<?php

/**

* ------------------------------------------

* 图片处理类 (GD2库)

* ------------------------------------------

*

* 根据实际需求设计的图片处理类, “居中剪裁”通常使用在用户头像、缩略图等场景, “等比缩放”通常用来压缩图片

*

* 1. 居中剪裁 (宽高自动)

* 2. 等比缩放 (宽高自动, 源图小于宽高的不做缩放)

* 3. 创建缩略图

* 4. 如果操作网络图片, 会在根目录生成"tmp.jpg" (用于测试)

*

*/

class Image

{

protected $source_image = ''; // 源文件路径

protected $width = ''; // 要设置的宽度

protected $height = ''; // 要设置的高度

protected $create_thumb = ''; // 是否创建缩略图

protected $thumb_marker = ''; // 缩略图后缀

public function __construct($config = array())

{

empty($config) or $this->initialize($config);

}

// 初始化配置

public function initialize($config)

{

$this->clear(); // 清除之前的配置

foreach ($config as $key => $val) {

if (isset($this->$key)) {

$this->$key = $val;

}

}

}

// 清除配置

public function clear()

{

$this->source_image = '';

$this->width = '';

$this->height = '';

$this->create_thumb = false;

$this->thumb_marker = '_thumb';

}

// 等比缩放

public function resize()

{

$source_path = $this->source_image;

$target_width = $this->width;

$target_height = $this->height;

list($source_width, $source_height) = $imagesize = getimagesize($source_path);

$source_mime = $imagesize['mime'];

switch ($source_mime) {

case 'image/gif':

$source_func = 'imagecreatefromgif';

$output_func = 'imagegif';

$suffix = '.gif';

break;

case 'image/png':

$source_func = 'imagecreatefrompng';

$output_func = 'imagepng';

$suffix = '.png';

break;

case 'image/jpeg':

$source_func = 'imagecreatefromjpeg';

$output_func = 'imagejpeg';

$suffix = '.jpg';

break;

default:

$source_func = 'imagecreatefromjpeg'; // 兼容app, 许多app上传的图片无mime信息

$output_func = 'imagejpeg';

$suffix = '.jpg';

break;

}

$source_image = $source_func($source_path);

$width_ratio = $target_width / $source_width;

$height_ratio = $target_height / $source_height;

// 源图宽高均小于要设置的值

if ($width_ratio >= 1 && $height_ratio >= 1) {

$target_image = $source_image;

} else {

// 根据缩放倍率小的宽或者高缩放

if ($width_ratio < $height_ratio) {

$zoom_width = $target_width;

$zoom_height = $source_height * ($target_width / $source_width);

} else {

$zoom_height = $target_height;

$zoom_width = $source_width * ($target_height / $source_height);

}

// 声明图片资源

$target_image = imagecreatetruecolor($zoom_width, $zoom_height);

// 保留png透明色

imagealphablending($target_image, false);

imagesavealpha($target_image, true);

// 缩放

imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $zoom_width, $zoom_height, $source_width, $source_height);

}

// 图片地址为url

if (strpos($source_path, 'http') !== false) {

$output_func($target_image, __DIR__ . '/tmp' . $suffix);

} else {

if ($this->create_thumb) {

$source_path = str_replace('.', $this->thumb_marker . '.', $source_path);

}

$output_func($target_image, $source_path);

}

//销毁资源

imagedestroy($source_image);

@imagedestroy($target_image);

}

// 居中剪裁

public function crop()

{

$source_path = $this->source_image;

$target_width = $this->width;

$target_height = $this->height;

list($source_width, $source_height) = $imagesize = getimagesize($source_path);

$source_mime = $imagesize['mime'];

$source_ratio = $source_height / $source_width;

$target_ratio = $target_height / $target_width;

if ($source_ratio > $target_ratio) {

// 源图过高

$cropped_width = $source_width;

$cropped_height = $source_width * $target_ratio;

$source_x = 0;

$source_y = ($source_height - $cropped_height) / 2;

} elseif ($source_ratio < $target_ratio) {

// 源图过宽

$cropped_width = $source_height / $target_ratio;

$cropped_height = $source_height;

$source_x = ($source_width - $cropped_width) / 2;

$source_y = 0;

} else {

// 源图适中

$cropped_width = $source_width;

$cropped_height = $source_height;

$source_x = 0;

$source_y = 0;

}

switch ($source_mime) {

case 'image/gif':

$source_func = 'imagecreatefromgif';

$output_func = 'imagegif';

$suffix = '.gif';

break;

case 'image/png':

$source_func = 'imagecreatefrompng';

$output_func = 'imagepng';

$suffix = '.png';

break;

case 'image/jpeg':

$source_func = 'imagecreatefromjpeg';

$output_func = 'imagejpeg';

$suffix = '.jpg';

break;

default:

$source_func = 'imagecreatefromjpeg'; // 兼容app, 许多app上传的图片无mime信息

$output_func = 'imagejpeg';

$suffix = '.jpg';

break;

}

$source_image = $source_func($source_path);

// 声明图片资源

$target_image = imagecreatetruecolor($target_width, $target_height);

$cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);

// 保留png透明色

imagealphablending($target_image, false);

imagesavealpha($target_image, true);

imagealphablending($cropped_image, false);

imagesavealpha($cropped_image, true);

// 裁剪

imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);

// 缩放

imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);

// 图片地址为url

if (strpos($source_path, 'http') !== false) {

$output_func($target_image, __DIR__ . '/tmp' . $suffix);

} else {

if ($this->create_thumb) {

$source_path = str_replace('.', $this->thumb_marker . '.', $source_path);

}

$output_func($target_image, $source_path);

}

// 销毁资源

imagedestroy($source_image);

imagedestroy($target_image);

imagedestroy($cropped_image);

}

}