PHP | imagecolorallocate() Function

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The imagecolorallocate() function is an inbuilt function in PHP which is used to set the color in an image. This function returns a color which is given in RGB format.

Syntax:

int imagecolorallocate ( $image, $red, $green, $blue )

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

$image: It is returned by one of the image creation functions, such as imagecreatetruecolor(). It is used to create size of image.
$red: This parameter is used to set value of red color component.
$green: This parameter is used to set value of green color component.
$blue: This parameter is used to set value of blue color component.

Return Value: This function returns a color identifier on success or FALSE if the color allocation failed.

Below programs illustrate the imagecolorallocate() function in PHP.

Program 1:

<?php 
  
// It create the size of image or blank image. 
$image_size = imagecreatetruecolor(500, 300); 
  
// Set the background color of image using 
// imagecolorallocate() function. 
$bg = imagecolorallocate($image_size, 0, 103, 0); 
  
// Fill background with above selected color. 
imagefill($image_size, 0, 0, $bg);  
  
// output image in the browser 
header("Content-type: image/png"); 
imagepng($image_size); 
  
// free memory 
imagedestroy($image_size); 
  
?> 

Output:

Program 2:

<?php 
  
// It create the size of image or blank image. 
$image_size = imagecreatetruecolor(500, 300); 
  
// Set the background color of image. 
$bg = imagecolorallocate($image_size, 0, 103, 0); 
  
// Fill background with above selected color. 
imagefill($image_size, 0, 0, $bg);  
  
// Set the colors of image 
$white_color = imagecolorallocate($image_size, 255, 255, 255); 
  
// Draw a circle 
imagearc($image_size, 200, 150, 200, 200,  0, 360, $white_color); 
// output image in the browser 
header("Content-type: image/png"); 
imagepng($image_size); 
  
// free memory 
imagedestroy($image_size); 
  
?> 