can also optionally specify that the css should be only valid for certain CSS media:

          :css-screen,projection: css/presentation.css
          :css-print: css/print.css

       You  can specify any number of css files in this way.  You can also add one extra CSS-file
       via a command-line parameter:
          hovercraft --css=my_extra.css presentationfile.rst outdir/

   Styling the console
       You can also optionally add styles to your slides that are only shown in when the slide is
       shown in the presenter console:

          :css-preview: css/slidepreview.css

       You can also style the presenter console itself:


       That css file needs to be based on the impressConsole.css used by the default template, as
       it replaces that file.

   Adding Javascript
       In a similar fashion you can add Javascript files to either header or body:

          :js-header: js/firstjsfile.js
          :js-body: js/secondjsfile.js

       You can also add one extra Javascript-file via a command-line parameter:
          hovercraft --js=my_extra.js presentationfile.rst outdir/

       If you want static content, content that doesn't move  with  each  slide;  for  example  a
       header,  footer, your company logo or a slide background pattern, then you can insert that
       content with the header and footer commands:

          .. header::

             .. image:: images/company-logo.png

          .. footer::

              "How to use Hovercraft", Yern Busfern, ImaginaryCon 2017

       The header will be located in the resulting HTML before the first  slide  and  the  footer
       will  be located after the last slide. However, they will be displayed statically on every
       slide, and you will have to position  them  with  CSS.  By  default  the  header  will  be
       displayed behind the slides and the footer in front of the slides, so the header is useful
       for background designs and the footer for designs that should be in the foreground.

       It doesn't matter where in the presentation you add these commands, I would recommend that
       you add them before the first slide.

   Styling a specific slide
       If  you want to have specific styling for a specific slide, it is a good idea to give that
       slide a unique ID:

          :id: the-slide-id

       You can then style that slide specifically with:

          div#the-slide-id {
              /* Custom CSS here */

       If you don't give it a specific ID, it will get an ID based on its  sequence  number.  And
       that  means the slide's ID will change if you insert or remove slides that came before it,
       and in that case your custom stylings of that slide will stop working.

   Adding a custom class to slides
       If you want to apply the same style to one or more slides you may prefer adding a class to
       those slides instead (or in addition to) a unique ID:

          :id: my-custom-class

       You can then style those slides by adding CSS rules with:

          .my-custom-class {
              /* Custom CSS here */

   Adding a custom directive
       If  you want to use a custom docutils directive, you'll want to run hovercraft in the same
       process where you register your directive. For example, you can create  a  custom  startup
       script like the following:

          from docutils import nodes
          from docutils.parsers.rst import Directive, directives

          import hovercraft

          class HelloWorld(Directive):
              def run(self):
                  para = nodes.paragraph(text='Hello World')
                  return [para]

          directives.register_directive('hello-world', HelloWorld)

          if __name__ == "__main__":
              cmd = ['--skip-help', 'slides.rst']

       While  creating  your  own  directive  might  be  daunting,  it's possible to reuse useful
       directives from other projects. For example, you can reuse Pelican's  custom  code  block,
       which  adds an hl_lines option to highlight specific lines of code. To use that directive,
       simply add the following import to the above script:

          import pelican.rstdirectives

   Portable presentations
       Since Hovercraft! generates HTML5 presentations, you can  use  any  computer  that  has  a
       modern  browser installed to view or show the presentation. This allows you both to put up
       the presentation online and to use a borrowed computer for  your  conference  or  customer

       When  you  travel  you  don't  know  what  equipment  you  have  to use when you show your
       presentaton, and it's surprisingly common to encounter a projector that refuses to talk to
       your computer. It is also very easy to forget your dongle if you have a MacBook, and there
       have even been cases of computers going completely black and dead when you connect them to
       a projector, even though all other computers seem to work fine.

       The  main  way  of  making  sure  your  presentation is portable is to try it on different
       browsers and different computers. But the latter can be unfeasible, not everyone has  both
       Windows,  Linux and OS X computers at home. To help make your presentations portable it is
       a good idea to define your own @font-face's and use them, so you are sure that the  target
       browser  will use the same fonts as you do. Hovercraft! will automatically find @font-face
       definitions and copy the font files to the target directory.

   impress.js fields
       The documentation on impress.js is contained as comments in the demo html file. It is  not
       always very clear, so here comes a short summary for convenience.

       The different data fields that impress.js will use in 0.5.3, which is the current version,
       are the following:

       · data-transition-duration: The time it will take to  move  from  one  slide  to  another.
         Defaults to 1000 (1 second). This is only valid on the presentation as a whole.

       · data-perspective:  Controls  the  "perspective"  in  the 3d effects. It defaults to 500.
         Setting it to 0 disables 3D effects.

       · data-x: The horizontal position of a slide in pixels. Can be negative.

