The Ipe file format¶

Ipe can store documents in two different formats. One of them is standard PDF, which can be read by any application capable of opening PDF files. (Ipe embeds its own information inside PDF files. The way this is done is not documented here, and may change between releases of Ipe.)

The second Ipe file format is a pure XML implementation. Files stored in this format can be parsed with any XML-aware application, and you can create XML files for Ipe from your own applications.

A DTD for the Ipe format is available as ipe.dtd. For instance, you can use this to validate an Ipe document using

xmllint --dtdvalid ipe.dtd --noout file.ipe

or

xmlstarlet val -d ipe.dtd file.ipe

The tags understood by Ipe are described informally in this section.

Ipe does not use a full XML-parser, in particular it does not understand namespaces and doesn’t allow certain elements that have no contents to be expanded (you cannot, for instance, write <info></info> instead of <info />).

Tags in the XML file can carry attributes other than the ones documented here. Ipe ignores all attributes it doesn’t understand, and they will be lost if the document is saved again from Ipe. Ipe will complain about any XML elements not described here, with the exception that you can use elements whose name starts with x- freely to add your own information inside an Ipe file.

An Ipe XML file must contain exactly one <ipe> element, while an Ipe stylesheet file must contain exactly one <ipestyle> element (both types of files are allowed to start with an <?xml> tag, which is simply ignored by Ipe). An Ipe file may also contain a <!DOCTYPE> tag.

All elements are documented below.

The `<ipe>` element¶

Attributes

version (required)

The value (a number, e.g. 70103 for Ipelib 7.1.3) indicates the earliest Ipelib version that can interpret the document. Ipe will refuse to load documents that require a version larger than its own, and may refuse to load documents that are too old (and which will have to be converted using a separate program).

creator (optional)

indicates the program that created the file. This information is not interpreted by Ipe at all.

Contents

An <info> element (optional),
a <preamble> element (optional),
a series of <bitmap> and <ipestyle> elements (optional),
a series of page elements.

The <ipestyle> elements form a cascade, with the last <ipestyle> element becoming the top-level style sheet. When symbolic names are looked up, the style sheets are checked from top to bottom. Ipe always appends the built-in standard style sheet at the bottom of the stack.

The `<info>` element¶

Attributes

title (optional): document title,
author (optional): document author,
subject (optional): document subject,
keywords (optional): document keywords,
language (optional): the document language, to be used for spell checking. E.g. de_DE for German spell checking. Currently has an effect only on Linux when spell checking is compiled in.
pagemode (optional): the only value understood by Ipe is fullscreen, which causes the document to be opened in full screen mode in PDF readers.
created (optional): creation time in PDF format, e.g. D:20030127204100.
modified (optional): modification time in PDF format,
numberpages (optional): if the value is yes, then Ipe will save PDF documents with visible page numbers on each page.
sequentialtext (optional): if the value is yes, then Ipe will typeset all text objects one by one, even if they are identical, in the order in which they appear in the document.
tex (optional): determines the TeX-engine used to translate your text. The possible values are pdftex, xetex, and luatex.

This element must be empty.

The `<preamble>` element¶

The contents of this element is LaTeX source code, to be used as the LaTeX preamble when running LaTeX to process the text objects in the document. It should not contain a \documentclass command, but can contain \usepackage commands and macro definitions.

If the preamble starts with %&, then the first line of the preamble will be placed at the top of the LaTeX source that Ipe produces to process text objects.

The `<bitmap>` element¶

Each <bitmap> element defines a bitmap to be used by <image> objects.

Attributes

id (required): the value must be an integer that will define the bitmap throughout the Ipe document,
width (required): integer width in pixels,
height (required): integer height in pixels,
ColorSpace (optional): possible values are DeviceGray, DeviceGrayAlpha, DeviceRGB (default value), and DeviceRGBAlpha. The suffix Alpha indicates the presence of an alpha channel.
ColorKey (optional): an RGB color in hexadecimal, indicating the transparent color (not supported for JPEG images and for images with alpha channel),
length (required unless there is no filter and no alpha channel): the number of bytes of image data,
Filter (optional): possible values are FlateDecode or DCTDecode to indicate a compressed image (the latter is used for JPEG images),
encoding (optional): possible value is base64 to indicate that the image data is base64-encoded (not in hexadecimal),
alphaLength (optional): indicates that the alpha channel is provided separately.

