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partially updated manual (work in progress) (HH)

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% language=uk
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-backend
\startchapter[reference=backend,title={The backend libraries}]
\section{The \type {pdf} library}
This library contains variables and functions that are related to the \PDF\
backend. You can find more details about the expected values to setters in \in
{section} [backendprimitives].
\subsection{\type {mapfile}, \type {mapline}}
\startfunctioncall
pdf.mapfile(<string> map file)
pdf.mapline(<string> map line)
\stopfunctioncall
These two functions can be used to replace primitives \type {\pdfmapfile} and
\type {\pdfmapline} inherited from \PDFTEX. They expect a string as only
parameter and have no return value. The first character in a map line can be
\type {-}, \type {+} or \type {=} which means as much as remove, add or replace
this line.
\subsection {\type {[set|get][catalog|info|names|trailer]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with metadata. The value types are strings and they are written out to the \PDF\
file directly after the token registers.
\subsection {\type {[set|get][pageattributes|pageresources|pagesattributes]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with page resources. The variables have no interaction with the corresponding \PDF\
backend token register. They are written out to the \PDF\ file directly after the
token registers.
\subsection{\type {[set|get][xformattributes|xformresources]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with reuseable boxes and images. The variables have no interaction with the
corresponding \PDF\ backend token register. They are written out to the \PDF\
file directly after the token registers.
\subsection{\type {getversion} and \type {[set|get]minorversion}}
The version is frozen in the binary but you can set the minor version. What minor
version you set depends on what \PDF\ features you use. This is out of control
of \LUATEX.
\subsection{\type {getcreationdate}}
This function returns a string with the date in the format that ends up in the
\PDF\ file, in this case it's: {\tttf \cldcontext{pdf.getcreationdate()}}.
\subsection{\type {[set|get]inclusionerrorlevel}, \type {[set|get]ignoreunknownimages}}
These variable control how error in included image are treated. They are modeled
after the \PDFTEX\ equivalents.
\subsection{\type {[set|get]suppressoptionalinfo}}
This bitset determnines what kind of info gets flushes. By default we flush all.
\subsection{\type {[set|get]trailerid}}
You can set your own trailer id. This has to be a valid array string
with checksums.
\subsection{\type {[set|get]compresslevel}}
These two functions set the level of compression. The minimum value is~0,
the maximum is~9.
\subsection{\type {[set|get]objcompresslevel}}
These two functions set the level of compression. The minimum value is~0,
the maximum is~9.
\subsection{\type {[set|get]gentounicode}}
This flag enables tounicode generation (like in \PDFTEX).
\subsection{\type {[set|get]omitcidset}}
This flag disables inclusion of a so called CIDSet which can be handy when aiming
at some of the many \PDF\ substandards.
\subsection{\type {[set|get]decimaldigits}}
These two functions set the accuracy of floats written to the \PDF file. You can
set any value but the backend will not go below~3 and above~6.
\subsection{\type {[set|get]pkresolution}}
These setter takes two arguments: the resolution and an optional zero or one that
indicates if this is a fixed one. The getter returns these two values.
\subsection{\type {getlast[obj|link|annot]} and \type {getretval}}
These status variables are similar to the ones traditionally used in the backend
interface at the \TEX\ end.
\subsection{\type {maxobjnum} and \type {objtype}, \type {fontname}, \type {fontobjnum},
\type {fontsize}, \type {xformname}}.
These (and some other) introspective helpers were moved from the the \type {tex}
namespace to the \type {pdf} namespace but kept their original names. They are
mostly used when you construct \PDF\ objects yourself and need for instance
information about a (to be) embedded font.
\subsection{\type {[set|get]origin}}
This one is used to set the horizonal and|/|or vertical offset, a traditional
backend property.
\starttyping
pdf.setorigin() -- sets both to 0pt
pdf.setorigin(tex.sp("1in")) -- sets both to 1in
pdf.setorigin(tex.sp("1in"),tex.sp("1in"))
\stoptyping
The counterpart of this function returns two values.
\subsection{\type {[set|get]imageresolution}}
These two functions relate to the imageresolution that is used when the image
itself doesn't provide a non|-|zero x or y resolution.
\subsection {\type {[set|get][link|dest|thread|xform]margin}}
These functions can be used to set and retrieve the margins that are added to the
natural bounding boxes of the respective objects.
\subsection {\type {get[pos|hpos|vpos]}}
These function get current location on the output page, measured from its lower
left corner. The values return scaled points as units.
\starttyping
local h, v = pdf.getpos()
\stoptyping
\subsection {\type {[has|get]matrix}}
The current matrix transformation is available via the \type {getmatrix} command,
which returns 6 values: \type {sx}, \type {rx}, \type {ry}, \type {sy}, \type
{tx}, and \type {ty}. The \type {hasmatrix} function returns \type {true} when a
matrix is applied.
\starttyping
if pdf.hasmatrix() then
local sx, rx, ry, sy, tx, ty = pdf.getmatrix()
-- do something useful or not
end
\stoptyping
\subsection {\type {print}}
You can print string to the \PDF\ document from within a within a \type
{\latelua} call. This function is not to be used inside \type {\directlua} unless
you know {\it exactly} what you are doing.
\startfunctioncall
pdf.print(<string> s)
pdf.print(<string> type, <string> s)
\stopfunctioncall
The optional parameter can be used to mimic the behavior of \PDF\ literals: the
\type {type} is \type {direct} or \type {page}.
\subsection {\type {immediateobj}}
This function creates a \PDF\ object and immediately writes it to the \PDF\ file.
It is modelled after \PDFTEX's \type {\immediate} \type {\pdfobj} primitives. All
function variants return the object number of the newly generated object.
\startfunctioncall
<number> n =
pdf.immediateobj(<string> objtext)
<number> n =
pdf.immediateobj("file", <string> filename)
<number> n =
pdf.immediateobj("stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.immediateobj("streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
The first version puts the \type {objtext} raw into an object. Only the object
wrapper is automatically generated, but any internal structure (like \type {<<
>>} dictionary markers) needs to provided by the user. The second version with
keyword \type {file} as first argument puts the contents of the file with name
\type {filename} raw into the object. The third version with keyword \type
{stream} creates a stream object and puts the \type {streamtext} raw into the
stream. The stream length is automatically calculated. The optional \type
{attrtext} goes into the dictionary of that object. The fourth version with
keyword \type {streamfile} does the same as the third one, it just reads the
stream data raw from a file.
An optional first argument can be given to make the function use a previously
reserved \PDF\ object.
\startfunctioncall
<number> n =
pdf.immediateobj(<integer> n, <string> objtext)
<number> n =
pdf.immediateobj(<integer> n, "file", <string> filename)
<number> n =
pdf.immediateobj(<integer> n, "stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.immediateobj(<integer> n, "streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
\subsection{\type{obj}}
This function creates a \PDF\ object, which is written to the \PDF\ file only
when referenced, e.g., by \type {refobj()}.
All function variants return the object number of the newly generated object, and
there are two separate calling modes. The first mode is modelled after \PDFTEX's
\type {\pdfobj} primitive.
\startfunctioncall
<number> n =
pdf.obj(<string> objtext)
<number> n =
pdf.obj("file", <string> filename)
<number> n =
pdf.obj("stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.obj("streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
An optional first argument can be given to make the function use a previously
reserved \PDF\ object.
\startfunctioncall
<number> n =
pdf.obj(<integer> n, <string> objtext)
<number> n =
pdf.obj(<integer> n, "file", <string> filename)
<number> n =
pdf.obj(<integer> n, "stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.obj(<integer> n, "streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
The second mode accepts a single argument table with key--value pairs.
\startfunctioncall
<number> n = pdf.obj {
type = <string>,
immmediate = <boolean>,
objnum = <number>,
attr = <string>,
compresslevel = <number>,
objcompression = <boolean>,
file = <string>,
string = <string>
}
\stopfunctioncall
The \type {type} field can have the values \type {raw} and \type {stream}, this
field is required, the others are optional (within constraints).
Note: this mode makes \type{obj} look more flexible than it actually is: the
constraints from the separate parameter version still apply, so for example you
can't have both \type {string} and \type {file} at the same time.
\subsection {\type {refobj}}
This function, the \LUA\ version of the \type {\pdfrefobj} primitive, references an
object by its object number, so that the object will be written out.
\startfunctioncall
pdf.refobj(<integer> n)
\stopfunctioncall
This function works in both the \type {\directlua} and \type {\latelua} environment.
Inside \type {\directlua} a new whatsit node \quote {pdf_refobj} is created, which
will be marked for flushing during page output and the object is then written
directly after the page, when also the resources objects are written out. Inside
\type {\latelua} the object will be marked for flushing.
This function has no return values.
\subsection {\type {reserveobj}}
This function creates an empty \PDF\ object and returns its number.
\startfunctioncall
<number> n = pdf.reserveobj()
<number> n = pdf.reserveobj("annot")
\stopfunctioncall
\subsection {\type {registerannot}}
This function adds an object number to the \type {/Annots} array for the current
page without doing anything else. This function can only be used from within
\type {\latelua}.
\startfunctioncall
pdf.registerannot (<number> objnum)
\stopfunctioncall
\subsection {\type {newcolorstack}}
This function allocates a new color stack and returns it's id. The arguments
are the same as for the similar backend extension primitive.
\startfunctioncall
pdf.newcolorstack("0 g","page",true) -- page|direct|origin
\stopfunctioncall
\subsection {\type {setfontattributes}}
This function will force some additional code into the font resource. It can for
instance be used to add a custom \type {ToUnicode} vector to a bitmap file.
\startfunctioncall
pdf.setfontattributes(<number> font id, <string> pdf code)
\stopfunctioncall
\section {The \type {pdfscanner} library}
The \type {pdfscanner} library allows interpretation of \PDF\ content streams and
\type {/ToUnicode} (cmap) streams. You can get those streams from the \type
{epdf} library, as explained in an earlier section. There is only a single
top|-|level function in this library:
\startfunctioncall
pdfscanner.scan (<Object> stream, <table> operatortable, <table> info)
\stopfunctioncall
The first argument, \type {stream}, should be either a \PDF\ stream object, or a
\PDF\ array of \PDF\ stream objects (those options comprise the possible return
values of \type {<Page>:getContents()} and \type {<Object>:getStream()} in the
\type {epdf} library).
The second argument, \type {operatortable}, should be a \LUA\ table where the
keys are \PDF\ operator name strings and the values are \LUA\ functions (defined
by you) that are used to process those operators. The functions are called
whenever the scanner finds one of these \PDF\ operators in the content stream(s).
The functions are called with two arguments: the \type {scanner} object itself,
and the \type {info} table that was passed are the third argument to \type
{pdfscanner.scan}.
Internally, \type {pdfscanner.scan} loops over the \PDF\ operators in the
stream(s), collecting operands on an internal stack until it finds a \PDF\
operator. If that \PDF\ operator's name exists in \type {operatortable}, then the
associated function is executed. After the function has run (or when there is no
function to execute) the internal operand stack is cleared in preparation for the
next operator, and processing continues.
