path: root/Build/source/texk/dvipng/doc/dvipng.info

This is dvipng.info, produced by makeinfo version 4.13 from dvipng.texi.

INFO-DIR-SECTION TeX
START-INFO-DIR-ENTRY
* DVI-to-PNG: (dvipng).              Translating TeX DVI files to Portable Network Graphics (PNG).
* dvipng: (dvipng).                  A DVI-to-PNG translator.
END-INFO-DIR-ENTRY


File: dvipng.info,  Node: Top,  Next: Introduction,  Up: (dir)

dvipng
******

This manual documents dvipng, a program to translate a DVI (DeVice
Independent) file into PNG (Portable Network Graphics).

   This file documents dvipng version 1.12

   Corrections or perhaps rewrites of sections are _very welcome_.

   Jan-AAke Larsson

* Menu:

* Introduction::                Introduction
* Installation::                How to compile and install dvipng
* Basic usage::                 First things first
* Command-line options::        Advanced usage
* Graphics::                    Including PostScript and/or bitmaps
* Color::                       Using color with dvipng
* Diagnosing problems::         Problems?
* Credits::                     People who have contributed
* Copying::                     GNU Lesser General Public License
* Index::                       General index


File: dvipng.info,  Node: Introduction,  Next: Installation,  Prev: Top,  Up: Top

1 Introduction
**************

This program makes PNG and/or GIF graphics from DVI files as obtained
from TeX and its relatives.

   If GIF support is enabled, GIF output is chosen by using the
`dvigif' binary or with the `--gif' option.

   It is intended to produce anti-aliased screen-resolution images as
fast as is possible. The target audience is people who need to generate
and regenerate many images again and again. The primary target is the
preview-latex (X)Emacs package, a package to preview formulas from
within (X)Emacs. Yes, you get to see your formulas in the (X)Emacs
buffer, see `http://www.gnu.org/software/auctex/preview-latex.html'.

   Another example is WeBWorK, an internet-based method for delivering
homework problems to students over the internet, giving students
instant feedback as to whether or not their answers are correct, see
`http://webwork.math.rochester.edu'.

   A more recent addition to the dvipng-using applications out there is
MediaWiki, the software behind Wikipedia and many other wikis out
there. Dvipng is used to render mathematical formulae from version
1.8.0 of MediaWiki, see `http://www.mediawiki.org'.

   Other applications may also benefit, like web applications as
latex2html and WYSIWYG editors like LyX.

   The benefits of `dvipng'/`dvigif' include

   * Speed. It is a very fast bitmap-rendering code for DVI files, which
     makes it suitable for generating large amounts of images
     on-the-fly, as needed in preview-latex, WeBWorK and others.

   * It does not read the postamble, so it can be started before TeX
     finishes. There is a `--follow' switch that makes dvipng wait at
     end-of-file for further output, unless it finds the POST marker
     that indicates the end of the DVI.

   * Interactive query of options. dvipng can read options interactively
     through stdin, and all options are usable. It is even possible to
     change the input file through this interface.

   * Supports PK, VF, PostScript Type1, and TrueType fonts, subfonts
     (i.e., as used in CJK-LaTeX), color specials, and inclusion of
     PostScript, PNG, JPEG or GIF images.

   * and more...



File: dvipng.info,  Node: Installation,  Next: Basic usage,  Prev: Introduction,  Up: Top

2 Installation
**************

Installing dvipng should be simple: merely `./configure', `make', and
`make install'.

* Menu:

* Prerequisites::
* Configure::
* Build/install::
* Installation outside the texmf tree::
* Advice for non-privileged users::


File: dvipng.info,  Node: Prerequisites,  Next: Configure,  Up: Installation

2.1 Prerequisites
=================

   * The GD Graphics Draw library, libgd

     The drawing library `libgd' is necessary, and is downloadable at
     `http://www.boutell.com/gd', and there are binary packages for
     most operating systems from their respective distributors. In any
     case, the latest version of the library installs using `autoconf'
     so it should not be difficult for you to install it from source,
     and then proceed with installing dvipng.

   * The path-searching library kpathsea

     Kpathsea is most likely included in your LaTeX installation, but it
     may happen that ./configure does not find it; see below. If you do
     not have it, download it from `http://www.ctan.org' and compile it.
     I have no experience with this, so I cannot help much here.

   * The font-rendering library FreeType 2

     While not strictly necessary, a recent FreeType 2 is recommended
     since dvipng currently will produce better-quality images when
     this library is available. To take advantage of this, you should
     have at least FreeType 2.1.9.

