(PHP 4 >= 4.0.6, PHP 5)
imagecolorexactalpha — Get the index of the specified color + alpha
Returns the index of the specified color+alpha in the palette of the image.
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.
The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.
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.
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
)
Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).