The \type {scanner} argument to the processing functions is needed because it
offers various methods to get the actual operands from the internal operand
stack.
A simple example of processing a \PDF's document stream could look like this:
\starttyping
function Do (scanner, info)
local val = scanner:pop()
local name = val[2] -- val[1] == 'name'
local resources = info.resources
local xobject = resources:lookup("XObject"):getDict():lookup(name)
print (info.space ..'Use XObject '.. name)
if xobject and xobject:isStream() then
local dict = xobject:getStream():getDict()
if dict then
local name = dict:lookup("Subtype")
if name:getName() == "Form" then
local newinfo = {
space = info.space .. " " ,
resources = dict:lookup("Resources"):getDict()
}
pdfscanner.scan(xobject, operatortable, newinfo)
end
end
end
end
operatortable = { Do = Do }
doc = epdf.open(arg[1])
pagenum = 1
while pagenum <= doc:getNumPages() do
local page = doc:getCatalog():getPage(pagenum)
local info = {
space = " " ,
resources = page:getResourceDict()
}
print('Page ' .. pagenum)
pdfscanner.scan(page:getContents(), operatortable, info)
pagenum = pagenum + 1
end
\stoptyping
This example iterates over all the actual content in the \PDF, and prints out the
found \type {XObject} names. While the code demonstrates quite some of the \type
{epdf} functions, let's focus on the type \type {pdfscanner} specific code
instead.
From the bottom up, the following line runs the scanner with the \PDF\ page's
top-level content.
\starttyping
pdfscanner.scan(page:getContents(), operatortable, info)
\stoptyping
The third argument, \type {info}, contains two entries: \type {space} is used to
indent the printed output, and \type {resources} is needed so that embedded \type
{XForms} can find their own content.
The second argument, \type {operatortable} defines a processing function for a
single \PDF\ operator, \type {Do}.
The function \type {Do} prints the name of the current \type {XObject}, and then
starts a new scanner for that object's content stream, under the condition that
the \type {XObject} is in fact a \type {/Form}. That nested scanner is called
with new \type {info} argument with an updated \type {space} value so that the
indentation of the output nicely nests, and with an new \type {resources} field
to help the next iteration down to properly process any other, embedded \type
{XObject}s.
Of course, this is not a very useful example in practise, but for the purpose of
demonstrating \type {pdfscanner}, it is just long enough. It makes use of only
one \type {scanner} method: \type {scanner:pop()}. That function pops the top
operand of the internal stack, and returns a \LUA\ table where the object at index
one is a string representing the type of the operand, and object two is its
value.
The list of possible operand types and associated \LUA\ value types is:
\starttabulate[|l|c|]
\NC \type{integer} \NC <number> \NC \NR
\NC \type{real} \NC <number> \NC \NR
\NC \type{boolean} \NC <boolean> \NC \NR
\NC \type{name} \NC <string> \NC \NR
\NC \type{operator} \NC <string> \NC \NR
\NC \type{string} \NC <string> \NC \NR
\NC \type{array} \NC <table> \NC \NR
\NC \type{dict} \NC <table> \NC \NR
\stoptabulate
In case of \type {integer} or \type {real}, the value is always a \LUA\ (floating
point) number.
In case of \type {name}, the leading slash is always stripped.
In case of \type {string}, please bear in mind that \PDF\ actually supports
different types of strings (with different encodings) in different parts of the
\PDF\ document, so may need to reencode some of the results; \type {pdfscanner}
always outputs the byte stream without reencoding anything. \type {pdfscanner}
does not differentiate between literal strings and hexadecimal strings (the
hexadecimal values are decoded), and it treats the stream data for inline images
as a string that is the single operand for \type {EI}.
In case of \type {array}, the table content is a list of \type {pop} return
values and in case of \type {dict}, the table keys are \PDF\ name strings and the
values are \type {pop} return values.
\blank
There are few more methods defined that you can ask \type {scanner}:
\starttabulate[|l|p|]
\NC \type{pop} \NC as explained above \NC \NR
\NC \type{popNumber} \NC return only the value of a \type {real} or \type {integer} \NC \NR
\NC \type{popName} \NC return only the value of a \type {name} \NC \NR
\NC \type{popString} \NC return only the value of a \type {string} \NC \NR
\NC \type{popArray} \NC return only the value of a \type {array} \NC \NR
\NC \type{popDict} \NC return only the value of a \type {dict} \NC \NR
\NC \type{popBool} \NC return only the value of a \type {boolean} \NC \NR
\NC \type{done} \NC abort further processing of this \type {scan()} call \NC \NR
\stoptabulate
The \type {popXXX} are convenience functions, and come in handy when you know the
type of the operands beforehand (which you usually do, in \PDF). For example, the
\type {Do} function could have used \type {local name = scanner:popName()}
instead, because the single operand to the \type {Do} operator is always a \PDF\
name object.
The \type {done} function allows you to abort processing of a stream once you
have learned everything you want to learn. This comes in handy while parsing
\type {/ToUnicode}, because there usually is trailing garbage that you are not
interested in. Without \type {done}, processing only end at the end of the
stream, possibly wasting \CPU\ cycles.
\section{The \type {epdf} library}
The \type {epdf} library provides \LUA\ bindings to many \PDF\ access functions
that are defined by the poppler \PDF\ viewer library (written in C$+{}+$ by
Kristian H\o gsberg, based on xpdf by Derek Noonburg). Within \LUATEX\ xpdf
functionality is being used since long time to embed \PDF\ files. The \type
{epdf} library allows to scrutinize an external \PDF\ file. It gives access to
its document structure: catalog, cross|-|reference table, individual pages,
objects, annotations, info, and metadata. The \type {epdf} library only provides
read|-|only access. At some point we might decide to limit the interface to a
reasonable subset.
For a start, a \PDF\ file is opened by \type {epdf.open()} with file name, e.g.:
\starttyping
doc = epdf.open("foo.pdf")
\stoptyping
This normally returns a \type {PDFDoc} userdata variable; but if the file could
not be opened successfully, instead of a fatal error just the value \type {nil} is
returned.
All \LUA\ functions in the \type {epdf} library are named after the poppler
functions listed in the poppler header files for the various classes, e.g., files
\type {PDFDoc.h}, \type {Dict.h}, and \type {Array.h}. These files can be found
in the poppler subdirectory within the \LUATEX\ sources. Which functions are
already implemented in the \type {epdf} library can be found in the \LUATEX\
source file \type {lepdflib.cc}. For using the \type {epdf} library, knowledge of
the \PDF\ file architecture is indispensable.
There are many different userdata types defined by the \type {epdf} library,
currently these are \type {AnnotBorderStyle}, \type {AnnotBorder}, \type
{Annots}, \type {Annot}, \type {Array}, \type {Attribute}, \type {Catalog}, \type
{Dict}, \type {EmbFile}, \type {GString}, \type {LinkDest}, \type {Links}, \type
{Link}, \type {ObjectStream}, \type {Object}, \type {PDFDoc}, \type
{PDFRectangle}, \type {Page}, \type {Ref}, \type {Stream}, \type {StructElement},
\type {StructTreeRoot} \type {TextSpan}, \type {XRefEntry} and \type {XRef}.
All these userdata names and the \LUA\ access functions closely resemble the
classes naming from the poppler header files, including the choice of mixed upper
and lower case letters. The \LUA\ function calls use object|-|oriented syntax,
e.g., the following calls return the \type {Page} object for page~1:
\starttyping
pageref = doc:getCatalog():getPageRef(1)
pageobj = doc:getXRef():fetch(pageref.num, pageref.gen)
\stoptyping
But writing such chained calls is risky, as an intermediate function may return
\type {nil} on error. Therefore between function calls there should be \LUA\ type
checks (e.g., against \type {nil}) done. If a non|-|object item is requested (for
instance a \type {Dict} item by calling \type {page:getPieceInfo()}, cf.~\type
{Page.h}) but not available, the \LUA\ functions return \type {nil} (without
error). If a function should return an \type {Object}, but it's not existing, a
\type {Null} object is returned instead, also without error. This is in|-|line
with poppler behavior.
All library objects have a \type {__gc} metamethod for garbage collection. The
\type {__tostring} metamethod gives the type name for each object.
These are the object constructors:
\startfunctioncall
<PDFDoc> = epdf.open(<string> PDF filename)
<PDFDoc> = epdf.openMemStream(<string> PDF code)
\stopfunctioncall
The functions \type {StructElement_Type}, \type {Attribute_Type} and \type
{AttributeOwner_Type} return a hash table \type {{<string>,<integer>}}.
