GD and Image Functions
PHP Manual

imagecolorresolvealpha

Get the index of the specified color + alpha or its closest possible alternative

Description

int imagecolorresolvealpha ( resource $image , int $red , int $green , int $blue , int $alpha )

This function is guaranteed to return a color index for a requested color, either the exact color or the closest possible alternative.

Parameters

image

An image resource, returned by one of the image creation functions, such as imagecreatetruecolor.

red

Value of red component.

green

Value of green component.

blue

Value of blue component.

alpha

A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.

The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.

Return Values

Returns a color index.

Examples

Example #1 Using imagecoloresolvealpha to get colors from an image

<?php
// Load an image
$im = imagecreatefromgif('phplogo.gif');

// Get closest colors from the image
$colors = array();
$colors[] = imagecolorresolvealpha($im, 255, 255, 255, 0);
$colors[] = imagecolorresolvealpha($im, 0, 0, 200, 127);

// Output
print_r($colors);

imagedestroy($im);
?>

The above example will output something similar to:

Array
(
    [0] => 89
    [1] => 85
)

See Also

  • imagecolorclosestalpha