DoDrawComplete should ignore scrolled Viewport.Location when excluding opaque view area

[fubar-coder]

Describe the bug

When I scroll the content of the "output" TextView, it seems that the "inputFrame" gets moved and its size changed(?) in a strange way, as if parts of the views below is "cleared" (overwritten with blank lines).

To Reproduce

Steps to reproduce the behavior:

1. Run the following code:

using System.Text;
using Terminal.Gui.App;
using Terminal.Gui.Drawing;
using Terminal.Gui.Drivers;
using Terminal.Gui.ViewBase;
using Terminal.Gui.Views;

using var app = Application.Create().Init();

using Window window = new();

window.BorderStyle = LineStyle.None;
window.Width = Dim.Fill();
window.Height = Dim.Fill();

var inputFrame = new FrameView()
{
    Y = Pos.Align(Alignment.End),
    Width = Dim.Fill(),
    Height = Dim.Auto(DimAutoStyle.Content, Dim.Absolute(3), Dim.Percent(50)),
    BorderStyle = LineStyle.None,
};

var output = new TextView()
{
    Width = Dim.Fill(),
    Height = Dim.Height(window) - Dim.Height(inputFrame) - 1,
};

var input = new TextView()
{
    Height = Dim.Auto(DimAutoStyle.Content, Dim.Absolute(3), Dim.Func(v => (v?.Frame.Height ?? 2) / 2, window)),
    Width = Dim.Fill(),
    WordWrap = true,
};

var outputText = new StringBuilder();

input.KeyDown +=
    (_, key) =>
    {
        // Just a way to add content to the output.
        outputText.Append (key.KeyCode == KeyCode.Enter ? "\n" : key.KeyCode.ToString ());
        output.Text = outputText.ToString ();
        key.Handled = false;
    };

inputFrame.Add(input);
window.Add(inputFrame);

window.Add(output);

app.Run(window);

2. Expected behavior: (describe what should happen)

Scrolling in the "output" TextView shouldn't affect the views below.

3. Actual behavior: (describe what actually happens)

It looks like part of the view(s) below the "output" TextView is overwritten with blank lines, almost as if it tries to clear some artifacts for/after scrolling. However, it may instead for some reason modify the Y and Height properties of the "inputFrame". I'm just not sure what happens.

Environment

Please run the following commands in your terminal and paste the output:

OS Information

OS: Microsoft Windows 11 Pro 10.0.26200

Terminal Information

Terminal: Windows Terminal 1.23.20211.0

PowerShell Version

Major  Minor  Patch  PreReleaseLabel BuildLabel
-----  -----  -----  --------------- ----------
7      6      0

.NET Information

10.0.201

.NET SDK:
 Version:           10.0.201
 Commit:            4d3023de60
 Workload version:  10.0.200-manifests.121cc9e6
 MSBuild version:   18.3.0-release-26153-122+4d3023de6

Laufzeitumgebung:
 OS Name:     Windows
 OS Version:  10.0.26200
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.201\

Installierte .NET-Workloads:
 [maui-windows]
   Installationsquelle: VS 17.14.37111.16, VS 18.4.11620.152
   Manifestversion:    10.0.20/10.0.100
   Manifestpfad:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maui\10.0.20\WorkloadManifest.json
   Installationstyp:              Msi

 [maccatalyst]
   Installationsquelle: VS 17.14.37111.16, VS 18.4.11620.152
   Manifestversion:    26.2.10217/10.0.100
   Manifestpfad:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maccatalyst\26.2.10217\WorkloadManifest.json
   Installationstyp:              Msi

 [ios]
   Installationsquelle: VS 17.14.37111.16, VS 18.4.11620.152
   Manifestversion:    26.2.10217/10.0.100
   Manifestpfad:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.ios\26.2.10217\WorkloadManifest.json
   Installationstyp:              Msi

 [android]
   Installationsquelle: VS 17.14.37111.16, VS 18.4.11620.152
   Manifestversion:    36.1.30/10.0.100
   Manifestpfad:       C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.android\36.1.30\WorkloadManifest.json
   Installationstyp:              Msi

Für die Verwendung von workload sets bei der Installation neuer Manifeste konfiguriert.
Es sind keine Workloadsätze installiert. Führen Sie „dotnet workload restore“ aus, um einen Workloadsatz zu installieren.

Host:
  Version:      10.0.5
  Architecture: x64
  Commit:       a612c2a105

.NET SDKs installed:
  6.0.428 [C:\Program Files\dotnet\sdk]
  8.0.411 [C:\Program Files\dotnet\sdk]
  9.0.312 [C:\Program Files\dotnet\sdk]
  10.0.104 [C:\Program Files\dotnet\sdk]
  10.0.201 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Invalid [C:\Entwicklung\Terminal.Gui\global.json]
    Version '10.0.0' is not valid for the 'sdk/version' value. SDK feature bands start at 1 - for example, 10.0.100

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

Terminal.Gui Version

Version:

0a87f873917178cb6d92d64724ae6b5432f952de
v2.0.0-beta.1-106-g0a87f8739-dirty

Screenshots, GIFs, or Terminal Output

Additional context

Add any other context about the problem here, such as:

• Does this happen consistently or intermittently?
• Did this work in a previous version?
• Are there any error messages in the console?
• Terminal configuration or settings that might be relevant?

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[tig]

@BDisp This didn't get closed automatically by #4726. Was it fixed?

[fubar-coder]

Nope, not fixed. Tested with commit 345c42f (develop branch). This are the bugs now:

Cursor position not updated after control position change

In the phase where the text control grows to match the number of lines, the cursor position isn't updated when the text control position changes. This didn't happen before, IIRC.

It's difficult to see, but the cursor is in the last line, but the text I enter is - correctly - in the line above, which is the line after the last line of the text controls ... text?

Scrolling still causes strange rendering behavior

This bug is still there:

[BDisp]

Sorry, I forgot to take a look at this issue but I'll.

[BDisp]

I think this issue is more about Pos/Dim layout than TextView itself. Can you give your opinion, @tig?

[BDisp]

I found something about this problem. Although the FrameView is correctly located, when the second TextView tries to draw, the IsValidLocation method returns false because the Clip contains a rectangle whose Y property is greater than that of the Frame.Y of the FrameView, and therefore it is not drawn, leaving the lines above blank.