Pure Python gestures

[mikael]

Python gesture implementation on Github for those situations where you cannot or do not want to use the ObjC gestures.

Simple usage example:

import pygestures

class MyTouchableView(pygestures.GestureView):
  
  def on_swipe(self, data):
    if data.direction in (data.UP, data.DOWN):
      print('I was swiped vertically')

Run the file as-is to play around with the gestures. (Green circles track your touches, crosshairs show the centroid, red circle reflects pan, pinch and rotation.)

In your subclass, implement any or all the methods below to handle gestures. All methods get an information object with attributes including:

• state - one of BEGAN, CHANGED, ENDED
• location - location of the touch, or the centroid of all touches, as a scene.Point
• no_of_touches - use this if you want to filter for e.g. only taps with 2 fingers

Methods:

• on_tap
• on_long_press
• on_swipe - data includes direction, one of UP, DOWN, LEFT, RIGHT
• on_swipe_up, on_swipe_down, on_swipe_left, on_swipe_right
• on_pan - data includes translation, the distance from the start of the gesture, as a scene.Point. For most purposes this is better than location, as it does not jump around if you add more fingers.
• on_pinch - data includes scale
• on_rotate - data includes rotation in degrees, negative for counterclockwise rotation

There are also prev_translation, prev_scale and prev_rotation, if you need them.

If it is more convenient to you, you can inherit GestureMixin together with ui.View or some other custom view class. In that case, if you want to use e.g. rotate, you need to make sure you have set multitouch_enabled = True.

[cvp]

@stephen I can understand that. Due to my experience of (very) old guy using (very) old tools, I like to do all myself and I never have used Scene. I also prefer do animations my self in update method.
Good luck and have fun...

[mikael]

@stephen, the original request for ”pull to refresh” was covered earlier with one line of ”math”. What are you trying to achieve here? Spring force? Coulomb effect?

If you like scene and like to play with forces, you could look at SpriteKit - but that would not be ”rolling your own”.

[stephen]

@mikael its ok but yes i was trying to acheive a spring like constraint. but ill go ahead a put it to the side for now. thanks for the reply.

[Drizzel]

I‘m trying to double tap on a TableViewCell without actually selecting it, but it should still be selectable on a single tap. How would I go about doing this?

Let’s assume I have this code:

import ui
import gestures

def double_tap(data):
    print('double tapped row', data.view.row)
def tap(data):
    print('tapped', data.view.row)
def long_press(data):
    print('long pressed', data.view.row)

def tableview_cell_for_row(tableview, section, row):
    data = tableview.data_source.items[row]
    cell = ui.TableViewCell('subtitle')
    cell.text_label.text = data
    cell.row = row
    gestures.doubletap(cell, double_tap)
    #gestures.tap(cell, tap, number_of_touches_required = 1)
    #gestures.long_press(cell, long_press, minimum_press_duration = .2)
    
    return cell
    
class Delegate():
    def tableview_did_select(self, tableview, section, row):
        print('selected row', row)

tv = ui.TableView()
tv.delegate = Delegate()
tv.data_source = ui.ListDataSource([str(x) for x in range(5)])
tv.data_source.delete_enabled = False
tv.data_source.tableview_cell_for_row = tableview_cell_for_row
tv.frame = (tv.frame[0], tv.frame[1], 400, 400)

tv.present(style = 'sheet')

[stephen]

@Drizzel said:

I‘m trying to double tap on a TableViewCell without actually selecting it, but it should still be selectable on a single tap. How would I go about doing this?

Let’s assume I have this code:

import ui
import gestures

def double_tap(data):
  print('double tapped row', data.view.row)
def tap(data):
  print('tapped', data.view.row)
def long_press(data):
  print('long pressed', data.view.row)

def tableview_cell_for_row(tableview, section, row):
  data = tableview.data_source.items[row]
  cell = ui.TableViewCell('subtitle')
  cell.text_label.text = data
  cell.row = row
  gestures.doubletap(cell, double_tap)
  #gestures.tap(cell, tap, number_of_touches_required = 1)
  #gestures.long_press(cell, long_press, minimum_press_duration = .2)
  
  return cell
  
class Delegate():
  def tableview_did_select(self, tableview, section, row):
      print('selected row', row)

tv = ui.TableView()
tv.delegate = Delegate()
tv.data_source = ui.ListDataSource([str(x) for x in range(5)])
tv.data_source.delete_enabled = False
tv.data_source.tableview_cell_for_row = tableview_cell_for_row
tv.frame = (tv.frame[0], tv.frame[1], 400, 400)

tv.present(style = 'sheet')

i believe you might wand def tableview_cell_for_row(tableview, section, row): as a method of class Delegate instead of a global function.