The contents of the <bitmap> element is the image data, either base64-encoded or in hexadecimal format. White space between bytes is ignored. If no filter is specified, pixels are stored row by row.

If alphaLength present, then the alpha channel follows the image data. If the data is deflated, image data and alpha channel are deflated separately. If no alphaLength is present, then the alpha component is part of each pixel before the color components.

Bitmaps use 8-bit color and alpha components. Bitmaps with color maps or with a different number of bits per component are not supported, and such support is not planned. (The Insert image function does allow you to insert arbitrary image formats, but they are stored as 8-bit per component images. Since the data is compressed, this does not seriously increase the image data size.)

The `<page>` element¶

Attributes

title (optional): title of this page (displayed at a fixed location in a format specified by the style sheet),
section (optional): Title of document section starting with this page. If the attribute is not present, this page continues the section of the previous page. If the attribute is present, but its value is an empty string, then the contents of the title attribute is used instead.
subsection (optional): Title of document subsection starting with this page. If the attribute is not present, this page continues the subsection of the previous page. If the attribute is present, but its value is an empty string, then the contents of the title attribute is used instead.
marked (optional): The page is marked for printing unless the value of this attribute is no.

Contents

An optional <notes> element,
a possibly empty sequence of <layer> elements,
a possibly empty sequence of <view> elements,
a possibly empty sequence of Ipe object elements.

If a page contains no layer element, Ipe automatically adds a default layer named alpha, visible and editable.

If a page contains no view element, a single view where all layers are visible is assumed.

The `<notes>` element¶

This element has no attributes. Its contents is plain text, containing notes for this page.

The `<layer>` element¶

Attributes

name (required): Name of the layer. It must not contain white space.
edit (optional): The value should be yes or no and indicates whether the user can select and modify the contents of the layer in the Ipe user interface (of course the user can always modify the setting of the attribute).
snap (optional): The value should be never, visible, or always, and indicates whether snapping to this layer is enabled. The default is visible.
data (optional): A free-use string associated with the layer. Ipe makes no use of this string, except for layers it creates itself for group edits.

The layer element must be empty.

The `<view>` element¶

Attributes

layers (required): The value must be a sequence of layer names defined in this page, separated by white space.
active (required): The layer that is the active layer in this view.
effect (optional): The symbolic name of a graphics effect to be used during the PDF page transition. The effect must be defined in the style sheet.
name (optional): The name of the view.
marked (optional): The view is marked for printing if the value of this attribute is yes.

The view element may be empty, or it may contain a sequence of attribute mappings and layer transformations.

An attribute mapping is a <map> element with three attributes

kind, from, and to. The kind attribute must have one of the following values:

pen, symbolsize, arrowsize, opacity, color, dashstyle, symbol

The attributes from and to must both be names of symbolic attribute values. The effect is that in this view, the symbolic attribute from is replaced by the symbolic attribute to for attributes of the given kind.

A layer transformation is a <transform> element. It must have two attributes: layer is the name of a layer of the page, matrix is a transformation matrix. In the view, all objects on that layer are transformed with this matrix.

Ipe object elements¶

Common attributes¶

layer (optional): Only allowed on top-level objects, that is, objects directly inside a <page> element. The value indicates into which layer the object goes. If the attribute is missing, the object goes into the same layer as the preceding object. If the first object has no layer attribute, it goes into the layer defined first in the page, or the default alpha layer.
matrix (optional): A sequence of six real numbers, separated by white space, indicating a transformation matrix for all coordinates inside the element (including embedded elements if this is a <group> element). A missing matrix attribute is interpreted as the identity matrix.
pin (optional): Possible values are yes (object is fixed on the page), h (object is pinned horizontally, but can move in the vertical direction), and v (the opposite). The default is no pinning.
transformations (optional): This attribute determines how objects can be deformed by transformations. Possible values are affine (the default), rigid, and translations.