\type {Annot} methods:
\startfunctioncall
<boolean> = <Annot>:isOK()
<boolean> = <Annot>:match(<Ref>)
<Object> = <Annot>:getAppearance() -- gone
<AnnotBorder> = <Annot>:getBorder() -- gone
\stopfunctioncall
\type {AnnotBorderStyle} methods (gone):
\startfunctioncall
<number> = <AnnotBorderStyle>:getWidth() -- gone
\stopfunctioncall
\type {Annots} methods:
\startfunctioncall
<integer> = <Annots>:getNumAnnots()
<Annot> = <Annots>:getAnnot(<integer>)
\stopfunctioncall
\type {Array} methods:
\startfunctioncall
<integer> = <Array>:getLength()
<Object> = <Array>:get(<integer>)
<Object> = <Array>:getNF(<integer>)
<string> = <Array>:getString(<integer>)
\stopfunctioncall
\type {Attribute} methods:
\startfunctioncall
<boolean> = <Attribute>:isOk()
<integer> = <Attribute>:getType()
<integer> = <Attribute>:getOwner()
<string> = <Attribute>:getTypeName()
<string> = <Attribute>:getOwnerName()
<Object> = <Attribute>:getValue()
<Object> = <Attribute>:getDefaultValue
<string> = <Attribute>:getName()
<integer> = <Attribute>:getRevision()
<boolean> = <Attribute>:isHidden()
<string> = <Attribute>:getFormattedValue()
\stopfunctioncall
\type {Catalog} methods:
\startfunctioncall
<boolean> = <Catalog>:isOK()
<integer> = <Catalog>:getNumPages()
<Page> = <Catalog>:getPage(<integer>)
<Ref> = <Catalog>:getPageRef(<integer>)
<string> = <Catalog>:getBaseURI()
<string> = <Catalog>:readMetadata()
<Object> = <Catalog>:getStructTreeRoot()
<integer> = <Catalog>:findPage(<integer> object number, <integer> object generation)
<LinkDest> = <Catalog>:findDest(<string> name)
<Object> = <Catalog>:getDests()
<integer> = <Catalog>:numEmbeddedFiles()
<EmbFile> = <Catalog>:embeddedFile(<integer>)
<integer> = <Catalog>:numJS()
<string> = <Catalog>:getJS(<integer>)
<Object> = <Catalog>:getOutline()
<Object> = <Catalog>:getAcroForm()
\stopfunctioncall
\type {EmbFile} methods:
\startfunctioncall
<integer> = <EmbFile>:size()
<string> = <EmbFile>:modDate()
<string> = <EmbFile>:createDate()
<string> = <EmbFile>:checksum()
<string> = <EmbFile>:mimeType()
<boolean> = <EmbFile>:isOk()
<string> = <EmbFile>:name() -- not (yet) implemented
<string> = <EmbFile>:description() -- not (yet) implemented
<Object> = <EmbFile>:streamObject() -- not (yet) implemented
<boolean> = <EmbFile>:save() -- will go
\stopfunctioncall
\type {FileSpec} methods:
\startfunctioncall
<boolean> = <FileSpec>:isOk()
<string> = <FileSpec>:getFileName()
<string> = <FileSpec>:getFileNameForPlatform()
<string> = <FileSpec>:getDescription()
<EmbFile> = <FileSpec>:getEmbeddedFile()
\stopfunctioncall
\type {Dict} methods:
\startfunctioncall
<integer> = <Dict>:getLength()
<boolean> = <Dict>:is(<string>)
<Object> = <Dict>:lookup(<string>)
<Object> = <Dict>:lookupNF(<string>)
<integer> = <Dict>:lookupInt(<string>, <string>)
<string> = <Dict>:getKey(<integer>)
<Object> = <Dict>:getVal(<integer>)
<Object> = <Dict>:getValNF(<integer>)
<boolean> = <Dict>:hasKey(<string>)
\stopfunctioncall
% \type {Link} methods:
% \startfunctioncall
% <boolean> = <Link>:isOK()
% <boolean> = <Link>:inRect(<number>, <number>)
% \stopfunctioncall
\type {LinkDest} methods:
\startfunctioncall
<boolean> = <LinkDest>:isOK()
<integer> = <LinkDest>:getKind()
<string> = <LinkDest>:getKindName()
<boolean> = <LinkDest>:isPageRef()
<integer> = <LinkDest>:getPageNum()
<Ref> = <LinkDest>:getPageRef()
<number> = <LinkDest>:getLeft()
<number> = <LinkDest>:getBottom()
<number> = <LinkDest>:getRight()
<number> = <LinkDest>:getTop()
<number> = <LinkDest>:getZoom()
<boolean> = <LinkDest>:getChangeLeft()
<boolean> = <LinkDest>:getChangeTop()
<boolean> = <LinkDest>:getChangeZoom()
\stopfunctioncall
\type {Links} methods:
% <Link> = <Links>:getLink(<integer>)
\startfunctioncall
<integer> = <Links>:getNumLinks()
\stopfunctioncall
\type {Object} methods:
\startfunctioncall
<Object> = <Object>:fetch(<XRef>)
<integer> = <Object>:getType()
<string> = <Object>:getTypeName()
<boolean> = <Object>:isBool()
<boolean> = <Object>:isInt()
<boolean> = <Object>:isReal()
<boolean> = <Object>:isNum()
<boolean> = <Object>:isString()
<boolean> = <Object>:isName()
<boolean> = <Object>:isNull()
<boolean> = <Object>:isArray()
<boolean> = <Object>:isDict()
<boolean> = <Object>:isStream()
<boolean> = <Object>:isRef()
<boolean> = <Object>:isCmd()
<boolean> = <Object>:isError()
<boolean> = <Object>:isEOF()
<boolean> = <Object>:isNone()
<boolean> = <Object>:getBool()
<integer> = <Object>:getInt()
<number> = <Object>:getReal()
<number> = <Object>:getNum()
<string> = <Object>:getString()
<string> = <Object>:getName()
<Array> = <Object>:getArray()
<Dict> = <Object>:getDict()
<Stream> = <Object>:getStream()
<Ref> = <Object>:getRef()
<integer> = <Object>:getRefNum()
<integer> = <Object>:getRefGen()
<string> = <Object>:getCmd()
<integer> = <Object>:arrayGetLength()
<Object> = <Object>:arrayGet(<integer>)
<Object> = <Object>:arrayGetNF(<integer>)
<integer> = <Object>:dictGetLength(<integer>)
<Object> = <Object>:dictLookup(<string>)
<Object> = <Object>:dictLookupNF(<string>)
<string> = <Object>:dictgetKey(<integer>)
<Object> = <Object>:dictgetVal(<integer>)
<Object> = <Object>:dictgetValNF(<integer>)
<boolean> = <Object>:streamIs(<string>)
= <Object>:streamReset() -- will go
<integer> = <Object>:streamGetChar()
<integer> = <Object>:streamLookChar()
<integer> = <Object>:streamGetPos()
= <Object>:streamSetPos(<integer>)
<Dict> = <Object>:streamGetDict()
\stopfunctioncall
\type {Page} methods:
\startfunctioncall
<boolean> = <Page>:isOk()
<integer> = <Page>:getNum()
<PDFRectangle> = <Page>:getMediaBox()
<PDFRectangle> = <Page>:getCropBox()
<boolean> = <Page>:isCropped()
<number> = <Page>:getMediaWidth()
<number> = <Page>:getMediaHeight()
<number> = <Page>:getCropWidth()
<number> = <Page>:getCropHeight()
<PDFRectangle> = <Page>:getBleedBox()
<PDFRectangle> = <Page>:getTrimBox()
<PDFRectangle> = <Page>:getArtBox()
<integer> = <Page>:getRotate()
<string> = <Page>:getLastModified()
<Dict> = <Page>:getBoxColorInfo()
<Dict> = <Page>:getGroup()
<Stream> = <Page>:getMetadata()
<Dict> = <Page>:getPieceInfo()
<Dict> = <Page>:getSeparationInfo()
<Dict> = <Page>:getResourceDict()
<Object> = <Page>:getAnnots()
<Links> = <Page>:getLinks(<Catalog>)
<Object> = <Page>:getContents()
\stopfunctioncall
\type {PDFDoc} methods:
\startfunctioncall
<boolean> = <PDFDoc>:isOk()
<integer> = <PDFDoc>:getErrorCode()
<string> = <PDFDoc>:getErrorCodeName()
<string> = <PDFDoc>:getFileName()
<XRef> = <PDFDoc>:getXRef()
<Catalog> = <PDFDoc>:getCatalog()
<number> = <PDFDoc>:getPageMediaWidth()
<number> = <PDFDoc>:getPageMediaHeight()
<number> = <PDFDoc>:getPageCropWidth()
<number> = <PDFDoc>:getPageCropHeight()
<integer> = <PDFDoc>:getNumPages()
<string> = <PDFDoc>:readMetadata()
<Object> = <PDFDoc>:getStructTreeRoot()
<integer> = <PDFDoc>:findPage(<integer> object number,
<integer> object generation)
<Links> = <PDFDoc>:getLinks(<integer>)
<LinkDest> = <PDFDoc>:findDest(<string>)
<boolean> = <PDFDoc>:isEncrypted()
<boolean> = <PDFDoc>:okToPrint()
<boolean> = <PDFDoc>:okToChange()
<boolean> = <PDFDoc>:okToCopy()
<boolean> = <PDFDoc>:okToAddNotes()
<boolean> = <PDFDoc>:isLinearized()
<Object> = <PDFDoc>:getDocInfo()
<Object> = <PDFDoc>:getDocInfoNF()
<integer> = <PDFDoc>:getPDFMajorVersion()
<integer> = <PDFDoc>:getPDFMinorVersion()
\stopfunctioncall
\type {PDFRectangle} methods:
\startfunctioncall
<boolean> = <PDFRectangle>:isValid() -- setindex/newindex will go
\stopfunctioncall
%\type {Ref} methods:
%
%\startfunctioncall
%\stopfunctioncall
\type {Stream} methods:
\startfunctioncall
<integer> = <Stream>:getKind()
<string> = <Stream>:getKindName()
= <Stream>:reset()
= <Stream>:close()
<integer> = <Stream>:getChar()
<integer> = <Stream>:lookChar()
<integer> = <Stream>:getRawChar()
<integer> = <Stream>:getUnfilteredChar()
= <Stream>:unfilteredReset()
<integer> = <Stream>:getPos()
<boolean> = <Stream>:isBinary()
<Stream> = <Stream>:getUndecodedStream()
<Dict> = <Stream>:getDict()
\stopfunctioncall
\type {StructElement} methods:
\startfunctioncall
<string> = <StructElement>:getTypeName()
<integer> = <StructElement>:getType()
<boolean> = <StructElement>:isOk()
<boolean> = <StructElement>:isBlock()
<boolean> = <StructElement>:isInline()
<boolean> = <StructElement>:isGrouping()
<boolean> = <StructElement>:isContent()
<boolean> = <StructElement>:isObjectRef()
<integer> = <StructElement>:getMCID()
<Ref> = <StructElement>:getObjectRef()
<Ref> = <StructElement>:getParentRef()
<boolean> = <StructElement>:hasPageRef()
<Ref> = <StructElement>:getPageRef()
<StructTreeRoot> = <StructElement>:getStructTreeRoot()
<string> = <StructElement>:getID()
<string> = <StructElement>:getLanguage()
<integer> = <StructElement>:getRevision()
<string> = <StructElement>:getTitle()
<string> = <StructElement>:getExpandedAbbr()
<integer> = <StructElement>:getNumChildren()
<StructElement> = <StructElement>:getChild()
<integer> = <StructElement>:getNumAttributes()
<Attribute> = <StructElement>:getAttribute(<integer>)
<string> = <StructElement>:appendAttribute(<Attribute>) -- will go
<Attribute> = <StructElement>:findAttribute(<Attribute::Type>,
boolean,Attribute::Owner)
<string> = <StructElement>:getAltText()
<string> = <StructElement>:getActualText()
<string> = <StructElement>:getText(<boolean>)
<table> = <StructElement>:getTextSpans()
\stopfunctioncall
\type {StructTreeRoot} methods:
\startfunctioncall
<StructElement> = <StructTreeRoot>:findParentElement
<PDFDoc> = <StructTreeRoot>:getDoc
<Dict> = <StructTreeRoot>:getRoleMap
<Dict> = <StructTreeRoot>:getClassMap
<integer> = <StructTreeRoot>:getNumChildren
<StructElement> = <StructTreeRoot>:getChild
<StructElement> = <StructTreeRoot>:findParentElement
\stopfunctioncall
\type {TextSpan} han only one method:
\startfunctioncall
<string> = <TestSpan>:getText()
\stopfunctioncall
\type {XRef} methods:
\startfunctioncall
<boolean> = <XRef>:isOk()
<integer> = <XRef>:getErrorCode()
<boolean> = <XRef>:isEncrypted()
<boolean> = <XRef>:okToPrint()
<boolean> = <XRef>:okToPrintHighRes()
<boolean> = <XRef>:okToChange()
<boolean> = <XRef>:okToCopy()
<boolean> = <XRef>:okToAddNotes()
<boolean> = <XRef>:okToFillForm()
<boolean> = <XRef>:okToAccessibility()
<boolean> = <XRef>:okToAssemble()
<Object> = <XRef>:getCatalog()
<Object> = <XRef>:fetch(<integer> object number,
<integer> object generation)
<Object> = <XRef>:getDocInfo()
<Object> = <XRef>:getDocInfoNF()
<integer> = <XRef>:getNumObjects()
<integer> = <XRef>:getRootNum()
<integer> = <XRef>:getRootGen()
<integer> = <XRef>:getSize()
<Object> = <XRef>:getTrailerDict()
\stopfunctioncall
There is an experimental function \type {epdf.openMemStream} that takes three
arguments:
\starttabulate
\NC \type {stream} \NC this is a (in low level \LUA\ speak) light userdata
object, i.e.\ a pointer to a sequence of bytes \NC \NR
\NC \type {length} \NC this is the length of the stream in bytes \NC \NR
\NC \type {name} \NC this is a unique identifier that is used for hashing the
stream, so that multiple doesn't use more memory \NC \NR
\stoptabulate
Instead of a light userdata stream you can also pass a \LUA\ string, in which
case the given length is (at most) the string length.
