$Id: README,v 1.4 2004/07/21 19:12:58 dlowder Exp $General=======The idea of tslib is to have a core library that provides standardisedservices, and a set of plugins to manage the conversion and filtering asneeded.The plugins for a particular touchscreen are loaded automatically by thelibrary under the control of a static configuration file, ts.conf.ts.conf gives the library basic configuration information.  Each linespecifies one module, and the parameters for that module.  The modulesare loaded in order, with the first one processing the touchscreen datafirst.  For example:  module_raw input  module variance delta=30  module dejitter delta=100  module linearThese parameters are described below.With this configuration file, we end up with the following data flowthrough the library:  raw read --> variance --> dejitter --> linear --> application  module       module       module       moduleYou can re-order these modules as you wish, add more modules, or remove themall together.  When you call ts_read(), the values you read are values thathave passed through the chain of filters and scaling conversions.  Anothercall is provided, ts_read_raw() which bypasses all the modules and reads theraw data directly from the device.There are a couple of programs in the tslib/test directory which give exampleusages.  They are by no means exhaustive, nor probably even good examples.They are basically the programs used to test this library.Environment Variables=====================TSLIB_TSDEVICE			TS device file name.				Default (non inputapi): /dev/touchscreen/ucb1x00				Default (inputapi): /dev/input/event0TSLIB_CALIBFILE			Calibration file.				Default: ${sysconfdir}/pointercalTSLIB_CONFFILE			Config file.				Default: ${sysconfdir}/ts.confTSLIB_PLUGINDIR			Plugin directory.				Default: ${datadir}/pluginsTSLIB_CONSOLEDEVICE		Console device.				Default: /dev/ttyTSLIB_FBDEVICE			Framebuffer device.				Default: /dev/fb0Module Creation Notes=====================For those creating tslib modules, it is important to note a couple things withregard to handling of the ability for a user to request more than one ts eventat a time.  The first thing to note is that the lower layers may send up lessevents than the user requested, because some events may be filtered out byintermediate layers. Next, your module should send up just as many eventsas the user requested in nr. If your module is one that consumes events,such as variance, then you loop on the read from the lower layers, and onlysend the events up when1) you have the number of events requested by the user, or2) one of the events from the lower layers was a pen release. Module Parameters=================module:	variance----------------Description:  Variance filter. Tries to do it's best in order to filter out random noise  coming from touchscreen ADC's. This is achieved by limiting the sample  movement speed to some value (e.g. the pen is not supposed to move quicker  than some threshold).  This is a 'greedy' filter, e.g. it gives less samples on output than  receives on input.Parameters:  delta	Set the squared distance in touchscreen units between previous and	current pen position (e.g. (X2-X1)^2 + (Y2-Y1)^2). This defines the	criteria for determining whenever two samples are 'near' or 'far'	to each other.	Now if the distance between previous and current sample is 'far',	the sample is marked as 'potential noise'. This doesn't mean yet	that it will be discarded; if the next reading will be close to it,	this will be considered just a regular 'quick motion' event, and it	will sneak to the next layer. Also, if the sample after the	'potential noise' is 'far' from both previously discussed samples,	this is also considered a 'quick motion' event and the sample sneaks	into the output stream.module: dejitter----------------Description:  Removes jitter on the X and Y co-ordinates. This is achieved by applying a  weighted smoothing filter. The latest samples have most weight; earlier  samples have less weight. This allows to achieve 1:1 input->output rate.Parameters:  delta	Squared distance between two samples ((X2-X1)^2 + (Y2-Y1)^2) that	defines the 'quick motion' threshold. If the pen moves quick, it	is not feasible to smooth pen motion, besides quick motion is not	precise anyway; so if quick motion is detected the module just	discards the backlog and simply copies input to output.module: linear--------------Description:  Linear scaling module, primerily used for conversion of touch screen  co-ordinates to screen co-ordinates.Parameters:  xyswap	interchange the X and Y co-ordinates -- no longer used or needed	if the new linear calibration utility ts_calibrate is used.