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Source code for kivy.input.postproc.calibration

'''
Calibration
===========

.. versionadded:: 1.9.0

Recalibrate input device to a specific range / offset.

Let's say you have 3 1080p displays, the 2 firsts are multitouch. By default,
both will have mixed touch, the range will conflict with each others: the 0-1
range will goes to 0-5760 px (remember, 3 * 1920 = 5760.)

To fix it, you need to manually reference them. For example::

    [input]
    left = mtdev,/dev/input/event17
    middle = mtdev,/dev/input/event15
    # the right screen is just a display.

Then, you can use the calibration postproc module::

    [postproc:calibration]
    left = xratio=0.3333
    middle = xratio=0.3333,xoffset=0.3333

Now, the touches from the left screen will be within 0-0.3333 range, and the
touches from the middle screen will be within 0.3333-0.6666 range.

'''

__all__ = ('InputPostprocCalibration', )

from kivy.config import Config
from kivy.logger import Logger


[docs]class InputPostprocCalibration(object): '''Recalibrate the inputs. The configuration must go within a section named `postproc:calibration`. Within the section, you must have line like:: devicename = param=value,param=value :Parameters: `xratio`: float Value to multiply X `yratio`: float Value to multiply Y `xoffset`: float Value to add to X `yoffset`: float Value to add to Y ''' def __init__(self): super(InputPostprocCalibration, self).__init__() self.devices = {} self.frame = 0 if not Config.has_section('postproc:calibration'): return default_params = {'xoffset': 0, 'yoffset': 0, 'xratio': 1, 'yratio': 1} for device_key, params_str in Config.items('postproc:calibration'): params = default_params.copy() for param in params_str.split(','): param = param.strip() if not param: continue key, value = param.split('=', 1) if key not in ('xoffset', 'yoffset', 'xratio', 'yratio'): Logger.error( 'Calibration: invalid key provided: {}'.format(key)) params[key] = float(value) self.devices[device_key] = params def process(self, events): # avoid doing any processing if there is no device to calibrate at all. if not self.devices: return events self.frame += 1 frame = self.frame for etype, event in events: # frame-based logic below doesn't account for # end events having been already processed if etype == 'end': continue if event.device not in self.devices: continue # some providers use the same event to update and end if 'calibration:frame' not in event.ud: event.ud['calibration:frame'] = frame elif event.ud['calibration:frame'] == frame: continue params = self.devices[event.device] event.sx = event.sx * params['xratio'] + params['xoffset'] event.sy = event.sy * params['yratio'] + params['yoffset'] event.ud['calibration:frame'] = frame return events