PHP下使用強(qiáng)大的imagick輕松生成組合縮略圖

project: blogtarget: use-imagick-to-composite-images-thumbnail.mddate: 2016-02-19status: publishtags:    - php    - imagick    - thumbnailcategories:    - php

這里說(shuō)的imagick 是 ImageMagick 在PHP下的擴(kuò)展。使用pecl安裝起來(lái)那叫一個(gè)輕松簡(jiǎn)單 —— 一條命令就搞定：

sudo pecl install imagick

（擴(kuò)展裝好后還是要在php.ini中加上extension=imagick.so，然后記得重啟apache或php-fpm服務(wù)。）

最近有個(gè)需求是要把多張圖片組合起來(lái)生成縮略圖，剛好用用這個(gè)強(qiáng)大的imagick擴(kuò)展。
這個(gè)需求是要這樣生成縮略圖：

1. 如果有1張圖片，就直接生成這張圖片的縮略圖；
2. 如果有2張圖片，則一張?jiān)谧筮呉粡堅(jiān)谟疫?，各一半?/li>
3. 如果有3張圖片，則兩張左邊平均分配，一張獨(dú)占右邊；
4. 如果有4張圖片，則像田字格一樣平均分配空間；
5. 更多張圖片，則只取前4張，按田字格方式生成縮略圖。

這規(guī)則還真不少，不過(guò)還不算太過(guò)復(fù)雜，很快搞出來(lái)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,                        ]                    ],                ];        }    }}

用個(gè)試試：

$thumbnail = \clarence\thumbnail\Thumbnail::createFromImages($srcImages, 240, 320);$thumbnail->writeImage($outputDir."/example.jpg");

效果立馬出來(lái)了：

贊一個(gè)~

（詳細(xì)代碼見 http://github.com/clarence-pan/thumbnail)