Basics only. Qt import included in lib folder. this is a startup for all developers. work in progress

PR Checklist:

• [x] All new features have been tested
• [ ] All new features have been documented
• [x] I have read the CONTRIBUTING.md file
• [x] I will abide by the code of conduct

In #319 we discussed that it was desired to remove the callbacks created by using an on_draw handler, and instead push drawing commands to a stack to be drawn with.

PR Checklist:

• [X] All new features have been tested
• [X] All new features have been documented
• [X] I have read the CONTRIBUTING.md file
• [X] I will abide by the code of conduct

Current status: fully implemented

• [X] Fix tests
• [X] Further testing with other contexts besides the default one

Signed-off-by: Bruno Rino [email protected]

When creating a widget in a TestCase, the factory always needs to be specified, as in:

        self.switch = toga.Switch(self.text,
                                  on_change=self.on_change,
                                  value=self.value,
                                  enabled=self.enabled,
                                  factory=toga_dummy.factory)

My suggestion is to add dummy to the list of know platforms, and manually set the platform in the TestCase subclass. This would avoid the repetitive factory=toga_dummy.factory.

I tested this against a single widget, and the test passed as intended.

PR Checklist:

• [ ] All new features have been tested
• [ ] All new features have been documented
• [x] I have read the CONTRIBUTING.md file
• [x] I will abide by the code of conduct

In High Sierra (macOS 10.13), I am unable to use Toga or Toga-demo due to a TypeError. I was able to duplicate this on a fresh install of High Sierra in a VM; when I installed Toga and Toga-demo on a fresh install of Sierra (10.12), Toga and Toga-demo worked with no issues.

This has similar symptoms as issue https://github.com/pybee/toga/issues/154, but downgrading Rubicon has not solved the problem.

Details

Python Installation

$ uname -a
Darwin Andrews-Mac.local 17.0.0 Darwin Kernel Version 17.0.0: Thu Aug 24 21:48:19 PDT 2017; root:xnu-4570.1.46~2/RELEASE_X86_64 x86_64
$
$ gcc --version
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 9.0.0 (clang-900.0.37)
Target: x86_64-apple-darwin17.0.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
$
$ CFLAGS="-I$(brew --prefix openssl)/include -O3" \
LDFLAGS="-L$(brew --prefix openssl)/lib" \
env PYTHON_CONFIGURE_OPTS="--enable-framework" pyenv install -v 3.6.3
...
Installed Python-3.6.3 to /Users/ame/.pyenv/versions/3.6.3
$ 
$ pyenv shell 3.6.3
$
$ python -V -V
Python 3.6.3 (default, Oct  9 2017, 17:43:29) 
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.37)]

Virtualenv

$ python -m venv .venv
$
$ source .venv/bin/activate
$
$ pip install toga toga-demo
Collecting toga
  Downloading toga-0.2.15-py3-none-any.whl
Collecting toga-demo
  Downloading toga_demo-0.2.15-py3-none-any.whl
Collecting toga-cocoa; sys_platform == "darwin" (from toga)
  Downloading toga_cocoa-0.2.15-py3-none-any.whl
Collecting toga-core>=0.2.15 (from toga-cocoa; sys_platform == "darwin"->toga)
  Downloading toga_core-0.2.15-py3-none-any.whl (413kB)
    100% |████████████████████████████████| 419kB 2.6MB/s 
Collecting rubicon-objc>=0.2.8 (from toga-cocoa; sys_platform == "darwin"->toga)
  Downloading rubicon_objc-0.2.8-py3-none-any.whl
Collecting colosseum>=0.1.6 (from toga-core>=0.2.15->toga-cocoa; sys_platform == "darwin"->toga)
  Downloading colosseum-0.1.6-py3-none-any.whl
Installing collected packages: colosseum, toga-core, rubicon-objc, toga-cocoa, toga, toga-demo
Successfully installed colosseum-0.1.6 rubicon-objc-0.2.8 toga-0.2.15 toga-cocoa-0.2.15 toga-core-0.2.15 toga-demo-0.2.15

First Attempt

$ toga-demo
Traceback (most recent call last):
  File "/Users/ame/workspace/org.elgert/toga/.venv/bin/toga-demo", line 11, in <module>
    sys.exit(run())
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/__main__.py", line 5, in run
    main().main_loop()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 167, in main_loop
    self._startup()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 95, in _startup
    self._impl = NSApplication.sharedApplication()
TypeError: 'ObjCInstance' object is not callable
$ 
$ python
Python 3.6.3 (default, Oct  9 2017, 17:43:29) 
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.37)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from rubicon.objc import *                        
>>> NSBundle = ObjCClass('NSBundle')           
>>> NSBundle.mainBundle()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'ObjCInstance' object is not callable
>>> exit()