Color attribute values¶

A color attribute value is either a symbolic name defined in one of the style sheets of the document, one of the predefined names

black or white, a single real number between $0$ (black) and $1$ (white) indicating a gray level, or three real numbers in the range $[0,1]$ indicating the red, green, and blue component (in this order), separated by white space.

Path construction operators¶

Graphical shapes in Ipe are described using a series of path construction operators with arguments. This generalizes the PDF path construction syntax.

Each operator follows its arguments. The operators are

m (moveto) (1 point argument):: begin new subpath.
l (lineto) (1 point argument):: add straight segment to subpath.
c (cubic B-spline) ($n$ point arguments):: add a uniform cubic B-spline with $n+1$ control points (the current position plus the $n$ arguments). If $n = 3$, this is equivalent to a single cubic Bézier spline, if $n = 2$ it is equivalent to a single quadratic Bézier spline.
q (deprecated) (2 point arguments):: identical to ‘c’.
e (ellipse) (1 matrix argument):: add a closed subpath consisting of an ellipse, the ellipse is the image of the unit circle under the transformation described by the matrix.
a (arcto) (1 matrix argument, 1 point argument):: add an elliptic arc, on the ellipse described by the matrix, from current position to given point.
s (deprecated) ($n$ point arguments):: add an “old style” uniform cubic B-spline as used by Ipe up to version 7.1.6.
C ($n$ point arguments plus one tension argument):: add a cardinal cubic spline through the given points and the given tension. (The definition of the tension in the literature varies. Ipe’s tangent is the factor by which the vector from previous to next point is multiplied to obtain the tangent vector at this point. So 0.5 corresponds to the Catmull-Rom spline.)
L ($n$ point arguments):: add a clothoid spline as computed by the libspiro library by Raph Levien. When Ipe writes clothoid splines, it includes the control points of the computed Bezier approximation in the path description, separated from the defining points by a *.
u (closed spline) ($n$ point arguments):: add a closed subpath consisting of a closed uniform B-spline with $n$ control points,
h (closepath) (no arguments):: close the current subpath. No more segments can be added to this subpath, so the next operator (if there is one) must start a new subpath.

A point argument is a pair of $x$ and $y$ coordinates.

A matrix argument is a sequence of 6 numbers $a, b, c, d, s, t$. They describe the affine transformation

$x' = a x + c y + s$

$y' = b x + d y + t$

Note that you write the matrix column by column!

Paths consisting of more than one closed loop are allowed. A subpath can consist of any mix of straight segments, elliptic arcs, and B-splines.

The `<group>` element¶

The <group> element allows to group objects together, so that they appear as one in the user interface.

Attributes

clip (optional): The value is a sequence of path construction operators, forming a clipping path for the objects inside the group.
url (optional): The value is a link action (and the attribute name is somewhat of a misnomer, as actions do not need to be URLs—see the description of group objects).
decoration (optional): The name of a decoration symbol. The default is normal, meaning no decoration.

The contents of the <group> element is a series of Ipe object elements.

The `<image>` element¶

Attributes

bitmap (required): Value is an integer referring to a bitmap defined in a <bitmap> element in the document,
rect (required): Four real coordinates separated by white space, in the order $x_{1}, y_{1}, x_{2}, y_{2}$, indicating two opposite corners of the image in Ipe coordinates).
opacity (optional): Opacity of the image. This must be a symbolic name. The default is normal, meaning fully opaque.

The image element is normally empty. However, it is allowed to omit the bitmap attribute. In this case, the <image> must carry all the attributes of the <bitmap> element, with the exception of id. The element contents is then the bitmap data, as described for <bitmap>.

The `<use>` element¶

The <use> element refers to a symbol (an Ipe object) defined in the style sheet. The attributes stroke, fill, pen, and size make sense only when the symbol accepts these parameters.

Attributes

name (required): The name of a symbol defined in a style sheet of the document.
pos (optional): Position of the symbol on the page (two real numbers, separated by white space). This is the location of the origin of the symbol coordinate system. The default is the origin.
stroke (optional): A stroke color (used whereever the symbol uses the symbolic color sym-stroke). The default is black.
fill (optional): A fill color (used whereever the symbol uses the symbolic color sym-fill). The default is white.
pen (optional): A line width (used whereever the symbol uses the symbolic value sym-pen). The default is normal.
size (optional): The size of the symbol, either a symbolic size (of type symbol size), or an absolute scaling factor. The default is $1.0$.

