(PHP 4 >= 4.0.6, PHP 5)
imagecolorclosestalpha вЂ” Get the index of the closest color to the specified color + alpha
Returns the index of the color in the palette of the image which is "closest" to the specified RGB value and alpha level.
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
Value of red component
Value of green component
Value of blue component
A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
Returns the index of the closest color in the palette.
Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).