Table of Contents

Class TerminalCapabilities

Namespace
ItTiger.TigerCli.Terminal
Assembly
ItTiger.TigerCli.dll
Detects the ANSI capability of a console stream for Auto. The decision is conservative about whether ANSI is allowed at all (redirected streams, NO_COLOR, CLICOLOR=0, and TERM=dumb/empty all disable it) but practical once it is: a normal interactive non-Windows terminal resolves to Ansi256 without requiring TERM to advertise 256color. The pure Detect(Func<string, string?>, bool, bool, bool) core takes all environment inputs as parameters so it can be unit-tested without touching the real process environment.
public static class TerminalCapabilities
Inheritance
TerminalCapabilities
Inherited Members

Fields

DefaultOutputHeight

Deterministic fallback height (in rows) used when a concrete terminal height is required (the full-screen render buffer and interactive viewport) but cannot be read safely. Structured, non-interactive output does not clamp to this — it leaves height unbounded under redirection.
public const int DefaultOutputHeight = 30

Field Value

int

DefaultOutputWidth

Deterministic fallback width (in columns) used by GetSafeOutputWidth(bool) when the real terminal width cannot be read safely. The fallback affects layout/wrapping only; it does not imply ANSI/colour support (that is decided separately by Detect(Func<string, string?>, bool, bool, bool)).
public const int DefaultOutputWidth = 120

Field Value

int

Methods

Detect(Func<string, string?>, bool, bool, bool)

Pure capability detection for Auto.
public static CliAnsiSupport Detect(Func<string, string?> getEnvironmentVariable, bool isRedirected, bool isWindows, bool windowsVtSupported)

Parameters

getEnvironmentVariable Func<string, string>
Environment-variable lookup (returns null when unset).
isRedirected bool
Whether the target stream is redirected/captured.
isWindows bool
Whether the host OS is Windows.
windowsVtSupported bool
Result of the Windows VT probe for this stream. Ignored on non-Windows.

Returns

CliAnsiSupport

ForStderr()

Detects the stderr ANSI capability from the real process environment.
public static CliAnsiSupport ForStderr()

Returns

CliAnsiSupport

ForStdout()

Detects the stdout ANSI capability from the real process environment.
public static CliAnsiSupport ForStdout()

Returns

CliAnsiSupport

GetSafeOutputHeight(bool)

Returns the current terminal height when it can be read safely, otherwise null. A null result means "no soft height bound" — structured output then emits all rows rather than clamping to a window that may not exist under redirection.
public static int? GetSafeOutputHeight(bool forError = false)

Parameters

forError bool
When true, gates on stderr redirection instead of stdout.

Returns

int?

GetSafeOutputWidth(bool)

Returns the current terminal width when it can be read safely, otherwise DefaultOutputWidth. The result is always at least 1.

WindowWidth is a terminal capability, not a guaranteed value: reading it when stdout is redirected, piped, captured, or there is no interactive console can throw (e.g. "The handle is invalid.") or report a nonsensical value. Rendering and layout code must call this instead of reading WindowWidth directly. 

public static int GetSafeOutputWidth(bool forError = false)

Parameters

forError bool
When true, gates on stderr redirection instead of stdout.

Returns

int

ResolveHeight(bool, Func<int>)

Pure height-resolution core (see ResolveWidth(bool, Func<int>)). Returns null when redirected, when readHeight throws, or when it yields a non-positive value.
public static int? ResolveHeight(bool isRedirected, Func<int> readHeight)

Parameters

isRedirected bool
readHeight Func<int>

Returns

int?

ResolveWidth(bool, Func<int>)

Pure width-resolution core, with redirection state and the raw width reader injected so it can be unit-tested without touching the real console. Returns DefaultOutputWidth when redirected, when readWidth throws, or when it yields a non-positive value; otherwise the value read (always at least 1).
public static int ResolveWidth(bool isRedirected, Func<int> readWidth)

Parameters

isRedirected bool
readWidth Func<int>

Returns

int
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