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|
% vim: tw=80
\_def\_pdfextra_version{0.2}
\_codedecl \RM {Extra PDF features (v\_pdfextra_version)}
\_namespace{pdfextra}
\_doc
\sec Package initialization
We ensure that hyperlinking is active. Our fallback \`\_linkcolor` must
exist. We also use it for `\hyperlinks` if the user didn't enable
`\hyperlinks` yet (we don't want to override user setting).
\_cod
\_ifdefined\_ilinkcolor\_else
\_ifdefined\_linkcolor
\_ea\_let\_ea\_linkcolor \_ifdefined\Blue\Blue\_else\_empty\_fi
\_else
\_let\_linkcolor\linkcolor
\_fi
\_fi
\_ifx\_dest\_destactive\_else
\_hyperlinks\_linkcolor\_linkcolor
\_fi
\_doc
We are in the \OpTeX/ package namespace. A couple of shortcuts are defined
here: \`\.isdefined`, \`\.trycs`, \`\.cs` \`\.slet`, \`\.slet`, \`\.sdef` and
\`\.sxdef`. They all hard code the package name, because we already have too
many levels of indirection.
\_cod
\_def\.isdefined#1{\_isdefined{_pdfextra_#1}}
\_def\.trycs#1{\_trycs{_pdfextra_#1}}
\_def\.cs#1{\_cs{_pdfextra_#1}}
\_def\.slet#1#2{\_slet{_pdfextra_#1}{_pdfextra_#2}}
\_def\.sdef#1{\_sdef{_pdfextra_#1}}
\_def\.sxdef#1{\_sxdef{_pdfextra_#1}}
\_doc
\sec Helper macros
The macros here are just helpers for the macros to follow. They are not
useful generally, but proved useful in the expandable context of writing to
PDF files.
Already the first one limits the use to \LuaTeX/ (but who needs other engines
anyways :). \`\.emptyor`<possibly empty text><text to use when first argument is
nonempty> checks whether the first argument is empty, if not it expands the
second argument which can use the text from the first argument with
\`\.nonempty`. \`\.attrorempty`<attribute name><value> builds upon the first
one and is really useful for PDF dictionaries, when we don't want to write an
attribute without a value (a default specified by standard will be used instead).
\_cod
\_def\.emptyor#1#2{%
\_immediateassignment\_edef\.nonempty{#1}%
\_ifx\.nonempty\_empty\_else #2\_fi
}
\_def\.attrorempty#1#2{\.emptyor{#2}{/#1 \.nonempty}}
\_doc
There is a dillema for handling colors. While typesetting it is possible to
use greyscale, CMYK or RGB colors. But there are contexts where it is
possible to only use RGB colors. We want to provide the user with two
possibilities of specifying colors:
\begitems
* RGB color using PDF triplet (e.g. `1 0 0`),
* \OpTeX/ color using control sequence (e.g. `\Blue`)
\enditems
Both are handled by \`\.colortorgbdef`<cs><color specification>, which
defines <cs> to the corresponding PDF RGB triplet. The indirection with
defining a macro is because we want to use the processed color within
expansion only contexts where grouping is not possible.
\_cod
\_def\.colortorgbdef#1#2{\_bgroup
\_def\_setrgbcolor##1{##1}%
\_def\_setcmykcolor##1{\_cmyktorgb ##1 ;}%
\_def\_setgreycolor##1{##1 ##1 ##1}%
\_xdef#1{#2}%
\_egroup
}
\_doc
\`\.xaddto``\macro`{<text>} is a natural extension of \OpTeX's `\addto` that
expands <text> and is global.\nl
\`\.tmp` is used throught the package for temporary values.
\_cod
\_def\.xaddto#1#2{\_edef\.tmp{#2}%
\_global\_ea\_addto\_ea#1\_ea{\.tmp}%
}
\_doc
This package defines a few commands in the form
`\macro[<name>][<optional arguments>]{<text>}`. To make it possible to omit
the `[<optional arguments>]` \`\.secondoptdef` is defined.
`\.secondoptdef\<macro><parameters>{<body>}`
defines `\macro` with first mandatory argument in brackets (saved to
\`\.name`). Second optional argument in brackets is scanned using helper
macro defined with `\optdef` and is saved to `\_opt` token list). Additional
<parameters> can be specified as with `\optdef` (numbered from `#1`).
\_cod
\_def\.secondoptdef#1{%
\_def#1[##1]{\_def\.name{##1}\.cs{sopt:\_string#1}}%
\_ea\_optdef\_csname _pdfextra_sopt:\_string#1\_endcsname[]%
}
\_doc
When processing comma separated lists sometimes it is needed to ignore the
remaining text. For this we use \`\.untilend` macro which ignores everything
up to dummy \`\.end`. This is analogous to \OpTeX/'s `\_finbody` used for the
same purpose. Sometimes `\.end` is used as sentinel and compared in `\ifx`
tests, hence we define it to a unique value.
\_cod
\_def\.untilend#1\.end{}
\_def\.end{_pdfextra_end}
\_doc
For various uses it is necessary to know the number of page where something
happens. This has to be handled asynchronously with `\write`. Here we use
\OpTeX/ specific `.ref` file and associated macros, but this could be
replaced as long as the same interface is exposed.
\`\.setpageof`<name> writes \`\.Xpageof`<name> to the `.ref` file. In the next
\TeX/ run `\.Xpageof` finds out the page number (`\gpageno`) from \OpTeX/'s
`\_currpage` and saves it so that \`\.pageof`<name> can retrieve it. In the
first run we can't be sure of the page where the content will end up. As a
rough estimate we take the current page~-- this actually works well for
slides where page breaks are manual.
When `.ref` file is read along with the defintion of `\.Xpageof` this package
has not been loaded yet. Hence we can't use namespaced variants of
`\.isdefined`, etc.
\_cod
\_refdecl{%
\_def\.Xpageof#1{\_isdefined{_pdfextra_pageof:#1}\_iffalse
\_sxdef{_pdfextra_pageof:#1}{\_ea\_ignoresecond\_currpage}\_fi
}%
}
\_def\.setpageof#1{\_openref \_ewref\.Xpageof{{#1}}}
\_def\.pageof#1{%
\.trycs{pageof:#1}{%
\_the\_numexpr\_gpageno+1\_relax % best effort = current page num
}%
}
\_doc
\label[files]
\sec Handling of files
Handling of files is a big topic of this package. Files are everywhere~--
files containing multimedia, JavaScript script files, attachments, externally
referred files\dots Therefore a more sophisticated mechanism for handling
files is needed. The mechanism introduced in this section handles all three
cases of a {\em file specification}:
\begitems
* files embedded in the PDF (\"e", embedded file),
* files determined by path (\"x", external file),
* files determined by URL (\"u", url file).
\enditems
Although ideally all three would be interchangible this is not always the
case, because e.g. some media files must be embedded and linking to external
resources does not work with embedded files.
In most cases there are two many names and other associated values involved:
\begitems
* Some kind of a \"friendly" name. This one is sometimes shown by PDF viewers.
* The real name of the file. Also shown but in different contexts.
* The path or URL used to determine the file.
* MIME type of the file.
\enditems
For example when talking about \OpTeX/'s documentation we might have a
friendly name of \"opdoc", file name of \"`optex-doc.pdf`", URL of
\"\url{http://petr.olsak.net/ftp/olsak/optex/optex-doc.pdf}" and MIME type of
\"application/pdf". Different subset of them is required in different
contexts, but the user should only have to specify the friendly name (by
which they will refer to the file) and the path/URL of the file. The rest
will be deduced. The friendly name is used as a handle and {\em is usable}
in all places where file specification is required (although it may not
produce conforming output, see above).
In this two step process~-- definition and (re)use~-- we introduce a command
for defining files: \`\filedef``/<type> [<friendly name>]{<path or URL>}`. The
macro itself does general definitions and dispatches the type dependant work
to other macros in the form `_filedef:<type>`.
\_cod
\_def\.filedef/#1#2[#3]#4{%
\.sxdef{filename:#3}{(\.filename{#4})}%
\_edef\.tmp{\.exttomime{\.fileext{#4}}}%
\_ifx\.tmp\_empty
\_opwarning{MIME type of '#4' unknown, using '\.defaultmimetype'}%
\_edef\.tmp{\.defaultmimetype}%
\_fi
\.sxdef{filemime:#3}{\.tmp}%
\.cs{filedef:#1}{#3}{#4}%
}
\_nspublic \filedef ;
\_doc
Types \"e", \"x", \"u" are predefined, anything else would essentialy be a
variant of these.
External file (\"x") is determined only by path.
\_cod
\.sdef{filedef:x}#1#2{%
\.slet{filespec:#1}{filename:#1}%
}
\_doc
URL file (\"u") is determined by URL. Using all sorts of characters is
allowed by using `\_detokenize`. This time it is necessary to create full
{\em file specification}~-- a dictionary, where the \"file system" is URL.
