calibration: add new calibration module, to recalibrate input depending of a device name.

kivy/input/postproc/__init__.py

@@ -12,12 +12,14 @@ from kivy.input.postproc.tripletap import InputPostprocTripleTap
 from kivy.input.postproc.ignorelist import InputPostprocIgnoreList
 from kivy.input.postproc.retaintouch import InputPostprocRetainTouch
 from kivy.input.postproc.dejitter import InputPostprocDejitter
+from kivy.input.postproc.calibration import InputPostprocCalibration
 
 # Mapping of ID to module
 kivy_postproc_modules = {}
 
 # Don't go further if we generate documentation
 if 'KIVY_DOC' not in os.environ:
+    kivy_postproc_modules['calibration'] = InputPostprocCalibration()
     kivy_postproc_modules['retaintouch'] = InputPostprocRetainTouch()
     kivy_postproc_modules['ignorelist'] = InputPostprocIgnoreList()
     kivy_postproc_modules['doubletap'] = InputPostprocDoubleTap()

kivy/input/postproc/calibration.py

@@ -0,0 +1,84 @@
+'''
+Calibration
+===========
+
+.. versionadded:: 1.8.1
+
+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
+
+
+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 = {}
+        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):
+        for etype, event in events:
+            if event.device not in self.devices:
+                continue
+            params = self.devices[event.device]
+            event.sx = event.sx * params['xratio'] + params['xoffset']
+            event.sy = event.sy * params['yratio'] + params['yoffset']
+        return events
+