PHP Manual: Paints pixels transparent

Description

bool Imagick::transparentPaintImage ( mixed $target , float $alpha , float $fuzz , bool $invert )

Paints pixels matching the target color transparent. This method is available if Imagick has been compiled against ImageMagick version 6.3.8 or newer.

Parameters

target: The target color to paint
alpha: The level of transparency: 1.0 is fully opaque and 0.0 is fully transparent.
fuzz: The amount of fuzz. For example, set fuzz to 10 and the color red at intensities of 100 and 102 respectively are now interpreted as the same color.
invert: If TRUE paints any pixel that does not match the target color.

Return Values

Returns TRUE on success.