imagelayereffect

(PHP 4 >= 4.3.0, PHP 5)

imagelayereffect — Set the alpha blending flag to use the bundled libgd layering effects

Descrição

bool imagelayereffect ( resource $image , int $effect )

Set the alpha blending flag to use the bundled libgd layering effects.

Parâmetros

image

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

effect

One of the following constants:

IMG_EFFECT_REPLACE: Use pixel replacement (equivalent of passing TRUE to imagealphablending())
IMG_EFFECT_ALPHABLEND: Use normal pixel blending (equivalent of passing FALSE to imagealphablending())
IMG_EFFECT_NORMAL: Same as IMG_EFFECT_ALPHABLEND.
IMG_EFFECT_OVERLAY: Overlay has the effect that black background pixels will remain black, white background pixels will remain white, but grey background pixels will take the colour of the foreground pixel.

Valor Retornado

Retorna TRUE em caso de sucesso ou FALSE em falhas.

Exemplos

Exemplo #1 imagelayereffect() example


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

// Set a background
imagefilledrectangle($im, 0, 0, 100, 100, imagecolorallocate($im, 220, 220, 220));

// Apply the overlay alpha blending flag
imagelayereffect($im, IMG_EFFECT_OVERLAY);

// Draw two grey ellipses
imagefilledellipse($im, 50, 50, 40, 40, imagecolorallocate($im, 100, 255, 100));
imagefilledellipse($im, 50, 50, 50, 80, imagecolorallocate($im, 100, 100, 255));
imagefilledellipse($im, 50, 50, 80, 50, imagecolorallocate($im, 255, 100, 100));

// Output
header('Content-type: image/png');

imagepng($im);
imagedestroy($im);
?>

O exemplo acima irá imprimir algo similar a:

Notas

Nota: Esta função somente está disponível se o PHP estiver compilado com a versão embarcada da biblioteca GD.

Nota: Esta função precisa do GD 2.0.1 ou posterior (2.0.28 ou posterior é recomendado).

imageline

imagejpeg

[edit] Last updated: Fri, 24 Feb 2012

add a note User Contributed Notes imagelayereffect

andrew at iwebsolutions dot co dot uk 06-Oct-2008 09:38


I have been getting a fatal error:



Fatal error: Call to undefined function imagelayereffect()



This doesn't work with Ubuntu server (8.04 lts) and the php5-gd package.  If you need this you will have to recompile PHP with GD built-in.

[myname] at mac dot com 23-Feb-2008 04:45


^^ my name is coreyward ^^



imagelayereffect needs to be applied to the destination image, not the source image. As noted, the only useful "effect" as of this time is IMG_EFFECT_OVERLAY since the others are merely another way of setting the alpha blending flag. 



You can also use imagecopymerge with a lower pct argument to blend two images with more control over the opacity at which the top image is blended. 



<?



// overlays $im_src onto $im_dst properly (assuming same dims)



imagelayereffect($im_dst, IMG_EFFECT_OVERLAY);

imagecopy($im_dst, $im_src, 0, 0, 0, 0, $im_dst_x, $im_dst_y);



?>

Remon 04-Feb-2008 06:12


I found the following example on a Chinese site and translated and adjusted it. It creates a portrait from the sample picture.



<?php



// Portrait image

$im = imagecreatefromjpeg( "sample.jpg");



// Get width and height

$w = imagesx($im); 

$h = imagesy($im);



// Non-through

$c_visible = 0x007F7F7F;

// Background (black) 

$c_bg = 0x00000000; 



// Create mask

$im_mask = imagecreatetruecolor($w,$h);

imageFilledRectangle($im_mask, 0,0, $w,$h, $c_bg); 

imageFilledEllipse ($im_mask, $w/2,$h/2, $w*.9,$h*.9, $c_visible);



// Only overlay seems to something useful

imagelayereffect($im_mask, IMG_EFFECT_OVERLAY);



imagecopy($im_mask, $im, 0,0, 0,0, $w,$h); 

imagedestroy($im);



imagepng($im_mask);

imagedestroy($im_mask);



?>



Try removing the 'create mask' code and just add another image with 'createimagefromjpeg' to see 'normal' overlay. It blends the colors like different layers in Photoshop.

05-Feb-2005 09:36


I assume, that the specific effects are similiar to those used in Adobe Photoshop for blending layers.

There might be things like IMG_EFFECT_MULTIPLY resulting of that.

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