       · data-y: The vertical position of a slide in pixels. Can be negative.

       · data-scale: Sets the scale of a slide, which is what creates the zoom.  Defaults to 1. A
         value  of  4  means  the  slide  is four times larger. In short: Lower means zooming in,
         higher means zooming out.

       · data-rotate-z: The rotation of a slide in the x-axis, in degrees. This  will  cause  the
         slide to be rotated clockwise or counter-clockwise.

       · data-rotate: The same as data-rotate-z.

       · data-rotate-x:  The  rotation  of  a slide in the x-axis, in degrees. This means you are
         moving the slide in a third dimension compared with other slides. This is generally cool
         effect, if used right.

       · data-rotate-y: The rotation of a slide in the x-axis, in degrees.

       · data-z:  This  controls  the  position of the slide on the z-axis. Setting this value to
         -3000 means it's positioned -3000  pixels  away.  This  is  only  useful  when  you  use
         data-rotate-x  or  data-rotate-y,  otherwise  it  will only give the impression that the
         slide is made smaller, which isn't really useful.

   Hovercraft! specialities
       Hovercraft!  has  some  specific  ways  it  uses  reStructuredText.  First  of  all,   the
       reStructuredText  "transition"  is used to mark the separation between different slides or
       steps. A transition is simply a line with four or more dashes:


       You don't have to use dashes, you  can  use  any  of  the  characters  used  to  underline
       headings,  =  -  `  :  .  '  "  ~  ^  _ * + #. And just as width headings, using different
       characters indicates  different  "levels".  In  this  way  you  can  make  a  hierarchical
       presentation, with steps and substeps.  However, impress.js does not support that, so this
       is only useful if you make your own templates that uses another  Javascript  library,  for
       example  Reveal.js. If you have more than one transition level with the templates included
       with Hovercraft, the resulting presentation may behave strangely.

       All reStructuredText fields are converted into attributes on the  current  tag.   Most  of
       these  will  typically be ignored by the rendering to HTML, but there are two places where
       the tags will make a difference, and that is by putting them first  in  the  document,  or
       first on a slide.

       Any  fields  you  put  first  in  a  document will be rendered into attributes on the main
       impress.js <div>. The only ones that Hovercraft! will  use  are  data-transition-duration,
       skip-help, auto-console and slide-numbers.

       Any  fields  you put first in a slide will be rendered into attributes on the slide <div>.
       This is used primarily to set the position/zoom/rotation of the  slide,  either  with  the
       data-x, data-y and other impress.js settings, or the hovercraft-path setting, more on that

       Hovercraft! will start making the first slide when it first encounters either a transition
       or a header. Everything that comes before that will belong to the presentation as a whole.

       A presentation can therefore look something like this:

          :data-transition-duration: 2000
          :skip-help: true

          .. title: Presentation Title


          This is the first slide

          Here comes some text.


          :data-x: 300
          :data-y: 2000

          This is the second slide

          #. Here we have

          #. A numbered list

          #. It will get correct

          #. Numbers automatically

   Relative positioning
       Hovercraft!  gives you the ability to position slides relative to each other.  You do this
       by starting the coordinates with "r". This will position the slide 500 pixels to the right
       and a thousand pixels above the previous slide:

          :data-x: r500
          :data-y: r-1000

       Relative  paths  allow  you  to  insert  and  remove  slides  and have other slides adjust
       automatically. It's generally the most useful way of positioning.

   Automatic positioning
       If you don't specify an attribute, the slide settings will be the  same  as  the  previous
       slide. This means that if you used relative positioning, the next slide will move the same

       This gives a linear movement, and your slides will end up in a straight line.

       By default the movement is 1600 pixels to  the  right,  which  means  that  if  you  don't
       position  any  slides at all, you get a standard presentation where the slides will simply
       slide from right to left.

   SVG Paths
       Hovercraft! supports positioning slides along an SVG path.  This  is  handy,  as  you  can
       create  a  drawing in a software that supports SVG, and then copy-paste that drawings path
       into your presentation.

       You specify the SVG path with the :hovercraft-path: field. For example:

          :hovercraft-path: m275,175 v-150 a150,150 0 0,0 -150,150 z

       Every following slide that does not have any explicit positioning will be placed  on  this

       There are some things you need to be careful about when using SVG paths.

   Relative and absolute coordinates
       SVG  coordinates can either be absolute, with a reference to the page origin; or relative,
       which is in reference to the last point. Hovercraft! can handle both, but what it can  not
       handle very well is a mixture of them.

       Specifically,  if  you  take  an SVG path that starts with a relative movement and extract
       that from the SVG document, you will lose the context. All  coordinates  later  must  then
       also be relative. If you have an absolute coordinate you then suddenly regain the context,
       and everything after the first absolute coordinate  will  be  misplaced  compared  to  the
       points that come before.