\_cod
\.sdef{filedef:u}#1#2{%
\.sdef{filespec:#1}{<</FS /URL /F (\_detokenize{#2})>>}%
}
\_doc
Embedded files (\"e") are the most interesting ones. For further use (e.g.
for displaying the embedded files as attachments) MIME type is required. It
is saved in the stream as a `\Subtype`, encoded as a PDF name (e.g.
`/video#2Fmp4`). The embedded file stream must be wrapped in a full {\em file
specification}, which has the `/EF` (\"embedded file") entry. Also the
friendly name is used for some purpose by PDF viewers, so it set in `/Desc`
(description).
\_cod
\.sdef{filedef:e}#1#2{%
\_edef\.tmp{\.cs{filemime:#1}}%
\_isfile{#2}\_iffalse
\_opwarning{file '#2' not found}%
\_fi
\_pdfobj stream
attr{/Type /EmbeddedFile /Subtype \_ea\.mimetoname\_ea[\.tmp]}
file {#2}%
\_pdfrefobj\_pdflastobj
\.sxdef{filestream:#1}{\_the\_pdflastobj\_space 0 R}%
\_pdfobj {<</Type /Filespec
/F \.cs{filename:#1}
/Desc (#1)
/EF << /F \_the\_pdflastobj \_space 0 R >>%
>>}%
\_pdfrefobj\_pdflastobj
\.sxdef{filespec:#1}{\_the\_pdflastobj\_space 0 R}%
}
\_doc
Now the less interesting part~-- determining the file names from paths and
determining MIME types. The file name is the part after the last \"`/`" (if
any). The file extension is the part after last \"`.`" (if any).
\_cod
\_def\.filename#1{\_ea\.filenameA#1/\.end}
\_def\.filenameA#1/#2{\_ifx\.end#2#1\_else\_afterfi{\.filenameA#2}\_fi}
\_def\.fileext#1{\_ea\.fileextA#1.\.end}
\_def\.fileextA#1.#2{\_ifx\.end#2#1\_else\_afterfi{\.fileextA#2}\_fi}
\_doc
MIME type is determined from file extension (e.g. `mp4` is \"video/mp4"). For
mapping of file extensions to MIME types we abuse \TeX/'s hash table which
gets populated with \"known MIME types". This necessarily means that the
database is incomplete. Users can define their own additional mappings, or
they can contribute generally useful ones to this package.
The default MIME type (used for unknown file extensions) is
\"application/octet-stream"~-- binary data.
The uninteresting MIME type database itself is at the very end (\ref[mime]).
\_cod
\_def\.mimetoname[#1/#2]{/#1\_csstring\#2F#2}
\_def\.defaultmimetype{application/octet-stream}
\_def\.exttomime#1{\.trycs{mimetype:#1}{}}
\_doc
Here we define an \OpTeX/ style \"is-macro" that checks whether the file has
already been defined~-- \`\.isfiledefined``{<name>}\iftrue` (or `\iffalse`).
The case where the file has not
been defined using `\filedef` can be handled in a lot of ways. As a default
we interpret <name> as path and try to embed it. Because the path from <name>
is used as the \"friendly name" the file will be embedded only once even when
requested more times.
\_cod
\_def\.isfiledefined#1#2{\.isdefined{filespec:#1}\_iftrue\_else
\_afterfi{\.fileundefined{#1}}\_fi#2%
}
\_def\.fileundefined#1{\_isfile{#1}\_iftrue\.filedef/e[#1]{#1}\_else
\_opwarning{file '#1' not found, ignored}\_ea\_unless\_fi
}
% strict requirement of preceeding `\filedef` can be set like this:
%\_def\.fileundefined#1{\_opwarning{file '#1' is not defined, ignored}\_unless}
\_doc
\label[actions]
\sec PDF actions
The core of interactivity in PDF are actions. They are all initialy handled
by \`\pdfaction``[<action spec>]`. <action spec> is a comma separated list of
`<type>:<arguments>`. Leading spaces in the elements of the list are ignored
using undelimited-delimited argument pair trick.
An invocation could look like this:
\begtt
\pdfaction[
js:{app.alert("Yay JavaScript, going to page 5");},
ilink:pg:5,
transition:Wipe,
]
\endtt
This is why we have to be very careful when loading the contents between `[]`
to arguments. In particular, we can't split immediatly using `[#1:#2]`,
because this would discard the braces guarding the comma in the JavaScript
code. However we also need to find out the {\em type} of action which is
taken as a type of the first action (`js` in this case).
\`\.pdfactiontype``[<action spec>]` does this~-- we don't mind that there the
braces are lost.
`\pdfaction` processes the list, to create a chain of actions using `/Next`
field. The handling of each action type is up to macro
`\_pdfextra_<type>action`, which receives `[<type>:<arguments>]`. Because of
this a single type handler can handle multiple different actions, as is the
case with `\.ilinkaction` which is the fallback for unknown action types.
\_cod
\_def\.pdfaction[#1#2]{\.pdfactionA#1#2,\.stop\.end}
\_def\.pdfactionA#1,#2#3\.end{%
<<%
\.pdfactionB[#1]%
% next action
\_ifx\.stop#3\_else\_space
/Next \_afterfi{\.pdfactionA#2#3\.end} % intentional space
\_fi
>>
}
\_def\.pdfactionB[#1:#2]{\.trycs{#1action}{\_ea\.ilinkaction}[#1:#2]}
\_nspublic \pdfaction ;
\_def\.pdfactiontype[#1:#2]{#1}
\_doc
\label[actions-additional]
\secc Additional actions
Some PDF objects, like pages and some annotations, can also have \"additional
actions". These are actions which will be executed when an event happens~--
like page getting opened for `/O` action in page's additonal actions or `/PO`
in annotation's additional actions. For constructing these additional actions
we define a helper macro \`\.pdfaactions`. The use is as something follows:
\begtt \catcode`<=13 \adef|{\csstring<}
/AA || \.pdfaactions{ {O} {<action spec 1>} {C} {<action spec 2>} } >>
\endtt
To produce something this:
\begtt \catcode`<=13 \adef|{\csstring<}
/AA || /O ||<action 1>>> /C ||<action 2>>> >>
\endtt
\_cod
\_def\.pdfaactions#1{<<\.pdfaactionsA #1\.end\.end>>}
\_def\.pdfaactionsA#1#2{\_ifx\.end#1\_else /#1 \_ea\.pdfaction\_ea[#2]\_ea\.pdfaactionsA\_fi}
\_doc
\label[actions-link]
\secc Link annotations
The main use of actions~-- annotations of `/Subtype /Link`. Annotation of
this type creates an active rectangular area on the page that executes a PDF
action (or chain of them in the general case).
\`\hlink``[<action spec>]<text>` is macro that typesets <text> and makes area
occupied by it active according to <action spec>. All action types are
supported, the mechanism is completely generic.
The `\pdfstartlink`/`\pdfendlink` primitives are used to denote the part of
the page where <text> appears as active. \LuaTeX/ will then handle even the
situations where <text> gets broken across multiple lines (by creating
multiple rectangular annotations to cover all `\hbox`es).
\_cod
\_def\.hlink[#1]#2{\_bgroup\_def\#{\_csstring\#}%
\_edef\.type{\.pdfactiontype[#1]}%
\_quitvmode\_pdfstartlink \.linkdimens
attr{\_pdfborder{\.type}}%
user{/Subtype /Link /A \.pdfaction[#1]}\_relax
\_localcolor\.linkcolor{\.type}#2\_pdfendlink\_egroup
}
\_nspublic \hlink ;
\_doc
Use `\hlink` as the backing command for OpTeX's \"higher level" linking
commands (`\ilink` and `\ulink`).
The lower level ones (`\xlink` and its predecessor `\link` actually have
completely different semantics with regards to color, so we keep them as they
are.
\_cod
\_protected\_def\_ilink[#1]#2{\.hlink[#1]{#2}}
\_protected\_def\_ulink[#1]#2{{\_escapechar=-1 \_ea}\_expanded
{\_noexpand\.hlink[url:\_detokenize{#1}]}{#2}}
\_public \link \ilink \ulink ;
%\_protected\_def\_link[#1]#2#3{\_hlink[#1]{#3}}
%\_protected\_def\_xlink#1#2#3#4{\_hlink[#1:#2]{#4}}
\_doc
Two customizations of `\hlinks` are possible:
\begitems
* Dimensions of rectangular areas created by
`\pdfstartlink`/`\pdfendlink`. This is done using \`\.linkdimens`
(analogous to \OpTeX's `\linkdimens`). Dimensions that are unset are taken
from the respective `\hbox`es. \`\lininglinks` sets the dimensions for
running text~-- it covers all space of a line using `\baselineskip`.
