src/thinkextend/image/driver/Imagick.php
public function thumb($width, $height, $type = THINKIMAGE_THUMB_SCALE)
    {
        if (empty($this->im)) {
            throw new \Exception('没有可以被缩略的图像资源');
        }

        //原图宽度和高度
        $w = $this->info['width'];
        $h = $this->info['height'];

        /* 计算缩略图生成的必要参数 */
        switch ($type) {
            /* 等比例缩放 */
            case THINKIMAGE_THUMB_SCALING:
                //原图尺寸小于缩略图尺寸则不进行缩略
                if ($w < $width && $h < $height) {
                    return;
                }

                //计算缩放比例
                $scale = min($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $x      = $y      = 0;
                $width  = $w * $scale;
                $height = $h * $scale;
                break;

            /* 居中裁剪 */
            case THINKIMAGE_THUMB_CENTER:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $w = $width / $scale;
                $h = $height / $scale;
                $x = ($this->info['width'] - $w) / 2;
                $y = ($this->info['height'] - $h) / 2;
                break;

            /* 左上角裁剪 */
            case THINKIMAGE_THUMB_NORTHWEST:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $x = $y = 0;
                $w = $width / $scale;
                $h = $height / $scale;
                break;

            /* 右下角裁剪 */
            case THINKIMAGE_THUMB_SOUTHEAST:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $w = $width / $scale;
                $h = $height / $scale;
                $x = $this->info['width'] - $w;
                $y = $this->info['height'] - $h;
                break;

            /* 填充 */
            case THINKIMAGE_THUMB_FILLED:
                //计算缩放比例
                if ($w < $width && $h < $height) {
                    $scale = 1;
                } else {
                    $scale = min($width / $w, $height / $h);
                }

                //设置缩略图的坐标及宽度和高度
                $neww = $w * $scale;
                $newh = $h * $scale;
                $posx = ($width - $w * $scale) / 2;
                $posy = ($height - $h * $scale) / 2;

                //创建一张新图像
                $newimg = new Imagick();
                $newimg->newImage($width, $height, 'white', $this->info['type']);

                if ('gif' == $this->info['type']) {
                    $imgs = $this->im->coalesceImages();
                    $img  = new Imagick();
                    $this->im->destroy(); //销毁原图

                    //循环填充每一帧
                    do {
                        //填充图像
                        $image = $this->_fill($newimg, $posx, $posy, $neww, $newh, $imgs);

                        $img->addImage($image);
                        $img->setImageDelay($imgs->getImageDelay());
                        $img->setImagePage($width, $height, 0, 0);

                        $image->destroy(); //销毁零时图片

                    } while ($imgs->nextImage());

                    //压缩图片
                    $this->im->destroy();
                    $this->im = $img->deconstructImages();
                    $imgs->destroy(); //销毁零时图片
                    $img->destroy(); //销毁零时图片

                } else {
                    //填充图像
                    $img = $this->_fill($newimg, $posx, $posy, $neww, $newh);
                    //销毁原图
                    $this->im->destroy();
                    $this->im = $img;
                }

                //设置新图像属性
                $this->info['width']  = $width;
                $this->info['height'] = $height;
                return;

            /* 固定 */
            case THINKIMAGE_THUMB_FIXED:
                $x = $y = 0;
                break;

            default:
                throw new \Exception('不支持的缩略图裁剪类型');
        }

        /* 裁剪图像 */
        $this->crop($w, $h, $x, $y, $width, $height);
    }
public function thumb($width, $height, $type = THINKIMAGE_THUMB_SCALE)
    {
        if (empty($this->im)) {
            throw new \Exception('没有可以被缩略的图像资源');
        }

        //原图宽度和高度
        $w = $this->info['width'];
        $h = $this->info['height'];

        /* 计算缩略图生成的必要参数 */
        switch ($type) {
            /* 等比例缩放 */
            case THINKIMAGE_THUMB_SCALING:
                //原图尺寸小于缩略图尺寸则不进行缩略
                if ($w < $width && $h < $height) {
                    return;
                }

                //计算缩放比例
                $scale = min($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $x      = $y      = 0;
                $width  = $w * $scale;
                $height = $h * $scale;
                break;

            /* 居中裁剪 */
            case THINKIMAGE_THUMB_CENTER:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $w = $width / $scale;
                $h = $height / $scale;
                $x = ($this->info['width'] - $w) / 2;
                $y = ($this->info['height'] - $h) / 2;
                break;

            /* 左上角裁剪 */
            case THINKIMAGE_THUMB_NORTHWEST:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $x = $y = 0;
                $w = $width / $scale;
                $h = $height / $scale;
                break;

            /* 右下角裁剪 */
            case THINKIMAGE_THUMB_SOUTHEAST:
                //计算缩放比例
                $scale = max($width / $w, $height / $h);

                //设置缩略图的坐标及宽度和高度
                $w = $width / $scale;
                $h = $height / $scale;
                $x = $this->info['width'] - $w;
                $y = $this->info['height'] - $h;
                break;

            /* 填充 */
            case THINKIMAGE_THUMB_FILLED:
                //计算缩放比例
                if ($w < $width && $h < $height) {
                    $scale = 1;
                } else {
                    $scale = min($width / $w, $height / $h);
                }

                //设置缩略图的坐标及宽度和高度
                $neww = $w * $scale;
                $newh = $h * $scale;
                $posx = ($width - $w * $scale) / 2;
                $posy = ($height - $h * $scale) / 2;

                //创建一张新图像
                $newimg = new Imagick();
                $newimg->newImage($width, $height, 'white', $this->info['type']);

                if ('gif' == $this->info['type']) {
                    $imgs = $this->im->coalesceImages();
                    $img  = new Imagick();
                    $this->im->destroy(); //销毁原图

                    //循环填充每一帧
                    do {
                        //填充图像
                        $image = $this->_fill($newimg, $posx, $posy, $neww, $newh, $imgs);

                        $img->addImage($image);
                        $img->setImageDelay($imgs->getImageDelay());
                        $img->setImagePage($width, $height, 0, 0);

                        $image->destroy(); //销毁零时图片

                    } while ($imgs->nextImage());

                    //压缩图片
                    $this->im->destroy();
                    $this->im = $img->deconstructImages();
                    $imgs->destroy(); //销毁零时图片
                    $img->destroy(); //销毁零时图片

                } else {
                    //填充图像
                    $img = $this->_fill($newimg, $posx, $posy, $neww, $newh);
                    //销毁原图
                    $this->im->destroy();
                    $this->im = $img;
                }

                //设置新图像属性
                $this->info['width']  = $width;
                $this->info['height'] = $height;
                return;

            /* 固定 */
            case THINKIMAGE_THUMB_FIXED:
                $x = $y = 0;
                break;

            default:
                throw new \Exception('不支持的缩略图裁剪类型');
        }

        /* 裁剪图像 */
        $this->crop($w, $h, $x, $y, $width, $height);
    }
生成缩略图

@param  integer $width  缩略图最大宽度
@param  integer $height 缩略图最大高度
@param  integer $type   缩略图裁剪类型