       Most  notable,  the  open  source  software  "Inkscape"  will  mix  absolute  and relative
       coordinates, if you allow it to use relative coordinates. You therefore need  to  go  into
       it's  settings  and uncheck the checkbox that allows you to use relative coordinates. This
       forces Inkscape to save all coordinates as absolute, which will work fine.

   Start position
       By default the start position of the path, and hence  the  start  position  of  the  first
       slide, will be whatever the start position would have been if the slide had no positioning
       at all. If you want to change this position then just include :data-x: or :data-y: fields.
       Both relative and absolute positioning will work here.

       In  all  cases,  the  first m or M command of the SVG path is effectively ignored, but you
       have to include it anyway.

   SVG transforms
       SVG allows you to draw up path and then transform it. Hovercraft! has no support for these
       transforms,  so  before you extract the path you should make sure the SVG software doesn't
       use transforms. In Inkscape you can do this by the "Simplify" command.

   Other SVG shapes
       Hovercraft! doesn't support other SVG shapes, just the path. This  is  because  organising
       slides  in  squares,  etc,  is quite simple anyway, and the shapes can be made into paths.
       Usually in the software you will have to select the shape and tell your software  to  make
       it  into  a path. In Inkscape, transforming an object into a path will generally mean that
       the whole path is made of CubicBezier curves, which are unnecessarily complex.  Using  the
       "Simplify" command in Inkscape is usually enough to make the shapes into paths.

       Hovercraft! will scale the path so that all the slides that need to fit into the path will
       fit into the path. If you therefore have several paths in your presentation, they will not
       keep  their relative sizes, but will be resized so the slides fit. If you need to have the
       shapes keep their relative sizes, you need to combine them into one path.

       To see how to use Hovercraft! in practice, there are three example presentations  included
       with Hovercraft!

                 The demo presentation you can see at

                 A step by step guide to the features of Hovercraft!

                 An explanation of how to use the positioning features.


       There  are  several  tricks  to  making  presentations.  I certainly do not claim to be an
       expert, but here are some beginners hints.

   Take it easy
       Don't go too heavy on the zoom. Having a difference between two slides in  scale  of  more
       than  5  is  rarely going to look good. It would make for a nice cool zooming effect if it
       did, but this is not what browsers are designed for, so it won't.

       And the 3D effects can be really cool if used well. But not all the time, it  gets  tiring
       for the audience.

       Try,  if you can, to use the zoom and 3D effects when they make sense in the presentation.
       You can for example mention the main topics on one slide, and then zoom in on  each  topic
       when  you  discuss  it in more detail. That way the effects help clarify the presentation,
       rather than distract from it.

   Custom fonts
       Browsers tend to render things subtly differently.

       They also have different default fonts, and different  operating  systems  have  different
       implementations  of  the  same  fonts.  So  to make sure you have as much control over the
       design as possible, you should always include fonts with the presentation. A  good  source
       for  free  fonts are Google Webfonts. Those fonts are free and open source, so you can use
       them with no cost and no risk of being sued. They  can  also  be  downloaded  or  included

   Online vs Downloaded
       If  you are making a presentation that is going to run on your computer at a conference or
       customer meeting, always download the fonts and have them as a part of  the  presentation.
       Put them in a folder called fonts under the folder where your presentation is.

       You  also  need  to  define the font-family in your CSS. Font Squirrel's webfont generator
       will provide you with a platform-independent toolkit for generating both the  varius  font
       formats and the CSS.

       If  the  presentation  is  online  only,  you can put an @include-statement in your CSS to
       include Googles webfonts directly:

          @import url(|Racing+Sans+One|Satisfy);

       But don't use this for things you need to show on your computer, as  it  requires  you  to
       have internet access.

   Test with different browsers
       If  you  are  putting the presentation online, test it with a couple of major browsers, to
       make sure nothing breaks and that everything still looks good.  Not only are there  subtle
       differences  in  how  things  may  get  positioned,  different  browsers  are also good at
       different things.

       I've tested some browsers, all on Ubuntu, and it is likely that they behave differently on
       other operating systems, so you have to try for yourself.

       Firefox  18  is quite slow to use with impress.js, especially for 3D stuff, so it can have
       very jerky movements from slide to slide. It does keep text looking  good  no  matter  how
       much you zoom. On the other hand, it refuses to scale text infinitely, so if you scale too
       much characters will not grow larger, they will instead start moving around.

       Firefox 19 is better, but for 3D stuff it's still a bit slow.

