先给大家炫下效果图，如果大家觉得还很满意，请继续往下阅读：

这里说的imagick 是 ImageMagick 在PHP下的扩展。使用pecl安装起来那叫一个轻松简单一条命令就搞定：

代码如下:

sudo pecl install imagick

（扩展装好后还是要在php.ini中加上extension=imagick.so，然后记得重启apache或php-fpm服务。）

最近有个需求是要把多张图片组合起来生成缩略图，刚好用用这个强大的imagick扩展。

这个需求是要这样生成缩略图：

1.如果有1张图片，就直接生成这张图片的缩略图；

2.如果有2张图片，则一张在左边一张在右边，各一半；

3.如果有3张图片，则两张左边平均分配，一张独占右边；

4.如果有4张图片，则像田字格一样平均分配空间；

5.更多张图片，则只取前4张，按田字格方式生成缩略图。

这规则还真不少，不过还不算太过复杂，很快搞出来了：

namespace clarencethumbnail;

class Thumbnail extends Imagick

{

/**

* @param array $images

* @param int $width

* @param int $height

* @return static

* @throws ThumbnailException

*/

public static function createFromImages($images, $width, $height){

if (empty($images)){

throw new ThumbnailException("No images!");

}

$thumbnail = new static();

$thumbnail->newImage($width, $height, 'white', 'jpg');

$thumbnail->compositeImages($images);

return $thumbnail;

}

public function compositeImages($images){

$imagesKeys = array_keys($images);

$compositeConfig = $this->calcCompositeImagesPosAndSize($images);

foreach ($compositeConfig as $index => $cfg){

$imgKey = $imagesKeys[$index];

$img = new Imagick($images[$imgKey]);

$img = $this->makeCompositeThumbnail($img, $cfg);

$this->compositeImage($img, self::COMPOSITE_OVER, $cfg['to']['x'], $cfg['to']['y']);

}

}

protected function makeCompositeThumbnail(Imagick $img, $cfg){

$img->cropThumbnailImage($cfg['size']['width'], $cfg['size']['height']);

return $img;

}

protected function calcCompositeImagesPosAndSize($images){

$width = $this->getImageWidth();

$height = $this->getImageHeight();

switch(count($images)){

case 0:

throw new ThumbnailException("No images!");

case 1:

// | 0 |

return [

0 => [

'to' => [ 'x' => 0, 'y' => 0 ],

'size' => [

'width' => $width,

'height' => $height,

]

]

];

case 2:

// | 0 | 1 |

return [

0 => [

'to' => [ 'x' => 0, 'y' => 0 ],

'size' => [

'width' => $width / 2,

'height' => $height,

]

],

1 => [

'to' => [ 'x' => $width / 2, 'y' => 0],

'size' => [

'width' => $width / 2,

'height' => $height,

]

]

];

case 3:

// | 0 | 1 |

// | 2 | |

return [

0 => [

'to' => [ 'x' => 0, 'y' => 0 ],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

1 => [

'to' => [ 'x' => $width / 2, 'y' => 0],

'size' => [

'width' => $width / 2,

'height' => $height,

]

],

2 => [

'to' => [ 'x' => 0, 'y' => $height / 2 ],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

];

default:

// >= 4:

// | 0 | 1 |

// | 2 | 3 |

return [

0 => [

'to' => [ 'x' => 0, 'y' => 0 ],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

1 => [

'to' => [ 'x' => $width / 2, 'y' => 0],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

2 => [

'to' => [ 'x' => 0, 'y' => $height / 2 ],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

3 => [

'to' => [ 'x' => $width / 2, 'y' => $height / 2],

'size' => [

'width' => $width / 2,

'height' => $height / 2,

]

],

];

}

}

}

用个试试：

代码如下:

$thumbnail = clarencethumbnailThumbnail::createFromImages($srcImages, 240, 320);

$thumbnail->writeImage($outputDir."/example.jpg");

以上内容给大家介绍了PHP利用imagick生成组合缩略图的相关知识，希望对大家有所帮助！