Support unicode chars in ListViews and TextFields

I am not sure if I just repeat issue #93 here. Sorry if I do.

Issue

I am currently using some unicode signs like: ≡ ⌂ ↑ ↓ …

While rendering them in a ListView or TextField, I got a IndexOutOfRangeException. In Labels, everything is okay.

   at System.Rune.bisearch(UInt32 rune, UInt32[,] table, Int32 max)
   at System.Rune.ColumnWidth(Rune rune)
   at Terminal.Gui.ListView.ListWrapper.RenderUstr(ustring ustr, Int32 col, Int32 line, Int32 width)
   at Terminal.Gui.ListView.ListWrapper.Render(Boolean marked, Int32 item, Int32 col, Int32 line, Int32 width)
   at Terminal.Gui.ListView.Redraw(Rect region)
   at Terminal.Gui.View.Redraw(Rect region)
   at Terminal.Gui.Window.Redraw(Rect bounds)
   at Terminal.Gui.View.Redraw(Rect region)
   at Terminal.Gui.Application.Redraw(View view)
   at Terminal.Gui.Application.Begin(Toplevel toplevel)
   at Terminal.Gui.Application.Run(Toplevel view)
   at grrui.Program.Main(String[] args) in D:\Develop\GitHub\RepoZ\grrui\Program.cs:line 43

It turns out that "\u2261" for example, returns Rune 8801. Rune.ColumnWidth(8801) throws.

How to reproduce

Simply replace the Example\demo.cs in your solution and hit <kbd>F5</kbd>.

using Terminal.Gui;

static class Demo {
    static void Main()
    {
	Application.Init();
	var top = Application.Top;
	var tframe = top.Frame;

	var win = new Window("Unicode chars") {
	    X = 0,
	    Y = 0,
	    Width = Dim.Fill(),
	    Height = Dim.Fill()
	};

	var unicodeChars = "\u2261 \u2302 \u2191 \u2193 \u2026";

	var lbl = new Label("They work in Labels: " + unicodeChars) 
	{
	    X = 1,
	    Y = 2
	};

	// ** COMMENT THIS OUT TO SEE THE CRASH **
	unicodeChars = "--CENSORED--";

	var txt = new TextField("But they won't work in TextFields: " + unicodeChars)
	{
	    X = Pos.Left(lbl),
	    Y = Pos.Bottom(lbl) + 1,
	    Width = 50
	};

	var lst = new ListView(new string[] {
	    "They won't work in ListViews as well.",
	    "Here they come: " + unicodeChars,
	    "If you want to try this out by yourself,",
	    "simply remove that line saying \"CENSORED\" in code."
	    }
	) {
	    X = Pos.Left(lbl),
	    Y = 6,
	    Width = Dim.Fill(),
	    Height = Dim.Fill()
	};
	lst.SelectedItem = 0;

	win.Add(lbl);
	win.Add(txt);
	win.Add(lst);
	top.Add(win);

	Application.Run();
    }
}

[awaescher]

I fixed this issue in NStack, so I opened a further issue over there to be able to fix it with PR44.

Let’s keep this one open until the fix made it into NStack and gui.cs updates to a new version.

[tig]

@awaescher Is there any way you could help us build unit tests for Unicode support? I can barely spell Unicode and I certainly don’t have many personal use cases beyond Powerline console symbols.

It seems you have an app with real requirements. Anything you could contribute would be appreciated. Even if it were just great text examples.