\`\nolininglinks` sets no dimensions, this is useful for buttons, that may
have larger height/depth than a line.
* The color is determined from the type of link (that is, the first action in
<action spec>) by checking `\_<type>linkcolor` (compatible with \OpTeX/).
As a fallback `\_ilinkcolor` is used (set by \OpTeX's `\hyperlinks`) for all links
except for URLs, where `\_elinkcolor` is used instead. If even these
fallback colors are not defined (`\hyperlinks` isn't used), then the most
generic `\_linkcolor` will be taken or no color will be set.
\enditems
\_cod
\_def\.lininglinks{%
\_def\.linkdimens{height.75\_baselineskip depth.25\_baselineskip}%
}
\_def\.nolininglinks{\_def\.linkdimens{}}
\.lininglinks
\_nspublic \lininglinks \nolininglinks ;
\_def\.linkcolor#1{\_trycs{_#1linkcolor}{\_trycs{_ilinkcolor}{\_trycs{_linkcolor}{}}}}
% \_urllinkcolor = \_elinkcolor with fallbacks
\_def\_urllinkcolor{\.linkcolor{e}}
\_doc
\secc Open action
The document itself has one action defined in the document catalog. It is
called `/OpenAction`. We allow the user to set it using the familiar
<action spec> syntax with the command \`\openaction``[<action spec>]`.
Internally we could directly set it by appending to the catalog
using the primitive `\pdfcatalog`, but \LuaTeX/ (pdf\TeX/ really) allows
setting the action with special syntax. This has the benefit that it is not
allowed to set the action more than once.
\_cod
\_def\.openaction[#1]{\_pdfcatalog{} openaction user{\.pdfaction[#1]}\_relax}
\_nspublic \openaction ;
\_doc
\label[actions-jump]
\secc Jump actions
These are the most typical actions. Even \LuaTeX/ itself handles them,
although we don't use the possibility for maintaining generality. There are a
few types of jump actions:
\begitems
* `/GoTo` actions are the classic internal links to named destinations in the
PDF file (created by `\pdfdest` primitive or \OpTeX/'s `\dest`). The
destination names include also the type of internal link (e.g.
`ref:section1`). They are handled by \`\.ilinkaction``[<type>:<name>]`.
* `/URI` actions which are in most cases used as \"goto URL" actions. These
are not that useful directly, because special characters should be handled
before this actions is used (like with `\url`). The low level use is
\`\.urlaction``[url:<url>]`.
* \"Goto remote" actions, which can jump to a destination in another PDF file~--
either determined by name, or by page number. The external files are
expected to be defined by `\filedef` (but not the embedded variant). The
use is either \`\.extrefaction``[extref:<name>:<named destination>]` for
links to named destination or \`\.extpgrefaction``[extpgref:<name>:<page number>]`
for page destinations. Customization is possible with \`\.extrefextra`, by
default opening in a new windows is requested.
\enditems
\_cod
\_def\.ilinkaction[#1:#2]{/S /GoTo /D (#1:#2)}
\_def\.urlaction[#1:#2]{/S /URI /URI (#2)}
\_def\.extrefaction[#1:#2:#3]{/S /GoToR
/F \.cs{filespec:#2}
/D (#3)
\.extrefextra
}
\_def\.extpgrefaction[#1:#2:#3]{/S /GoToR
/F \.cs{filespec:#2}
/D [\_the\_numexpr#3-1\_relax\_space /Fit]
\.extrefextra
}
\_def\.extrefextra{/NewWindow true}
\_doc
Transition action is not really a jump action in of itself, but is only
useful when chained after jump actions, so we define it here. Transitions
(as page attributes) are handled more thoroughly in section~\ref[transitions].
The use would look something like:\nl
\`\.transitionaction`%
`[transition:<animation type>:<duration>:<raw PDF attributes>]`, where all fields
omitted from right take the default values.
\_cod
\_def\.transitionaction[#1:#2]{/S /Trans \.attrorempty{Trans}{\.maketrans[#2]}}
\_doc
\secc Named actions
User can request arbitrary \"named" action with
\`\.namedaction``[named:<name>]`. See user documentation for details.
\_cod
\_def\.namedaction[#1:#2]{/S /Named /N /#2}
\_doc
\secc JavaScript actions
JavaScript actions have two forms, either \`\.jsaction``[js:<name>]` or
`\.jsaction``[js:<script>]`. The first variant uses contents of `\filedef`'d
<name>, the second one uses <script> directly. There is no special catcode
handling.
\_cod
\_def\.jsaction[#1:#2]{/S /JavaScript
/JS \_ifcsname _pdfextra_filestream:#2\_endcsname \_lastnamedcs \_else
(#2)
\_fi
}
\_doc
\sec Page attributes
PDF represents pages as dictionaries. The dictionaries get generated by \LuaTeX/,
which fills in some attributes {\em attributes} (like `/Content` with
contents of the page and `/Annots` with array of annotations). We can add
more using `\pdfpageattr` primitive token list register. While not that many
are generally useful, there are a few interesting ones. For example
transitions can be set using page attributes, or we might want to set
additional actions (`/AA`) to listen for page events.
While the so called \"page objects" are in a tree structure (for fast lookup),
only the leaves are real \"pages". PDF allows some attributes to be inherited
from parent page objects, but not all of them and certainly not those we are
interested in.
The mechanism introduced in this section is optional, because it takes
complete control over `\pdfpageattr`. It gets activated when
\`\initpageattributes` is first used (which happens automatically for some
functionality exposed by this package), but may be activated by the user for
any other purpose. Only attributes listed in \`\pageattributes` are
processed.
We set the attributes anew for each page, by hooking into \OpTeX/'s
`\_begoutput`. Because `\pdfpageattr` token list doesn't get expanded before
written out to PDF, we expand it using the assignment in `\edef` trick. The
token list gets expanded, but the assignment is not made until it reaches
main processor when the temporary control sequence gets expanded.
\_cod
% pdfpagattr managament (default for all pages vs current page override)
\_def\.pageattributes{{Trans}{Dur}{Rotate}{AA}}
\_def\.initpageattributes{%
% add hook for setting primitive \pdfpageattr
\_addto\_begoutput{\_edef\.tmp{\_pdfpageattr={\.pdfpageattributes}}\.tmp}%
% no need to do this twice
\_let\.initpageattributes=\_relax
}
\_nspublic \pageattributes \initpageattributes ;
\_doc
The user interface we want to expose has two parts:
\begitems
* setting the page attribute for just this one page (\`\.pdfcurrentpageattr`),
* setting the default attribute (used when current page value is not set)
(\`\.pdfdefaultpageattr`).
\enditems
The first one of course brings in the typical \TeX/ problem of knowing the
page where something occurs. As always, the page number contained in
`\gpageno` during processing of said content may of course not actually be
the number of the page where the content ends up! Hence, we need to note the
page number with a delayed write, using `\.setpageof` and later `\.pageof`.
The different settings of page attributes should have distinct names, we use
the \`\.pageattrcount` counter for this.
\_cod
\_newcount\.pageattrcount
\_def\.pdfcurrentpageattr#1#2{\.initpageattributes
\_incr\.pageattrcount
\.setpageof{pageattr:\_the\.pageattrcount}%
\.sxdef{pdfpgattr:\.pageof{pageattr:\_the\.pageattrcount}:#1}{#2}%
}
\_def\.pdfdefaultpageattr#1#2{\.initpageattributes
\.sxdef{pdfpgattr:#1}{#2}%
}
\_doc
Finally, the macro \`\pdfpageattributes` takes care of setting generating the
contents of `\pdfpageattr`. For each attribute in `\pageattributes` it first
checks its current page value, only then the default value. If neither is
set, nothing is added.
\_cod
\_def\.pdfpageattributes{\_ea\.pdfpageattributesA\.pageattributes\.end}
\_def\.pdfpageattributesA#1{\_ifx\.end#1\_else
% use current page override or "default"
% don't emit anything if the value is empty
\.attrorempty{#1}{%
\.trycs{pdfpgattr:\_the\_gpageno:#1}{\.trycs{pdfpgattr:#1}{}}%
}%
\_ea\.pdfpageattributesA\_fi
}
\_doc
Each attributes then has two switches for the respective default and current
values. For defining a few of them a helper is introduced:\nl\indent
\`\.pdfpageattributesetters`` <attribute> \<default setter> \<current setter> {<value>}`,
\nl
where <attribute> is name of the attribute without the slash
(e.g. `MediaBox`), the two control sequences name the future user setters,
which will take single argument in brackets
(e.g. `\mediabox` and `\thismediabox`) and the <value> can use the
argument.
