Modern Tui TuiLuminance

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TuiLuminance

Returns how bright a colour looks, from 0.0 to 1.0.

Syntax

TuiLuminance( byval r as int32, byval g as int32, byval b as int32 ) as float64

Description

Perceptual brightness, 0.0 to 1.0, using the Rec. 709 weights. This is the bottom rung of the ladder: on a mono terminal a colour becomes bold or not depending on which side of the threshold it lands.

Example

#import "std/tui"
using tui

print TuiLuminance( 255, 255, 255 )    '' 0.9999999999999999 -- the weights
                                       '' sum to 1 in exact arithmetic, not in
                                       '' binary floating point. Compare with
                                       '' a threshold, never for equality.
print TuiLuminance( 0, 0, 0 )          '' 0
print TuiLuminance( 0, 255, 0 ) > TuiLuminance( 0, 0, 255 )   '' true: green
                                       '' reads brighter than blue

See also

TuiColor	TuiColor.Equals	TuiDefaultColor	TuiIndexed	TuiBlack	TuiGreen
TuiColor.IsDefault	TuiColor.Index	TuiAnsi	TuiRgb	TuiRed	TuiYellow

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Library: Terminal TUI Library
Category: Terminal TUI Library
Documented under: Colour and Style
Working examples: hello.tiko · form.tiko · dashboard.tiko

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