PHP imagealphablending() Function: Setting Image Blending Mode

The imagealphablending() function in PHP enables or disables alpha blending for true‑color images created with the GD library, allowing two different drawing modes.

Parameters

image : The image resource returned by functions such as imagecreatetruecolor().

blendmode : A boolean indicating whether to enable ( true) or disable ( false) blending mode.

Return value

Returns TRUE on success; on failure it returns FALSE.

Example usage

<?php
// Create image
$im = imagecreatetruecolor(100, 100);

// Set alphablending to on
imagealphablending($im, true);

// Draw a square
imagefilledrectangle($im, 30, 30, 70, 70, imagecolorallocate($im, 255, 0, 0));

// Output
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
?>

This example demonstrates creating a 100×100 image, enabling alpha blending, drawing a red square, and sending the image to the browser as a PNG.