     FreeType 2 will enable direct support for PostScript and TrueType
     fonts, so that dvipng will not need to generate bitmapped variants
     on disk of the TeX fonts since modern TeX distributions include
     PostScript versions of them. Then, you can render images at
     different (and unusual) resolutions without cluttering the disk
     with lots of bitmapped fonts.

     Finally, it will enable subfont support in dvipng. That is, if you
     want to render CJK-LaTeX characters, you must have FreeType 2
     installed.

   * The font-rendering library T1lib

     An alternative to FreeType 2 is T1lib, but this will enable only
     PostScript fonts in dvipng and will not include subfont support.
     Also here, you can render images at different (and unusual)
     resolutions without cluttering the disk with lots of bitmapped
     fonts. If both FreeType 2 and T1lib are present, FreeType will be
     internally preferred by dvipng but T1lib can be chosen at runtime.

   * libpng and libz

     To be able to compress and write PNG files to disk, dvipng (or
     really libgd) uses libpng which in turn uses libz. These should be
     available on any modern system, if not, download them and install
     them.

   * The `texinfo' package

     This is needed for building the documentation.


File: dvipng.info,  Node: Configure,  Next: Build/install,  Prev: Prerequisites,  Up: Installation

2.2 Configure
=============

The first step is to configure the source code, telling it where
various files will be.  To do so, run

     ./configure OPTIONS

   (Note: if you have fetched dvipng from CVS rather than a regular
release, you will have to first generate `./configure' by running
`autoconf' 2.53 or later.)

   On many machines, you will not need to specify any options, but if
`configure' cannot determine something on its own, you'll need to help
it out. For a list of the options type

     ./configure --help

   On some machines, the libraries will be installed in directories that
are not in the linker's search path. This will generate an error when
running `./configure', indicating that it cannot find libgd or
libkpathsea (most likely). You then need to specify the path to the
respective library's object files. They are typically called e.g.,
`libgd.a' or `libgd.so'. If they are located in e.g., `/sw/local/lib',
do

     ./configure LDFLAGS=-L/sw/local/lib

   If the library is available as a shared object file (`.so'), the
runtime linker may also need to be told where to find the library, then
use

     ./configure LDFLAGS='-L/sw/local/lib -R/sw/local/lib'

   When either of these is necessary, it is likely that the C header
files are also installed in directories that are not in the C
preprocessor's search path. This will also generate an error when
running `./configure', indicating that it cannot find e.g., `gd.h' or
`kpathsea.h' (most likely). You then need to specify the path to the
respective library's C header files. If they are located in e.g.,
`/sw/local/include', do

     ./configure CPPFLAGS=-I/sw/local/include

   On my SUN Solaris workstation, I had to combine this into

     ./configure CPPFLAGS='-I/sw/local/include -I/sw/tex/teTeX/1.0/include'\
         LDFLAGS='-L/sw/local/lib -R/sw/local/lib -L/sw/tex/teTeX/1.0/lib/'

where the backslash denotes a continuation of the line.


File: dvipng.info,  Node: Build/install,  Next: Installation outside the texmf tree,  Prev: Configure,  Up: Installation

2.3 Build/install
=================

Once `configure' has been run, simply enter

     make

at the prompt to compile the C code, and build the documentation files.
To install the files into the locations chosen earlier, type

     make install

You may need special privileges to install, e.g., if you are installing
into system directories.


File: dvipng.info,  Node: Installation outside the texmf tree,  Next: Advice for non-privileged users,  Prev: Build/install,  Up: Installation

2.4 Installation outside the texmf tree
=======================================

In some cases, a dvipng binary installed outside the texmf tree will
not be able to find virtual fonts, or the PostScript font maps
(normally used by dvips). This may be because _only_ $SELFAUTOLOC,
$SELFAUTODIR, and $SELFAUTOPARENT are used in the texmf tree
configuration file `texmf.cnf'. If so, give the switch
`--enable-selfauto-set' to `./configure'. This will make dvipng adjust
these three internally so that kpathsea thinks that dvipng _is_
installed in the texmf tree.


File: dvipng.info,  Node: Advice for non-privileged users,  Prev: Installation outside the texmf tree,  Up: Installation

2.5 Installation for non-privileged users
=========================================

Often people without system administration privileges want to install
software for their private use. In that case you need to specify more
options to the `configure' script, usually this is done by using the
`--prefix' option to the `configure' script, and let it point to the
personal home directory. In that way, resulting binaries will be
installed under the `bin' subdirectory of your home directory, manual
pages under `man' and so on. That way, it is reasonably easy to
maintain a bunch of additional packages, since the prefix argument is
supported by most `configure' scripts.