The <use> element must be empty.

The `<text>` element¶

Attributes

stroke (optional): The stroke color. If the attribute is missing, black will be used.
type (optional): Possible values are label (the default) and minipage.
size (optional): The font size—either a symbolic name defined in a style sheet, or a real number. The default is normal.
pos (required): Two real numbers separated by white space, defining the position of the text on the paper.
width (required for minipage objects, optional for label objects): The width of the object in points.
height (optional): The total height of the object in points.
depth (optional): The depth of the object in points.
valign (optional): Possible values are top (default for a minipage object), bottom (default for a label object), center, and baseline.
halign (optional): Possible values are left, right, and center. left is the default. This determines the position of the reference point with respect to the text box.
style (optional): Selects a LaTeX style to be used for formatting the text, and must be a symbolic name defined in a style sheet. There are separate definitions for minipages and for labels. For minipages, the standard style sheet defines the styles normal, center, itemize, and item. If the attribute is not present, the normal style is applied.
opacity (optional): Opacity of the element. This must be a symbolic name. The default is normal, meaning fully opaque.

The dimensions are recomputed by Ipe when running LaTeX, with the exception of width for minipage objects whose width is fixed.

The contents of the <text> element must be a legal LaTeX fragment that can be interpreted by LaTeX inside \hbox, possibly using the macros or packages defined in the preamble.

The `<path>` element¶

Attributes

stroke (optional): The stroke color. If the attribute is missing, the shape will not be stroked.
fill (optional): The fill color. If the attribute is missing, the shape will not be filled.
dash (optional): Either a symbolic name defined in a style sheet, or a dash pattern in PDF format, such as [3 1] 0 for three pixels on, one off, starting with the first pixel. If the attribute is missing, a solid line is drawn.
pen (optional): The line width, either symbolic (defined in a style sheet), or as a single real number. The default value is normal.
cap (optional): The line cap setting of PDF as an integer. If the argument is missing, the setting from the style sheet is used.
join (optional): The line join setting of PDF as an integer. If the argument is missing, the setting from the style sheet is used.
fillrule (optional): Possible values are wind and eofill, selecting one of two algorithms for determining whether a point lies inside a filled object. If the argument is missing, the setting from the style sheet is used.
arrow (optional): The value consists of a symbolic name, say triangle for an arrow type (a symbol with name arrow/triangle(spx)), followed by a slash and the size of the arrow. The size is either a symbolic name (of type arrowsize) defined in a style sheet, or a real number. If the attribute is missing, no arrow is drawn.
rarrow (optional): Same for an arrow in the reverse direction (at the beginning of the first subpath).
opacity (optional): Opacity of the element. This must be a symbolic name. The default is normal, meaning fully opaque.
stroke-opacity (optional): Opacity of the stroked part of the element. This must be a symbolic name. The default is to use the opacity attribute.
tiling (optional): A tiling pattern to be used to fill the element. The default is not to tile the element. If the element is not filled, then the tiling pattern is ignored.
gradient (optional): A gradient pattern to be used to fill the element. If the element is not filled, then the gradient pattern is ignored. If gradient is set, then tiling is ignored.

The contents of the <path> element is a sequence of path construction operators. The entire shape will be stroked and/or filled with a single stroke and fill operation.

The `<ipestyle>` element¶

Attributes

name (optional): The name serves to identify the style sheet informally, and can be used to automatically update the style sheet from a file with the matching name.

The contents of the <ipestyle> element is a series of style definition elements, in no particular order. These elements are described below.

The `<symbol>` element¶

Attributes

name (required): The name identifies the symbol and must be unique in the style sheet. For parameterized symbols, the name must end with the pattern (s?f?p?x?), where s stands for stroke, f for fill, p for pen, and x for size.
transformations (optional): As for objects.
xform (optional): If this attribute is set, a PDF XForm will be created for this symbol when saving or exporting to PDF. It implies transformations="translations", and will be ignored if any of the symbol parameters (that is, stroke, fill, pen, or size) are used. Setting this attribute will cause the PDF output to be significantly smaller for a complicated symbol that is used often (for instance, a complicated background used on every page).
snap (optional): A list of space-separated coordinates for the snap positions of the symbol.

