$canvasGrayscale

The $canvasGrayscale function converts the current canvas to grayscale, removing all color information (saturation) while preserving the brightness.

Syntax

$canvasGrayscale

Parameters

None.

Return value

None. The canvas is modified directly.

Behavior

• Each pixel of the canvas is converted to a shade of gray depending on its luminance.
• The formula typically uses a weighted average of the RGB channels (30% red, 59% green, 11% blue).
• The operation is irreversible (unless you save the state beforehand).

Examples

Simple conversion to black and white

$canvasLoad[$attachment]
$canvasGrayscale
$attachCanvas[]
$sendMessage[🎨 Image converted to grayscale!]

Old photo effect

$canvasLoad[$attachment]
$canvasGrayscale
$canvasColor[#6b4c2a]  ;; Sepia effect via tinting
$attachCanvas[]
$sendMessage[🕰️ Vintage effect applied!]

Before/After comparison

$var[original;$attachment]
$canvasLoad[$var[original]]
$attachCanvas[before.png]

$canvasGrayscale
$attachCanvas[after.png]
$sendMessage[⚫ Original vs Grayscale:]

Notes

• The canvas must be created or loaded before calling this function (via $canvasCreate[], $canvasLoad[], etc.).
• To invert the colors, use $canvasInvert instead.
• For rotation, use $canvasRotate[degrees].