asciimatics_button_bug_demo.py

asciimatics_button_bug_demo.py

#!/usr/bin/env python3

## This simple application demonstrates a bug in
## the mouse-click handling for buttons, in asciimatics:
## mouse-clicks on the right side of buttons, fail to register.
## It seems especially evident in buttons with short label strings.


## Dependency:
##     pip install asciimatics

##  Loosely based on the quick_model.py example script.
##  See also the similar contact_list.py example script (which uses sqlite).
##  asciimatics toolkit tutorial:
##  https://asciimatics.readthedocs.io/en/stable/widgets.html


from asciimatics.widgets import Frame, ListBox, Layout, Divider, Text, \
    Button, TextBox, Widget
from asciimatics.scene import Scene
from asciimatics.screen import Screen
from asciimatics.exceptions import ResizeScreenError, NextScene, StopApplication
from asciimatics.event import KeyboardEvent

import sys

## We don't use a proper model, just a placeholder
class DemoModel(object):
      def __init__(self):
          pass


class DemoView(Frame):
    def __init__(self, screen, model):
        super(DemoView, self).__init__(screen,
                                          screen.height * 2 // 3,
                                          screen.width * 2 // 3,
                                          hover_focus=True,
                                          can_scroll=False,
                                          title="Demo Application")
#                                         reduce_cpu=True)
        self._model = model ## Placeholder model object

        ## Create the form
        layout = Layout([100], fill_frame=True) # single column occupying 100% of available width
        self.add_layout(layout)
        layout.add_widget(Button("Overwrite text in text box (1)", self._button1_clicked))
        layout.add_widget(Button("Overwrite text in text box (2)", self._button2_clicked))

        ## Clicking on the right side of this button doesn't work
        layout.add_widget(Button("Short one", self._shortButton_clicked))

        layout.add_widget(Button("Overwrite text in text box (3)", self._button3_clicked))
        layout.add_widget(Button("Overwrite text in text box (4)", self._button4_clicked))

        layout.add_widget(Button("Click here to exit", self._quit))

        self.text_widget = Text(label="Status", name="status_text", readonly=True)
        self.text_widget.value = "[ Ready ]"
        layout.add_widget(self.text_widget)

        self.fix()


    def _button1_clicked(self):
        self.text_widget.value = "BUTTON 1 CLICKED"
        return

    def _button2_clicked(self):
        self.text_widget.value = "BUTTON 2 CLICKED"
        return

    def _shortButton_clicked(self):
        self.text_widget.value = "SHORT BUTTON CLICKED"
        return

    def _button3_clicked(self):
        self.text_widget.value = "BUTTON 3 CLICKED"
        return

    def _button4_clicked(self):
        self.text_widget.value = "BUTTON 4 CLICKED"
        return


    @staticmethod
    def _quit():
        exit(0)
#       raise StopApplication("User pressed quit")


    def process_event(self, event):
        # Allow standard event processing first
        if super(DemoView, self).process_event(event) is None:
            return

        # If that didn't handle it, check for a key that this demo understands.
        if isinstance(event, KeyboardEvent):
            c = event.key_code
            if c in (ord("q"), ord("Q")):
                raise StopApplication("User exit")
            else:
                # Not a recognised key - pass on to other handlers.
                return event
        else:
            # Ignore other types of events.
            return event


the_model = DemoModel()

def demo(screen, scene):
    scenes = [
        Scene([DemoView(screen, the_model)], -1, name="Demo")
    ]

    screen.play(scenes, stop_on_resize=True, start_scene=scene, allow_int=True)


last_scene = None
while True:
    try:
        Screen.wrapper(demo, catch_interrupt=True, arguments=[last_scene])
        sys.exit(0)
    except ResizeScreenError as e:
        last_scene = e.scene