php man page for imagecolorallocatealpha

IMAGECOLORALLOCATEALPHA(3)						 1						IMAGECOLORALLOCATEALPHA(3)

imagecolorallocatealpha - Allocate a color for an image

SYNOPSIS
       int imagecolorallocatealpha (resource  $image, int  $red, int  $green, int  $blue, int  $alpha)

DESCRIPTION
       imagecolorallocatealpha(3) behaves identically to imagecolorallocate(3) with the addition of the transparency parameter $alpha.

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

	      o $red
		-Value of red component.

	      o $green
		-Value of green component.

	      o $blue
		-Value of blue component.

	      o $alpha
		- A value between 0 and 127.  0 indicates completely opaque while 127 indicates completely transparent.

	The $red, $green and $blue parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.

RETURN VALUES
	A color identifier or FALSE if the allocation failed.

       Warning

	      This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on
	      Booleans for more information. Use the === operator for testing the return value of this function.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.1.3	|						    |
       |	|						    |
       |	|  Returns FALSE if the allocation  failed.  Previ- |
       |	| ously -1 was returned.			    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      Example of using imagecolorallocatealpha(3)

	      <?php
	      $size = 300;
	      $image=imagecreatetruecolor($size, $size);

	      // something to get a white background with black border
	      $back = imagecolorallocate($image, 255, 255, 255);
	      $border = imagecolorallocate($image, 0, 0, 0);
	      imagefilledrectangle($image, 0, 0, $size - 1, $size - 1, $back);
	      imagerectangle($image, 0, 0, $size - 1, $size - 1, $border);

	      $yellow_x = 100;
	      $yellow_y = 75;
	      $red_x	= 120;
	      $red_y	= 165;
	      $blue_x	= 187;
	      $blue_y	= 125;
	      $radius	= 150;

	      // allocate colors with alpha values
	      $yellow = imagecolorallocatealpha($image, 255, 255, 0, 75);
	      $red    = imagecolorallocatealpha($image, 255, 0, 0, 75);
	      $blue   = imagecolorallocatealpha($image, 0, 0, 255, 75);

	      // drawing 3 overlapped circle
	      imagefilledellipse($image, $yellow_x, $yellow_y, $radius, $radius, $yellow);
	      imagefilledellipse($image, $red_x, $red_y, $radius, $radius, $red);
	      imagefilledellipse($image, $blue_x, $blue_y, $radius, $radius, $blue);

	      // don't forget to output a correct header!
	      header('Content-Type: image/png');

	      // and finally, output the result
	      imagepng($image);
	      imagedestroy($image);
	      ?>

	      The above example will output something similar to:[NOT DISPLAYABLE MEDIA]Output of example : Example of using imagecolorallocateal-
	      pha()

NOTES
       Note

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

SEE ALSO
       imagecolorallocate(3), imagecolordeallocate(3).

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