IMAGECOLORAT(3) 1 IMAGECOLORAT(3)
imagecolorat - Get the index of the color of a pixel
SYNOPSIS
int imagecolorat (resource $image, int $x, int $y)
DESCRIPTION
Returns the index of the color of the pixel at the specified location in the image specified by $image.
If PHP is compiled against GD library 2.0 or higher and 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:
PARAMETERS
o $
image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).
o $x
- x-coordinate of the point.
o $y
- y-coordinate of the point.
RETURN VALUES
Returns the index of the color.
EXAMPLES
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(3)
<?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)
}
SEE ALSO
imagecolorset(3), imagecolorsforindex(3), imagesetpixel(3).
PHP Documentation Group IMAGECOLORAT(3)
