(PHP 4, PHP 5, PHP 7)
imagecolorat — Get the index of the color of a pixel
imagecolorat ( resource $image , int $x , int $y ) : int|false
Returns the index of the color of the pixel at the specified location in the image specified by image.
If the image is a truecolor image, this function returns the RGB value of that pixel as integer. Use bitshifting and masking to access the distinct red, green and blue component values:
image
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
x
x-coordinate of the point.
y
y-coordinate of the point.
Returns the index of the color or false on failure.
This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.
Example #1 Access distinct RGB values
<?php
$im = imagecreatefrompng("php.png");
$rgb = imagecolorat($im, 10, 15);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
var_dump($r, $g, $b);
?> The above example will output something similar to:
int(119) int(123) int(180)
Example #2 Human-readable RGB values using imagecolorsforindex()
<?php
$im = imagecreatefrompng("php.png");
$rgb = imagecolorat($im, 10, 15);
$colors = imagecolorsforindex($im, $rgb);
var_dump($colors);
?> The above example will output something similar to:
array(4) {
["red"]=>
int(119)
["green"]=>
int(123)
["blue"]=>
int(180)
["alpha"]=>
int(127)
}
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Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.imagecolorat.php