initial python app version

README.md

@@ -94,6 +94,9 @@ which use the device may be confused by that and could crash.
 
 `networktablet` will display a status line for every touch/motion event it receives.
 
+Addendum:
+
+The `python-app` directory contains an optional program implementing a workaround for the common problem of `networktablet` executing and connecting and receiving input events but GIMP being unable to see a device named "Network Tablet". You may need to install the dependencies with `pip3 install -r requirements.txt`
 
 Part 2: App
 -----------

python-app/main.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+import subprocess
+import pyautogui
+from collections import defaultdict
+
+
+INTMAX = 65536
+WIDTH, HEIGHT = pyautogui.size()
+ASPECT_RATIOS = defaultdict(lambda: (16, 9))
+default_ratios = [
+    ("Galaxy Note 4", (16, 9)),
+]
+
+
+class Event:
+
+    def __str__(self):
+        return "{}({})".format(
+            self.__class__.__name__,
+            ', '.join(
+                ["{}={}".format(k, v) for k, v in self.__dict__.items()]))
+
+
+class PositionEvent(Event):
+    """Model of position events."""
+
+    def __init__(self, x, y, pressure):
+        super().__init__()
+        self.x = x
+        self.y = y
+        self.pressure = pressure
+
+
+class ButtonEvent(Event):
+    """Model of button events."""
+
+    def __init__(self, button_id, button_status):
+        super().__init__()
+        self.id = button_id
+        self.status = button_status
+
+
+class PositionManager:
+    """Model for handling relative vs. absolute movement and track button states."""
+
+    def __init__(self, device, aspect_ratio=None):
+        if aspect_ratio is None:
+            try:
+                r = ASPECT_RATIOS[device]
+                self.xscale = r[0] / r[1]
+            except KeyError:
+                raise ValueError("Sorry, that is an unsupported device.")
+        self.last_pos_event = None
+        self._deltas = [0, 0]
+        # only track movement delta when btn id -1 state is 1
+        self.button_states = defaultdict(lambda: 0)
+
+    def consume(self, event):
+        if isinstance(event, PositionEvent):
+            if self.last_pos_event is not None:
+                # skip non-relative movement events
+                if self.button_states.get(-1, None) == 1:
+                    self._deltas[0] = (
+                        event.x - self.last_pos_event.x) * self.xscale * HEIGHT / INTMAX
+                    self._deltas[1] = (
+                        event.y - self.last_pos_event.y) * HEIGHT / INTMAX
+            self.last_pos_event = event
+        elif isinstance(event, ButtonEvent):
+            self.button_states[event.id] = event.status
+        return tuple(self._deltas)
+
+    @property
+    def deltas(self):
+        return tuple(self._deltas)
+
+
+def process_line(l):
+    if l.startswith("."):
+        return PositionEvent(*[int(i.split(":")[1].strip()) for i in l.split(",")])
+    elif l.startswith("sent button"):
+        ss = l.split(":")[1].strip()
+        return ButtonEvent(*[int(i.strip()) for i in ss.split(",")])
+    else:
+        raise ValueError("Invalid command string: {}".format(l))
+
+
+def main():
+    # necessary to prevent pyautogui calls from causing unnecessary delays
+    pyautogui.PAUSE = 0
+    cmd = ["../driver-uinput/networktablet"]
+    try:
+        p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    except FileNotFoundError:
+        print("ERROR: Did you build the binary?")
+        quit()
+
+    movement_manager = PositionManager("Galaxy Note 4")
+    while True:
+        line = p.stdout.readline().decode("utf-8")
+        if not line:
+            break
+        try:
+            e = process_line(line)
+            print(e)
+            movement_manager.consume(e)
+            dx, dy = movement_manager.deltas
+            pyautogui.moveRel(dx, dy, 0)
+
+            if movement_manager.button_states.get(0, None) == 1:
+                pyautogui.mouseDown(button="left")
+            else:
+                pyautogui.mouseUp(button="left")
+        except ValueError:
+            pass
+
+
+if __name__ == '__main__':
+    main()

python-app/requirements.txt

@@ -0,0 +1 @@
+pyautogui