imagecolorexactalpha

(PHP 4 >= 4.0.6, PHP 5)

imagecolorexactalpha — Get the index of the specified color + alpha

Descrierea

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.

Parametri

image: O resursă - imagine, întoarsă de una din funcțiile de creare a imaginilor, cum ar fi imagecreatetruecolor().
red: Valoarea componentei roșii.
green: Valoarea componentei verzi.
blue: Valoarea componentei albastre.
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.

Valorile întoarse

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.

Exemple

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);
?>

Exemplul de mai sus va afișa ceva similar cu:

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

Note

Notă: Această funcție necesită GD 2.0.1 sau ulterioară (2.0.28 sau ulterioară este recomandată).

Vedeți de asemenea

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

add a note User Contributed Notes imagecolorexactalpha

matt at matt-darby dot com 11-Jul-2005 12:09


Note that a color allocated with imagecolorexactalpha won't show alpha (it will be opaque) when used with imageline(). Use imagerectangle() set to your normal start and end points instead.



Ensure that the image is created via imagecreatetruecolor() as well!

phpdoc-comment at aditus dot nu 08-Nov-2002 03:01


What might be misleading in the docs is that if the specified color + alpha channel does not exist it will be created. So if you like to use an alpha channel in your image enable alpha blending and then create you color using this method.

add a note