   You'll have to add something like `/home/myself/bin' to your `PATH'
shell variable, if it isn't there already, and similarly set the
`INFOPATH' and `MANPATH' variables to be able to access the
documentation.


File: dvipng.info,  Node: Basic usage,  Next: Command-line options,  Prev: Installation,  Up: Top

3 Basic usage of dvipng
***********************

To use dvipng at its simplest, simply type

     dvipng foo

where `foo.dvi' is the output of TeX that you want to convert to PNG
format. If there are four pages in `foo.dvi', those pages will be
output as `foo1.png', `foo2.png', `foo3.png', and `foo4.png',
respectively.

   If you have enabled the PostScript font support (via FreeType or
T1lib), fonts will be rendered as they are needed. Otherwise, if you
use fonts that have not been used on your system before, they may be
automatically generated; this process can take a few minutes, so
progress reports appear by default. The next time the same font is
used, it will have been saved on disk, so rendering will go much
faster. (If dvipng tries to endlessly generate the same fonts over and
over again, something is wrong. *Note Unable to generate fonts:
(kpathsea)Unable to generate fonts.)

   Many options are available (see the next section).  For a brief
summary of available options, just type

     dvipng --help


File: dvipng.info,  Node: Command-line options,  Next: Graphics,  Prev: Basic usage,  Up: Top

4 Command-line options
**********************

dvipng has a plethora of command line options.  Reading through this
section will give a good idea of the capabilities of the driver.

* Menu:

* Option summary::              Quick listing, from dvipng --help.
* Option details::              More information about each option.


File: dvipng.info,  Node: Option summary,  Next: Option details,  Up: Command-line options

4.1 Option summary
==================

Here is a handy summary of the options; it is printed out when you run
dvipng with no arguments or with the standard `--help' option.

     This is ./dvipng 1.12 Copyright 2002-2008 Jan-Ake Larsson

     Usage: ./dvipng [OPTION]... FILENAME[.dvi]
     Options are chosen to be similar to dvips' options where possible:
       -d #         Debug (# is the debug bitmap, 1 if not given)
       -D #         Output resolution
       -l #         Last page to be output
       -o f         Output file, '%d' is pagenumber
       -O c         Image offset
       -p #         First page to be output
       -pp #,#..    Page list to be output
       -q*          Quiet operation
       -T c         Image size (also accepts '-T bbox' and '-T tight')
       -v*          Verbose operation
       -            Interactive query of options

     These do not correspond to dvips options:
       -bd #        Transparent border width in dots
       -bd s        Transparent border fallback color (TeX-style color)
       -bg s        Background color (TeX-style color or 'Transparent')
       --depth*     Output the image depth on stdout
       --dvinum*    Use TeX page numbers in output filenames
       -fg s        Foreground color (TeX-style color)
       --follow*    Wait for data at end-of-file
       --freetype*  FreeType font rendering (default on)
       --gamma #    Control color interpolation
       --gif        Output GIF images (dvigif default)
       --height*    Output the image height on stdout
       --noghostscript*  Don't use ghostscript for PostScript specials
       --nogssafer* Don't use -dSAFER in ghostscript calls
       --palette*   Force palette output
       --picky      When a warning occurs, don't output image
       --png        Output PNG images (dvipng default)
       --strict     When a warning occurs, exit
       --t1lib*     T1lib font rendering (default on)
       --truecolor* Truecolor output
       -Q #         Quality (T1lib and PK subsampling)
       -z #         PNG compression level

        # = number   f = file   s = string  * = suffix, '0' to turn off
            c = comma-separated dimension pair (e.g., 3.2in,-32.1cm)


File: dvipng.info,  Node: Option details,  Prev: Option summary,  Up: Command-line options

4.2 Option details
==================

Many of the parameterless options listed here can be turned off by
suffixing the option with a zero (`0'); for instance, to turn off page
reversal, use `-r0'.  Such options are marked with a trailing `*'.

`-'
     Read additional options from standard input after processing the
     command line.

`--help'
     Print a usage message and exit.

`--version'
     Print the version number and exit.