The function returns a \type{epdf} object and a string. The string can be used in
the \type {img} library instead of a filename. You need to prevent garbage
collection of the object when you use it as image (for instance by storing it
somewhere).
Both the memory stream and it's use in the image library is experimental and can
change. In case you wonder where this can be used: when you use the swiglib
library for \type {graphicmagick}, it can return such a userdata object. This
permits conversion in memory and passing the result directly to the backend. This
might save some runtime in one|-|pass workflows. This feature is currently not
meant for production and we might come up with a better implementation.
\stopchapter
\stopcomponent
% language=uk
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-backend
\startchapter[reference=backend,title={The backend libraries}]
\section{The \type {pdf} library}
This library contains variables and functions that are related to the \PDF\
backend. You can find more details about the expected values to setters in \in
{section} [backendprimitives].
\subsection{\type {mapfile}, \type {mapline}}
\startfunctioncall
pdf.mapfile(<string> map file)
pdf.mapline(<string> map line)
\stopfunctioncall
These two functions can be used to replace primitives \type {\pdfmapfile} and
\type {\pdfmapline} inherited from \PDFTEX. They expect a string as only
parameter and have no return value. The first character in a map line can be
\type {-}, \type {+} or \type {=} which means as much as remove, add or replace
this line.
\subsection {\type {[set|get][catalog|info|names|trailer]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with metadata. The value types are strings and they are written out to the \PDF\
file directly after the token registers.
\subsection {\type {[set|get][pageattributes|pageresources|pagesattributes]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with page resources. The variables have no interaction with the corresponding \PDF\
backend token register. They are written out to the \PDF\ file directly after the
token registers.
\subsection{\type {[set|get][xformattributes|xformresources]}}
These functions complement the corresponding \PDF\ backend token lists dealing
with reuseable boxes and images. The variables have no interaction with the
corresponding \PDF\ backend token register. They are written out to the \PDF\
file directly after the token registers.
\subsection{\type {getversion} and \type {[set|get]minorversion}}
The version is frozen in the binary but you can set the minor version. What minor
version you set depends on what \PDF\ features you use. This is out of control
of \LUATEX.
\subsection{\type {getcreationdate}}
This function returns a string with the date in the format that ends up in the
\PDF\ file, in this case it's: {\tttf \cldcontext{pdf.getcreationdate()}}.
\subsection{\type {[set|get]inclusionerrorlevel}, \type {[set|get]ignoreunknownimages}}
These variable control how error in included image are treated. They are modeled
after the \PDFTEX\ equivalents.
\subsection{\type {[set|get]suppressoptionalinfo}}
This bitset determnines what kind of info gets flushes. By default we flush all.
\subsection{\type {[set|get]trailerid}}
You can set your own trailer id. This has to be a valid array string
with checksums.
\subsection{\type {[set|get]compresslevel}}
These two functions set the level of compression. The minimum value is~0,
the maximum is~9.
\subsection{\type {[set|get]objcompresslevel}}
These two functions set the level of compression. The minimum value is~0,
the maximum is~9.
\subsection{\type {[set|get]gentounicode}}
This flag enables tounicode generation (like in \PDFTEX).
\subsection{\type {[set|get]omitcidset}}
This flag disables inclusion of a so called CIDSet which can be handy when aiming
at some of the many \PDF\ substandards.
\subsection{\type {[set|get]decimaldigits}}
These two functions set the accuracy of floats written to the \PDF file. You can
set any value but the backend will not go below~3 and above~6.
\subsection{\type {[set|get]pkresolution}}
These setter takes two arguments: the resolution and an optional zero or one that
indicates if this is a fixed one. The getter returns these two values.
\subsection{\type {getlast[obj|link|annot]} and \type {getretval}}
These status variables are similar to the ones traditionally used in the backend
interface at the \TEX\ end.
\subsection{\type {maxobjnum} and \type {objtype}, \type {fontname}, \type {fontobjnum},
\type {fontsize}, \type {xformname}}.
These (and some other) introspective helpers were moved from the the \type {tex}
namespace to the \type {pdf} namespace but kept their original names. They are
mostly used when you construct \PDF\ objects yourself and need for instance
information about a (to be) embedded font.
\subsection{\type {[set|get]origin}}
This one is used to set the horizonal and|/|or vertical offset, a traditional
backend property.
\starttyping
pdf.setorigin() -- sets both to 0pt
pdf.setorigin(tex.sp("1in")) -- sets both to 1in
pdf.setorigin(tex.sp("1in"),tex.sp("1in"))
\stoptyping
The counterpart of this function returns two values.
\subsection{\type {[set|get]imageresolution}}
These two functions relate to the imageresolution that is used when the image
itself doesn't provide a non|-|zero x or y resolution.
\subsection {\type {[set|get][link|dest|thread|xform]margin}}
These functions can be used to set and retrieve the margins that are added to the
natural bounding boxes of the respective objects.
\subsection {\type {get[pos|hpos|vpos]}}
These function get current location on the output page, measured from its lower
left corner. The values return scaled points as units.
\starttyping
local h, v = pdf.getpos()
\stoptyping
\subsection {\type {[has|get]matrix}}
The current matrix transformation is available via the \type {getmatrix} command,
which returns 6 values: \type {sx}, \type {rx}, \type {ry}, \type {sy}, \type
{tx}, and \type {ty}. The \type {hasmatrix} function returns \type {true} when a
matrix is applied.
\starttyping
if pdf.hasmatrix() then
local sx, rx, ry, sy, tx, ty = pdf.getmatrix()
-- do something useful or not
end
\stoptyping
\subsection {\type {print}}
You can print string to the \PDF\ document from within a within a \type
{\latelua} call. This function is not to be used inside \type {\directlua} unless
you know {\it exactly} what you are doing.
\startfunctioncall
pdf.print(<string> s)
pdf.print(<string> type, <string> s)
\stopfunctioncall
The optional parameter can be used to mimic the behavior of \PDF\ literals: the
\type {type} is \type {direct} or \type {page}.
\subsection {\type {immediateobj}}
This function creates a \PDF\ object and immediately writes it to the \PDF\ file.
It is modelled after \PDFTEX's \type {\immediate} \type {\pdfobj} primitives. All
function variants return the object number of the newly generated object.
\startfunctioncall
<number> n =
pdf.immediateobj(<string> objtext)
<number> n =
pdf.immediateobj("file", <string> filename)
<number> n =
pdf.immediateobj("stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.immediateobj("streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
The first version puts the \type {objtext} raw into an object. Only the object
wrapper is automatically generated, but any internal structure (like \type {<<
>>} dictionary markers) needs to provided by the user. The second version with
keyword \type {file} as first argument puts the contents of the file with name
\type {filename} raw into the object. The third version with keyword \type
{stream} creates a stream object and puts the \type {streamtext} raw into the
stream. The stream length is automatically calculated. The optional \type
{attrtext} goes into the dictionary of that object. The fourth version with
keyword \type {streamfile} does the same as the third one, it just reads the
stream data raw from a file.
An optional first argument can be given to make the function use a previously
reserved \PDF\ object.
\startfunctioncall
<number> n =
pdf.immediateobj(<integer> n, <string> objtext)
<number> n =
pdf.immediateobj(<integer> n, "file", <string> filename)
<number> n =
pdf.immediateobj(<integer> n, "stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.immediateobj(<integer> n, "streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
\subsection{\type{obj}}
This function creates a \PDF\ object, which is written to the \PDF\ file only
when referenced, e.g., by \type {refobj()}.
All function variants return the object number of the newly generated object, and
there are two separate calling modes. The first mode is modelled after \PDFTEX's
\type {\pdfobj} primitive.
\startfunctioncall
<number> n =
pdf.obj(<string> objtext)
<number> n =
pdf.obj("file", <string> filename)
<number> n =
pdf.obj("stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.obj("streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
An optional first argument can be given to make the function use a previously
reserved \PDF\ object.
\startfunctioncall
<number> n =
pdf.obj(<integer> n, <string> objtext)
<number> n =
pdf.obj(<integer> n, "file", <string> filename)
<number> n =
pdf.obj(<integer> n, "stream", <string> streamtext, <string> attrtext)
<number> n =
pdf.obj(<integer> n, "streamfile", <string> filename, <string> attrtext)
\stopfunctioncall
The second mode accepts a single argument table with key--value pairs.
\startfunctioncall
<number> n = pdf.obj {
type = <string>,
immmediate = <boolean>,
objnum = <number>,
attr = <string>,
compresslevel = <number>,
objcompression = <boolean>,
file = <string>,
string = <string>
}
\stopfunctioncall
The \type {type} field can have the values \type {raw} and \type {stream}, this
field is required, the others are optional (within constraints).
Note: this mode makes \type{obj} look more flexible than it actually is: the
constraints from the separate parameter version still apply, so for example you
can't have both \type {string} and \type {file} at the same time.
\subsection {\type {refobj}}
This function, the \LUA\ version of the \type {\pdfrefobj} primitive, references an
object by its object number, so that the object will be written out.
\startfunctioncall
pdf.refobj(<integer> n)
\stopfunctioncall
This function works in both the \type {\directlua} and \type {\latelua} environment.
Inside \type {\directlua} a new whatsit node \quote {pdf_refobj} is created, which
will be marked for flushing during page output and the object is then written
directly after the page, when also the resources objects are written out. Inside
\type {\latelua} the object will be marked for flushing.
This function has no return values.
\subsection {\type {reserveobj}}
This function creates an empty \PDF\ object and returns its number.
\startfunctioncall
<number> n = pdf.reserveobj()
<number> n = pdf.reserveobj("annot")
\stopfunctioncall
\subsection {\type {registerannot}}
This function adds an object number to the \type {/Annots} array for the current
page without doing anything else. This function can only be used from within
\type {\latelua}.
\startfunctioncall
pdf.registerannot (<number> objnum)
\stopfunctioncall
\subsection {\type {newcolorstack}}
This function allocates a new color stack and returns it's id. The arguments
are the same as for the similar backend extension primitive.
\startfunctioncall
pdf.newcolorstack("0 g","page",true) -- page|direct|origin
\stopfunctioncall
\subsection {\type {setfontattributes}}
This function will force some additional code into the font resource. It can for
instance be used to add a custom \type {ToUnicode} vector to a bitmap file.
