Table Of Contents
This class allows you to easily create new gestures and compare them:
from kivy.gesture import Gesture, GestureDatabase # Create a gesture g = Gesture() g.add_stroke(point_list=[(1,1), (3,4), (2,1)]) g.normalize() # Add it to the database gdb = GestureDatabase() gdb.add_gesture(g) # And for the next gesture, try to find it! g2 = Gesture() # ... gdb.find(g2)
You don’t really want to do this: it’s more of an example of how to construct gestures dynamically. Typically, you would need a lot more points, so it’s better to record gestures in a file and reload them to compare later. Look in the examples/gestures directory for an example of how to do that.
- class kivy.gesture.Gesture(tolerance=None)¶
A python implementation of a gesture recognition algorithm by Oleg Dopertchouk: http://www.gamedev.net/reference/articles/article2039.asp
Implemented by Jeiel Aranal (firstname.lastname@example.org), released into the public domain.
Adds a stroke to the gesture and returns the Stroke instance. Optional point_list argument is a list of the mouse points for the stroke.
Calculates the dot product of the gesture with another gesture.
Extract the rotation to apply to a group of points to minimize the distance to a second group of points. The two groups of points are assumed to be centered. This is a simple version that just picks an angle based on the first point of the gesture.
- get_score(comparison_gesture, rotation_invariant=True)¶
Returns the matching score of the gesture against another gesture.
Runs the gesture normalization algorithm and calculates the dot product with self.
- class kivy.gesture.GestureDatabase¶
Class to handle a gesture database.
Add a new gesture to the database.
- find(gesture, minscore=0.9, rotation_invariant=True)¶
Find a matching gesture in the database.
Convert a gesture into a unique string.
Convert a unique string to a gesture.
- class kivy.gesture.GestureStroke¶
Gestures can be made up of multiple strokes.
- add_point(x=x_pos, y=y_pos)¶
Adds a point to the stroke.
- center_stroke(offset_x, offset_y)¶
Centers the stroke by offseting the points.
Normalizes strokes so that every stroke has a standard number of points. Returns True if stroke is normalized, False if it can’t be normalized. sample_points controls the resolution of the stroke.
- points_distance(point1=GesturePoint, point2=GesturePoint)¶
Returns the distance between two GesturePoints.
Scales the stroke down by scale_factor.
Finds the length of the stroke. If a point list is given, finds the length of that list.