[stephen]

@Drizzel
im sure there is a much simpler way but...

why not have a state checker give x time to look for a second tap before executing functionality for a single tap? possibly a decorator?

[mikael]

@Drizzel, below works to separate the two gestures, but we lose the visual feedback for the tap selection, you would need to implement that yourself.

Better would be to find the built-in tap and give our doubletap preference over it, but I could not (yet...?) find it on the tableview, cell, content view, or the label.

import ui
import gestures

def double_tap(data):
    print('double tapped row', data.view.row)
    
def tap(data):
    print('tapped', data.view.row)
    
def tableview_cell_for_row(tableview, section, row):
    data = tableview.data_source.items[row]
    cell = ui.TableViewCell('subtitle')
    cell.selectable = False
    cell.text_label.text = data
    cell.row = row
    doubler = gestures.doubletap(cell, double_tap)
    tapper = gestures.tap(cell, tap)
    doubler.before(tapper)
    return cell
    
class Delegate():
    def tableview_did_select(self, tableview, section, row):
        print('selected row', row)

tv = ui.TableView(allows_selection=False)
tv.delegate = Delegate()
tv.data_source = ui.ListDataSource([str(x) for x in range(5)])
tv.data_source.delete_enabled = False
tv.data_source.tableview_cell_for_row = tableview_cell_for_row

tv.present('fullscreen')

[Drizzel]

@mikael thanks, that works. I just change the cell‘s background color to lightgrey for visual feedback

[Drizzel]

@stephen True, I corrected it :) The code was a bit rushed 🤷‍♂️

[stephen]

awesome 😎🤓😊

[mikael]

@Drizzel, here’s a version that supports both the doubletap and regular row selection.

import ui
import gestures

def double_tap(data):
    print('double tapped row', data.view.row)
    
def tableview_cell_for_row(tableview, section, row):
    data = tableview.data_source.items[row]
    cell = ui.TableViewCell('subtitle')
    cell.text_label.text = data
    cell.row = row
    doubler = gestures.doubletap(cell, double_tap)
    doubler.recognizer.delaysTouchesBegan = True
    return cell
    
class Delegate():
    def tableview_did_select(self, tableview, section, row):
        print('selected row', row)

tv = ui.TableView()
tv.delegate = Delegate()
tv.data_source = ui.ListDataSource([str(x) for x in range(5)])
tv.data_source.delete_enabled = False
tv.data_source.tableview_cell_for_row = tableview_cell_for_row

tv.present('fullscreen')

[Anxietier]

hi, i found another bug, after i use 5 fingers to switch app and get back, multi-touch would be not working

[cvp]

@mikael Do you think it would be possible to use you gestures module on an objectiveC object?

I want to add gestures on a SceneView object, but functions like tap require their view parameter as an object having objc_instance property (see UIGestureRecognizerDelegate init).

[cvp]

@mikael I solved it with

    def scene_view_tap(self,sender):
        location = self.recognizer.locationInView_(self.scene_view)
        node = self.scene_view.hitTest_options_(location,None)
        print(node)

.
.
.
        self.gesture_recognizer_target = ui.Button()
        self.gesture_recognizer_target.action = self.scene_view_tap
        UITapGestureRecognizer = ObjCClass('UITapGestureRecognizer')
        self.recognizer = UITapGestureRecognizer.alloc().initWithTarget_action_(self.gesture_recognizer_target, sel('invokeAction:')).autorelease()
        scene_view.addGestureRecognizer_(self.recognizer)
        self.scene_view = scene_view

[mikael]

@cvp, forgot to advertise earlier that the latest version of gestures in the ui3 module accepts ObjC views in addition to ui module views.

from ui3.gestures import *

tap(objc_view, handler)

[cvp]

@mikael thanks, I'll try

Édit: done, ok
Re-Edit: marvelous module

[itibettravel]

This post is deleted!