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imagelayereffect

(PHP 4 >= 4.3.0, PHP 5)

imagelayereffectSet the alpha blending flag to use the bundled libgd layering effects

설명

bool imagelayereffect ( resource $image , int $effect )

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

인수

image

imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.

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.

반환값

성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.

예제

Example #1 imagelayereffect() example

<?php
// Setup an image
$im imagecreatetruecolor(100100);

// Set a background
imagefilledrectangle($im00100100imagecolorallocate($im220220220));

// Apply the overlay alpha blending flag
imagelayereffect($imIMG_EFFECT_OVERLAY);

// Draw two grey ellipses
imagefilledellipse($im50504040imagecolorallocate($im100255100));
imagefilledellipse($im50505080imagecolorallocate($im100100255));
imagefilledellipse($im50508050imagecolorallocate($im255100100));

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

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

위 예제의 출력 예시:

Output of example : imagelayereffect()

주의

Note: 이 함수는 PHP에 포함된 GD 라이브러리를 사용하여 컴파일하였을 경우에만 사용할 수 있습니다.

Note: 이 함수는 GD 2.0.1 이상이 필요합니다. (2.0.28 이상을 권장합니다)

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User Contributed Notes 4 notes

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0
andrew at iwebsolutions dot co dot uk
5 years ago
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.
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0
[myname] at mac dot com
6 years ago
^^ 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);

?>
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0
Remon
6 years ago
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.
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0
Anonymous
9 years ago
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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