The contents of the <symbol> element is a single Ipe object.

The `<preamble>` element¶

See the <preamble> elements inside <ipe> elements.

The `<textstyle>` element¶

Attributes

name (required): The symbolic name (to be used in the style attribute of <text> elements),
begin (required): LaTeX code to be placed before the text of the object when it is formatted,
end (required): LaTeX code to be placed after the text of the object when it is formatted.
type (optional): Either label or minipage (the default).

The `<layout>` element¶

It defines the layout of the frame on the paper and the paper size.

Attributes

paper (required): The size of the paper.
origin (required): The lower left corner of the frame in the paper coordinate system.
frame (required): The size of the frame.
skip (optional): The default paragraph skip between textboxes.
crop (optional): If the value of crop is yes, Ipe will create a CropBox attribute when saving to PDF.

The `<titlestyle>` element¶

It defines the appearance of the page title on the page.

Attributes

pos (required): The position of the title reference point in the frame coordinate system.
color (required): The color of the title.
size (required): The title font size (same as for <text> elements).
halign (optional): The horizontal alignment (same as for <text> elements).
valign (optional): The vertical alignment (same as for <text> elements).

The `<pagenumberstyle>` element¶

It defines the appearance of page numbers on the page. The contents of the element is a template for a text object.

Attributes

pos (required): The position of the page number on the page.
color (optional): The color of the page number. The default is black.
size (optional): The font size (same as for <text> elements). The default is normal.
halign (optional): The horizontal alignment (same as for <text> elements).
valign (optional): The vertical alignment (same as for <text> elements).

The `<textpad>` element¶

It defines padding around text objects for the computation of bounding boxes. The four required attributes are left,

right, top, and bottom.

The `<pathstyle>` element¶

It defines the default setting for path objects.

Attributes

cap (optional): Same as for <path> elements.
join (optional): Same as for <path> elements.
fillrule (optional): Same as for <path> elements.

The `<opacity>` element¶

The opacity element defines a possible opacity value (also known as an alpha-value). All opacity values used in a document must be defined in the style sheet.

Attributes

name (required): A symbolic name, to be used in the opacity attribute of a text or path element.
value (required): An absolute value for the opacity, between 0.001 and 1.000. A value of 1.0 implies that the element is fully opaque.

The `<gradient>` element¶

The gradient element defines a gradient pattern.

Attributes of <gradient>

name (required): The symbolic name (to be used in the gradient attribute of <path> elements).
type (required): Possible values are axial and radial.
extend (optional): yes or no (the default). Indicates whether the gradient is extended beyond the boundaries.
coords (required): For axial shading: the coordinates of the endpoints of the axis (in the order x1 y1 x2 y2). For radial shading: the center and radius of both circles (in the order cx1 cy1 r1 cx2 cy2 r2).
matrix (optional): A transformation that transforms the gradient coordinate system into the coordinate system of the path object using the gradient. The default is the identity matrix.

The contents of the <gradient> element are <stop> elements defining the color stops of the gradient. There must be at least two stops. Stops must be defined in increasing offset order. It is not necessary that the first offset is 0.0 and the last one is 1.0.

Attributes of <stop>

offset (required): Offset of the color stop (a number between 0.0 and 1.0).
color (required): Color at this color stop (three numbers). Symbolic names are not allowed.

The `<tiling>` element¶

The tiling element defines a tiling pattern. Only very simple patterns that hatch the area with a line are supported.

Attributes

name (required): The symbolic name (to be used in the tiling attribute of <path> elements).
angle (required): Slope of the hatching line in degrees, between -90 and +90 degrees.
width (required): Width of the hatching line.
step (required): Distance from one hatching line to the next.

Here, width and step are measured in the y-direction if the absolute value of angle is less than 45 degrees, and in the x-direction otherwise.

The `<effect>` element¶

The effect element defines a graphic effect to be used during a PDF page transition. Acrobat Reader supports these effects, but not all PDF viewers do.