Downgrade Rubicon

Rubicon-objc==0.2.7

$ pip install rubicon-objc==0.2.7
Collecting rubicon-objc==0.2.7
  Downloading rubicon_objc-0.2.7-py3-none-any.whl
Installing collected packages: rubicon-objc
  Found existing installation: rubicon-objc 0.2.8
    Uninstalling rubicon-objc-0.2.8:
      Successfully uninstalled rubicon-objc-0.2.8
Successfully installed rubicon-objc-0.2.7
$
$ toga-demo
Traceback (most recent call last):
  File "/Users/ame/workspace/org.elgert/toga/.venv/bin/toga-demo", line 11, in <module>
    sys.exit(run())
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/__main__.py", line 5, in run
    main().main_loop()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 167, in main_loop
    self._startup()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 95, in _startup
    self._impl = NSApplication.sharedApplication()
TypeError: 'ObjCInstance' object is not callable

Rubicon-objc==0.2.6

$ pip install rubicon-objc==0.2.6
Collecting rubicon-objc==0.2.6
  Downloading rubicon_objc-0.2.6-py3-none-any.whl
Installing collected packages: rubicon-objc
  Found existing installation: rubicon-objc 0.2.7
    Uninstalling rubicon-objc-0.2.7:
      Successfully uninstalled rubicon-objc-0.2.7
Successfully installed rubicon-objc-0.2.6
$
$ toga-demo
Traceback (most recent call last):
  File "/Users/ame/workspace/org.elgert/toga/.venv/bin/toga-demo", line 7, in <module>
    from toga_demo.__main__ import run
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/__main__.py", line 2, in <module>
    from toga_demo.app import main
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/app.py", line 4, in <module>
    import toga
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga/__init__.py", line 114, in <module>
    set_platform()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga/__init__.py", line 86, in set_platform
    local_vars['platform'] = importlib.import_module(module_name)
  File "/Users/ame/.pyenv/versions/3.6.3/Python.framework/Versions/3.6/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/__init__.py", line 2, in <module>
    from .app import *
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 8, in <module>
    from .command import Command, Group
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/command.py", line 3, in <module>
    from .widgets.icon import Icon
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/widgets/icon.py", line 4, in <module>
    from ..libs import NSImage
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/libs/__init__.py", line 1, in <module>
    from .appkit import *
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/libs/appkit.py", line 232, in <module>
    NSColor.declare_class_property('alternateSelectedControlColor')
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/rubicon/objc/objc.py", line 1300, in __getattr__
    raise AttributeError('%s.%s %s has no attribute %s' % (type(self).__module__, type(self).__qualname__, self.objc_class.name, name))
AttributeError: rubicon.objc.objc.ObjCClass NSColor has no attribute declare_class_property

Rubicon-objc==0.2.4

$ pip install rubicon-objc==0.2.4
Collecting rubicon-objc==0.2.4
  Downloading rubicon_objc-0.2.4-py3-none-any.whl
Installing collected packages: rubicon-objc
  Found existing installation: rubicon-objc 0.2.6
    Uninstalling rubicon-objc-0.2.6:
      Successfully uninstalled rubicon-objc-0.2.6
Successfully installed rubicon-objc-0.2.4
$
$ toga-demo
Traceback (most recent call last):
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/rubicon/objc/objc.py", line 1274, in __getattr__
    return self.__dict__[name]
KeyError: 'declare_class_property'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/ame/workspace/org.elgert/toga/.venv/bin/toga-demo", line 7, in <module>
    from toga_demo.__main__ import run
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/__main__.py", line 2, in <module>
    from toga_demo.app import main
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_demo/app.py", line 4, in <module>
    import toga
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga/__init__.py", line 114, in <module>
    set_platform()
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga/__init__.py", line 86, in set_platform
    local_vars['platform'] = importlib.import_module(module_name)
  File "/Users/ame/.pyenv/versions/3.6.3/Python.framework/Versions/3.6/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/__init__.py", line 2, in <module>
    from .app import *
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/app.py", line 8, in <module>
    from .command import Command, Group
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/command.py", line 3, in <module>
    from .widgets.icon import Icon
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/widgets/icon.py", line 4, in <module>
    from ..libs import NSImage
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/libs/__init__.py", line 1, in <module>
    from .appkit import *
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/toga_cocoa/libs/appkit.py", line 232, in <module>
    NSColor.declare_class_property('alternateSelectedControlColor')
  File "/Users/ame/workspace/org.elgert/toga/.venv/lib/python3.6/site-packages/rubicon/objc/objc.py", line 1277, in __getattr__
    raise AttributeError('ObjCClass %s has no attribute %s' % (self.name, name))
AttributeError: ObjCClass NSColor has no attribute declare_class_property