`-bd NUM'

`-bd COLOR_SPEC'

`-bd 'NUM COLOR_SPEC''
     Set the pixel width of the transparent border (default 0). Using
     this option will make the image edges transparent, but it only
     affects pixels with the background color. Giving a COLOR_SPEC will
     set the fallback color, to be used in viewers that cannot handle
     transparency (the default is the background color). The color spec
     should be in TeX color \special syntax, e.g., 'rgb 1.0 0.0 0.0'.
     Setting the fallback color makes the default border width 1 px.
     *Note Color::.

`--bdpi NUM'
     Set the base (Metafont) resolution, both horizontal and vertical,
     to NUM dpi (dots per inch). This option is necessary when manually
     selecting Metafont mode with the -mode option (see below).

`-bg COLOR_SPEC'
     Choose background color for the images. This option will be
     ignored if there is a background color \special in the DVI. The
     color spec should be in TeX color \special syntax, e.g., 'rgb 1.0
     0.0 0.0'. You can also specify 'Transparent' or 'transparent'
     which will give you a transparent background with the normal
     background as a fallback color. A capitalized 'Transparent' will
     give a full-alpha transparency, while an all-lowercase
     'transparent' will give a simple fully transparent background with
     non-transparent antialiased pixels. The latter would be suitable
     for viewers who cannot cope with a true alpha channel.  GIF images
     do not support full alpha transparency, so in case of GIF output,
     both variants will use the latter behaviour.  *Note Color::.

`-d NUM'
     Set the debug flags, showing what dvipng (thinks it) is doing.
     This will work unless dvipng has been compiled without the `DEBUG'
     option (not recommended). Set the flags as you need them, use `-d
     -1' as the first option for maximum output. *Note Debug options::.

`-D NUM'
     Set the output resolution, both horizontal and vertical, to NUM
     dpi (dots per inch).

     One may want to adjust this to fit a certain text font size (e.g.,
     on a web page), and for a text font height of FONT_PX pixels (in
     Mozilla) the correct formula is
          DPI = FONT_PX * 72.27 / 10 [px * TeXpt/in / TeXpt]
     The last division by ten is due to the standard font height 10pt in
     your document, if you use 12pt, divide by 12. Unfortunately, some
     proprietary browsers have font height in pt (points), not pixels.
     You have to rescale that to pixels, using the screen resolution
     (default is usually 96 dpi) which means the formula is
          FONT_PX = FONT_PT * 96 / 72 [pt * px/in / (pt/in)]
     On some high-res screens, the value is instead 120 dpi. Good luck!

`--depth*'
     Report the depth of the image. This only works reliably when the
     LaTeX style `preview.sty' from preview-latex is used with the
     `active' option. It reports the number of pixels from the bottom
     of the image to the baseline of the image. This can be used for
     vertical positioning of the image in, e.g., web documents, where
     one would use (Cascading StyleSheets 1)
          <IMG SRC="FILENAME.PNG" STYLE="vertical-align: -DEPTHpx">
     The depth is a negative offset in this case, so the minus sign is
     necessary, and the unit is pixels (px).

`--dvinum*'
     Set this option to make the output page number be the TeX page
     numbers rather than the physical page number. See the `-o' switch.

`-fg COLOR_SPEC'
     Choose foreground color for the images. This option will be
     ignored if there is a foreground color \special in the DVI. The
     color spec should be in TeX color \special syntax, e.g., 'rgb 1.0
     0.0 0.0'.  *Note Color::.

`--follow*'
     Wait for data at end-of-file. One of the benefits of dvipng is
     that it does not read the postamble, so it can be started before
     TeX finishes. This switch makes dvipng wait at end-of-file for
     further output, unless it finds the POST marker that indicates the
     end of the DVI. This is similar to `tail -f' but for DVI-to-PNG
     conversion.

`--freetype*'
     Enable/disable FreeType font rendering (default on). This option is
     available if the FreeType2 font library was present at compilation
     time.  If this is the case, dvipng will have direct support for
     PostScript Type1 and TrueType fonts internally, rather than using
     `gsftopk' for rendering the fonts. If you have PostScript versions
     of Computer Modern installed, there will be no need to generate
     bitmapped variants on disk of these. Then, you can render images
     at different (and unusual) resolutions without cluttering the disk
     with lots of bitmapped fonts.  Note that if you have both FreeType
     and T1lib on your system, FreeType will be preferred by dvipng. If
     you for some reason would want to use T1lib rendering, use this
     option.

