Application views do not refresh when the cursor is moved.

[kacperpikacz]

Describe the bug
Application views do not refresh when the cursor is moved. Affected versions are all above 1.9.0

Screenshots

To Reproduce

using Terminal.Gui;

namespace Test
{
    public class Program
    {
        static readonly List<string> GlobalList = new() { "1" };
        static readonly ListView GlobalListView = new() { Width = Dim.Fill(), Height = Dim.Fill() };
        static object? _token = null;

        static void Main()
        {

            Application.Init();

            var startButton = new Button("Start");
            var stopButton = new Button("Stop") { Y = 1 };
            var container = new View() { X = Pos.Center(), Y = Pos.Center(), Width = 8, Height = 8, ColorScheme = Colors.Error };
            
            startButton.Clicked += Start;
            stopButton.Clicked += Stop;

            GlobalListView.SetSource(GlobalList);
            container.Add(GlobalListView);

            Application.Top.Add(container);
            Application.Top.Add(startButton, stopButton);
            Application.Run();

            return;
        }

        private static void Start()
        {
            _token = Application.MainLoop.AddTimeout(TimeSpan.FromMilliseconds(100), Add);
        }

        private static void Stop()
        {
            Application.MainLoop.RemoveTimeout(_token);
        }

        private static bool Add(MainLoop mainLoop)
        {
            GlobalList.Add(new Random().Next(100).ToString());
            GlobalListView.MoveDown();
            
            return true;
        }
    }
}

Expected behavior
Application views should refresh

Desktop
MacOS Ventura

[BDisp]

I tested it on macOS Big Sur hosted on Windows 11 with VirtualBox and it's working well. Unfortunately it isn't possible install macOS Ventura on a Windows 11 with VirtualBox and so I can't test it.

[kacperpikacz]

Anyone else with Mac?

[BDisp]

@kacperpikacz can you run your code with the PR #2848, please. I think it is unrelated because is an issue that affect the SynchronizationContext but worth to try.

[kacperpikacz]

@BDisp nothing changed after running code with #2848

[BDisp]

I already suspect that. The fix was for threading issue. I hope someone else with macOS Ventura can confirm that, because with Big Sur the timer is always refreshing the screen.

[TylerReid]

@BDisp I am on Ventura, and after applying your changes the UICatalog threading example works now. Before I had to move my mouse or do other inputs in order to get the async tasks to start, but now it works as expected.

[BDisp]

@BDisp I am on Ventura, and after applying your changes the UICatalog threading example works now. Before I had to move my mouse or do other inputs in order to get the async tasks to start, but now it works as expected.

Thanks for your answer, although this should be witted on the #306.
In this issue I ask, as you are on Ventura, if you can run the example code above and confirm if you have the same behavior as @kacperpikacz meant on this issue, please.

[TylerReid]

@BDisp Ah, I misunderstood. Your change did not fix this issue:

Screen.Recording.2023-09-21.at.12.48.30.PM.mov

[BDisp]

@TylerReid thanks very much. My fix was only for the threading issue and this one is different. It doesn't use no thread at all and if we continuously move the mouse, the console isn't refreshed. I don't have a mac, but only Big Sur installed on Oracle VM VirtualBox and this behavior doesn't happens. Due this limitation I can't find what is causing this behavior on Ventura. I already tried to install it on VirtualBox without success. It seems that now isn't possible to install it on a non-mac machine.

[BDisp]

@kacperpikacz and @TylerReid please run the Mouse scenario of the UICatalog and see the output for the mouse move event. Perhaps it's returning some other event. Thanks.

[TylerReid]

@BDisp I see a steady stream of ReportMousePosition events getting reported when I move in the same way.

[BDisp]

@BDisp I see a steady stream of ReportMousePosition events getting reported when I move in the same way.

And when the mouse is continuously moved do the report still refreshing or not?

[TylerReid]

Yes, the report list refreshes with no pauses

[kacperpikacz]

The problem is laying somewhere inside ProcessInput method from CursesDriver. In 1.9 there was no GetEscSeq method. Also when moving cursor slowly the problem is not present.

Commenting Curses.timeout (10) in ProcessInput will help but will not solve the problem completely.

Maybe #2375

v1.14

terminal.mov

v1.9

terminal.2.mov

using Terminal.Gui;

namespace Test
{
    public class Program
    {
        static readonly List<string> GlobalList = new() { "1" };
        static readonly ListView GlobalListView = new() { Width = Dim.Fill(), Height = Dim.Fill() };

        static Label CounterLabel = new();
        static Label BlinkingLabel = new();

        static int Counter = 0;

        static object? _listToken = null;
        static object? _blinkToken = null;
        static object? _countToken = null;

        static void Main()
        {
            Application.Init();

            var startButton = new Button("Start");
            var stopButton = new Button("Stop") { Y = 1 };
            var container = new View() { X = Pos.Center(), Y = Pos.Center(), Width = 8, Height = 8, ColorScheme = Colors.Error };

            CounterLabel = new Label("0") { X = container.X - 4, Y = container.Y - 6};
            BlinkingLabel = new Label("Blink") { X = CounterLabel.X, Y = CounterLabel.Y + 11 };

            startButton.Clicked += Start;
            stopButton.Clicked += Stop;

            GlobalListView.SetSource(GlobalList);
            container.Add(GlobalListView);