But only if the menubar wasn't defined in the application code. Here's a slightly modified example code I'm running:

import toga

def build(app):
    box = toga.Box()
    button = toga.Button('Hello world', on_press=lambda _: print("hello"))
    box.add(button)
    return box

if __name__ == '__main__':
    app = toga.App('First App', 'org.pybee.sample', startup=build)
    app.main_loop()

Here's how it looks like to me:

Note that the button is behind the menubar (although no menubar was requested in the code). When I click on the menubar (including the Application or Help menu items), the button is being pressed instead.

I've tried this with a few GTK themes, including Arc-OSX-dark, Mint-X, Redmond and Adwaita, and in every case it behaves this way.

When I try running the tutorials from the master branch on Ubuntu I get the following error: from toga.style.pack import * ImportError: No module named 'toga.style'

It is perfectly valid Python to define either a full or partial GUI widget hierarchy in the following way.

    self.content = Box(
        style=Pack(flex=1, direction=COLUMN),
        children=[
            TextInput(
                id='node_name_input',
                placeholder='Enter topic name'
            ),
            Box(
                style=Pack(flex=1),
                children=[
                    Button(
                        'Ok',
                        on_press=self.on_accept
                    ),
                    Button(
                        'Cancel',
                        on_press=self.on_close
                    )
                ]
            )
        ]
    )

In this example I subsequently want to get the value of the TextInput box when the 'Ok' button is clicked but because of the way it has been declared I have no immediate reference to it. It would be useful to have a method in the base Window class that mimics the HTML DOM getElementById() that returns a reference to the widget given its 'id'.

Moved the icons file resolution to the backend for cocoa and winforms.

Now, backends can get their proprietary file format ('.icns' for cocoa and '.ico') or create icons from '.bmp' or '.png' files. (Although I didn't find a bmp icon file, so I only tested ico and png on winforms.) I also adjusted tests because now core/icon doesn't automatically add '.icns' to the icon filename.

If this is acceptable, we will need to test and update other backends, too.

There is an issue about lack of icons in windows in briefcase.

PR Checklist:

• [ ] All new features have been tested
• [x] All new features have been documented
• [x] I have read the CONTRIBUTING.md file
• [x] I will abide by the code of conduct

Recently, pygobject can be installed from pip. So this PR recommends the user to install pygobject through pip.

It also deletes redundant code that handles different operating systems which was sometimes found to be incorrect.

Fixes https://github.com/pybee/toga/issues/371

I am really not sure if I missed any sensitive branches that just needed to be there, I will need some help on that.

PR Checklist:

• [x] All new features have been tested
• [x] All new features have been documented
• [x] I have read the CONTRIBUTING.md file
• [x] I will abide by the code of conduct

In order to learn some of the internals of toga I've been working at trying to get the winforms backend working for tutorial 2. This involves implementing some new components for the winforms backend:

• SplitContainer (partially done)
• Table (done)
• Command (not started)

Bug Description

In my application I'm using a single toga.Window and switch its content multiple times instead of opening new windows. In my main box box1 I have button that replace the content of the window with box2, and in box2 I have a "back" button that replace the content of the window back to box1.

When I'm clicking the button that move from box1 to box2 everything is fine. When I try to got back to to box1 using the "back" button I get a RuntimeError that "Already have a container".

This is a bug.

How I fixed it

When setting the container of a widget in windows, first if the widget already has a container, setting it to None and removing it from Controls. After that, if the new container is not None, setting it.

This way we can remove boxes from the window and move them back freely.

PR Checklist:

• [X] All new features have been tested
• [X] All new features have been documented
• [X] I have read the CONTRIBUTING.md file
• [X] I will abide by the code of conduct

Describe the bug

On Windows, when a selection widget is created with a list containing an empty string (eg: toga.Selection(items=['1','a','','4']) ), the widget returns '' for the "value" attribute.