\_cod
\_def\.pdfpageattributesetters#1 #2#3#4{%
\.sdef{\_csstring#2}[##1]{\.pdfdefaultpageattr{#1}{#4}}%
\.sdef{\_csstring#3}[##1]{\.pdfcurrentpageattr{#1}{#4}}%
\_nspublic #2 #3 ;
}
\_doc
Some of the useful attributes are `/Rotate`, which rotates the pages visually
(can be set with \`\defaultpagerotate` and \`\pagerotate`), and the additional
actions (`/AA`, see section~\ref[actions-additional], set using
\`\defaultpageactions` \`\pageactions`).
\_cod
\.pdfpageattributesetters Rotate \defaultpagerotate \pagerotate {#1}
\.pdfpageattributesetters AA \defaultpageactions \pageactions {\.pdfaactions{#1}}
\_doc
\label[transitions]
\secc Transitions, page durations
There are predefined types of transitions, like `/Wipe`, `/Box`, `/Split`,
etc. Most have other customizible attributes~-- usually directions set in
different ways depending on the animation type at hand, but the most
important attribute is the duration of the animation. Parsing friendly user
notation in the form of
`[<animation type>:<duration>:<other raw attributes>]`, where fields from the
right may be omitted to produce the default value, is handled by
\`\.maketrans`. This macro is also used by transition actions
(see~\ref[actions-jump]). The defaults are simply those defined by PDF
standard (no transition, 1 second duration and the respective default
directions).
\_cod
\_def\.maketrans[#1]{\.maketransA#1:::\.end}
\_def\.maketransA#1:#2:#3:#4\.end{%
\.emptyor{#1}{<</S /\.nonempty \.attrorempty{D}{#2} #3>>}
}
\_doc
The attribute setters for transitions (\`\transitions`, \`\transition`) are a
simple wrappers. Similiar is the
setting of page duration in seconds after which PDF viewer automatically
advances to the next page (\`\defaultpageduration`, \`\pageduration`).
\_cod
\.pdfpageattributesetters Trans \transitions \transition {\.maketrans[#1]}
\.pdfpageattributesetters Dur \defaultpageduration \pageduration {#1}
\_doc
\label[nametrees]
\sec Name trees -- attachments and document level JavaScript
These don't have any last place to be in, so they are documented separately,
here. Attaching files using `/FileAttachment` annotations:
\begitems \style n
* is intended more towards viewers of the document for extra additions and
* doesn't work in the viewers as well as one would like.
\enditems
That is why instead embed files using normal `\filedef` and then allow them
to be added to the document level `/EmbeddedFiles` entry, which means they
will be shown in the user interface by PDF viewers. `/EmbeddedFiles` is a
document level name tree (contained inside `/Names` entry of `/Catalog`) that
maps names of files to their objects. Although we simplify matters by
constructing more of an array.
What works very similiarly is document level JavaScript. It is a name tree
within `/JavaScript` field. It maps names of JavaScript actions to their
object numbers. The names aren't very useful, but the actions have their
purpose. They are executed in turn after the document is opened. Hence they
can be used to predefine JavaScript functions in the global context, to be
used later within actions explicitly activated by the user.
The user level commands are \`\attach``[<name>]` (to attach a previously
`\filedef`'d name with fallback to embedding now if it is a valid path) and
\`\dljavascript``[<name>]{<script>}` (adds action that executes <script>
after document is opened, <name> is more or less meaningless).
Internally the commands construct lists of what ends up in the resulting name
array, i.e. pairs {\visiblesp `(<name>) <object number> 0 R `}. Intermediate
macros \`\.embeddedfiles` and \`\.dljavascripts` are used for this.
In the case of file attachments, nothing happens if file is defined and not
found by the fallback.
\_cod
% file attachment
\_def\.embeddedfiles{}
\_def\.attach[#1]{\.isfiledefined{\.name}\_iftrue
\.xaddto\.embeddedfiles{(#1) \.cs{filespec:#1} }\_fi
}
\_nspublic \attach ;
\_def\.dljavascripts{}
\_def\.dljavascript[#1]#2{%
\_immediate\_pdfobj{<< \.jsaction[js:{#2}] >>}%
\.xaddto\.dljavascripts{(#1) \_the\_pdflastobj \_space 0 R }%
}
\_nspublic \dljavascript ;
\_doc
Renditions (see \ref[mm-renditions]) also need their name tree. This package
mostly doesn't play well with Unicode filenames, that is why they are
forbidden. However, Renditions that are accessed from JavaScript have to be
named/present in a `/Renditions` name tree, with the names encoded in the PDF
encoding (UTF-16BE).\nl
The names and object references are collected in \`\.renditions`. Unicode
encoding is hacked with \`\.pdfstringtounicode`.
\_cod
\_def\.pdfstringstrip(#1){#1}%
\_def\.pdfstringtounicode#1#2{%
\_ea\_pdfunidef\_ea#1\_ea{\_ea\.pdfstringstrip\_expanded{\.cs{filename:#2}}}%
}
\_def\.renditions{}
\_doc
Object creation, which is common to all name trees, is handled by\nl\indent
\`\.makenamearray``<name tree name><name tree content>`.\nl
It doesn't do anything
for empty lists, to not bloat PDF files when this mechanism isn't used.
\_cod
\_def\.makenamearray#1#2{\_ifx#2\_empty\_else
\_immediate\_pdfobj {<< /Names [ #2 ] >>}%
\_pdfnames{/#1 \_the\_pdflastobj \_space 0 R }\_fi
}
\_doc
The lists themselves can only be written out to the PDF file at the very end
of the run. We use \OpTeX/'s `\_byehook`, which is run in `\_bye`. But `\bye`
itself may be predefined by the user, for example when using some of the
\OpTeX/ tricks. We just hope that the user keeps `\_byehook`.
\_cod
\_addto\_byehook{%
\.makenamearray{EmbeddedFiles}\.embeddedfiles
\.makenamearray{JavaScript}\.dljavascripts
\.makenamearray{Renditions}\.renditions
}
\_doc
\sec Viewer preferences
There are a few customizations of display (and other preferences of PDF
viewers) possible in the document catalog or its subdictionary
`/ViewerPreferences`. Most are not that useful. The interesting
ones are implemented by \`\fullscreen`, \`\showoutlines`, \`\showattached`.
They all set the page mode using \`\.setpagemode`. We don't handle respecting
the last setting (using \`\_byehook`). To prevent invalid PDF files, we set
`\.setpagemode` to `\_relax` after use.
\_cod
\_def\.setpagemode#1{\_pdfcatalog{/PageMode /#1}\_glet\.setpagemode=\_relax}
\_def\.fullscreen{\.setpagemode{FullScreen}}
\_def\.showoutlines{\.setpagemode{UseOutlines}}
\_def\.showattached{\.setpagemode{UseAttachments}}
\_nspublic \fullscreen \showoutlines \showattached ;
\_doc
Only the setting of duplex / double sided printing and display is in the
nested dictionary. It is handled by \`\duplexdisplay`. The simplistic version
does not handle more attributes in `/ViewerPreferences`. We also set the
meaning to `\_relax` to prevent more (erroneous) uses.
\_cod
\_def\.duplexdisplay{\_pdfcatalog{%
/PageLayout /TwoPageRight
/ViewerPreferences <<
/Duplex /DuplexFlipLongEdge
>>}%
\_glet\.duplexdisplay=\_relax
}
\_def\duplexdisplay{\.duplexdisplay}
\_doc
\sec Multimedia
PDF essentially allows insertion of different types of multimedia:
\begitems
* images,
* audio/video,
* 3D art.
\enditems
The first is pretty standard and handled normally by the engine (\LuaTeX).
Others are possible, but have to be done manually according to one of the
mechanisms specified by PDF standard:
\begitems
* Sounds (audio only),
* Movies (video and/or audio),
* Renditions (video and/or audio),
* 3D annotations (3D art),
* Rich Media (video and/or audio, 3D art)
\enditems
Sadly all these mechanisms are badly flawed, each in different ways. At least
we try to use the one that works in the viewers.
For audio/video \"Movies" are the simplest mechanism, but they have been
deprecated in PDF 2.0 and no longer work in Acrobat/Foxit (same for
\"Sounds").
\"Renditions" are complicated, partly dependant on JavaScript, but at least
supported by Acrobat, Foxit, Evince and Okular.
\"Rich media" annotations were designed for Flash. This use case is no longer possible
today, but the obscurities remain. They are unnecessiraly complicated, but can
be used without Flash too. Although the result is very plain for audio/video~--
no controls can be displayed and there are no associated actions.
\"3D annotations" are reasonably simple, but also flawed. They cannot reuse
embedded file as a source for 3D data. Hence it is better and more consistent
to use Rich Media for 3D annotations. It even has additional benefits, like
the possibility of using multiple initialization scripts.