            Application.Top.Add(container, CounterLabel, BlinkingLabel);
            Application.Top.Add(startButton, stopButton);
            Application.Run();

            return;
        }

        private static void Start()
        {
            _listToken = Application.MainLoop.AddTimeout(TimeSpan.FromMilliseconds(100), Add);
            _blinkToken = Application.MainLoop.AddTimeout(TimeSpan.FromMilliseconds(1000), Blink);
            _countToken = Application.MainLoop.AddTimeout(TimeSpan.FromMilliseconds(1000), Count);
        }

        private static void Stop()
        {
            Application.MainLoop.RemoveTimeout(_listToken);
            Application.MainLoop.RemoveTimeout(_blinkToken);
            Application.MainLoop.RemoveTimeout(_countToken);
        }

        private static bool Add(MainLoop mainLoop)
        {
            GlobalList.Add(new Random().Next(100).ToString());
            GlobalListView.MoveDown();
            
            return true;
        }

        private static bool Blink(MainLoop mainLoop)
        {
            Application.MainLoop.Invoke(() =>
            {
                if (BlinkingLabel.Visible)
                {
                    BlinkingLabel.Visible = false;
                    System.Diagnostics.Debug.WriteLine(BlinkingLabel.Visible);
                }
                else
                {
                    BlinkingLabel.Visible = true;
                    System.Diagnostics.Debug.WriteLine(BlinkingLabel.Visible);
                }
                
            });

            return true;
        }

        private static bool Count(MainLoop mainLoop)
        {
            Application.MainLoop.Invoke(() =>
            {
                Counter++;
                CounterLabel.Text = Counter.ToString();
            });
            
            return true;
        }
    }
}

[BDisp]

Commenting Curses.timeout (10) in ProcessInput will help but will not solve the problem completely.

This is necessary for waiting a while after a Esc key is detected to check if it was pressed alone or if it's part of a escape sequence, like Key.Home or mouse event, etc.

Well, I think the culprit is the poll method waiting infinitely if pollTimeout=-1 until some action is detected. I did the fix in the #2848.
I also did some change to your code:
Avoid initialize a view twice because if you use Debug.Assert with Responder.Instances to validate all instances it will fail. So, only declare the fields or initialize with all properties or initialize only with new(); and setting the properties in the Main().

        static Label CounterLabel;
        static Label BlinkingLabel; 

You don't need to use the return; in a void Main. Instead replace it with Application.Shutdown();

Also for accurating that the timeout action is running on the UI thread, change the Add method to call the Application.MainLoop.Invoke:

	private static bool Add(MainLoop mainLoop)
	{
		Application.MainLoop.Invoke(() => {
			GlobalList.Add(new Random().Next(100).ToString());
			GlobalListView.MoveDown();
		});

		return true;
	}

I appreciate you can run to check if the issue still persist or not. If it's fix I'll also do a commit to the v2 as well. Thanks.

[BDisp]

You also should avoid setting the view position by using the view.X or view.Y because they will only have the correct value after running and you are only playing with fixed values until achieve the correct values. The correct way to position them is using the Pos.X(View) and Pos.Y(View) which the are dynamically calculate on the LayoutSubviews method:

CounterLabel = new Label ("0") { X = Pos.X (container), Y = Pos.Y (container) - 2 };
BlinkingLabel = new Label ("Blink") { X = Pos.X (container), Y = Pos.Bottom (container) + 1 };

[kacperpikacz]

After running with #2848, I see no more problem present. Good job @BDisp

[kacperpikacz]

Sorry, I've used wrong source. The problem is still present plus problem with resizing appear.

terminal3.mov

[BDisp]

But are you sure you are running with the #2848? You'll have to debug that and try to find the cause because I can't. Loo at the IMainLoopDriver.EventsPending of the UnixMainLoop.cs. The fixes I did was for CursesDriver which freeze on the var n = poll (pollmap, (uint)pollmap.Length, pollTimeout);.

[kacperpikacz]

Yes, i can confirm that after running on #2848 the problem is still present + resizing terminal will cause complete freeze of the app.

After implementing ConsoleDriver and CursesDriver from 1.9 the problem is not present.

Maybe it has something with #2375

[BDisp]

Yes it's reproducing in macOS Monterey. The resizing terminal issue didn't happens before I had commit the latest changes?

[kacperpikacz]

No issue with resizing before.

And only pollTimeout = 0 will help when you exit the cursor from terminal. The app will continue to refresh the views.

I will also try to reproduce it on Intel Ventura, currently im on Silicon.

[BDisp]

Thanks, can you test the threading scenario, please?

[BDisp]

On resizing in the CursesDriver.cs on the ProcessInput method this var code = Curses.get_wch (out wch); is returning code = -1 which is equal to Curses.ERR and wch = 0. That why the ProcessWinChange method doesn't run. On Linux this doesn't happens at all. I have to do some workaround on this.

[kacperpikacz]

Threading scenario, when I don't move cursor the return will never happen. Tested on develop, no issue, with #2848

threading.mov

[kacperpikacz]

Latest commit, fixes issue with resizing. But still the views will not refresh when moving cursor fast.

void IMainLoopDriver.Setup (MainLoop mainLoop)
{
	this.mainLoop = mainLoop;
	pipe (wakeupPipes);
	AddWatch (wakeupPipes [0], Condition.PollIn, ml => {
+		read (wakeupPipes [1], ignore, (IntPtr)1);
		return true;
	});
}

public override void Refresh ()
{
	Curses.raw ();
	Curses.noecho ();
	Curses.refresh ();
+	ProcessWinChange ();
}

[kacperpikacz]

Running on #2848. Inside GetEscSeq()method there is code = Curses.get_wch(out wch2) which returns -1.

code.mov

[Likarion]

Under SSH, the terminal mouse drop into the "SELECT " state and mouse click don't working. When install 1.9.0 all works ok.

[kacperpikacz]

The bug is still not fixed completly.

[BDisp]

The bug is still not fixed completly.

@kacperpikacz you are right. There still some more issue. But the related with this issue is already fix. Instead of reopening this I'll use the #2865, which is more related with the resize issue. Thanks.

[kacperpikacz]

Can someone take a look at this please?