On Android, the selection's "value" attribute is set to None if the selection item is an empty string.

I don't have MacOS, iOS, or Linux devices so I don't know what happens there.

Steps to reproduce

0. Create Beeware Project
1. Go to the app.py file
2. Create a list "list_1" containing an empty string
3. Create the base app class with the startup function and setup main box + window
4. In the startup function, create a selection with the items being that of list_1. Store it as a class attribute for future access.
5. Define a class function that outputs the selection value via print or info_dialog.
6. Create Button to call the output function
7. Add Selector & Button to main box
8. Compile the code for both Windows and Android & launch them.
9. Select the empty item of the selector
10. Press the button
11. Watch as the devices disagree on the value.

Expected behavior

I would expect the selector value attribute to be an empty string as that was what the item was, and that is what the selector widget understands when values are written to it.

Screenshots

The source code I used:

"""
Testing Crashes
"""
import toga
class TestLab(toga.App):
    def startup(self):
        main_box=toga.Box()
        self.select=toga.Selection(items=['A','B','0','','1','+','-'])
        main_box.add(self.select)
        main_box.add(toga.Button('Get',on_press=self.valuedump))
        self.main_window=toga.MainWindow(title=self.formal_name)
        self.main_window.content=main_box
        self.main_window.show()
    async def valuedump(self,widget):
        q=self.select.value
        print('GET',q,type(q))
        self.main_window.info_dialog('Selection Value',f'Value: "{q}"\n Type: {type(q)}')
def main():return TestLab()

On Windows:

On Android:

Environment

Windows 8.1 / Android 11

• Python version: 3.10.0
  • Briefcase: 3.11
  • Toga: 0.3.0.dev8

Logs

Windows: briefcase.2022_12_27-17_09_47.run.log

Android: briefcase.2022_12_27-17_17_14.run.log

Additional context

No response

Describe the bug

(.venv) paul@desktop:~/st/toga$  cd /home/paul/st/toga ; /usr/bin/env /home/paul/st/toga/.venv/bin/python /home/paul/.vscode/extensions/ms-python.python-2022.20.1/pythonFiles/lib/python/debugpy/adapter/../../debugpy/launcher 34737 -- /home/paul/st/toga/print.py 
/home/paul/st/toga/.venv/lib/python3.11/site-packages/toga_gtk/app.py:65: DeprecationWarning: There is no current event loop
  self.loop = asyncio.get_event_loop_policy().get_event_loop()
/home/paul/st/toga/.venv/lib/python3.11/site-packages/toga_gtk/app.py:40: DeprecationWarning: Gtk.Window.set_wmclass is deprecated
  self.native.set_wmclass(app.interface.name, app.interface.name)
WARNING: Can't find icon resources/toga; falling back to default icon
hello

Steps to reproduce

1. Install the prerequisites and Toga in venv.
2. Run the script from https://toga.readthedocs.io/en/latest/tutorial/tutorial-0.html.
3. Click on Help->About First App

import toga


def button_handler(widget):
    print("hello")


def build(app):
    box = toga.Box()

    button = toga.Button("Hello world", on_press=button_handler)
    button.style.padding = 50
    button.style.flex = 1
    box.add(button)

    return box


def main():
    return toga.App("First App", "org.beeware.helloworld", startup=build)


if __name__ == "__main__":
    main().main_loop()

Expected behavior

No warnings?

Screenshots

No response

Environment

• Operating System: Ubuntu 22.04.1
• Python version: 3.11.1
• Software versions:
  • Briefcase:
  • Toga: 0.3.0.dev39
  • ...

Logs

Additional context

No response

What is the problem or limitation you are having?

I would like to make an app, which plays sound effects on button press the only solution i could find was this.

Describe the solution you'd like

a sound playing api, with support for mp3 or wav

Describe alternatives you've considered

https://stackoverflow.com/questions/74120614/how-to-play-sound-in-an-android-app-created-by-beeware-using-python

Additional context

No response

Describe the bug

This appeared in #1687 when xvfb-run was missing from the Toga testbed CI command. I can also reproduce it locally.

