php man page for imagealphablending

IMAGEALPHABLENDING(3)							 1						     IMAGEALPHABLENDING(3)

imagealphablending - Set the blending mode for an image

SYNOPSIS
       bool imagealphablending (resource  $image, bool	$blendmode)

DESCRIPTION
       imagealphablending(3)  allows  for two different modes of drawing on truecolor images. In blending mode, the alpha channel component of the
       color supplied to all drawing function, such as imagesetpixel(3) determines how much of the underlying color should  be	allowed  to  shine
       through.  As a result, gd automatically blends the existing color at that point with the drawing color, and stores the result in the image.
       The resulting pixel is opaque. In non-blending mode, the drawing color is copied literally with its alpha  channel  information,  replacing
       the destination pixel. Blending mode is not available when drawing on palette images.

PARAMETERS
	      o $
		image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).

	      o $blendmode
		- Whether to enable the blending mode or not. On true color images the default value is TRUE otherwise the default value is FALSE

RETURN VALUES
	Returns TRUE on success or FALSE on failure.

EXAMPLES
       Example #1

	      imagealphablending(3) usage example

	      <?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);
	      ?>

NOTES
       Note

	      This function requires GD 2.0.1 or later (2.0.28 or later is recommended).

PHP Documentation Group 												     IMAGEALPHABLENDING(3)