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# imagecolorallocatealpha

(PHP 4 >= 4.3.2, PHP 5)

imagecolorallocatealpha -- Allocate a color for an image

## Beschreibung

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

imagecolorallocatealpha() behaves identically to imagecolorallocate() with the addition of the transparency parameter `alpha`.

## Parameter Liste

`image`

  An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().

`red`

  Value of red component

`green`

  Value of green component

`blue`

  Value of blue component

`alpha`

  A value between `0` and `127`. `0` indicates completely opaque while `127` indicates completely transparent.

The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.

## Rückgabewerte

A color identifier or `FALSE` if the allocation failed.

## ChangeLog

Version | Beschreibung
--- | ---
Prior to 5.1.3 | Returns -1 if the allocation failed.

## Beispiele

Beispiel 1. Example of using imagecolorallocatealpha()
`<?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); ?>`
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

## Anmerkungen

> Anmerkung: Diese Funktion setzt die GD Bibliothek in der Version 2.0.1 oder höher voraus.

## Siehe auch

imagecolorallocate()
imagecolordeallocate()

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