Command/externalfigure

From ConTeXt wiki


\externalfigure

Syntax (autogenerated)

\externalfigure[...][...][...=...,...]
[...]file
[...]name
...=...,...inherits from \setupexternalfigure


Syntax

\externalfigure[...][...,...=...,...]
[...] file
[...,...=...,...] see \useexternalfigure


Description

The \externalfigure command is used to include an external figure/movie inside ConTeXt. Includes both local files or remote files hosted on HTTP servers.

The simplest way to insert an image is to use:

\externalfigure[cow.pdf]

This command places the PDF image cow.pdf in a \vbox; the width and height of the image are equal to the natural dimensions of the image.

To set the width of the image to a specific size, say 1cm, use:

\externalfigure[cow.pdf][width=1cm]

which gives

Similarly, to set the height of the image to a specific size, say 2cm, use:

\externalfigure[cow.pdf][height=2cm]

which gives

If only the width or height of the image is specified, the other dimension is scaled appropriately to keep the aspect ratio.

To include a specific page, say page 5, of a multi-page PDF file, use:

\externalfigure[filename.pdf][page=5]

These four variations cover 90% of the use cases.


How the filetype is determined

  • File extension: Normally, the type of file is determined by the extension of the file (in a case-insensitive manner).
  • method=type If the file uses a non-standard extension, specify the file type using method=type where type is any of the file extensions that is recognized by \externalfigure.
  • auto: When the file extension is .auto or method=auto is used, ConTeXt reads the first few bytes of the file to determine the filetype. Such an auto-discovery is useful for remote images that do not have a file extension.

If the extension of the file is not specified, ConTeXt searches for all possible extensions in the order given below.

Historically, when postscript output was used, the order in which the file extensions were searched depended on the output format (PDF or PS). With recent releases of ConTeXt, PDF is the default output format, so for all practical purposes, the order in which the file extensions are searched is fixed.

Natively supported image formats

The following image formats are supported natively in MkIV:

  • PDF: File extension .pdf. By default, mediabox is used to determine size. Use size=artbox to use artbox.
  • MPS (MetaPost Output): File extension .mps or .[digits]. Converted to PDF on the fly using MPtoPDF.
  • JPEG: File extension .jpg and .jpeg
  • PNG: File extesion .png
  • JPEG 2000: File extesion .jp2
  • JBIG and JBIG2: File extension .jbig, .jbib2, and .jb2

Image formats supported through external converters

The following formats are converted to PDF by external programs before being included. The conversion generates a new file with a prefix m_k_i_v_ and a suffix .pdf added to the name of the original file (the original extension is nor removed). The result is cached, and the conversion is rerun only if the timestamp of the original file is newer than the converted file.


  • SVG: File extension .svg and .svgz. Converted to PDF using Inkscape.
For the conversion to work, inkscape should be in the PATH. The following command is used for conversion:
   inkscape [inputfile] --export-dpi=600 -A [outputfile] 
(Note: Conversion to PNG is also possible, but I don't know the details on how to active that -- 03:32, 29 November 2012 (CET)).


For the conversion to work, on Windows gswin32c must be in the PATH; on other platforms gs must be in the PATH. The following command line options are passed to Ghostscript
   gs -q -sDEVICE=pdfwrite -dNOPAUSE -dNOCACHE -dBATCH [resolution] -sOutputFile=[outputfile] [inputfile] -c quit
By default, the [resolution] is prepress. Use resolution=low to change the [resolution] to screen and resolution=meidum to change the [resolution] to ebook.
For the conversion to work, gm should be in the PATH. The following command is used for the conversion:
   gm convert [inputfile] [outputfile]
For the conversion to work, gm should be in the PATH. The following command is used for the conversion:
   gm convert [inputfile] [outputfile]

Supported movie formats

The following movie formats are supported.


NOTE: Movie inclusion only works in Adobe Acrobat but does not work on Linux

Support for special TeX formats

The following special formats are supported:

  • buffer: Typeset the buffer with the given name and include the result as a PDF file.
  • tex: Typeset the TeX file using context and include the result as a PDF file

Command options

interaction

By default, the interactive elements of the included PDF file are discarded. To enable the interactive elements of the included PDF file, use

\externalfigure[filename.pdf][interaction=yes]

Example

Including a local image

In the example below, no file name extension is used. ConTeXt searches for an image file in the following order: cow.pdf, cow.mps, cow.1, cow.2, etc., cow.jpg, cow.png, cow.jp2, cow.jbig, cow.jbig2, cow.jb2. The file cow.pdf, which is distributed as part of the ConTeXt distribution, is found and displayed.

\externalfigure[cow][width=4cm]

ConTeXt distribution also includes a sample image hacker.jpg. To include it use:

\externalfigure[hacker][height=3cm]

Include a remote image

\externalfigure[http://placekitten.com/g/200/300][method=jpg]

Rotate an image

  • Rotate by 90, 180, or 270 degrees: Use orientation=90|180|270 to rotate an image in multiples of 90. For example:
\externalfigure[mill][orientation=180]


  • Rotate by an arbitrary angle: Use \rotate command.
\rotate[rotation=45]{\externalfigure[mill]}

Flip an image

Use \mirror to horizontally flip an image

\mirror{\externalfigure[cow][width=3cm]}

Error Messages

When a file is specified by its full name, and is not found, no error message is displayed in the log; rather a gray box is shown in the generated PDF which indicates that the figure was not found. For example (note that cat.pdf should not exist in the current directory)

\externalfigure[cat.pdf]

Tracking

The following trackers are available for \externalfigures (MkIV only)

  • graphics.locating: Gives details about where the image files are searched, what strategy was used to infer the file format, and what was the inferred file format.
  • graphics.conversion: Gives details about the conversion from one file format to another
  • graphics.inclusions: Gives details of including a movie

The trackers are enabled using

 \enabletrackers[...tracker...]

or

 context --trackers=list [filename]

When graphics.locating tracker is enabled, including a known file gives the following information on the terminal

 graphics        > inclusion > locations: local,global
 graphics        > inclusion > path list: . .. ../..
 graphics        > inclusion > strategy: unknown format, prefer quality
 graphics        > inclusion > found: ./cow.pdf -> /opt/context-minimals/texmf-context/tex/context/sample/cow.pdf
 graphics        > inclusion > format natively supported by backend: pdf

If the asked file does not exist, the following information is displayed.


 graphics        > inclusion > locations: local,global
 graphics        > inclusion > path list: . .. ../..
 graphics        > inclusion > strategy: forced format pdf
 graphics        > inclusion > not found: cat.pdf
 graphics        > inclusion > not found: ./cat.pdf
 graphics        > inclusion > not found: ../cat.pdf
 graphics        > inclusion > not found: ../../cat.pdf
 graphics        > inclusion > format not supported: %s

When graphics.conversion tracker is enabled, and, including a file type that requires conversion, say PS, displays the following message on the terminal

 graphics        > inclusion > checking conversion of './tiger.ps' (./tiger.ps): old format 'ps', new format 'pdf', conversion 'default', resolution 'default'
 graphics        > inclusion > no need to convert './tiger.ps' (tiger.ps) from 'ps' to 'pdf'
 graphics        > inclusion > new graphic, hash: m_k_i_v_tiger.ps.pdf->1->crop->unknown->unknown->unknown->

When graphics.inclusion tracker is enabled, including a movie displays the following message on the terminal

 graphics        > inclusion > including movie 'clip.mov': width 5594039.4330709, height 5594039.4330709


See also

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