(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.
Пример #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);
?>
Результатом выполнения данного примера будет что-то подобное:
Array ( [0] => 16711680 [1] => 2130706432 [2] => 939524095 [3] => 342163252 )
Замечание: Эта функция нуждается в GD версии 2.0.1 или выше.