Get the index of the specified color + alpha

imagecolorexact
imagecolormatch
GD and Image Functions
PHP Manual

# imagecolorexactalpha

(PHP 4 >= 4.0.6, PHP 5, PHP 7)

imagecolorexactalpha — Get the index of the specified color + alpha

### Description

int imagecolorexactalpha ( resource `$image` , int `$red` , int `$green` , int `$blue` , int `$alpha` )

Returns the index of the specified color+alpha in the palette of the image.

### 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 the index of the specified color+alpha in the palette of the image, or -1 if the color does not exist in the image's palette.

### Examples

Example #1 Get colors from the GD logo

`<?php
// Setup an image
$im = imagecreatefrompng('./gdlogo.png');
$colors = Array();
$colors[] = imagecolorexactalpha($im, 255, 0, 0, 0);
$colors[] = imagecolorexactalpha($im, 0, 0, 0, 127);
$colors[] = imagecolorexactalpha($im, 255, 255, 255, 55);
$colors[] = imagecolorexactalpha($im, 100, 255, 52, 20);
print_r($colors);
// Free from memory
imagedestroy($im);
?>`

The above example will output something similar to:

    Array
    (
        [0] => 16711680
        [1] => 2130706432
        [2] => 939524095
        [3] => 342163252
    )

### Notes

> Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).

### See Also

- imagecolorclosestalpha() - Get the index of the closest color to the specified color + alpha

imagecolorexact
imagecolormatch
GD and Image Functions
PHP Manual