\startfunctioncall
pdf.setfontattributes(<number> font id, <string> pdf code)
\stopfunctioncall
\section {The \type {pdfscanner} library}
The \type {pdfscanner} library allows interpretation of \PDF\ content streams and
\type {/ToUnicode} (cmap) streams. You can get those streams from the \type
{epdf} library, as explained in an earlier section. There is only a single
top|-|level function in this library:
\startfunctioncall
pdfscanner.scan (<Object> stream, <table> operatortable, <table> info)
\stopfunctioncall
The first argument, \type {stream}, should be either a \PDF\ stream object, or a
\PDF\ array of \PDF\ stream objects (those options comprise the possible return
values of \type {<Page>:getContents()} and \type {<Object>:getStream()} in the
\type {epdf} library).
The second argument, \type {operatortable}, should be a \LUA\ table where the
keys are \PDF\ operator name strings and the values are \LUA\ functions (defined
by you) that are used to process those operators. The functions are called
whenever the scanner finds one of these \PDF\ operators in the content stream(s).
The functions are called with two arguments: the \type {scanner} object itself,
and the \type {info} table that was passed are the third argument to \type
{pdfscanner.scan}.
Internally, \type {pdfscanner.scan} loops over the \PDF\ operators in the
stream(s), collecting operands on an internal stack until it finds a \PDF\
operator. If that \PDF\ operator's name exists in \type {operatortable}, then the
associated function is executed. After the function has run (or when there is no
function to execute) the internal operand stack is cleared in preparation for the
next operator, and processing continues.
The \type {scanner} argument to the processing functions is needed because it
offers various methods to get the actual operands from the internal operand
stack.
A simple example of processing a \PDF's document stream could look like this:
\starttyping
function Do (scanner, info)
local val = scanner:pop()
local name = val[2] -- val[1] == 'name'
local resources = info.resources
local xobject = resources:lookup("XObject"):getDict():lookup(name)
print (info.space ..'Use XObject '.. name)
if xobject and xobject:isStream() then
local dict = xobject:getStream():getDict()
if dict then
local name = dict:lookup("Subtype")
if name:getName() == "Form" then
local newinfo = {
space = info.space .. " " ,
resources = dict:lookup("Resources"):getDict()
}
pdfscanner.scan(xobject, operatortable, newinfo)
end
end
end
end
operatortable = { Do = Do }
doc = epdf.open(arg[1])
pagenum = 1
while pagenum <= doc:getNumPages() do
local page = doc:getCatalog():getPage(pagenum)
local info = {
space = " " ,
resources = page:getResourceDict()
}
print('Page ' .. pagenum)
pdfscanner.scan(page:getContents(), operatortable, info)
pagenum = pagenum + 1
end
\stoptyping
This example iterates over all the actual content in the \PDF, and prints out the
found \type {XObject} names. While the code demonstrates quite some of the \type
{epdf} functions, let's focus on the type \type {pdfscanner} specific code
instead.
From the bottom up, the following line runs the scanner with the \PDF\ page's
top-level content.
\starttyping
pdfscanner.scan(page:getContents(), operatortable, info)
\stoptyping
The third argument, \type {info}, contains two entries: \type {space} is used to
indent the printed output, and \type {resources} is needed so that embedded \type
{XForms} can find their own content.
The second argument, \type {operatortable} defines a processing function for a
single \PDF\ operator, \type {Do}.
The function \type {Do} prints the name of the current \type {XObject}, and then
starts a new scanner for that object's content stream, under the condition that
the \type {XObject} is in fact a \type {/Form}. That nested scanner is called
with new \type {info} argument with an updated \type {space} value so that the
indentation of the output nicely nests, and with an new \type {resources} field
to help the next iteration down to properly process any other, embedded \type
{XObject}s.
Of course, this is not a very useful example in practise, but for the purpose of
demonstrating \type {pdfscanner}, it is just long enough. It makes use of only
one \type {scanner} method: \type {scanner:pop()}. That function pops the top
operand of the internal stack, and returns a \LUA\ table where the object at index
one is a string representing the type of the operand, and object two is its
value.
The list of possible operand types and associated \LUA\ value types is:
\starttabulate[|l|c|]
\NC \type{integer} \NC <number> \NC \NR
\NC \type{real} \NC <number> \NC \NR
\NC \type{boolean} \NC <boolean> \NC \NR
\NC \type{name} \NC <string> \NC \NR
\NC \type{operator} \NC <string> \NC \NR
\NC \type{string} \NC <string> \NC \NR
\NC \type{array} \NC <table> \NC \NR
\NC \type{dict} \NC <table> \NC \NR
\stoptabulate
In case of \type {integer} or \type {real}, the value is always a \LUA\ (floating
point) number.
In case of \type {name}, the leading slash is always stripped.
In case of \type {string}, please bear in mind that \PDF\ actually supports
different types of strings (with different encodings) in different parts of the
\PDF\ document, so may need to reencode some of the results; \type {pdfscanner}
always outputs the byte stream without reencoding anything. \type {pdfscanner}
does not differentiate between literal strings and hexadecimal strings (the
hexadecimal values are decoded), and it treats the stream data for inline images
as a string that is the single operand for \type {EI}.
In case of \type {array}, the table content is a list of \type {pop} return
values and in case of \type {dict}, the table keys are \PDF\ name strings and the
values are \type {pop} return values.
\blank
There are few more methods defined that you can ask \type {scanner}:
\starttabulate[|l|p|]
\NC \type{pop} \NC as explained above \NC \NR
\NC \type{popNumber} \NC return only the value of a \type {real} or \type {integer} \NC \NR
\NC \type{popName} \NC return only the value of a \type {name} \NC \NR
\NC \type{popString} \NC return only the value of a \type {string} \NC \NR
\NC \type{popArray} \NC return only the value of a \type {array} \NC \NR
\NC \type{popDict} \NC return only the value of a \type {dict} \NC \NR
\NC \type{popBool} \NC return only the value of a \type {boolean} \NC \NR
\NC \type{done} \NC abort further processing of this \type {scan()} call \NC \NR
\stoptabulate
The \type {popXXX} are convenience functions, and come in handy when you know the
type of the operands beforehand (which you usually do, in \PDF). For example, the
\type {Do} function could have used \type {local name = scanner:popName()}
instead, because the single operand to the \type {Do} operator is always a \PDF\
name object.
The \type {done} function allows you to abort processing of a stream once you
have learned everything you want to learn. This comes in handy while parsing
\type {/ToUnicode}, because there usually is trailing garbage that you are not
interested in. Without \type {done}, processing only end at the end of the
stream, possibly wasting \CPU\ cycles.
\section{The \type {epdf} library}
The \type {epdf} library provides \LUA\ bindings to many \PDF\ access functions
that are defined by the poppler \PDF\ viewer library (written in C$+{}+$ by
Kristian H\o gsberg, based on xpdf by Derek Noonburg). Within \LUATEX\ xpdf
functionality is being used since long time to embed \PDF\ files. The \type
{epdf} library allows to scrutinize an external \PDF\ file. It gives access to
its document structure: catalog, cross|-|reference table, individual pages,
objects, annotations, info, and metadata. The \type {epdf} library only provides
read|-|only access. At some point we might decide to limit the interface to a
reasonable subset.
For a start, a \PDF\ file is opened by \type {epdf.open()} with file name, e.g.:
\starttyping
doc = epdf.open("foo.pdf")
\stoptyping
This normally returns a \type {PDFDoc} userdata variable; but if the file could
not be opened successfully, instead of a fatal error just the value \type {nil} is
returned.
All \LUA\ functions in the \type {epdf} library are named after the poppler
functions listed in the poppler header files for the various classes, e.g., files
\type {PDFDoc.h}, \type {Dict.h}, and \type {Array.h}. These files can be found
in the poppler subdirectory within the \LUATEX\ sources. Which functions are
already implemented in the \type {epdf} library can be found in the \LUATEX\
source file \type {lepdflib.cc}. For using the \type {epdf} library, knowledge of
the \PDF\ file architecture is indispensable.
There are many different userdata types defined by the \type {epdf} library,
currently these are \type {AnnotBorderStyle}, \type {AnnotBorder}, \type
{Annots}, \type {Annot}, \type {Array}, \type {Attribute}, \type {Catalog}, \type
{Dict}, \type {EmbFile}, \type {GString}, \type {LinkDest}, \type {Links}, \type
{Link}, \type {ObjectStream}, \type {Object}, \type {PDFDoc}, \type
{PDFRectangle}, \type {Page}, \type {Ref}, \type {Stream}, \type {StructElement},
\type {StructTreeRoot} \type {TextSpan}, \type {XRefEntry} and \type {XRef}.
All these userdata names and the \LUA\ access functions closely resemble the
classes naming from the poppler header files, including the choice of mixed upper
and lower case letters. The \LUA\ function calls use object|-|oriented syntax,
e.g., the following calls return the \type {Page} object for page~1:
\starttyping
pageref = doc:getCatalog():getPageRef(1)
pageobj = doc:getXRef():fetch(pageref.num, pageref.gen)
\stoptyping
But writing such chained calls is risky, as an intermediate function may return
\type {nil} on error. Therefore between function calls there should be \LUA\ type
checks (e.g., against \type {nil}) done. If a non|-|object item is requested (for
instance a \type {Dict} item by calling \type {page:getPieceInfo()}, cf.~\type
{Page.h}) but not available, the \LUA\ functions return \type {nil} (without
error). If a function should return an \type {Object}, but it's not existing, a
\type {Null} object is returned instead, also without error. This is in|-|line
with poppler behavior.
All library objects have a \type {__gc} metamethod for garbage collection. The
\type {__tostring} metamethod gives the type name for each object.
These are the object constructors:
\startfunctioncall
<PDFDoc> = epdf.open(<string> PDF filename)
<PDFDoc> = epdf.openMemStream(<string> PDF code)
\stopfunctioncall
The functions \type {StructElement_Type}, \type {Attribute_Type} and \type
{AttributeOwner_Type} return a hash table \type {{<string>,<integer>}}.