`--gamma NUM'
     Control the interpolation of colors in the greyscale anti-aliasing
     color palette.  Default value is 1.0.  For 0 < NUM < 1, the fonts
     will be lighter (more like the background), and for NUM > 1, the
     fonts will be darker (more like the foreground).

`--gif*'
     The images are output in the GIF format, if GIF support is enabled.
     This is the default for the `dvigif' binary, which only will be
     available when GIF support is enabled. GIF images are palette
     images (see the `--palette' option) and does not support true alpha
     channels (see the `--bg' option). See also the `--png' option.

`--height*'
     Report the height of the image. This only works reliably when the
     LaTeX style `preview.sty' from preview-latex is used with the
     `active' option. It reports the number of pixels from the top of
     the image to the baseline of the image. The total height of the
     image is obtained as the sum of the values reported from
     `--height' and `--depth'.

`-l [=]NUM'
     The last page printed will be the first one numbered NUM. Default
     is the last page in the document.  If NUM is prefixed by an equals
     sign, then it (and the argument to the `-p' option, if specified)
     is treated as a physical (absolute) page number, rather than a
     value to compare with the TeX `\count0' values stored in the DVI
     file.  Thus, using `-l =9' will end with the ninth page of the
     document, no matter what the pages are actually numbered.

`--mode MODE'
     Use MODE as the Metafont device name for the PK fonts (both for
     path searching and font generation). This needs to be augmented
     with the base device resolution, given with the `--bdpi' option.
     See the file `ftp://ftp.tug.org/tex/modes.mf' for a list of
     resolutions and mode names for most devices. *Note Unable to
     generate fonts: (kpathsea)Unable to generate fonts.

`-M*'
     Turns off automatic PK font generation (`mktexpk'). This will have
     no effect when using PostScript fonts, since no PK font generation
     will be done anyway.

`--noghostscript*'
     This switch prohibits the internal call to GhostScript for
     displaying PostScript specials. `--noghostscript0' turns the call
     back on.

`--nogssafer*'
     Normally, if GhostScript is used to render PostScript specials, the
     GhostScript interpreter is run with the option `-dSAFER'. The
     `--nogssafer' option runs GhostScript without `-dSAFER'. The
     `-dSAFER' option in Ghostscript disables PostScript operators such
     as deletefile, to prevent possibly malicious PostScript programs
     from having any effect.

`-o NAME'
     Send output to the file NAME. A single occurrence of `%d' or
     `%01d', ..., `%09d' will be exchanged for the physical page number
     (this can be changed, see the `--dvinum' switch). The default
     output filename is `FILE%d.png' where the input DVI file was
     `FILE.dvi'.

`-O X-OFFSET,Y-OFFSET'
     Move the origin by X-OFFSET,Y-OFFSET, a comma-separated pair of
     dimensions such as `.1in,-.3cm'.  The origin of the page is
     shifted from the default position (of one inch down, one inch to
     the right from the upper left corner of the paper) by this amount.

`-p [=]NUM'
     The first page printed will be the first one numbered NUM. Default
     is the first page in the document.  If NUM is prefixed by an
     equals sign, then it (and the argument to the `-l' option, if
     specified) is treated as a physical (absolute) page number, rather
     than a value to compare with the TeX `\count0' values stored in the
     DVI file.  Thus, using `-p =3' will start with the third page of
     the document, no matter what the pages are actually numbered.

`--palette*'
     Starting from `dvipng' 1.8, the output PNG will be a truecolor png
     when an external image is included, to avoid unnecessary delay and
     quality reduction, and enable the EPS translator to draw on a
     transparent background and outside of the boundingbox. This switch
     will force palette (256-color) output and make `dvipng' revert to
     the old behaviour, where included images were opaque and always
     clipped to the boundingbox. This will also override the
     `--truecolor' switch if present.

`--picky*'
     No images are output when a warning occurs. Normally, dvipng will
     output an image in spite of a warning, but there may be something
     missing in this image. One reason to use this option would be if
     you have a more complete but slower fallback converter. Mainly,
     this is useful for failed figure inclusion and unknown \special
     occurrences, but warnings will also occur for missing or unknown
     color specs and missing PK fonts.

`--png*'
     The images are output in the PNG format. This is the default for
     the `dvipng' binary. See also the `--gif' option.

