PHP | imagecolorallocate() Function

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);

?>

Output:

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