\type {Annot} methods:
\startfunctioncall
<boolean> = <Annot>:isOK()
<boolean> = <Annot>:match(<Ref>)
<Object> = <Annot>:getAppearance() -- gone
<AnnotBorder> = <Annot>:getBorder() -- gone
\stopfunctioncall
\type {AnnotBorderStyle} methods (gone):
\startfunctioncall
<number> = <AnnotBorderStyle>:getWidth() -- gone
\stopfunctioncall
\type {Annots} methods:
\startfunctioncall
<integer> = <Annots>:getNumAnnots()
<Annot> = <Annots>:getAnnot(<integer>)
\stopfunctioncall
\type {Array} methods:
\startfunctioncall
<integer> = <Array>:getLength()
<Object> = <Array>:get(<integer>)
<Object> = <Array>:getNF(<integer>)
<string> = <Array>:getString(<integer>)
\stopfunctioncall
\type {Attribute} methods:
\startfunctioncall
<boolean> = <Attribute>:isOk()
<integer> = <Attribute>:getType()
<integer> = <Attribute>:getOwner()
<string> = <Attribute>:getTypeName()
<string> = <Attribute>:getOwnerName()
<Object> = <Attribute>:getValue()
<Object> = <Attribute>:getDefaultValue
<string> = <Attribute>:getName()
<integer> = <Attribute>:getRevision()
<boolean> = <Attribute>:isHidden()
<string> = <Attribute>:getFormattedValue()
\stopfunctioncall
\type {Catalog} methods:
\startfunctioncall
<boolean> = <Catalog>:isOK()
<integer> = <Catalog>:getNumPages()
<Page> = <Catalog>:getPage(<integer>)
<Ref> = <Catalog>:getPageRef(<integer>)
<string> = <Catalog>:getBaseURI()
<string> = <Catalog>:readMetadata()
<Object> = <Catalog>:getStructTreeRoot()
<integer> = <Catalog>:findPage(<integer> object number, <integer> object generation)
<LinkDest> = <Catalog>:findDest(<string> name)
<Object> = <Catalog>:getDests()
<integer> = <Catalog>:numEmbeddedFiles()
<EmbFile> = <Catalog>:embeddedFile(<integer>)
<integer> = <Catalog>:numJS()
<string> = <Catalog>:getJS(<integer>)
<Object> = <Catalog>:getOutline()
<Object> = <Catalog>:getAcroForm()
\stopfunctioncall
\type {EmbFile} methods:
\startfunctioncall
<integer> = <EmbFile>:size()
<string> = <EmbFile>:modDate()
<string> = <EmbFile>:createDate()
<string> = <EmbFile>:checksum()
<string> = <EmbFile>:mimeType()
<boolean> = <EmbFile>:isOk()
<string> = <EmbFile>:name() -- not (yet) implemented
<string> = <EmbFile>:description() -- not (yet) implemented
<Object> = <EmbFile>:streamObject() -- not (yet) implemented
<boolean> = <EmbFile>:save() -- will go
\stopfunctioncall
\type {FileSpec} methods:
\startfunctioncall
<boolean> = <FileSpec>:isOk()
<string> = <FileSpec>:getFileName()
<string> = <FileSpec>:getFileNameForPlatform()
<string> = <FileSpec>:getDescription()
<EmbFile> = <FileSpec>:getEmbeddedFile()
\stopfunctioncall
\type {Dict} methods:
\startfunctioncall
<integer> = <Dict>:getLength()
<boolean> = <Dict>:is(<string>)
<Object> = <Dict>:lookup(<string>)
<Object> = <Dict>:lookupNF(<string>)
<integer> = <Dict>:lookupInt(<string>, <string>)
<string> = <Dict>:getKey(<integer>)
<Object> = <Dict>:getVal(<integer>)
<Object> = <Dict>:getValNF(<integer>)
<boolean> = <Dict>:hasKey(<string>)
\stopfunctioncall
% \type {Link} methods:
% \startfunctioncall
% <boolean> = <Link>:isOK()
% <boolean> = <Link>:inRect(<number>, <number>)
% \stopfunctioncall
\type {LinkDest} methods:
\startfunctioncall
<boolean> = <LinkDest>:isOK()
<integer> = <LinkDest>:getKind()
<string> = <LinkDest>:getKindName()
<boolean> = <LinkDest>:isPageRef()
<integer> = <LinkDest>:getPageNum()
<Ref> = <LinkDest>:getPageRef()
<number> = <LinkDest>:getLeft()
<number> = <LinkDest>:getBottom()
<number> = <LinkDest>:getRight()
<number> = <LinkDest>:getTop()
<number> = <LinkDest>:getZoom()
<boolean> = <LinkDest>:getChangeLeft()
<boolean> = <LinkDest>:getChangeTop()
<boolean> = <LinkDest>:getChangeZoom()
\stopfunctioncall
\type {Links} methods:
% <Link> = <Links>:getLink(<integer>)
\startfunctioncall
<integer> = <Links>:getNumLinks()
\stopfunctioncall
\type {Object} methods:
\startfunctioncall
<Object> = <Object>:fetch(<XRef>)
<integer> = <Object>:getType()
<string> = <Object>:getTypeName()
<boolean> = <Object>:isBool()
<boolean> = <Object>:isInt()
<boolean> = <Object>:isReal()
<boolean> = <Object>:isNum()
<boolean> = <Object>:isString()
<boolean> = <Object>:isName()
<boolean> = <Object>:isNull()
<boolean> = <Object>:isArray()
<boolean> = <Object>:isDict()
<boolean> = <Object>:isStream()
<boolean> = <Object>:isRef()
<boolean> = <Object>:isCmd()
<boolean> = <Object>:isError()
<boolean> = <Object>:isEOF()
<boolean> = <Object>:isNone()
<boolean> = <Object>:getBool()
<integer> = <Object>:getInt()
<number> = <Object>:getReal()
<number> = <Object>:getNum()
<string> = <Object>:getString()
<string> = <Object>:getName()
<Array> = <Object>:getArray()
<Dict> = <Object>:getDict()
<Stream> = <Object>:getStream()
<Ref> = <Object>:getRef()
<integer> = <Object>:getRefNum()
<integer> = <Object>:getRefGen()
<string> = <Object>:getCmd()
<integer> = <Object>:arrayGetLength()
<Object> = <Object>:arrayGet(<integer>)
<Object> = <Object>:arrayGetNF(<integer>)
<integer> = <Object>:dictGetLength(<integer>)
<Object> = <Object>:dictLookup(<string>)
<Object> = <Object>:dictLookupNF(<string>)
<string> = <Object>:dictgetKey(<integer>)
<Object> = <Object>:dictgetVal(<integer>)
<Object> = <Object>:dictgetValNF(<integer>)
<boolean> = <Object>:streamIs(<string>)
= <Object>:streamReset() -- will go
<integer> = <Object>:streamGetChar()
<integer> = <Object>:streamLookChar()
<integer> = <Object>:streamGetPos()
= <Object>:streamSetPos(<integer>)
<Dict> = <Object>:streamGetDict()
\stopfunctioncall
\type {Page} methods:
\startfunctioncall
<boolean> = <Page>:isOk()
<integer> = <Page>:getNum()
<PDFRectangle> = <Page>:getMediaBox()
<PDFRectangle> = <Page>:getCropBox()
<boolean> = <Page>:isCropped()
<number> = <Page>:getMediaWidth()
<number> = <Page>:getMediaHeight()
<number> = <Page>:getCropWidth()
<number> = <Page>:getCropHeight()
<PDFRectangle> = <Page>:getBleedBox()
<PDFRectangle> = <Page>:getTrimBox()
<PDFRectangle> = <Page>:getArtBox()
<integer> = <Page>:getRotate()
<string> = <Page>:getLastModified()
<Dict> = <Page>:getBoxColorInfo()
<Dict> = <Page>:getGroup()
<Stream> = <Page>:getMetadata()
<Dict> = <Page>:getPieceInfo()
<Dict> = <Page>:getSeparationInfo()
<Dict> = <Page>:getResourceDict()
<Object> = <Page>:getAnnots()
<Links> = <Page>:getLinks(<Catalog>)
<Object> = <Page>:getContents()
\stopfunctioncall
\type {PDFDoc} methods:
\startfunctioncall
<boolean> = <PDFDoc>:isOk()
<integer> = <PDFDoc>:getErrorCode()
<string> = <PDFDoc>:getErrorCodeName()
<string> = <PDFDoc>:getFileName()
<XRef> = <PDFDoc>:getXRef()
<Catalog> = <PDFDoc>:getCatalog()
<number> = <PDFDoc>:getPageMediaWidth()
<number> = <PDFDoc>:getPageMediaHeight()
<number> = <PDFDoc>:getPageCropWidth()
<number> = <PDFDoc>:getPageCropHeight()
<integer> = <PDFDoc>:getNumPages()
<string> = <PDFDoc>:readMetadata()
<Object> = <PDFDoc>:getStructTreeRoot()
<integer> = <PDFDoc>:findPage(<integer> object number,
<integer> object generation)
<Links> = <PDFDoc>:getLinks(<integer>)
<LinkDest> = <PDFDoc>:findDest(<string>)
<boolean> = <PDFDoc>:isEncrypted()
<boolean> = <PDFDoc>:okToPrint()
<boolean> = <PDFDoc>:okToChange()
<boolean> = <PDFDoc>:okToCopy()
<boolean> = <PDFDoc>:okToAddNotes()
<boolean> = <PDFDoc>:isLinearized()
<Object> = <PDFDoc>:getDocInfo()
<Object> = <PDFDoc>:getDocInfoNF()
<integer> = <PDFDoc>:getPDFMajorVersion()
<integer> = <PDFDoc>:getPDFMinorVersion()
\stopfunctioncall
\type {PDFRectangle} methods:
\startfunctioncall
<boolean> = <PDFRectangle>:isValid() -- setindex/newindex will go
\stopfunctioncall
%\type {Ref} methods:
%
%\startfunctioncall
%\stopfunctioncall
\type {Stream} methods:
\startfunctioncall
<integer> = <Stream>:getKind()
<string> = <Stream>:getKindName()
= <Stream>:reset()
= <Stream>:close()
<integer> = <Stream>:getChar()
<integer> = <Stream>:lookChar()
<integer> = <Stream>:getRawChar()
<integer> = <Stream>:getUnfilteredChar()
= <Stream>:unfilteredReset()
<integer> = <Stream>:getPos()
<boolean> = <Stream>:isBinary()
<Stream> = <Stream>:getUndecodedStream()
<Dict> = <Stream>:getDict()
\stopfunctioncall
\type {StructElement} methods:
\startfunctioncall
<string> = <StructElement>:getTypeName()
<integer> = <StructElement>:getType()
<boolean> = <StructElement>:isOk()
<boolean> = <StructElement>:isBlock()
<boolean> = <StructElement>:isInline()
<boolean> = <StructElement>:isGrouping()
<boolean> = <StructElement>:isContent()
<boolean> = <StructElement>:isObjectRef()
<integer> = <StructElement>:getMCID()
<Ref> = <StructElement>:getObjectRef()
<Ref> = <StructElement>:getParentRef()
<boolean> = <StructElement>:hasPageRef()
<Ref> = <StructElement>:getPageRef()
<StructTreeRoot> = <StructElement>:getStructTreeRoot()
<string> = <StructElement>:getID()
<string> = <StructElement>:getLanguage()
<integer> = <StructElement>:getRevision()
<string> = <StructElement>:getTitle()
<string> = <StructElement>:getExpandedAbbr()
<integer> = <StructElement>:getNumChildren()
<StructElement> = <StructElement>:getChild()
<integer> = <StructElement>:getNumAttributes()
<Attribute> = <StructElement>:getAttribute(<integer>)
<string> = <StructElement>:appendAttribute(<Attribute>) -- will go
<Attribute> = <StructElement>:findAttribute(<Attribute::Type>,
boolean,Attribute::Owner)
<string> = <StructElement>:getAltText()
<string> = <StructElement>:getActualText()
<string> = <StructElement>:getText(<boolean>)
<table> = <StructElement>:getTextSpans()
\stopfunctioncall
\type {StructTreeRoot} methods:
\startfunctioncall
<StructElement> = <StructTreeRoot>:findParentElement
<PDFDoc> = <StructTreeRoot>:getDoc
<Dict> = <StructTreeRoot>:getRoleMap
<Dict> = <StructTreeRoot>:getClassMap
<integer> = <StructTreeRoot>:getNumChildren
<StructElement> = <StructTreeRoot>:getChild
<StructElement> = <StructTreeRoot>:findParentElement
\stopfunctioncall
\type {TextSpan} han only one method:
\startfunctioncall
<string> = <TestSpan>:getText()
\stopfunctioncall
\type {XRef} methods:
\startfunctioncall
<boolean> = <XRef>:isOk()
<integer> = <XRef>:getErrorCode()
<boolean> = <XRef>:isEncrypted()
<boolean> = <XRef>:okToPrint()
<boolean> = <XRef>:okToPrintHighRes()
<boolean> = <XRef>:okToChange()
<boolean> = <XRef>:okToCopy()
<boolean> = <XRef>:okToAddNotes()
<boolean> = <XRef>:okToFillForm()
<boolean> = <XRef>:okToAccessibility()
<boolean> = <XRef>:okToAssemble()
<Object> = <XRef>:getCatalog()
<Object> = <XRef>:fetch(<integer> object number,
<integer> object generation)
<Object> = <XRef>:getDocInfo()
<Object> = <XRef>:getDocInfoNF()
<integer> = <XRef>:getNumObjects()
<integer> = <XRef>:getRootNum()
<integer> = <XRef>:getRootGen()
<integer> = <XRef>:getSize()
<Object> = <XRef>:getTrailerDict()
\stopfunctioncall
There is an experimental function \type {epdf.openMemStream} that takes three
arguments:
\starttabulate
\NC \type {stream} \NC this is a (in low level \LUA\ speak) light userdata
object, i.e.\ a pointer to a sequence of bytes \NC \NR
\NC \type {length} \NC this is the length of the stream in bytes \NC \NR
\NC \type {name} \NC this is a unique identifier that is used for hashing the
stream, so that multiple doesn't use more memory \NC \NR
\stoptabulate
Instead of a light userdata stream you can also pass a \LUA\ string, in which
case the given length is (at most) the string length.