`-pp FIRSTPAGE-LASTPAGE'
     Print pages FIRSTPAGE through LASTPAGE; but not quite equivalent
     to `-p FIRSTPAGE -l LASTPAGE'. For example, when rendering a book,
     there may be several instances of a page in the DVI file (one in
     `\frontmatter', one in `\mainmatter', and one in `\backmatter').
     In case of several pages matching, `-pp FIRSTPAGE-LASTPAGE' will
     render _all_ pages that matches the specified range, while `-p
     FIRSTPAGE -l LASTPAGE' will render the pages from the _first_
     occurrence of FIRSTPAGE to the _first_ occurrence of LASTPAGE.
     This is the (undocumented) behaviour of dvips. In dvipng you can
     give both kinds of options, in which case you get all pages that
     matches the range in `-pp' between the pages from `-p' to `-l'.
     Also multiple `-pp' options accumulate, unlike `-p' and `-l'.  The
     `-' separator can also be `:'. Note that `-pp -1' will be
     interpreted as "all pages up to and including 1", if you want a
     page numbered -1 (only the table of contents, say) put `-pp -1--1',
     or more readable, `-pp -1:-1'.

`-q*'
     Run quietly.  Don't chatter about pages converted, etc. to standard
     output; report no warnings (only errors) to standard error.

`-Q NUM'
     Set the quality to NUM. That is, choose the number of antialiasing
     levels for PK and T1lib rendering to be NUM*NUM+1. The default
     value is 4 which gives 17 levels of antialiasing for antialiased
     fonts from these two. If FreeType is available, its rendering is
     unaffected by this option.

`-r*'
     Toggle output of pages in reverse/forward order. By default, the
     first page in the DVI is output first.

`--strict*'
     The program exits when a warning occurs. Normally, dvipng will
     output an image in spite of a warning, but there may be something
     missing in this image. One reason to use this option would be if
     you have a more complete but slower fallback converter. See the
     `--picky' option above for a list of when warnings occur.

`-T IMAGE_SIZE'
     Set the image size to IMAGE_SIZE which can be either of `bbox',
     `tight', or a comma-separated pair of dimensions HSIZE,VSIZE such
     as `.1in,.3cm'. The default is `bbox' which produces a PNG that
     includes all ink put on the page and in addition the DVI origin,
     located 1in from the top and 1in from the left edge of the paper.
     This usually gives whitespace above and to the left in the
     produced image. The value `tight' will make dvipng only include
     all ink put on the page, producing neat images.

`--t1lib*'
     Enable/disable T1lib font rendering (default on). This option is
     available if the T1lib font library was present at compilation
     time. If this is the case, dvipng will have direct support for
     PostScript Type1 fonts internally, rather than using `gsftopk' for
     rendering the fonts. If you have PostScript versions of Computer
     Modern installed, there will be no need to generate bitmapped
     variants on disk of these.  Then, you can render images at
     different (and unusual) resolutions without cluttering the disk
     with lots of bitmapped fonts. Note that if you have both FreeType
     and T1lib on your system FreeType will be preferred by dvipng, and
     if you for some reason rather want to use T1lib, give the option
     `--freetype0' (see above).

`--truecolor*'
     This will make `dvipng' generate truecolor output. Note that
     truecolor output is automatic if you include an external image in
     your DVI, e.g., via a PostScript special (i.e., the `graphics' or
     `graphicx' package). This switch is overridden by the `--palette'
     switch.

`-v*'
     Enable verbose operation. This will currently indicate what fonts
     is used, in addition to the usual output.

`-x NUM'
     Set the x magnification ratio to NUM/1000. Overrides the
     magnification specified in the DVI file.  Must be between 10 and
     100000.  It is recommended that you use standard magstep values
     (1095, 1200, 1440, 1728, 2074, 2488, 2986, and so on) to help
     reduce the total number of PK files generated.  NUM may be a real
     number, not an integer, for increased precision.

`-z NUM'
     Set the PNG compression level to NUM. This option is enabled if
     your `libgd' is new enough. The default compression level is 1,
     which selects maximum speed at the price of slightly larger PNGs.
     For an older `libgd', the hard-soldered value 5 is used. The
     include file `png.h' says

          Currently, valid values range from 0 - 9, corresponding
          directly to the zlib compression levels 0 - 9 (0 - no
          compression, 9 - "maximal" compression). Note that tests have
          shown that zlib compression levels 3-6 usually perform as
          well as level 9 for PNG images, and do considerably fewer
          calculations. In the future, these values may not correspond
          directly to the zlib compression levels.


File: dvipng.info,  Node: Graphics,  Next: Color,  Prev: Command-line options,  Up: Top

5 Graphics
**********

`dvipng' attempts to handle graphics as included by the `graphicx' and
`graphics' packages, without the need of specifying a driver to these
packages. This means that it recognizes the encapsulated postscript
inclusion meant for `dvips', but is also able (from version 1.8) to
include bitmapped graphics, see the details below.

