How does it support ANSI sequences?

[ArsenShnurkov]

something like https://github.com/binondord/AckTerm

How Ansi, VT100, ECMA-48 color displaying is implemented ?

[ArsenShnurkov]

TerminalControl is derived from CharacterDocumentViewer:
https://github.com/poderosaproject/poderosa/blob/master/TerminalEmulator/TerminalControl.cs#L42
which in turn is derived from System.Windows.Forms.Control:
https://github.com/poderosaproject/poderosa/blob/master/Core/CharacterDocumentViewer.cs#L41

CharacterDocumentViewer overrides OnPaint method:
https://github.com/poderosaproject/poderosa/blob/master/Core/CharacterDocumentViewer.cs#L395
which uses Hdc as an argument for GLine.Render (was it impossible to pass Graphics instead?)
https://github.com/poderosaproject/poderosa/blob/master/Core/CharacterDocumentViewer.cs#L558
GLine.Render uses some mono unfriendly code (from Win32 class):
https://github.com/poderosaproject/poderosa/blob/master/Core/GLine.cs#L300

This is probably done for using Win32.ETO_OPAQUE

https://github.com/mono/mono/search?q=ExtTextOut
- no results
"WARNING **: Failed to load function ExtTextOut from gdi32.dll"

it is from
https://github.com/poderosaproject/poderosa/blob/master/Plugin/Win32.cs#L88
[DllImport("gdi32.dll", CharSet = CharSet.Unicode)]
public static extern unsafe int ExtTextOut(IntPtr hdc, int x, int y, int options, RECT* lprc, char* text, int length, int* lpdx);

http://www.mono-project.com/docs/gui/drawing/

AckTerm uses Graphics.DrawString (from .Net 1.1)
MyPad uses TextRenderer.DrawText (from .Net 2.0)

So, why not to replace ExtTextOut with TextRenderer.DrawText ?

Here are nonexplaining notes:

poderosa/ChangeLog.txt

Lines 176 to 181 in 4f6d735

	* Refactoring and improvements about GLine.
	Background fill and drawing text are done by ExtTextOut().
	It makes rendering slightly faster if background fill is required.
	Drawing contiguous ASCII characters without background fill may be
	slightly slower.
	But it is not a problem because such drawing is fast enough.