PHP | imagecolortransparent() Function Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The imagecolortransparent() function is an inbuilt function in PHP which is used to define color as transparent. It sets the color of a transparent image. It returns the identifier of the new transparent color. If an image has no transparent color and color not specified then it returns -1. Syntax: int imagecolortransparent ( $image, $color ) Parameters: This function accepts two 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. $color: This parameter is used to set the color identifier created by imagecolorallocate() function. Return Value: This function returns the identifier of the new transparent color. If the color of an image is not specified and the image has no transparent color then it returns -1. Below programs illustrate the imagecolortransparent() function in PHP: Program 1: php <?php // Create an image of size 500x400 $image = imagecreatetruecolor(500, 400); // Allocate green color to image $green = imagecolorallocate($image, 0, 153, 0); // Allocate black color to image $black = imagecolorallocate($image, 0, 0, 0); // Make the background transparent imagecolortransparent($image, $black); // Draw a green filled rectangle imagefilledrectangle($image, 50, 50, 450, 300, $green); // Output the image to the browser header('Content-Type: image/png'); imagepng($image); imagedestroy($image); ?> output: Program 2: php <?php // Create an image of size 500x400 $image = imagecreatetruecolor(500, 400); // Allocate green color to image $green = imagecolorallocate($image, 0, 153, 0); // Allocate black color to image $black = imagecolorallocate($image, 0, 0, 0); // Make the background transparent imagecolortransparent($image, $black); // Function to draw the circle imageellipse($image, 250, 200, 250, 250, $green); // Output the image to the browser header('Content-Type: image/png'); imagepng($image); imagedestroy($image); ?> Output: Related Articles: PHP | imageellipse() Function PHP | imagecolorstotal() Function PHP | imagecolorresolve() Function Reference: https://www.php.net/manual/en/function.imagecolortransparent.php Comment More infoAdvertise with us Next Article PHP | imagecolorset() Function V vijay_raj Follow Improve Article Tags : Misc Web Technologies PHP Image-Processing PHP-function +1 More Practice Tags : Misc Similar Reads PHP | imagecolorset() Function The imagecolorset() function is an inbuilt function in PHP which is used to set the color for the specified palette index. It is used to specify the index in the palette to the specified color. To perform the actual flood-fill, it is useful to create the flood-fill-like effects in palleted images wi 2 min read PHP | imagecolorset() Function The imagecolorset() function is an inbuilt function in PHP which is used to set the color for the specified palette index. It is used to specify the index in the palette to the specified color. To perform the actual flood-fill, it is useful to create the flood-fill-like effects in palleted images wi 2 min read PHP | imagecolorset() Function The imagecolorset() function is an inbuilt function in PHP which is used to set the color for the specified palette index. It is used to specify the index in the palette to the specified color. To perform the actual flood-fill, it is useful to create the flood-fill-like effects in palleted images wi 2 min read PHP | imagecolorat() function 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:Â Â int imagecolorat( $image, $x, $y ) Parameters: This function accepts three parameters as mentioned above and d 2 min read PHP | imagecolorat() function 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:Â Â int imagecolorat( $image, $x, $y ) Parameters: This function accepts three parameters as mentioned above and d 2 min read PHP | imagecolorat() function 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:Â Â int imagecolorat( $image, $x, $y ) Parameters: This function accepts three parameters as mentioned above and d 2 min read Like