* Menu:

* Encapsulated PostScript::    An internal call to GhostScript
* Bitmapped graphics::         PNG, JPEG and GIF


File: dvipng.info,  Node: Encapsulated PostScript,  Next: Bitmapped graphics,  Up: Graphics

5.1 Encapsulated PostScript
===========================

When an EPS file is included, a call to GhostScript is performed to
produce a bitmapped image that can be included. The default is to
produce an image with transparent background, at the same size as the
DVI page currently being converted to PNG, and include that as
foreground on the PNG. Of course, if the image is to be cropped, that
is done. The included image will be a truecolor image, so for maximum
performance the output PNG will be in truecolor mode as well.

   This conversion needs the `pngalpha' output device to be present in
your copy of GhostScript. If that device is not present, or you use the
`--palette' switch or request GIF output, the fallback is to use the
`png16m' device to produce a cropped opaque image for inclusion. Other
relevant switches are `--noghostscript' and `--nogssafer'. *Note Option
details::.

   The most common problem with including graphics is an incorrect
bounding box. Complain to whoever wrote the software that generated the
file if the bounding box is indeed incorrect. An adjusted boundingbox
can be specified in the `\includegraphics' call, as in this example
(using `graphicx'):

     \includegraphics[bb=10 20 100 200]{imagename.eps}


File: dvipng.info,  Node: Bitmapped graphics,  Prev: Encapsulated PostScript,  Up: Graphics

5.2 Bitmapped graphics
======================

dvipng can include PNG, JPEG and GIF graphics. When including such
images via `\includegraphics' you need to specify the bounding box
since TeX itself cannot read them from the files in question.  The
bounding box size should be given as `0 0 w h' in pixels, e.g., if the
file `imagename.png' is 300x400 pixels, the inclusion would read

     \includegraphics[bb=0 0 300 400]{imagename.png}

   The default size is the image size in bp ("big points" in TeX
nomenclature or PostScript points as other people have it, 72 per inch).
That is, default resolution will be 72 dpi for included bitmaps, which
is the default size in the few other bitmap-capable drivers that are
known to me (dvipdfm and PDFLaTeX).

   If you want 100 dpi you need to specify the width accordingly. You
just divide your image width by 100: a 135 pixel wide image at 100 dpi
will take up 1.35 inches. If you want 200 dpi you divide by 200, and so
on. Simple, eh? The example above at 200 dpi would be 1.5 inches wide:

     \includegraphics[bb=0 0 300 400,witdh=1.5in]{imagename.png}


File: dvipng.info,  Node: Color,  Next: Diagnosing problems,  Prev: Graphics,  Up: Top

6 Color
*******

To support color, dvipng recognizes a certain set of specials as
generated by the `color' and `xcolor' style files. These specials start
with the keyword `color' or the keyword `background', followed by a
color specification.

* Menu:

* Color specifications::
* Color specials::


File: dvipng.info,  Node: Color specifications,  Next: Color specials,  Up: Color

6.1 Color specifications
========================

The color specification supported by dvipng is by-value or by-name. The
by-value spec starts with the name of a color model (one of `rgb',
`hsb', `cmy', `cmyk', or `gray') followed by the appropriate number of
parameters. Thus, the color specification `rgb 0.3 0.4 0.5' would
correspond to the color that is `0.3 0.4 0.5' in its red, blue and
green values. The color model used internally in dvipng is `RGB'
(discretized to 256 levels), for details on the formulas used in
conversion, see the `xcolor' documentation.

   By-name color specifications are single (case-dependent) words and
are compared with color names defined in `dvipsnam.def' (from the
`graphics' bundle), `svgnam.def' and `xcolor.sty' (from the `xcolor'
bundle). See the `xcolor' documentation for a list of names and the
corresponding colors.

   On the command-line, the name `Transparent' can also be used as an
argument to `--bg' to choose transparent background.  *Note Option
details::.


File: dvipng.info,  Node: Color specials,  Prev: Color specifications,  Up: Color

6.2 Color specials
==================

We will describe `background' first, since it is the simplest. The
`background' keyword must be followed by a color specification.  That
color specification is used as a fill color for the background. The
last `background' special on a page is the one that gets used, and is
used for the whole of the page image. (This is possible because the
prescan phase of dvipng notices all of the color specials so that the
appropriate information can be written out during the second phase.)