The function returns a \type{epdf} object and a string. The string can be used in
the \type {img} library instead of a filename. You need to prevent garbage
collection of the object when you use it as image (for instance by storing it
somewhere).
Both the memory stream and it's use in the image library is experimental and can
change. In case you wonder where this can be used: when you use the swiglib
library for \type {graphicmagick}, it can return such a userdata object. This
permits conversion in memory and passing the result directly to the backend. This
might save some runtime in one|-|pass workflows. This feature is currently not
meant for production and we might come up with a better implementation.
\stopchapter
\stopcomponent
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\environment luatex-style
\environment luatex-logos
\startcomponent luatex-contents
\starttitle[title=Contents]
\start
\definecolor[maincolor][black]
\placelist
[chapter,section,subsection]
[criterium=text]
\stop
\stoptitle
\stopcomponent
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-contents
\starttitle[title=Contents]
\start
\definecolor[maincolor][black]
\placelist
[chapter,section,subsection]
[criterium=text]
\stop
\stoptitle
\stopcomponent
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\environment luatex-style
\environment luatex-logos
\startcomponent luatex-export-titlepage
\setupexport
[cssfile=extra-styles.css]
\settaggedmetadata
[ title={LuaTeX Reference Manual},
copyright={LuaTeX Development Team},
version={\documentvariable{version}},
status={\documentvariable{status}},
snapshot={\documentvariable{snapshot}},
date={\rawdate[weekday,day,month,year]},
url={www.luatex.org}]
\setupbackgrounds
[leftpage]
[setups=pagenumber:left]
\setupbackgrounds
[rightpage]
[setups=pagenumber:right]
\startpreamble
This document is derived from the original manual. When examples are given,
they assume processing by \LUATEX\ and therefore will not show up as
intended. The \PDF\ version is the real reference.
\stoppreamble
\stopcomponent
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-export-titlepage
\setupexport
[cssfile=extra-styles.css]
\settaggedmetadata
[ title={LuaTeX Reference Manual},
copyright={LuaTeX Development Team},
version={\documentvariable{version}},
status={\documentvariable{status}},
snapshot={\documentvariable{snapshot}},
date={\rawdate[weekday,day,month,year]},
url={www.luatex.org}]
\setupbackgrounds
[leftpage]
[setups=pagenumber:left]
\setupbackgrounds
[rightpage]
[setups=pagenumber:right]
\startpreamble
This document is derived from the original manual. When examples are given,
they assume processing by \LUATEX\ and therefore will not show up as
intended. The \PDF\ version is the real reference.
\stoppreamble
\stopcomponent
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\startcomponent luatex-firstpage
\startstandardmakeup
\start
\raggedleft
\definedfont[Bold*default at 48pt]
\setupinterlinespace
\blue Lua\TeX \endgraf Reference \endgraf Manual \endgraf
\stop
\vfill
\definedfont[Bold*default at 12pt]
\starttabulate[|l|l|]
\NC copyright \EQ Lua\TeX\ development team \NC \NR
\NC more info \EQ www.luatex.org \NC \NR
\NC version \EQ \currentdate \doifsomething{\documentvariable{snapshot}}{(snapshot \documentvariable{snapshot})} \NC \NR
\stoptabulate
\stopstandardmakeup
\setupbackgrounds
[leftpage]
[setups=pagenumber:left]
\setupbackgrounds
[rightpage]
[setups=pagenumber:right]
\stopcomponent
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% language=uk
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-introduction
\startchapter[title=Introduction]
This is the reference manual of \LUATEX. We don't claim it is complete and we
assume that the reader knows about \TEX\ as described in \quotation {The \TEX\
Book}, the \quotation {\ETEX\ manual}, the \quotation {\PDFTEX\ manual}, etc.
Additional reference material is published in journals of user groups and
\CONTEXT\ related documentation.
It took about a decade to reach stable version 1.0, but for good reason.
Successive versions brought new functionality, more control, some cleanup of
internals and experimental features evolved into stable ones or were dropped.
Already quite early \LUATEX\ could be used for production and it was used on a
daily basis by the authors. Successive versions sometimes demanded a adaption to
the \LUA\ interfacing, but the concepts were unchanged. The current version can
be considered stable in functionality and there will be no fundamental changes.
Of course we then can decide to move towards version 2.00 with different
properties.
Don't expect \LUATEX\ to behave the same as \PDFTEX ! Although the core
functionality of that 8 bit engine was starting point, it has been combined with
the directional support of \OMEGA\ (\ALEPH). But, \LUATEX\ can behave different
due to its wide (32 bit) characters, many registers and large memory support.
There is native \UTF\ input, support for large (more that 8 bit) fonts, and the
math machinery is tuned for \OPENTYPE\ math. There is support for directional
typesetting too. The log output can differ from other engines and will likely
differ more as we move forward. When you run plain \TEX\ for sure \LUATEX\ runs
slower than \PDFTEX\ but when you run for instance \CONTEXT\ \MKIV\ in many cases
it runs faster, especially when you have a bit more complex documents or input.
Anyway, 32 bit all||over combined with more features has a price, but on a modern
machine this is no real problem.
Testing is done with \CONTEXT, but \LUATEX\ should work fine with other macro
packages too. For that purpose we provide generic font handlers that are mostly
the same as used in \CONTEXT. Discussing specific implementations is beyond this
manual. Even when we keep \LUATEX\ lean and mean, we already have enough to
discuss here.
\LUATEX\ consists of a number of interrelated but (still) distinguishable parts.
The organization of the source code is adapted so that it can glue all these
components together. We continue cleaning up side effects of the accumulated
code in \TEX\ engines (especially code that is not needed any longer).
\startitemize[packed]
\startitem
Most of \PDFTEX\ version 1.40.9, converted to \CCODE. Some experimental
features have been removed and some utility macros are not inherited as
their functionality can be done in \LUA. The number of backend interface
commands has been reduced to a few. The extensions are separated from the
core (which we keep close to the original \TEX\ core). Some mechanisms
like expansion and protrusion can behave different from the original due
to some cleanup and optimization. Some whatsit based functionality (image
support and reusable content) is now core functionality.
\stopitem
\startitem
The direction model and some other bits from \ALEPH\ RC4 (derived from
\OMEGA) is included. The related primitives are part of core \LUATEX\ but
at the node level directional support is no longer based on so called
whatsits but on real nodes. In fact, whatsits are now only used for
backend specific extensions.
\stopitem
\startitem
Neither \ALEPH's I/O translation processes, nor tcx files, nor \ENCTEX\
can be used, these encoding|-|related functions are superseded by a
\LUA|-|based solution (reader callbacks). In a similar fashion all file
\IO\ can be intercepted.
\stopitem
\startitem
We currently use \LUA\ 5.3.*. There are few \LUA\ libraries that we
consider part of the core \LUA\ machinery, for instance \type {lpeg}.
There are additional \LUA\ libraries that interface to the internals of
\TEX. We also keep the \LUA\ 5.2 \type {bit32} library around.
\stopitem
\startitem
There are various \TEX\ extensions but only those that cannot be done
using the \LUA\ interfaces. The math machinery often has two code paths:
one traditional and the other more suitable for wide \OPENTYPE\ fonts.
\stopitem
\startitem
The fontloader uses parts of \FONTFORGE\ 2008.11.17 combined with
additional code specific for usage in a \TEX\ engine. We try to minimize
specific font support to what \TEX\ needs: character references and
dimensions and delegate everything else to \LUA. That way we keep \TEX\
open for extensions without touching the core.
\stopitem
\startitem
The \METAPOST\ library is integral part of \LUATEX. This gives \TEX\ some
graphical capabilities using a relative high speed graphical subsystem.
Again \LUA\ is used as glue between the frontend and backend. Further
development of \METAPOST\ is closely related to \LUATEX.
\stopitem
\stopitemize
We try to keep upcoming versions compatible but intermediate releases can contain
experimental features. A general rule is that versions that end up on \TEX live
and|/|or are released around \CONTEXT\ meetings are stable. Future versions will
probably become a bit leaner and meaner. Some libraries might become external as
we don't want to bloat the binary and also don't want to add more hard coded
solutions. After all, with \LUA\ you can extend the core functionality. The less
dependencies, the better.
The \TEXLIVE\ version is to be considered the current stable version. Any version
between the yearly \TEXLIVE\ releases are to be considered beta. The beta
releases are normally available via the \CONTEXT\ distribution channels (the
garden and so called minimals).