In the end, this package exposes two user commands corresponding to two
mechanisms~-- first are Renditions (`\render`) for audio/video that works in most
browsers and Rich Media (`\RM`) mainly for 3D art, but also for audio/video
with limited possibilities.
Both mechanisms have an annotation at their core. Annotations is essentially
a rectangular area on page. The area corresponds to where the
multimedium will show up. After activating the area somehow (by user click,
or action) the multimedium will start playing. Before annotations the
rectangular area will show something that is called \"normal appearance".
This appearance is of type form XObject. Those are really similiar to pages~--
they have dimensions, contents made up of PDF graphics operators, \dots,
but they are reusable. Not that useful for annotations where we will need the
form only once, but nice anyways. pdf\TeX/ has primitives for creating them~--
`\pdfxform` and friends. They essentially do the same code like `\shipout`
does, but instead of page, they make this reusable object. One can then
either use this reusable object in another page/form, but we will indirectly
refer to it for the appearance.
Important aspect of annotations is that they are really only rectangular
areas on the page, but they are not really part of the page. They sort of sit
on another level and are not influenced by PDF graphic operators which make
the page. In pdf\TeX/ annotations are handled by {\em whatsit} nodes. While
most nodes map to known primitive \TeX/ concepts (like typeset characters,
boxes, rules, etc.) Whatsits are essentially commands for \TeX/ that are
delayed until page is being shipped out (written to PDF file). `\write`,
`\special`, and most pdf\TeX/ commands create whatsits. For annotationos this
is important, because this means that the engine only stores the information
about annotation that we specify, but creates it at due time, when it should
be written to PDF.
Because whatsits are essentially dimensionless and we want it to be a part of
normal \TeX/ typesetting material we create the annotation (whatsit) in
`\hbox`. This box will be otherwise empty, because the apperance of the
rectangular area is determined by the normal appearance field (`/N` in
`/AP`). We set the dimensions of the box to the dimensions of normal
appearance. Everything will line up nicely, because when processed, the
annotation will take dimensions from the box.
All of these concepts are implemented in:\nl\indent
\`\.boxedannot``[<type>:<name>]{<appearance>}{<special text>}{<annotation attributes>}`\nl
<type> is used to determine the annotation border (same principle as with
Link annotations, section~\ref[actions-link]), <name> will be used as the
annotation name (`/NM`), <special text> is used for influencing the
`\pdfannot` primitive, and <annotation attributes> will become the body of
the annotation.
\_cod
\_def\.boxedannot[#1:#2]#3#4#5{%
\_setbox0=\_hbox{#3}\_setbox2=\_null
\_ht2=\_ht0 \_wd2=\_wd0 \_dp2=\_dp0
\_preshipout0 \box0
\_immediate\_pdfxform0
% box with annotation both stretching to dimensions of appearance
\_hbox{\.setpageof{#1:#2}%
\_pdfannot #4 {#5
/AP <</N \_the\_pdflastxform \_space 0 R>>
\_pdfborder{#1}
/NM (#2)
/Contents (#1 '#2')
}%
\_copy2
}%
}
\_doc
There is another weird thing common to both multimedia mechanisms~--
the redefinition of `\.name`. It is initially
set by `\.secondoptdef` to <name>, but may be redefined by user supplied
`name` key-value parameter. This should be used when there are multiple uses
of the same content. Otherwise samely named annotations would be
indistinguishable both for PDF viewer and our handling of actions (which
would all refer only to the first instance).
To somewhat overcome this, trying to use the same <name> (within the same
type of annotaiton) will use dummy name from \`\.unnamedannotcount` (for
uniqueness). This means that <name> will always refer to the first instance.
\`\.redefinename` handles this.
\_cod
\_newcount\.unnamedannotcount
\_def\.redefinename#1{%
\.isdefined{#1:\.name}\_iftrue
\_incr\.unnamedannotcount
\_edef\.name{\_the\.unnamedannotcount}%
\_else
\_edef\.name{\_kv{name}}%
\_fi
}
\_doc
\label[mm-renditions]
\secc Renditions (audio/video)
There are three main types of PDF objects involved in the Renditions
(\"Multimedia") mechanism:
\begitems
* Screen annotations define the area for playing multimedia.
* Rendition objects define the multimedia to play.
* Rendition actions associate Rendition objects with Screen annotations.
\enditems
You can theoretically arbitrarily mix and match rendition objects and screen
annotations by invoking different actions. In practice Evince and Okular do
really simplistic parsing and don't fully support the actions fully. But by
keeping it simple it is possible to make it work almost the same in all
viewers that support renditions.
Different sources of audio/video should be possible. In fact all three file
specifications (embedded files, files specified by URL/path) could work.
Again in practice embedded file is the safest bet, that works in all viewers
that support renditions.
The user facing command is:\nl\indent
\`\render``[<name>][<optional key-value paramers>]{<horizontal material>}`\nl\noindent
<name> is the friendly name set using `\filedef` or file path if <name> isn't
`\filedef`d and is to be embedded. The key-value parameters in brackets
can be entirely omitted. They can influence the playback (except for `controls`
most are not well supported). Default values are taken from
`\.renderdefaults`.
`\render` doesn't do anything (except print warning) if file <name> isn't
defined and <name> isn't a path to file that can be embedded.
The first PDF object it defines is Rendition, which specifies information
about the multimedium (name, file specification, MIME type and options from
key-value parameters). Some of the fields are in `/BE` (\"best effort")
dictionaries. This is due to the very general design of Renditions, which
theoretically allows the PDF viewer to choose from multiple Renditions if
they know they can't support some of the requested features. But that is not
much useful in practice, so we just don't complicate it.
Next defined object is Screen annotation, which complicates thing by
requiring (`/P`) reference to the page where the annotation is (handled by
`\setpageof` and `\pageof` pair). Important field is `/A` which specifies
actions that shall be executed when the screen area is clicked. We let the
user change the action, but the sensible default of starting to play the
multimedium is used (and this is the only thing that works in some viewers
anyways). Additional actions `/AA` may be used to react to events like mouse
over or page open/close~-- the most probable use case is autoplay on page
open, for which shortcut of \`\renditionautoplay` is defined.
The code is slightly complicated by the fact, that actions need to reference
the Rendition and Screen objects. In the case of the action contained in
Screen annotation this essentialy involves a self reference. Hence it is
needed to first reserve an object number and later use it for the annotation.
Because the object numbers may also be needed by actions defined later, we need
to save them to `\_pdfextra_rendition:<name>` and `\_pdfextra_screen:<name>`
respectively, but also define aliases with empty names, so users can easily
reference the latest rendition.
\_cod
\.secondoptdef\.render#1{\.isfiledefined{\.name}\_iftrue\_bgroup
\_ea\_readkv\_ea{\_ea\.renderdefaults\_ea,\_the\_opt}%
\.colortorgbdef\.bgcolor{\_kv{background}}%
% rendition object ("media specifaction")
\.pdfstringtounicode\.uiname\.name
\_pdfobj {<</Type /Rendition
/S /MR
/N \.uiname
/C <<%/Type /MediaClip
/S /MCD % subtype MediaClipData
/D \.cs{filespec:\.name}
/CT (\.cs{filemime:\.name})
/P << /TF (TEMPALWAYS) >> % allow creating temporary files
>>
/P <<%/Type /MediaPlayParams
/BE << /C \_kv{controls} /V \_kv{volume} /RC \_kv{repeat} >>
>>
/SP <<%/Type /MediaScreenParams
/BE << /O \_kv{opacity} /B [\.bgcolor] >>
>>
>>}\_pdfrefobj\_pdflastobj
\.xaddto\.renditions{\.uiname \_the\_pdflastobj \_space 0 R }%
\.redefinename{rendition}%
\.sxdef{rendition:\.name}{\_the\_pdflastobj}%
% screen annotation ("screen space allocation")
\_pdfannot reserveobjnum% "self" reference will be needed inside screen annot.
\.sxdef{screen:\.name}{\_the\_pdflastannot}%
% aliases to latest rendition/screen with empty name
\_global\.slet{rendition:}{rendition:\.name}%
\_global\.slet{screen:}{screen:\.name}%
\_edef\.action{\_kv{action}}\_edef\.aactions{\_kv{aactions}}%
\.boxedannot[rendition:\.name]{#1}{useobjnum\_the\_pdflastannot}{%
/Subtype /Screen
% reference to page of the rendition (\setpageof done by \.boxedannot)
% the spaces are weird, but \pdfpageref eats them
/P \_pdfpageref\.pageof{rendition:\.name} \_space 0 R
/A \_ea\.pdfaction\_ea[\.action]
/AA \_ea\.pdfaactions\_ea{\.aactions}
}%
\_egroup\_fi
}
\_nspublic \render ;
\_doc
Here are the defaults used for `\render`~-- \`\.renderdefaults`. Users can
redefine them all together or override as needed with key-value parameters.
