Get the index of the color of a pixel

imagecolorallocatealpha
imagecolorclosest
GD and Image Functions
PHP Manual

# imagecolorat

(PHP 4, PHP 5)

imagecolorat — Get the index of the color of a pixel

### Description

int imagecolorat ( resource `$image` , int `$x` , int `$y` )

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

`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.

### 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()

`<?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() - Set the color for the specified palette index
- imagecolorsforindex() - Get the colors for an index
- imagesetpixel() - Set a single pixel

imagecolorallocatealpha
imagecolorclosest
GD and Image Functions
PHP Manual