PHP利用imagick生成组合缩略图

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：

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 \clarence\thumbnail;
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：

$thumbnail = \clarence\thumbnail\thumbnail::createfromimages($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！