
Create and use images with MetaPost
The functionality to create and embed MetaPost graphics is still very new and experimental. The interface may still change or disappear altogether. In this respect, it should be used with caution. |
MetaPost is a programming language that can be used to create graphics.
For example, one creates from the following program code:
beginfig(1)
for a=0 upto 9:
draw (0,0){dir 45}..{dir -10a}(6cm,0);
endfor
endfig;
a graphic:

MetaPost and the speedata Publisher
The idea now is to be able to use these images in the speedata Publisher as well. To do this, you first define a graphic and then use it later in the box command:
<Layout
xmlns="urn:speedata.de:2009/publisher/en"
xmlns:sd="urn:speedata:2009/publisher/functions/en">
<!-- no beginfig() ... endfig necessary -->
<DefineGraphic name="dottedbox">
pickup pencircle scaled 1mm;
draw (0,0) -- (box.width,0) -- (box.width, box.height) --
(box.width, box.height) -- (0, box.height ) -- cycle
dashed withdots withcolor 0.7red ;
</DefineGraphic>
<!-- same, but uses predefined path box: -->
<DefineGraphic name="dottedboxsimple">
pickup pencircle scaled 1mm;
draw box dashed withdots withcolor 0.7red ;
</DefineGraphic>
<Record element="data">
<PlaceObject row="1" column="1">
<Box height="2" width="5" graphic="dottedbox" />
</PlaceObject>
</Record>
</Layout>
The width of the box and the height of the box are defined with the variables box.width
and box.height
in MetaPost.
This allows you to adjust the graphic to the defaults in the Publisher.
Coordinates
The origin of the coordinate system is in the lower left corner of the box, so positive values go in the right and up direction.
Variables
Variables for MetaPost can be set with <SetVariable>
.
<SetVariable
variable="curcol"
type="mp:rgbcolor"
select="'colors_mycolor'"/>
The assignment is evaluated at the beginning of the MetaPost context. Thus curcol
is available at the beginning of the graphics.
Predefined values
-
All colors defined in the layout can be used in MetaPost with the prefix
colors.
:<DefineColor name="mycolor" value="#FF4E00"/> <DefineGraphic name="dots"> pickup pencircle scaled 3mm; for i=0 upto 3: draw (i * 1cm, i * 1cm) withcolor colors.mycolor ; endfor; </DefineGraphic> <Record element="data"> <PlaceObject row="1" column="1"> <Box height="5" width="1" graphic="dots" /> </PlaceObject> </Record>
- CSS level 3 colors are defined in RGB colorspace.
-
The width and height of a box can be accessed via
box.width
andbox.height
-
The box' path is saved in the variable
box
(see the example above). - Hans Hagen’s MetaFun macro package is included (parts of it).
-
In page types you can also access these variables:
Variable Description page.width
Page width page.height
Page height page.margin.left
Margin left page.margin.right
Margin right page.margin.top
Margin top page.margin.bottom
Margin bottom page.trim
Bleed
MetaPost resources
There are a number of manuals and tutorials for MetaPost:
- The MetaPost manual (mpman) can be obtained from CTAN: http://mirrors.ctan.org/systems/doc/metapost/mpman.pdf
- Learning MetaPost by doing by André Heck: https://staff.fnwi.uva.nl/a.j.p.heck/Courses/mptut.pdf
- MetaPost examples: http://tex.loria.fr/prod-graph/zoonekynd/metapost/metapost.html
- A Beginner’s Guide to MetaPost for Creating High-Quality Graphics http://www.tug.org/pracjourn/2006-4/henderson/henderson.pdf
- Puzzling graphics in MetaPost https://www.pragma-ade.com/articles/art-puzz.pdf
- MetaFun (a macro package that is based on MetaPost - not all commands are supported by the speedata Publisher) https://www.pragma-ade.com/general/manuals/metafun-p.pdf