The defaults correspond to values specified by PDF standard. Other values may
not be respected by all viewers.
\_cod
\_def\.renderdefaults{%
name=\.name,
controls=false,
volume=100,
repeat=1,
opacity=1.0,
background=1 1 1,
action=rendition::play,
aactions={},
}
\_doc
Most probable use of additional actions is to start auto-start playing of the
multimedium. For this purpose \`\renditionautoplay` is defined as a shorthand
for action to play the lastly defined rendition on page visible event.
\_cod
\_def\.renditionautoplay{{PV}{rendition::play}}
\_nspublic \renditionautoplay ;
\_doc
\seccc Rendition actions
Rendition actions unfortunately use cryptic symbolic numbers (`0`, `1`, `2`
and `3`) for actions that could be called `play`, `stop`, `pause` and
`resume` respectively. Except for these predefined actions (that use `/OP`)
running of JavaScript is possible using `/JS (<script>)` with potential
fallback to `/OP`. This is dangerous teritory, because support of the right
API in the viewer is very low. Although it is possible to define such action
type by:
\begtt
\.sdef{renditionaction:myaction}{/JS (app.alert("something useful");) /OP 0}
\endtt
The use of rendition action is:
\`\.renditionaction``[rendition:<name>:<action type>]`. Empty name refers to
last rendition, so e.g.`\.renditionaction``[rendition::pause]` is possible.
\_cod
\.sdef{renditionaction:play}{/OP 0}
\.sdef{renditionaction:stop}{/OP 1}
\.sdef{renditionaction:pause}{/OP 2}
\.sdef{renditionaction:resume}{/OP 3}
\_def\.renditionaction[#1:#2:#3]{/S /Rendition
\.cs{renditionaction:#3}
/R \.cs{rendition:#2} 0 R
/AN \.cs{screen:#2} 0 R%
}
\_doc
\secc Rich Media (3D/audio/video)
Some principles seen with Renditions (section~\ref[mm-renditions]) apply here
too. But additionally we deal with 3D specifics and unfortunate Flash
leftovers.
Unlike Renditions both page area and multimedium specifaction are handled in
a single annotation~-- the Rich Media annotation. The code is unfortunately
obscured due to the weird requirements, but this is essentially what we are
trying to create with \`\RM`:
\begtt
/Type /Annot
/Subtype /RichMedia
/RichMediaSettings <<
/Activation <<
/Condition /PV
/Scripts [ 14 0 R ]
>>
/Deactivation << /Condition /XD >>
>>
/RichMediaContent <<
/Assets << /Names [ (kladka.prc) 2 0 R (wireframe.js) 14 0 R ] >>
/Configurations [ <<
/Type /RichMediaConfiguration
/Subtype /3D
/Instances [ <<
/Type /RichMediaInstance
/Subtype /3D
/Asset 2 0 R
>> ]
>> ]
>>
\endtt
The activation/deactivation will be dealt with later. But we see that to
insert a simple 3D file, we have to pack it inside a file specification
(indirect reference to object `2 0 R`), then in \"instance", inside a
\"configuration" inside \"content". As if it wasn't enough the names
(normally contained in the file specification) have to be specified again in
`Assets` name tree that uselessly maps names to file specifications. Because
this is a 3D Rich Media annotation there are other files at play~--
initialization scripts. These are specified in `/Scripts` and are executed in
turn when the annotation is activated. Not shown is, that some
\"configurations" and \"instances" actually have to be specified indirectly.
If it wasn't for Flash we could do with something like:
\begtt
/Type /Annot
/Subtype /RichMedia
/Activation /PV
/Scripts [ 14 0 R ]
/Deactivation /XD
/Content 2 0 R
\endtt
Which contains equivalent information. But unfortunately here we are\dots
\_cod
\.secondoptdef\.RM#1{\.isfiledefined{\.name}\_iftrue
\_edef\.tmp{\.cs{filemime:\.name}}%
\_edef\.subtype{\_ea\.mimetormsubtype\_ea[\.tmp]\_space}%
\_ifx\.subtype\_space
\_opwarning{unknown rich media type for '\.name', ignored}\_else
\_bgroup
\_ea\_readkv\_ea{\_ea\.RMdefaults\_ea,\_the\_opt}%
% Instance that has the media file as an asset
\_pdfobj {<</Type /RichMediaInstance
/Subtype /\.subtype
/Asset \.cs{filespec:\.name}
>>}\_pdfrefobj\_pdflastobj
% Configuration with one single instance (the above)
\_pdfobj {<</Type /RichMediaConfiguration
/Subtype /\.subtype
/Instances [ \_the\_pdflastobj \_space 0 R ]
>>}\_pdfrefobj\_pdflastobj \_edef\.configuration{\_the\_pdflastobj}%
\_edef\.names{\.cs{filename:\.name} \.cs{filespec:\.name} }% initial asset
\.redefinename{rm}%
\_def\.scriptfilespecs{}%
\_edef\.views{\_kv{views}}\_edef\.scripts{\_kv{scripts}}%
\_ifx\.views\_empty \_edef\.views{\.name}\_fi
\_ea\.DDDscripts\_ea{\.scripts}%
% annotation in hbox
\.boxedannot[rm:\.name]{#1}{}{%
/Subtype /RichMedia
/RichMediaSettings <<
/Activation <<
/Condition \.cs{activation:\_kv{activation}}
\.emptyor{\.scriptfilespecs}{/Scripts [ \.nonempty ]}
/Presentation << /Toolbar \_kv{toolbar} \.RMpresentationextra >>
>>
/Deactivation << /Condition \.cs{deactivation:\_kv{deactivation}} >>
>>
/RichMediaContent <<
/Assets << /Names [ \.names ] >>
/Configurations [ \.configuration \_space 0 R ]
\.emptyor{\_ea\.DDDviews\_ea{\.views}}{/Views [ \.nonempty ]}
>>
}%
\.sxdef{rm:\.name}{\_the\_pdflastannot}%
\_global\.slet{rm:}{rm:\.name}%
\_egroup\_fi\_fi
}
\_nspublic \RM ;
\_doc
The code is similiar to `\render`, but we also ignore everything if we don't
recognize the type of media (`Video`, `Sound` or `3D`). For that we use a
simple mapping from MIME types with \`\.mimetormsubtype`. This means that
although we aim Rich Media mostly for 3D art it may also be used for Video
and Sound.
\_cod
\_def\.mimetormsubtype[#1/#2]{\.cs{rmtype:#1}}
\.sdef{rmtype:model}{3D}
\.sdef{rmtype:video}{Video}
\.sdef{rmtype:audio}{Sound}
\_doc
Then we also need to construct the weird name \"tree" (essentialy an array in
our case) and script array. \`\.DDDscripts` and \`\.DDDviews` do this.
Name tree is accumulated in `\.names`, and starts with the media file. After
that each script is added to \`\.names` and \`\.scriptfilespecs`. The scripts
are passed as a comma separated array. Ignoring initial spaces is done using
undelimited-delimited argument pair trick.
\_cod
\_def\.DDDscripts#1{\.DDDscriptsA#1,,,\.end}
\_def\.DDDscriptsA#1#2,{\_ifx,#1\_ea\.untilend\_else
\.isfiledefined{#1#2}\_iftrue%
\_addto\.scriptfilespecs{\.cs{filespec:#1#2} }%
\_addto\.names{\.cs{filename:#1#2} \.cs{filespec:#1#2} }%
\_fi
\_ea\.DDDscriptsA\_fi
}
\_doc
For 3D views we need to process yet another comma separated list, this time
with \`\.DDDviews`. The result has to be separated by spaces and we also
don't want to emit something if the specified view was invalid. Unfortunately
this is expansion only context, so we can't issue a warning.
As a user convenience, before `\.DDDview` is executed, view with the name of
`\.name` is tried instead of empty view array. This means that for simple 3D
art with one view, one can create view with the same name as the 3D object
and not have to specify anything. We also take the name only after it is
redefined from optional key-value parameters~-- this is so we can support
even the case of e.g. `screw` 3D model used twice, once with `name=screw1`,
another time with `name=screw2` (with the corresponding `screw1` and `screw2`
views). This is probably less useful, but\dots
\_cod
\_def\.DDDviews#1{\.DDDviewsA#1,,,\.end}
\_def\.DDDviewsA#1#2,{\_ifx,#1\_ea\.untilend\_else
\.isdefined{3dview:#1#2}\_iftrue
\_lastnamedcs\_space \_fi
\_ea\.DDDviewsA\_fi
}
\_doc
The activation/deactivation names are kind of cryptic, so we give them
descriptive names. Default is explicit (de)activation. Instead of `/PV` (page
visible) and `/PI` (page invisible) it would be possible to use \"page open"
and \"page close". These are slightly different in cases when more pages are
shown on screen at once, because only one page is \"open", while multiple are
\"visible".
