XY-pic Reference Manual - Index of /

Implementation details are not covered here, but in the full TEXnical documentation [17]. This section briefly discusses various aspects of the current XY-pic kernel implementation that the user should be familiar with.

Loading XY-pic

Rosehkrisrose@tug.orgi After reviewing the XY-pic environment in §1, this section documents the basic concepts of XY-pic construction in §2, including maintenance. The following sections give the exact syntax rules of the main XY-pic constructs:. positional language in §3, object constructions in §4 and pictorial "decorations" in §5.

Logo, version, and messages

If you use LATEX, then this file makes it possible to load XY-pic as a "package" using the LATEX command 2ε[9]\usepackage:. where thehoptionis shall be construed as passing to. These will automatically call any backend plugins required to best mimic LATEX 2ε behavior.

Fonts

The only exceptions to this are the options that have the same name as the Part IV driver package options, which appear incf. or the LATEX 2ε graphics bundle. The file also works as a LATEX 2.09 [8] 'style option' although you must then load options using the \xyoption mechanism described in §7.

Allocations

All positions can be written , where X is the TEX dimension distance to the right and Y the distance up from the zero position 0 on the XY image (0 of course has coordinates <0mm,0mm>). When an XY image is entered in inmath mode, the reference point becomes "vcenter" instead, i.e. we use the point .

Objects

We explain the language components in general terms in this§ and in more detail in the following§§. The zero position does not have to be in the image, but Xmin≤Xmax∧Ymin≤Ymax always applies.

Connections

Decorations

The XY-pic state

The exact details of the connection depend on the actual object and are described generally in §4. Thus, the first interpretation has c set to the bottom element of the stack and the last hash set tos0.

Figure 1: h pos i itions.

Circle segments

The set of simple vertices contains basic objects that are useful as markers and arrowheads that create connections, so each is shown at the end of a dot connection of the appropriate type. These tips are combinations of simple tips provided for convenience (and optimized for efficiency).

Text

XY-pic is provided with a growing number of options that support specialized drawing tasks as well as exotic output devices with special graphics functions. Finally, it is possible to declare hcodei as some commands to be executed before each actual execution of \xywithoption{hoptioni}{.

Option file format

These must all be loaded using this uniform interface to ensure that the XY-pic environment is set up properly while reading the option. Sometimes some declarations from an option or header file or whatever only make sense after a specific other option is loaded.

Driver options

Specifying a larger size for the "drop" object is a way to get a dotted curve (see the example in the next note). If there is more than one, the one that appears earliest on the curve is found.

Figure 7: Syntax for curves.

Circles and Ellipses

Quadratic Splines

Circles made with \frm{o} have radius as (R+ L)/2 and with \frm{o} have radius as hdimeni; \frm{oo} makes a double circle, with the outermost circle being the same as \frm{o}. Do: Allow hframe versions such as those used for routing ie. \frm2{-}should be the same as.

Figure 8: Plain h frame i s.

Brackets

Thehframeis\frm{-}and\frm{=}allows an optional corner radius that rounds the corners of the frame with quarter circles of the specified radius. Without special support for rendering the ellipses, either via ahdriverior using the arc attribute, the ellipse will be drawn as a circle with radius approximately the average of the major and minor axes.

Filled regions

The box \of{,} puts a shadow, made up of lines, in the image below the (supposedly rectangular) object, creating the illusion of.

Framing as object modifier

Using curves for frames

Also the shape of the 'caps' at each end of the poly line can be changed. It is applied to the entire current subject, whether it is text, an XY pic line, curve or arrowhead, or a composite object such as an array or the entire image. MovieSetup{width=width,height=height,. that . . specify the other arguments required by the movie class but ignored by the XY-pic movie extension).

Figure 10: Rotations, scalings, and flips Scaling and Scaled Text The h shape i modifier

Why use PostScript

Eberhard Matte's em-TEX implementation provides a series\special commands to facilitate drawing lines, both on screen and with various printing devices. Better results can be obtained with the PostScript back-end and dvipshdriveri, as a version of dvips is available for em-TEX. Once loaded with \xyoption{emtex}, with a suitable hdriveri also specified or later specified, the following commands are available to disable/enable the em-TEX backend.

Polygon shapes

This is useful for drawing connections with a 'center marker' especially with arrows, so the 'mapsto' example explained below can be changed to a 'breakto' example: typing. Firstpis is set to the ending object of the previous segment (for the first segment, this is c just before the path command) and cis is set to the hposition that starts the hsegmenti, and the currenthslide is applied. To shift a segment means to move each of the p, cobjects in the direction perpendicular to the current direction at each.

Figure 14: h path i s Note, however, that what goes into ~+{. . . } is

Arrows

See curve alignment described in §8 for how control points are used; when the list of checkpoints is analyzed pi the source and c the target of the arrow. As in the second example above, only the upper or lower curved arrow can be set using the \.uppertwocell and \.lowertwocell shape control sequences. Otherwise, if the first character in the label is * then the label is set as an XY-pichobject, as with \drop