Attributes

name (required): The symbolic name (to be used in the effect attribute of <view> elements).
duration (optional): Value must be a real number, indicating the duration of display in seconds.
transition (optional): Value must be a real number, indicating the duration of the transition effect in seconds.
effect (optional): a number indicated the desired effect. The value must be an integer between 0 and 27 (see ipe::Effect::TEffect for the exact meaning).

Other style definition elements¶

The remaining style definition elements are:

<color>: Defines a symbolic color. The value must be an absolute color, that is either a single gray value (between 0 and 1), or three components (red, green, blue) separated by space.
<dashstyle>: Defines a symbolic dashstyle. The value must be a correct dashstyle description, e.g. [3 5 2 5] 0.
<pen>: Defines a symbolic pen width. The value is a single real number.
<textsize>: Defines a symbolic text size. The value is a piece of LaTeX source code selecting the desired font size.
<textstretch>: Defines a symbolic text stretch factor. The symbolic name is shared with <textsize> elements. The value is a single real number.
<symbolsize>: Defines a symbolic size for symbols. The value is a single real number, and indicates the scaling factor used for the symbol.
<arrowsize>: Defines a symbolic size for arrows. The value is a single real number.
<gridsize>: Defines a grid size. The symbolic name cannot actually be used by objects in the document — it is only used to fill the grid size selector in the user interface.
<anglesize>: Defines an angular snap angle. The symbolic name cannot actually be used by objects in the document — it is only used to fill the angle selector in the user interface.

Common attributes

name (required): A symbolic name, which must start with a letter “a” to “z” or “A” to “Z”.
value (required): A legal absolute value for the type of attribute.

The Ipe file format¶

The `<ipe>` element¶

The `<info>` element¶

The `<preamble>` element¶

The `<bitmap>` element¶

The `<page>` element¶

The `<notes>` element¶

The `<layer>` element¶

The `<view>` element¶

Ipe object elements¶

Common attributes¶

Color attribute values¶

Path construction operators¶

The `<group>` element¶

The `<image>` element¶

The `<use>` element¶

The `<text>` element¶

The `<path>` element¶

The `<ipestyle>` element¶

The `<symbol>` element¶

The `<preamble>` element¶

The `<textstyle>` element¶

The `<layout>` element¶

The `<titlestyle>` element¶

The `<pagenumberstyle>` element¶

The `<textpad>` element¶

The `<pathstyle>` element¶

The `<opacity>` element¶

The `<gradient>` element¶

The `<tiling>` element¶

The `<effect>` element¶

Other style definition elements¶

Table of Contents

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This Page

The Ipe file format¶

The <ipe> element¶

The <info> element¶

The <preamble> element¶

The <bitmap> element¶

The <page> element¶

The <notes> element¶

The <layer> element¶

The <view> element¶

Ipe object elements¶

Common attributes¶

Color attribute values¶

Path construction operators¶

The <group> element¶

The <image> element¶

The <use> element¶

The <text> element¶

The <path> element¶

The <ipestyle> element¶

The <symbol> element¶

The <preamble> element¶

The <textstyle> element¶

The <layout> element¶

The <titlestyle> element¶

The <pagenumberstyle> element¶

The <textpad> element¶

The <pathstyle> element¶

The <opacity> element¶

The <gradient> element¶

The <tiling> element¶

The <effect> element¶

Other style definition elements¶

The `<ipe>` element¶

The `<info>` element¶

The `<preamble>` element¶

The `<bitmap>` element¶

The `<page>` element¶

The `<notes>` element¶

The `<layer>` element¶

The `<view>` element¶

The `<group>` element¶

The `<image>` element¶

The `<use>` element¶

The `<text>` element¶

The `<path>` element¶

The `<ipestyle>` element¶

The `<symbol>` element¶

The `<preamble>` element¶

The `<textstyle>` element¶

The `<layout>` element¶

The `<titlestyle>` element¶

The `<pagenumberstyle>` element¶

The `<textpad>` element¶

The `<pathstyle>` element¶

The `<opacity>` element¶

The `<gradient>` element¶

The `<tiling>` element¶

The `<effect>` element¶