\blank[1*big]
Hans Hagen, Harmut Henkel, \crlf
Taco Hoekwater \& Luigi Scarso
\blank[3*big]
\starttabulate
\NC Version \EQ \currentdate \NC \NR
\NC \LUATEX \EQ version \cldcontext{status.luatex_version/100},
revision \cldcontext{status.luatex_revision},
number \cldcontext{environment.luatexversion} \NC \NR
\NC \CONTEXT \EQ MkIV \contextversion \NC \NR
\stoptabulate
\stopchapter
\stopcomponent
% language=uk
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-introduction
\startchapter[title=Introduction]
This is the reference manual of \LUATEX. We don't claim it is complete and we
assume that the reader knows about \TEX\ as described in \quotation {The \TEX\
Book}, the \quotation {\ETEX\ manual}, the \quotation {\PDFTEX\ manual}, etc.
Additional reference material is published in journals of user groups and
\CONTEXT\ related documentation.
It took about a decade to reach stable version 1.0, but for good reason.
Successive versions brought new functionality, more control, some cleanup of
internals. Experimental features evolved into stable ones or were dropped.
Already quite early \LUATEX\ could be used for production and it was used on a
daily basis by the authors. Successive versions sometimes demanded a adaption to
the \LUA\ interfacing, but the concepts were unchanged. The current version can
be considered stable in functionality and there will be no fundamental changes.
Of course we then can decide to move towards version 2.00 with different
properties.
Don't expect \LUATEX\ to behave the same as \PDFTEX ! Although the core
functionality of that 8 bit engine was starting point, it has been combined with
the directional support of \OMEGA\ (\ALEPH). But, \LUATEX\ can behave different
due to its wide (32 bit) characters, many registers and large memory support. The
\PDF\ code produced differs from \PDFTEX\ but users will normally not notice
that. There is native \UTF\ input, support for large (more than 8 bit) fonts, and
the math machinery is tuned for \OPENTYPE\ math. There is support for directional
typesetting too. The log output can differ from other engines and will likely
differ more as we move forward. When you run plain \TEX\ for sure \LUATEX\ runs
slower than \PDFTEX\ but when you run for instance \CONTEXT\ \MKIV\ in many cases
it runs faster, especially when you have a bit more complex documents or input.
Anyway, 32 bit all||over combined with more features has a price, but on a modern
machine this is no real problem.
Testing is done with \CONTEXT, but \LUATEX\ should work fine with other macro
packages too. For that purpose we provide generic font handlers that are mostly
the same as used in \CONTEXT. Discussing specific implementations is beyond this
manual. Even when we keep \LUATEX\ lean and mean, we already have enough to
discuss here.
\LUATEX\ consists of a number of interrelated but (still) distinguishable parts.
The organization of the source code is adapted so that it can glue all these
components together. We continue cleaning up side effects of the accumulated
code in \TEX\ engines (especially code that is not needed any longer).
\startitemize[packed]
\startitem
We started out with most of \PDFTEX\ version 1.40.9. The code base was
converted to \CCODE\ and split in modules. Experimental features were
been removed and utility macros are not inherited because their
functionality can be programmed in \LUA. The number of backend interface
commands has been reduced to a few. The so called extensions are
separated from the core (which we try to keep close to the original \TEX\
core). Some mechanisms like expansion and protrusion can behave different
from the original due to some cleanup and optimization. Some whatsit
based functionality (image support and reusable content) is now core
functionality. We don't stay in sync with \PDFTEX\ development.
\stopitem
\startitem
The direction model from \ALEPH\ RC4 (which is derived from \OMEGA) is
included. The related primitives are part of core \LUATEX\ but at the
node level directional support is no longer based on so called whatsits
but on real nodes with relevant properties. The number of directions is
limited to the useful set and the backend has been made direction aware.
\stopitem
\startitem
Neither \ALEPH's I/O translation processes, nor tcx files, nor \ENCTEX\
are available. These encoding|-|related functions are superseded by a
\LUA|-|based solution (reader callbacks). In a similar fashion all file
\IO\ can be intercepted.
\stopitem
\startitem
We currently use \LUA\ 5.3.*. There are few \LUA\ libraries that we
consider part of the core \LUA\ machinery, for instance \type {lpeg}.
There are additional \LUA\ libraries that interface to the internals of
\TEX. We also keep the \LUA\ 5.2 \type {bit32} library around.
\stopitem
\startitem
There are various \TEX\ extensions but only those that cannot be done
using the \LUA\ interfaces. The math machinery often has two code paths:
one traditional and the other more suitable for wide \OPENTYPE\ fonts. Here
we follow the \MICROSOFT\ specifications as much as possible. Some math
functionality has been opened up a bit so that users have more control.
\stopitem
\startitem
The fontloader uses parts of \FONTFORGE\ 2008.11.17 combined with
additional code specific for usage in a \TEX\ engine. We try to minimize
specific font support to what \TEX\ needs: character references and
dimensions and delegate everything else to \LUA. That way we keep \TEX\
open for extensions without touching the core. In order to minimize
dependencies at some point we may decide to make this an optional
library.
\stopitem
\startitem
The \METAPOST\ library is integral part of \LUATEX. This gives \TEX\ some
graphical capabilities using a relative high speed graphical subsystem.
Again \LUA\ is used as glue between the frontend and backend. Further
development of \METAPOST\ is closely related to \LUATEX.
\stopitem
\startitem
The virtual font technology that comes with \TEX\ has been integrated
into the font machinery in a way that permits creating virtual fonts
at runtime. Because \LUATEX\ can also act as a \LUA\ interpreter this
means that a complete \TEX\ workflow can be built without the need for
additional programs.
\stopitem
\stopitemize
We try to keep upcoming versions compatible but intermediate releases can contain
experimental features. A general rule is that versions that end up on \TEX live
and|/|or are released around \CONTEXT\ meetings are stable. Future versions will
probably become a bit leaner and meaner. Some libraries might become external as
we don't want to bloat the binary and also don't want to add more hard coded
solutions. After all, with \LUA\ you can extend the core functionality. The less
dependencies, the better.
The \TEXLIVE\ version is to be considered the current stable version. Any version
between the yearly \TEXLIVE\ releases are to be considered beta and in the
repository end up as trunk releases. We have an experimental branch that we use
for development but there is no support for any of its experimental features.
Intermediate releases (from trunk) are normally available via the \CONTEXT\
distribution channels (the garden and so called minimals).
\blank[big]
\startlines
Hans Hagen
Harmut Henkel
Taco Hoekwater
Luigi Scarso
\stoplines
\blank[3*big]
\starttabulate[|||]
\NC Version \EQ \currentdate \NC \NR
\NC \LUATEX \EQ \cldcontext{LUATEXENGINE} %
\cldcontext{LUATEXVERSION} / %
\cldcontext{LUATEXFUNCTIONALITY}
\NC \NR
\NC \CONTEXT \EQ MkIV \contextversion \NC \NR
\stoptabulate
\stopchapter
\stopcomponent
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\startenvironment luatex-logos
\logo[DFONT] {dfont}
\logo[CFF] {cff}
\logo[CMAP] {CMap}
\logo[PATGEN] {patgen}
\logo[MP] {MetaPost}
\logo[METAPOST] {MetaPost}
\logo[MPLIB] {MPlib}
\logo[COCO] {coco}
\logo[SUNOS] {SunOS}
\logo[BSD] {bsd}
\logo[SYSV] {sysv}
\logo[DPI] {dpi}
\logo[DLL] {dll}
\logo[OPENOFFICE]{OpenOffice}
\logo[OCP] {OCP}
\stopenvironment
\startenvironment luatex-logos
\logo[DFONT] {dfont}
\logo[CFF] {cff}
\logo[CMAP] {CMap}
\logo[PATGEN] {patgen}
\logo[MP] {MetaPost}
\logo[METAPOST] {MetaPost}
\logo[MPLIB] {MPlib}
\logo[COCO] {coco}
\logo[SUNOS] {SunOS}
\logo[BSD] {bsd}
\logo[SYSV] {sysv}
\logo[DPI] {dpi}
\logo[DLL] {dll}
\logo[OPENOFFICE]{OpenOffice}
\logo[OCP] {OCP}
\stopenvironment
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\environment luatex-style
\environment luatex-logos
\startcomponent luatex-titlepage
\startstandardmakeup
\switchtobodyfont
[mainfacemedium]
\definedfont[Bold*default at \the\dimexpr.08\paperheight\relax] \setupinterlinespace
\setlayer
[page]
{\useMPgraphic{luapage}}
\setlayerframed
[page]
[preset=middletop,
voffset=.05\paperheight]
[align=middle,
foregroundcolor=blue,
frame=off]
{Lua\TeX\\Reference Manual}
\definedfont[Bold*default at 18pt] \setupinterlinespace
\setlayerframed
[page]
[preset=rightbottom,
offset=.01\paperheight]
[align=flushright,
foregroundcolor=blue,
frame=off]
{\doifsomething{\documentvariable{status}}{\documentvariable{status}\par}
\currentdate[month,space,year]\par
Version \documentvariable{version}}
\stopstandardmakeup
\startstandardmakeup
\start
\raggedleft
\definedfont[Bold*default at 48pt]
\setupinterlinespace
\blue Lua\TeX \endgraf Reference \endgraf Manual \endgraf
\stop
\vfill
\definedfont[Bold*default at 12pt]
\starttabulate[|l|l|]
\NC copyright \EQ Lua\TeX\ development team \NC \NR
\NC more info \EQ www.luatex.org \NC \NR
\NC version \EQ \currentdate \doifsomething{\documentvariable{snapshot}}{(snapshot \documentvariable{snapshot})} \NC \NR
\stoptabulate
\stopstandardmakeup
\setupbackgrounds
[leftpage]
[setups=pagenumber:left]
\setupbackgrounds
[rightpage]
[setups=pagenumber:right]
\stopcomponent
\environment luatex-style
\environment luatex-logos
\startcomponent luatex-titlepage
\startstandardmakeup
\switchtobodyfont
[mainfacemedium]
\definedfont[Bold*default at \the\dimexpr.06\paperheight\relax] \setupinterlinespace
\setlayer
[page]
{\useMPgraphic{luapage}}
\setlayerframed
[page]
[preset=righttop,
location=middletop,
hoffset=.500\measured{paperwidth},
voffset=.175\measured{paperheight}]
[align=middle,
foregroundcolor=white,
frame=off]
{Lua\TeX\crlf Reference\crlf Manual}
\definedfont[Bold*default at 14pt] \setupinterlinespace
\setlayerframed
[page]
[preset=rightbottom,
offset=.025\measured{paperheight}]
[align=flushright,
foregroundcolor=white,
frame=off]
{\doifsomething{\documentvariable{status}}{\documentvariable{status}\par}
\currentdate[month,space,year]\par
Version \documentvariable{version}}
\setlayerframed
[page]
[preset=middle,
hoffset=-.5\dimexpr\measured{paperwidth}-\measured{spinewidth}\relax]
[width=.7\measured{paperwidth},
align=normal,
foregroundstyle=\bf,
foregroundcolor=white,
frame=off]
{\getbuffer[backpage]}
\stopstandardmakeup
\stopcomponent
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