<html> <head> <title>Developer's Guide: File Format</title> </head> <body bgcolor=white text=black link=blue vlink=navy alink=red> <TABLE WIDTH="100%"> <TR> <TH ALIGN="left" WIDTH="33%"><img SRC="Images/arrow-left.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Prev"></TH> <TH ALIGN="center" WIDTH="33%"><img SRC="Images/arrow-up.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Up"></TH> <TH ALIGN="right" WIDTH="33%"><img SRC="Images/arrow-right.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Next"></TH> </TR> <TR> <TD ALIGN="left"><A HREF="devguide-26.html">Message Passing</A></TD> <TD ALIGN="center"><A HREF="devguide.html">Developer's Guide</A></TD> <TD ALIGN="right"></TD> </TR> </TABLE> <HR NOSHADE> <H1><FONT face="Helvetica,Arial"><A NAME="N1"></A>File Format</font></H1> <P>Sketch stores drawings in plain ASCII files using a line oriented format. The main idea is that each line of an sk file looks like a Python function call. Originally, this was just for convenience, as the import filter just had to define all those functions in a dictionary, and read and (r)eval each line.</P> <P>That turned out to be quite slow, probably because each line is compiled to bytecode and then executed just once. Sketch now uses a parser written in C. This is much faster and doesn't have the potential security problems of eval.</P> <P>All function arguments are Python literals, ints, floats, strings (delimited with single- or double-quotes, the usual \ escapes are allowed, but no triple quoted strings or raw strings), tuples and lists. Keyword arguments are also allowed. </P> <P>Boolean values are represented as the ints 0 or 1.</P> <P>Colors are represented by float triples describing the RGB values, each in the range 0..1 (e.g. red (1.0, 0.0, 0.0)).</P> <P>All sk files start with '##Sketch' followed by two numbers, the major and minor version number of the file format.</P> <P>Lines starting with # are comments, empty lines are ignored.</P> <H2><FONT face="Helvetica,Arial"><A NAME="N2"></A>Overall structure</font></H2> <P>The first function in an sk-file is always 'document()'. This function takes no parameters.</P> <P>The next part defines global parameters like the page layout and objects like styles.</P> <P>After this follow the layers from bottom to top.</P> <H2><FONT face="Helvetica,Arial"><A NAME="N3"></A>Globals</font></H2> <P>Functions for global parameters:</P> <P> <DL> <DT><B>layout(<i>format</i>, <i>orientation</i>)</B><DD> <P><i>format</i> is either the name of a predefined paper-format or a tuple (<i>width</i>, <i>height</i>) in pt. See Sketch/Lib/pagelayout.py for a list of predefined paper-formats.</P> <P><i>orientation</i> is 0 for portrait or 1 for landscape.</P> <DT><B>dstyle(<i>name</i>)</B><DD> <P>Define the style named <i>name</i> (a string). The preceding functions define the properties of this style. See the section on <A HREF="#N8">properties</A> for details.</P> </DL> </P> <H2><FONT face="Helvetica,Arial"><A NAME="N4"></A>Layers</font></H2> <P>There are three kinds of layers, <EM>normal layers</EM>, <EM>grid layers</EM> and <EM>guide layers</EM>.</P> <P>Normal layers and guide layers can contain other objects. All objects defined after a layer function are part of that layer. A layer is implicitly closed by another layer function or the end of file.</P> <P>The layer functions:</P> <P> <DL> <DT><B>layer(<i>name</i>, <i>visible</i>, <i>printable</i>, <i>locked</i>, <i>outlined</i>, <i>outline_color</i>)</B><DD> <P>Start a normal layer named <i>name</i> (a string). The booleans <i>visible</i>,<i>printable</i>, <i>locked</i> and <i>outlined</i> determine whether the layer is visible, printable, locked or only shown outlined.</P> <P><i>outline_color</i> defines the color used for the outlines of the objects in the layer.</P> <DT><B>grid(<i>geometry</i>)</B><DD> <P>Define the grid-layer. The <i>geometry</i> is a tuple of the form (<i>xorig</i>, <i>yorig</i>, <i>xwidth</i>, <i>ywidth</i>)</P> <DT><B>guidelayer(<i>name</i>, <i>visible</i>, <i>printable</i>, <i>locked</i>, <i>outlined</i>, <i>outline_color</i>)</B><DD> <P>Start the guide layer. The arguments are the same as for the normal layer, but the arguments <i>printable</i> and <i>outlined</i> will be ignored and set to 0 and 1 respectively.</P> </DL> </P> <H2><FONT face="Helvetica,Arial"><A NAME="N5"></A>Objects</font></H2> <H3><FONT face="Helvetica,Arial"><A NAME="N6"></A>Primitives</font></H3> <P>Primitives </P> <H3><FONT face="Helvetica,Arial"><A NAME="N7"></A>Compound Objects</font></H3> <H2><FONT face="Helvetica,Arial"><A NAME="N8"></A>Properties </font></H2> <HR NOSHADE> <TABLE WIDTH="100%"> <TR> <TD ALIGN="left"><A HREF="devguide-26.html">Message Passing</A></TD> <TD ALIGN="center"><A HREF="devguide.html">Developer's Guide</A></TD> <TD ALIGN="right"></TD> </TR> <TR> <TH ALIGN="left" WIDTH="33%"><img SRC="Images/arrow-left.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Prev"></TH> <TH ALIGN="center" WIDTH="33%"><img SRC="Images/arrow-up.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Up"></TH> <TH ALIGN="right" WIDTH="33%"><img SRC="Images/arrow-right.png" WIDTH="16" HEIGHT="16" ALIGN="top" ALT="Next"></TH> </TR> </TABLE> </body> </html>