       Chrome 24 is fast, but will not redraw text in different sizes, but will instead create an
       image  of  them and rescale them, resulting in the previous slide having a fuzzy pixelated

       Epiphany 3.4.1 is comparable to Firefox 19, possibly a bit smoother, and  the  text  looks
       good.  But  it  has  bugs  in  how  it handles 3D data, and the location bar is visible in
       fullscreen mode, making it less suitable for any sort of presentation.


       Luckily, for most cases you don't need  to  create  your  own  template,  as  the  default
       template  is  very  simple  and  most things you need to do is doable with css. However, I
       don't want Hovercraft! to set up a wall where it isn't flexible enough for your needs,  so
       I added support to make your own templates.

       You need to create your own template if you are unsatisfied with the HTML that Hovercraft!
       generates,  for  example  if  you  need  to  use  another  version  of  HTML  or  if   the
       reStructuredText  you  are  using  isn't  being  rendered in a way that is useful for you.
       Although if you aren't happy with the HTML generated from the reStructuredText that  could
       very well be a bug, so open an issue on Github for discussion.

       Hovercraft!  generates  presentations by converting the reStructuredText into XML and then
       using XSLT to translate the XML into HTML.

       Templates are directories with a configuration file, a template XSL file, and  any  number
       of CSS, JS and other resource files.

   The template configuration file
       The  configuration  file  is  normally  called  template.cfg,  but  if  you  have  several
       configuration files in one template directory,  you  can  specify  which  one  to  use  by
       specifying  the  full  path  to  the  configuration file. However, if you just specify the
       template directory, template.cfg will be used.

       Template files are in configparser format, which is an extended ini-style format. They are
       very  simple, and have only one section, [hovercraft]. Any other sections will be ignored.
       Many of the parameters are lists that often do not fit on one line. In that case  you  can
       split  the  line up over several lines, but indenting the lines. The amount of indentation
       doesn't make any difference, except aesthetically.

       The parameters in the [hovercraft] section are:

          · template The name of the xsl template.

          · css A list of CSS filenames separated by whitespace. These files will get included in
            the final file with "all" as the media specification.

          · css-<media>  A  list  of  CSS filenames separated by whitespace. These files will get
            included in the final file with the media given in the parameter. So the files listed
            for the parameter "css-print" will get "print" as their media specification and a key
            like "css-screen,print" will return media "screen,print".

          · js-header A list of filenames separated by whitespace. These files will get  included
            in the target file as header script links.

          · js-body A list of filenames separated by whitespace. These files will get included in
            the target file as script links at  the  end  of  the  file.  The  files  impress.js,
            impressConsole.js and hovercraft.js typically need to be included here.

          · resources  A  list  of  filenames  separated by whitespace that will be copied to the
            target directory, but nothing else is done with them. Images and fonts  used  by  CSS
            will be copied anyway, but other resources may be added here.

          · resource-directories A list of directory names separated by whitespace. These will be
            treated like resources above, ie only copied to the target directory.  The  directory
            contents  will  be copied recursively, but hidden files (like files starting with a .
            are ignored.

       An example:

          template = template.xsl

          css = css/screen.css

          css-print = css/print.css

          js-header = js/dateinput.js

          js-body = js/impress.js

          resources = images/back.png

   The template file
       The file specified with the template parameters is the  actual  XSLT  template  that  will
       perform the translation from XML to HTML.

       Most    of    the    time   you   can   just   copy   the   default   template   file   in
       hovercraft/templates/default/template.xsl  and  modify  it.  XSLT  is  very  complex,  but
       modifying  the  templates HTML is quite straightforward as long as you don't have to touch
       any of the <xsl:...> tags.

       Also, the HTML that is generated is XHTML compatible and quite straightforward, so for the
       most  case  all  you  would  need  to generate another version of HTML, for example strict
       XHTML, would be to change the doctype.

       But if you need to add or change the main generated HTML  you  can  add  and  change  HTML
       statements  in  this  main  file as you like. See for example how the little help-popup is
       added to the bottom of the HTML.

       If you want to change the way the reStructuredText is rendered things  get  slightly  more
       complex. The XSLT rules that convert the reStructuredText XML into HTML are contained in a
       separate file, reST.xsl. For the most part you can just include it in  the  template  file
       with the following code:

          <xsl:import href="resource:templates/reST.xsl" />

       The  resource:  part  here  is not a part of XSLT, but a part of Hovercraft!  It tells the
       XSLT translation that the file specified should not be looked up on the file  system,  but
       as  a  Python  package  resource.  Currently  the templates/reST.xsl file is the only XSLT
       resource import available.

       If you need to change the way reStructuredText is rendered you need to make a copy of that
       file  and  modify  it.  You  then  need to make a copy of the main template and change the
       reference in it to your modified XSLT file.

       None of the XSLT files need to be copied to the target, and should  not  be  listed  as  a
       resource in the template configuration file.


       Lennart Regebro


       2013-2019, Lennart Regebro