   The `color' special itself has three forms. The first is just
`color' followed by a color specification. In this case, the current
global color is set to that color; the color stack must be empty when
such a command is executed.

   The second form is `color push' followed by a color specification.
This saves the current color on the color stack and sets the color to be
that given by the color specification.  This is the most common way to
set a color.

   The final form of the `color' special is just `color pop', with no
color specification; this says to pop the color last pushed on the
color stack from the color stack and set the current color to be that
color.

   dvipng correctly handles these color specials across pages, even when
the pages are rendered repeatedly or in reverse order.


File: dvipng.info,  Node: Diagnosing problems,  Next: Credits,  Prev: Color,  Up: Top

7 Diagnosing problems
*********************

You've gone through all the trouble of installing dvipng, carefully read
all the instructions in this manual, and still can't get something to
work. The following sections provide some helpful hints if you find
yourself in such a situation.

* Menu:

* Contact information::         Who to ask.
* Debug options::               Getting diagnostics.


File: dvipng.info,  Node: Contact information,  Next: Debug options,  Up: Diagnosing problems

7.1 Contact information
=======================

Bug reports should be sent to <dvipng@nongnu.org>.

   Questions, suggestions for new features, pleas for help, and/or
praise should go to <dvipng@nongnu.org>. For more information on this
mailing list, send a message with just the word `help' as subject or
body to <dvipng-request@nongnu.org> or look at
`http://lists.nongnu.org/mailman/listinfo/dvipng'.

   Offers to support further development will be appreciated. For
developer access, ask on <dvipng@nongnu.org>.

   For details on the TeX path-searching library, and `mktexpk'
problems, *note Common problems: (kpathsea)Common problems.


File: dvipng.info,  Node: Debug options,  Prev: Contact information,  Up: Diagnosing problems

7.2 Debug options
=================

The `-d' flag to dvipng helps in tracking down certain errors.  The
parameter to this flag is an integer that tells what errors are
currently being tracked.  To track a certain class of debug messages,
simply provide the appropriate number given below; if you wish to track
multiple classes, sum the numbers of the classes you wish to track.  To
track all classes, you can use `-1'.

   Some of these debugging options are actually provided by Kpathsea
(*note Debugging: (kpathsea)Debugging.).

   The classes are:
1
     Normal dvi op-codes

2
     Virtual fonts

4
     PK fonts

8
     TFM files

16
     Glyph rendering

32
     FreeType calls

64
     Encoding loads

128
     Color specials

256
     GhostScript specials

512
     T1lib calls

1024
     Kpathsea `stat' calls

2048
     Kpathsea hash table lookups

4096
     Kpathsea path element expansion

8192
     Kpathsea path searches



File: dvipng.info,  Node: Credits,  Next: Copying,  Prev: Diagnosing problems,  Up: Top

8 Credits
*********

A number of persons have contributed, if I forget to mention someone, I
apologize. First and foremost we have David Kastrup whose preview-latex
project provided the incentive to write this program.  There is also a
number of people who have contributed by reporting bugs and suggesting
improvements as the thing has evolved. These include but is perhaps not
limited to (in semi-random order): Thomas Esser (teTeX), Christian
Schenk (MIKTeX), Brian R Furry (debian package), Angus Leeming (LyX),
Thomas Boutell (libgd), John Jones (first user report), Uwe Kern
(xcolor), Karl Berry (TeX Live), David Harvey (hinting in Freetype),
Neal Harmon, Alan Shutko, Reiner Stieb, Nick Alcock, Adam Buchbinder,
Svend Tollak Munkejord, James Longstreet, Bernhard Simon, Bob McElrath,
Georg Schwarz, Jason Farmer, Brian V. Smith, Samuel Hathaway, Thomas R.
Shemanske, Stephen Gibson, Christian Ridderstro"m, Ezra Peisach,
William H Wheeler, Thomas Klausner, Harald Koenig, Adrian Bunk, Kevin
Smith, Jason Riedy, Wolfram Krause, Reinhard Kotucha, and Takeshi Abe.


File: dvipng.info,  Node: Copying,  Next: Index,  Prev: Credits,  Up: Top

9 Copying
*********

This program is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

   This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
License along with this program. If not, see
<http://www.gnu.org/licenses/>.



Copyright (C) 2002-2008 Jan-AAke Larsson


File: dvipng.info,  Node: Index,  Prev: Copying,  Up: Top

Index
*****