\_cod
\.sdef{activation:explicit}{/XA}
\.sdef{activation:auto}{/PV}
\.sdef{deactivation:explicit}{/XD}
\.sdef{deactivation:auto}{/PI}
\_doc
Additional means of customization are here. \`\.RMdefaults` contains the
default key-value parameters. \`\.RMpresentationextra` can be used to set
more attributes in `/RichMediaPresentation` dictionary (although those are
more specific and not generally useful).
\_cod
\_def\.RMdefaults{%
name=\.name,
activation=explicit,
deactivation=explicit,
toolbar=true,
views=,
scripts=,
}
\_def\.RMpresentationextra{}
\_doc
For scripting using JavaScript actions one needs to access the 3D context of
the 3D / Rich Media annotation. This requires the page number. We can't use
`this.pageNum`, because the script strictly doesn't have to be on
the same page. We use `\.pageof` (`\.setpageof` was done in `\.boxedannot`)
to retrieve the page number in next run. Also PDF indexes page numbers from
0. \`\DDDannot``{<name>}`. and \`\DDDcontext``{<name>}` allow this.
\_cod
\_def\.DDDannot#1{%
this.getAnnotRichMedia(\_the\_numexpr\.pageof{rm:#1}-1\_relax, '#1')%
}
\_def\.DDDcontext#1{\.DDDannot{#1}.context3D}
\_nspublic \DDDannot \DDDcontext ;
\_doc
\label[mm-3dviews]
\secc 3D views
This is the interesting part about 3D art. They can have a set of predefined
views~-- although a user may start from one, they can interactively change
all the aspects by dragging with mouse or messing with the settings shown by
right click menu.
There are several transformations that have to be done before it is possible
to display 3D scene on a computer screen:
\begitems \style n
* 3D transformation from the coordinate system of 3D artwork (\"model") to the \"world
coordinate system".
* 3D transformation from the world coordinate system to camera coordinate
system.
* projection to 2D (3D to 2D transformation).
\enditems
When talking about PDF, positive $x$ goes to the right, positive $y$ up, and
positive $z$ \"away" from us (\"into the page"). This means we are working
with a left handed coordinate system. In camera space, the camera sits at
$(0, 0, 0)$ facing towards positive $z$ with positive $x$ and $y$ going right
and up respectively. Projection (one way or another) discards the $z$
coordinate.
Although the transformations are not strictly linear, they are essentially
done using multiplication by {\em transformation matrices}. The matrix for
\"model to world" (or \"model") transformation is part of the 3D art file and can't
be changed. However, we can make it up, because we can fully control the
second transformation (\"world to camera" or \"view" transformation)~--
although we don't specify the \"world to camera" matrix but rather its
inverse, the \"camera to world" matrix (`/C2W`). This matrix has the $4 \times 4$
form, which also allows {\em linear transformation} and {\em translation}:
$$
M_{c2w} = \pmatrix{a & d & g & t_x \cr b & e & h & t_y \cr c & f & i & t_z \cr 0 & 0 & 0 & 1}
$$
Here we use the column major convention, which is also the order how we would
write the matrix to PDF file, where it is an array of 12 elements:
\begtt \catcode`\$=3
/C2W [$a$ $b$ $c$ $d$ $e$ $f$ $g$ $h$ $i$ $t_x$ $t_y$ $t_z$]
\endtt
In the rendering pipeline everything is transformed from world coordinates to
camera space coordinates. We can think about the process also in the other
way. Using $M_{c2w}$ we specify camera's position and orientation in the
world coordinate system. Due to how transformation using matrix
multiplication works, the first column in the $M_{c2w}$ matrix (vector $(a,
b, c)^T$) specifies how \"positive $x$ direcetion" (\"right") from camera
space ends up in world coordinate system. Similiarly for $(d, e, f)^T$ being
the image of positive $y$ (\"up") and $(g, h, i)^T$ being the image of
positive $z$ (\"forward"). The last column, $(t_x, t_y, t_z)^T$ represents
translation from camera space to world. Translation of origin (camera
position) will leave it in the point with coordinates $(t_x, t_y, t_z)$.
Because of these associations with the intuitive meanings of $x$,
$y$, $z$ in camera space we also sometimes call the vectors in the first
three columns of $M_{c2w}$ \"right", \"up" and \"forward" and the last one
\"eye":
$$
\vec{R} = \pmatrix{a \cr b \cr c}\!, \quad
\vec{U} = \pmatrix{d \cr e \cr f}\!, \quad
\vec{F} = \pmatrix{g \cr h \cr i}\!, \quad
\vec{E} = \pmatrix{t_x \cr t_y \cr t_z}\!.
$$
We usually want $\vec{R}$, $\vec{U}$ and $\vec{F}$ to form an orthonormal set
of vectors, i.e. all of unit length and each pair is orthogonal. The
orthoganility will come from the way we calculate them, but the normality has
to be ensured by normalizing the vectors after computing them, which will not
be explicitly written out in the following text. $\vec{E}$ is a positional,
not directional, vector and it's length will be preserved.
Now we only need a convenient way to calculate all four vectors. A wide spread
method is sometimes called \"look at". It essentially involves having two
points: \"eye" ($E$, position of the camera) and \"target" ($T$, the point
where the camera is pointing at). The camera position is already provided:
$$
\vec{E} = E
$$
From these two points alone we can easily calculate the forward vector, which
corresponds to the direction of the camera:
$$
\vec{F} = \overrightarrow{ET} = T - E
$$
When we now imagine the point $E$ and vector $\vec{F}$ looking towards $T$ we
can see that there is a degree of freedom~-- the camera can rotate about the
forward vector. There is no other way than to arbitrarily choose
either up or right vector. Usually we choose an arbitrary \"global up" vector
$U_G$, which will influence the general direction of the final up vector.
This is because we use it to calculate the right vector:
$$
\vec{R} = \vec{U}_G \times \vec{F}
$$
The cross product makes it so that:
\begitems \style n
* $\vec{R}$ is perpendicular to $\vec{F}$
* it is also perpendicular to global up vector ($\vec{U}_G$) which we used to
get rid of remaining degree of freedom.
\enditems
Now that we have two orthonormal vectors (with the normalization not being
explicit) we can calculate the remaining up vector:
$$
\vec{U} = \vec{F} \times \vec{R}
$$
The last mysterious part about the calculation are the cross products. They
are of course not commutitative, so why e.g. $\vec{U}_G \times \vec{F}$ and
not the other way around? This is because we have to preserve the relations
these vectors had as directions of positive axes of the original camera
space. There we had positive $x$ going right, positive $y$ up and positive
$z$ forward in a left handed coordinate system. This means that following
holds (according the left hand rule):
$$\eqalign{
\vec{R} &= \vec{U} \times \vec{F} \cr % j * k = i
\vec{U} &= \vec{F} \times \vec{R} \cr % k * i = j
\vec{F} &= \vec{R} \times \vec{U} \cr % i * j = k
}$$
The scheme has one flaw though. When the directions of global up vector
$\vec{U}_G$ and forward vector $\vec{F}$ are linearly dependent the computed
right vector will be $(0, 0, 0)$. Hence some handling of this special case is
needed.
The \"look at" method is essentially what is used in Alexander Grahn's
package movie15\fnote{\url{https://www.ctan.org/pkg/movie15}}. Although the
input aren't two points, but rather a \"center of orbit" point ($COO$, our
\"target"), \"center of orbit to camera vector" ($\overrightarrow{C2C}$,
default is $(0, -1, 0)$) and distance of camera from the center of orbit
($ROO$). The value used for the arbitrary \"global up" vector is $(0, 0, 1)$.
When forward vector is $(0, 0, z)$, then global up is chosen to be $(0, -1,
0)$ or $(0, 1, 0)$ to handle the \"0 right vector" issue.
Because the movie15 method of providing the parameters is used in essentially
all packages that handle PDF 3D art (movie15, media9, rmannot, Con\TeX/t) we
also follow the suite.
\`\DDDview`[<view name>][<key-value parameters>] is the command for defining
3D views. These have to be saved into separate PDF objects anyways, using
this interface we allow their reuse. If <view name> is same as <name> of
`\RM` argument and no other views are specified <view name> view is
automatically used (see `\RM` for details).
Key-value parameters are not optional this time, because rarely one suffices
with default values~-- different 3D views are about customization. Handling
of them is not as straightforward as before. We initially read the key-value
parameters only to determine the `method` used for calculating the `/C2W`
matrix. Then we reread key-value parameters again, this time with also with
the default values for this particular method. Not that the general 3d views
details are changed, but the methods themselves have key-value parameters of
their own, and we support specifying them in this \"flat" way.
