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PHP | imagecolorat() function
  • Last Updated : 23 Aug, 2019

The imagecolorat() function is an inbuilt function in PHP which is used to get the index of the color of the pixel. This function returns the pixel value at the specified location.

Syntax:

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

Parameters: This function accepts three parameters as mentioned above and described below:

  • $image: The imagecreatetruecolor() function is used to create an image in a given size.
  • $x: This parameter is used to hold the x-coordinate of the point.
  • $y: This parameter is used to hold the y-coordinate of the point.

Return Value: This function returns the color index (color pixel value) or FALSE on failure.

Below program illustrate the imagecolorat() function in PHP.



Note: The image given below is used in the following program.
geeks image

Program 1:

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code

<?php
  
// store the image in variable
$image = imagecreatefrompng("gfg.png");
  
// Calculate rgb pixel value at perticular point.
$rgb = imagecolorat($image, 30, 25);
$red = ($rgb >> 16) & 255;
$green = ($rgb >> 8) & 255;
$blue = $rgb & 255;
  
var_dump($red, $green, $blue);
?>

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Output:

int(34) 
int(170) 
int(66)

Program 2:

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close

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brightness_4
code

<?php
  
// store the image in variable.
$image = imagecreatefrompng("gfg.png");
  
// Calculate rgb pixel value at perticular point.
$rgb = imagecolorat($image, 30, 25);
  
// Assign color name and its value.
$colors = imagecolorsforindex($image, $rgb);
  
var_dump($colors);
?>

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Output:

array(4) { 
    ["red"]=> int(34) 
    ["green"]=> int(170) 
    ["blue"]=> int(66) 
    ["alpha"]=> int(0) 
}

Reference: http://php.net/manual/en/function.imagecolorat.php

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