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<title>Blinker - Canvas</title>
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<h1>Blinker - Canvas</h1>
<p>
The canvas module allows to merge several streams into one.
It works lie a canvas, onto which rectangular sections of
different streams are drawn.
The result obtained on the canvas is then sent to a single output
stream.
</p>
<h2>Configuration</h2>
<p>
The configuration of the canvas module with name <code>NAME</code>
is located in the <code>canvas/NAME</code> subdirectory.
</p>
<h3>Format</h3>
<p>
The file <code>format</code> describes the format of the canvas,
i.e. its dimensions, the number of channels and the color depth on
each channel.
The file must contain a string
<code><width>x<height>-<channels>/<colors></code>,
e.g. <code>18x8-1/256</code> for 18 pixels width, 8 pixels height
in 256 grayscales.
</p>
<h3>Input List</h3>
<p>
The inputs to be drawn onto the canvas are configured in the
<code>inputs</code> subdirectory.
Each input is configured in an own subdirectory in <code>inputs</code>.
E.g. the configurations for inputs with names <code>top</code>
and <code>bottom</code> reside in subdirectories <code>inputs/top</code>
and <code>inputs/bottom</code> respectively.
All inputs are drawn to the canvas in alphanumerical order, i.e.
<code>top</code> is painted over <code>bottom</code> on overlapping
pixels.
</p>
<p>
The configuration inside an input subdirectory consists of the following
settings:
</p>
<h4>Input Stream</h4>
<p>
The file <code>instream</code> contains the name of the stream to
read for this input.
</p>
<h4>Source Position</h4>
<p>