Steps to reproduce

Unset the DISPLAY environment variable, then try to run the app:

$ briefcase dev

[testbed] Starting in dev mode...
===========================================================================
Unable to init server: Could not connect: Connection refused
Unable to init server: Could not connect: Connection refused

(__main__.py:20685): Gtk-CRITICAL **: 08:59:26.455: _gtk_style_provider_private_get_settings: assertion 'GTK_IS_STYLE_PROVIDER_PRIVATE (provider)' failed

(__main__.py:20685): Gtk-CRITICAL **: 08:59:26.460: _gtk_style_provider_private_get_settings: assertion 'GTK_IS_STYLE_PROVIDER_PRIVATE (provider)' failed

(__main__.py:20685): Gtk-CRITICAL **: 08:59:26.460: _gtk_style_provider_private_get_settings: assertion 'GTK_IS_STYLE_PROVIDER_PRIVATE (provider)' failed
Fatal Python error: Segmentation fault

Current thread 0x00007ff9f3404740 (most recent call first):
  File "/home/smith/git/beeware/toga/gtk/src/toga_gtk/icons.py", line 14 in __init__
  File "/home/smith/git/beeware/toga/core/src/toga/icons.py", line 77 in __init__
  File "/home/smith/git/beeware/toga/core/src/toga/app.py", line 455 in icon
  File "/home/smith/git/beeware/toga/core/src/toga/app.py", line 330 in __init__
  File "/home/smith/git/beeware/toga/testbed/src/testbed/app.py", line 27 in main
  File "/home/smith/git/beeware/toga/testbed/src/testbed/__main__.py", line 4 in <module>
  File "/home/smith/.pyenv/versions/3.8.12/lib/python3.8/runpy.py", line 87 in _run_code
  File "/home/smith/.pyenv/versions/3.8.12/lib/python3.8/runpy.py", line 97 in _run_module_code
  File "/home/smith/.pyenv/versions/3.8.12/lib/python3.8/runpy.py", line 207 in run_module
  File "<string>", line 1 in <module>

Problem running application 'testbed'

AppImage is much worse because it doesn't give any hint of what the cause of the crash is:

$ briefcase run

[testbed] Starting app...
===========================================================================
/tmp/.mount_Toga_TpKBh1e/AppRun.wrapped: line 11: 22376 Segmentation fault      "${APPDIR}/usr/bin/python3" -u -s -X utf8 -c "import runpy, sys; sys.path.pop(0); runpy.run_module('${BRIEFCASE_MAIN_MODULE}', run_name='__main__', alter_sys=True)" "$@"

Problem running app testbed.

Expected behavior

When unable to connect to the display, both run and dev should give an actionable error message, not a segfault, and ideally not a Python traceback either.

Screenshots

No response

Environment

• Operating System: Debian 10
• Python version: 3.8
• Software versions:
  • Briefcase: 0.3.11
  • Toga: 0.3.0dev39

Logs

No response

Additional context

No response

Describe the bug

On macOS, Toga apps don't respond to Cmd-W for close or Cmd-M for minimize. They only respond to Cmd-Q for quit.

I also notice the app doesn’t have a Window menu, which is where those commands would normally appear.

Steps to reproduce

• On macOS, run briefcase dev in any app.
• When the window appears, press Cmd-W or Cmd-M.
• Computer gives an error sound, and nothing happens.

Expected behavior

Toga should support all standard window management commands on each OS.

Screenshots

Environment

• Operating System: macOS 12.6
• Python version: 3.11
• Software versions:
  • Briefcase: 0.3.11
  • Toga: 0.3.0dev39

Logs

No response

Additional context

No response

What is the problem or limitation you are having?

The current implementation of event handlers on toga.Canvas has some interesting quirks.

1. It allows for a "double click drag"... and I'm not even sure what that would mean.
2. It is closely bound to a mouse-driven implementation (in particular, it references alt and double click)

Describe the solution you'd like

It might make more sense to drop the clicks argument to the event handlers, and have separate events for:

• on_press and on_alt_press
• on_activate (i.e., double click) and on_alt_activate
• on_drag
• on_release and on_alt_release

That would make events a lot closer to their "functional" purpose, rather than tying them to a specific implementation (e.g. - what is a double click on a touchscreen?) It would de-emphasize the importance of clicks, especially in the context of drag; and it would put the focus on press/activate, rather than release events.

The general advice would be to avoid using "alt" press (or, at least, provide different ways of accessing that functionality); this is consistent with the sort of approach taken by the macOS style guide, which allows for "right click" actions, but encourages that to be an interface for "power users".

This would simplify the winforms and GTK implementations (which currently need to do imml-level stateful tracking of the current click state), and makes the API for mobile canvas less of a band-aid (as we can use long-press or force-press events for "activate").

Describe alternatives you've considered

Do nothing. The current API works; it's just not ideal.

Additional context

No response