Additionally we allow the different methods used to compute `/C2W` to not be
expandable. Hence they are executed outside of expansion only context and are
fully processed~-- the text they add to 3D view PDF object is temporarily
stored in \`\.viewparams`.
The rest is simply setting sensible defaults (or user overrides) for
internal/external name of the view (`/IN` and `/XN`, one is used for
scripting, one is shown by the PDF viewer), background color, rendering mode,
and lighting. Cross sections and nodes are currently not supported, although
users can hook in their own code using `\.DDDviewextra`,
`\.DDDrendermodeextra` or `\.DDDprojectionextra`.
We have to be careful about setting rendering mode and lighting scheme,
because they normally fall back to the values specified in 3D art file, which
we can't access, so better not set them to anything if they are empty.
\_cod
\_def\.DDDview[#1][#2]{\_bgroup
\_readkv{\.DDDviewdefaults,#2}%
\_edef\.tmp{\.DDDviewdefaults,\.cs{3dview:\_kv{method}:defaults}}%
\_readkv{\.tmp,#2}%
\.colortorgbdef\.bgcolor{\_kv{background}}%
\.cs{3dview:\_kv{method}}% sets \.viewparams (/MS, /C2W, /CO)
\_pdfobj {<</Type /3DView
/XN (#1)
/IN (#1)
\.viewparams % /MS, /C2W, /CO
/P <<
\.cs{3dprojection:\_kv{projection}}
\.DDDprojectionextra
>>
/BG <<%/Type /3DBG
/Subtype /SC
/C [\.bgcolor]
>>
\.emptyor{\_kv{rendermode}}{%
/RM <<%/Type /3DRenderMode
/Subtype /\.nonempty
\.DDDrendermodeextra >> }%
\.emptyor{\_kv{lighting}}{%
/LS <<%/Type /3DLightingScheme
/Subtype /\.nonempty >> }%
>>}%
\_pdfrefobj\_pdflastobj
\.sxdef{3dview:#1}{\_the\_pdflastobj \_space 0 R}%
\_egroup
}
\_nspublic \DDDview ;
\_doc
\`\.DDDviewdefaults` stores default key-value parameters for 3D views. They
are mostly the PDF standard defaults or what movie15/media9 uses (for
compatibility).\`\.DDDviewextra`, \`\.DDDrendermodeextra` or
\`\.DDDprojectionextra` can be used by the users to hook themself into 3D
view object creation.
\_cod
\_def\.DDDviewdefaults{
projection=perspective,
scale=1,
ps=Min,
FOV=30,
background=1 1 1,
rendermode=,
lighting=,
method=media9,
}
\_def\.DDDprojectionextra{}
\_def\.DDDrendermodeextra{}
\_def\.DDDviewextra{}
\_doc
There are two different projection methods:
\begitems
* Orthographic: $z$ coordinate is simply thrown away, `scale` is used for scaling
the result. For technical parts where we want lines that are parallel stay
parallel in the view.
* Perspective: is the way human eye sees. `FOV` can be used to set field of
view. (`ps` parameter for additonal scaling to fit width/height is also
available, but the default is fine for casual users).
\enditems
\_cod
\.sdef{3dprojection:ortho}{/Subtype /O /OS \_kv{scale}}
\.sdef{3dprojection:perspective}{/Subtype /P /FOV \_kv{FOV} /PS /\_kv{ps}}
\_doc
We offer the possibility of setting`/C2W` matrix and `/CO` (distance from
camera to center of orbit) directly using `method=manual`.
\_cod
\.sdef{3dview:manual:defaults}{
matrix=1 0 0 0 1 0 0 0 1 0 0 0 ,
centeroforbit=0,
}
\.sdef{3dview:manual}{\_edef\.viewparams{
/MS /M
/C2W [\_kv{matrix}]
/CO \_kv{centeroforbit}
}}
\_doc
Another simple way of specifying camera position/orientation is to use a
named setting of U3D file using a U3D path with `method=u3d`.
\_cod
\.sdef{3dview:u3d:defaults}{
u3dpath=,
}
\.sdef{3dview:u3d}{%
\_pdfunidef\.tmp{\_kv{u3dpath}}%
\_edef\.viewparams{
/MS /U3D
/U3DPath \.tmp \_space
}}
\_doc
The most advanced method of setting `/C2W` matrix and `/CO` is
`method=media9`. It is thoroughly explained above, the few differences are
because the input values are not two points. Also for conciseness \"x", \"y"
and \"z" are used instead of right, up and forward. The calculations are
done in Lua, for simplicity.
We expect the user to supply the numbers in the form \"`1 2 3`", but in Lua we
need them comma separated (\"1, 2, 3"). \`\.luatriplet` does this. Just in
case the code is somehow adapted without ensuring that $x$ and $z$ are
orthonormal, we normalize also $y$ after the second cross product.
\_cod
\_def\.luatriplet#1 #2 #3 {#1, #2, #3}
\.sdef{3dview:media9:defaults}{%
roo=0,
coo=0 0 0,
c2c=0 -1 0,
}
\.sdef{3dview:media9}{\_edef\.viewparams{
/MS /M
/C2W [\_directlua{
local function normalize(x, y, z)
local len = math.sqrt(x*x + y*y + z*z)
if len \csstring\~= 0 then return x/len, y/len, z/len else return 0, 0, 0 end
end
local function cross(ux, uy, uz, vx, vy, vz)
return uy*vz - uz*vy, uz*vx - ux*vz, ux*vy - uy*vx
end
local function printmat(...)
local arr = table.pack(...)
for k, v in ipairs(arr) do
arr[k] = string.format("\_pcent.6f", v)
end
tex.print(table.concat(arr, " "))
end
local roo = \_kv{roo}
local coo_x, coo_y, coo_z = \_ea\.luatriplet\_expanded{\_kv{coo}}
local c2c_x, c2c_y, c2c_z = normalize(\_ea\.luatriplet\_expanded{\_kv{c2c}})
local eye_x, eye_y, eye_z = coo_x + c2c_x*roo, coo_y + c2c_y*roo, coo_z + c2c_z*roo
local z_x, z_y, z_z = -c2c_x, -c2c_y, -c2c_z
local up_x, up_y, up_z = 0, 0, 1
if math.abs(z_x) + math.abs(z_y) < 0.0000001 then % z_x == 0 and z_y == 0
if z_z < 0.0000001 then % z_z <= 0
up_x, up_y, up_z = 0, 1, 0
else
up_x, up_y, up_z = 0, -1, 0
end
end
local x_x, x_y, x_z = normalize(cross(up_x, up_y, up_z, z_x, z_y, z_z))
local y_x, y_y, y_z = normalize(cross(z_x, z_y, z_z, x_x, x_y, x_z))
local eye_x, eye_y, eye_z = coo_x - z_x*roo, coo_y - z_y*roo, coo_z - z_z*roo
printmat(x_x, x_y, x_z, y_x, y_y, y_z, z_x, z_y, z_z, eye_x, eye_y, eye_z)
}]
/CO \_kv{roo}
}}
\_doc
Last, but not least, is an action for setting the 3D view of a 3D/RM annotation
using an action. \`\.goto3dviewaction``[goto3dview:<name>:<view>]`. <name> is
name of the annotation which will be influenced. <view> is passed directly to
PDF. Therefore it can be either an index to the view array (starting at 0) or name
of view in parentheses~-- \"`(<view name>)`".
\_cod
\.sdef{goto3dviewaction}[#1:#2:#3]{/S /GoTo3DView
/TA \.cs{rm:#2} 0 R
/V #3
}
\_doc
\label[mime]
\sec MIME type database
This is the uninteresting MIME type database teased in section~\ref[files].
Ideally this would only be a subset of what IANA defines at
\url{https://www.iana.org/assignments/media-types/media-types.xhtml}.
But there are additions like `model/u3d` and `model/prc`, which don't
seem to be official, yet. Other \"unofficial" MIME types are taken from
Mozilla's \"common" lists:
\begitems
* \url{https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types}.
* \url{https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types}
\enditems
\`\.mimetype``{<extension>}{<MIME type>}` is a shortcut of mapping
<extension> to <MIME type>.
\_cod
\_def\.mimetype#1#2{\_sdef{_pdfextra_mimetype:#1}{#2}}
\.mimetype{js}{application/javascript}
\.mimetype{pdf}{application/pdf}
\.mimetype{prc}{model/prc}
\.mimetype{u3d}{model/u3d}
\.mimetype{wav}{audio/x-wav}
\.mimetype{mp3}{audio/mpeg}
\.mimetype{opus}{audio/opus}
\.mimetype{avi}{video/x-msvideo}
\.mimetype{mp4}{video/mp4}
\.mimetype{webm}{video/webm}
\_endnamespace
\_endcode
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