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74600c0
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doc
canvas.html
fix canvas doc
Stefan Schuermans
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74600c0
at 2018-08-14 13:10:32
canvas.html
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<html> <head> <title>Blinker - Canvas</title> </head> <body> <h1>Blinker - Canvas</h1> <p> The canvas module allows to merge several streams into one. It works like 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>canvases/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> The file <code>srcpos</code> defines the top-left corner of the recangular section to be taken from the stream. The file must contain a string <code><x>,<y></code>. </p> <h4>Size</h4> <p> The file <code>size</code> defines the size of the recangular section to be taken from the stream. The file must contain a string <code><width>x<height></code>. </p> <h4>Destination Position</h4> <p> The file <code>destpos</code> defines the top-left corner of the recangular section on the canvas to draw to. The file must contain a string <code><x>,<y></code>. </p> <h3>Output Stream</h3> <p> The file <code>outstream</code> contains the name of the stream to send the frames to. </p> </body> </html>
