+Xournal stores its data in gzipped XML-like files. The gzipped data consists
+of a succession of XML tags describing the document. By convention, the
+first few lines contain a header in the following format:
+<pre>
+<?xml version="1.0" standalone="no"?>
+<title>Xournal document - see http://math.mit.edu/~auroux/software/xournal/</title>
+<xournal version="..."/>
+</pre>
+The <title> and <xournal> tags may only appear within the file
+header (not within the pages of the document). The <i>version</i> attribute of
+the <xournal> tag indicates which version of Xournal was used to
+create the document; it is currently ignored, but may be used in a later
+release if the file format changes in an incompatible manner.
+</p>
+<p>
+The rest of the file is a sequence of pages, specified by a
+<page> tag, whose attributes <i>width</i> and <i>height</i> specify the
+physical size of the page in points (1/72 in). The width and height
+parameters are floating point values. The format of a page is therefore:
+<pre>
+<page width="..." height="...">
+... page contents ...
+</page>
+</pre>
+</p>
+<h3 class="subsub">Page background</h3>
+<p>
+The first entry within a page describes the page background.
+It consists of a <background> tag followed by several mandatory
+XML attributes. The first attribute is always <i>type</i>, which
+can take three possible values: "solid" for a solid background, "pixmap"
+for a bitmap background, and "pdf" if the background is a page of a PDF
+document. The rest of the attributes depends on the type of background.
+<ul>
+<li><p> Solid background: <tt><background type="solid" color="..."
+style="..." /></tt> <br />The <i>color</i> attribute takes one of
+the standard values "white", "yellow", "pink", "orange", "blue", "green",
+or can specify a hexadecimal RGBA value in the format "#rrggbbaa". The
+<i>style</i> attribute takes one of the standard values "plain", "lined",
+"ruled", or "graph".</p>
+</li>
+<li><p> Bitmap background: <tt><background type="pixmap" domain="..."
+filename="..." /></tt> <br />
+The <i>domain</i> attribute takes one of the standard values "absolute",
+"attach", or "clone". A value of "absolute" indicates that the bitmap is
+found in the file specified by <i>filename</i>. The bitmap can be in any
+format recognized by the gdk-pixbuf library; this includes most of the
+common bitmap formats (JPEG, PNG, BMP, GIF, PCX, PNM, TIFF, ...).
+<br />A value
+of "attach" indicates that the bitmap is an attachment to the Xournal file.
+The bitmap is in PNG format, and resides in a file whose name is derived
+from that of the main Xournal file by appending to it a dot and the contents
+of the <i>filename</i> attribute. For example, if the Xournal file is in
+<tt>file.xoj</tt> and the <i>filename</i> attribute is <tt>"bg_1.png"</tt>
+then the bitmap file is <tt>file.xoj.bg_1.png</tt> (Xournal saves attached
+bitmaps sequentially in files ...bg_1.png, ...bg_2.png, etc.)
+<br />A value of "clone" indicates that the bitmap is identical to the
+background of a previous page of the journal; the <i>filename</i> attribute
+then specifies the page number, starting with 0 for the first page. For
+example, if a <i>filename</i> value of <tt>"1"</tt> indicates that the
+background bitmap is identical to that of the second page.
+</p>
+</li>
+<li><p> PDF background: <tt><background type="pdf" domain="..."
+filename="..." pageno="..." /></tt> or
+<tt><background type="pdf" pageno="..." /></tt>
+<br />The <i>domain</i> and <i>filename</i> attributes must be specified
+for the first page of the journal that uses a PDF background, and must
+be omitted subsequently for every other page that uses a PDF background.
+The <i>domain</i> attribute takes one of the standard values
+"absolute" and "attach"; the PDF document is to be found in the file
+specified by <i>filename</i> (if <i>domain</i> is "absolute"), or in the
+file whose name is obtained by appending a dot and the contents of the
+<i>filename</i> attribute to the name of the main Xournal file (if
+<i>domain</i> is "attach"). The <i>pageno</i> attribute specifies which
+page of the PDF file is used as background, starting with 1 for the first
+page of the PDF file.
+</p>
+</li>
+</ul>
+</p>
+<h3 class="subsub">Layers and strokes</h3>
+<p>
+After the line specifying the background, the remainder of a <page>
+section is occupied by one or more layer sections
+<pre><layer> ... </layer></pre>
+describing the various strokes within a layer. Every page must
+contain at least one layer; a layer may be empty. The successive layers
+are listed in their stacking order, from bottom to top.
+</p>
+<p>
+A layer consist of a collection of items, listed in the order in which
+they should be drawn
+(from bottom-most to top-most).
+As of the current version, the only legal contents within a layer are
+strokes. The format of a stroke is:
+<pre><stroke tool="..." color="..." width="...">
+... list of coordinates ...
+</stroke>
+</pre>
+The <i>tool</i> attribute can take the values "pen", "highlighter", or
+"eraser" depending on the tool used to create the stroke (pen, highlighter,
+or whiteout eraser); a value of "highlighter" indicates that the stroke
+should be painted in a partially transparent manner (Xournal uses an alpha
+coefficient of 0.5).
+The <i>color</i> attribute can take one of the standard values "black",
+"blue", "red", "green", "gray", "lightblue", "lightgreen", "magenta",
+"orange", "yellow", "white", or can specify a hexadecimal RGBA value in
+the format "#rrggbbaa". The <i>width</i> attribute is a floating-point
+number and specifies the width of the stroke in points (1/72 in).
+</p>
+<p>
+The list of coordinates is simply a succession of floating-point values,
+separated by whitespace.
+The number of given values must be even; consecutive pairs of values give
+the <i>x</i> and <i>y</i> coordinates of each point along the stroke.
+These values are expressed in points (1/72 in). The coordinates (0,0)
+represent the top-left corner of the page: hence x is measured from the left
+of the page, and y is measured from the top of the page.
+</p>
+<p>
+Every stroke must contain at least two points (four floating point values).
+Moreover, two consecutive points on the stroke should be spaced no more
+than 5 units apart or so; longer line segments should be subdivided as
+appropriate (otherwise the eraser tool will not interact properly with the
+stroke). The default precision used by Xournal for the x,y coordinates is
+0.01 unit (1/7200 in).
projects / xournal.git / blobdiff