php 生成图像的步骤：
imagecreatefromjpeg()//读取原图片文件，解析成图片
ImageCreateTrueColor();//创建一个黑色背景图片
imagecopyresampled();//将原来图片的部分提取出来生成目标图片
imagejpeg();目标图片生成文件。
图片方法文档：http://php.net/manual/zh/ref.image.php
掏中并且压缩类
class lswimage {
private $filename;
private $ext;
private $x;
private $y;
private $x1;
private $y1;
private $width;
private $height;
private $dst_name;
private $jpeg_quality = 90;
private $mark_img="/data/water.png";
/**
* 截取并且压缩图片 陈荣达
* @param type $filename 原来文件
* @param type $dst_w 压缩的宽度
* @param type $dst_h 压缩的高度
* @param type $dst_name 压缩的命名：比如y_480_***.jpg, 只需要赋予$dst_name="y_480"即可
*/
public function index($filename, $dst_w, $dst_h, $dst_name) {
//初始化
$this->width = $dst_w;
$this->height = $dst_h;
$this->dst_name = $dst_name;
//判断比例 以便截取
$proportion = $dst_h / $dst_w;
//获取待处理图片信息
$image_info = getimagesize($filename);
//算出需要的高度
$need_height = $image_info['0'] * $proportion;
//进行比较
if ($image_info['1'] > $need_height) {//实际的高比需要的高大
$src_y = ($image_info['1'] - $need_height) / 2;
$src_x = 0;
$src_h = $need_height;
$src_w = $image_info['0'];
} else if ($image_info['0'] < $need_height) {//实际的高比需要的高小
$need_width = $image_info['1'] / $proportion;
$src_y = 0;
$src_x = ($image_info['0'] - $need_width) / 2;
$src_h = $image_info['1'];
$src_w = $need_width;
} else {//实际的高与需要的高相等，那么就不需要截取了，直接压缩
$src_y = 0;
$src_x = 0;
$src_h = $image_info['1'];
$src_w = $image_info['0'];
}
$this->initialize($filename, $src_x, $src_y, $src_w, $src_h);
$this->generate_shot();
}
/**
* 给图片添加水印
* @param filepath $src 待处理图片
* @param filepath $mark_img 水印图片路径
* @param string $position 水印位置 lt左上 rt右上 rb右下 lb左下 其余取值为中间
* @param int $quality jpg图片质量，仅对jpg有效 默认85 取值 0-100之间整数
* @param int $pct 水印图片融合度(透明度)
*
* @return void
*/
public function water_mark($src, $position = 'rb', $pct = 80) {
$mark_img= $this->mark_img;
$quality= $this->jpeg_quality;
if (function_exists('imagecopy') && function_exists('imagecopymerge')) {
$data = getimagesize($src);
if ($data[2] > 3) {
return false;
}
$src_width = $data[0];
$src_height = $data[1];
$src_type = $data[2];
$data = getimagesize($mark_img);
$mark_width = $data[0];
$mark_height = $data[1];
$mark_type = $data[2];
if ($src_width < ($mark_width + 20) || $src_width < ($mark_height + 20)) {
return false;
}
switch ($src_type) {
case 1:
$src_im = imagecreatefromgif($src);
$imagefunc = function_exists('imagejpeg') ? 'imagejpeg' : '';
break;
case 2:
$src_im = imagecreatefromjpeg($src);
$imagefunc = function_exists('imagegif') ? 'imagejpeg' : '';
break;
case 3:
$src_im = imagecreatefrompng($src);
$imagefunc = function_exists('imagepng') ? 'imagejpeg' : '';
break;
}
switch ($mark_type) {
case 1:
$mark_im = imagecreatefromgif($mark_img);
break;
case 2:
$mark_im = imagecreatefromjpeg($mark_img);
break;
case 3:
$mark_im = imagecreatefrompng($mark_img);
break;
}
switch ($position) {
case 'lt':
$x = 10;
$y = 10;
break;
case 'rt':
$x = $src_width - $mark_width - 10;
$y = 10;
break;
case 'rb':
$x = $src_width - $mark_width - 10;
$y = $src_height - $mark_height - 10;
break;
case 'lb':
$x = 10;
$y = $src_height - $mark_height - 10;
break;
default:
$x = ($src_width - $mark_width - 10) / 2;
$y = ($src_height - $mark_height - 10) / 2;
break;
}
if (function_exists('imagealphablending'))
imageAlphaBlending($mark_im, true);
// imageCopyMerge($src_im, $mark_im, $x, $y, 0, 0, $mark_width, $mark_height, $pct);
imagecopy($src_im, $mark_im, $x, $y, 0, 0, $mark_width, $mark_height);
if ($src_type == 2) {
$imagefunc($src_im, $src, $quality);
} else {
$imagefunc($src_im, $src);
}
}
}
/**
* 初始化截图对象
* @param filename 源文件路径全明
* @param width 截图的宽
* @param height 截图的高
* @param x 横坐标1
* @param y 纵坐标1
* @param x1 横坐标1
* @param y1 横坐标2
*
*/
private function initialize($filename, $x, $y, $x1, $y1) {
if (file_exists($filename)) {
$this->filename = $filename;
$pathinfo = pathinfo($filename);
$this->ext = $pathinfo['extension'];
} else {
$e = new Exception('the file is not exists!', 1050);
throw $e;
}
$this->x = $x;
$this->y = $y;
$this->x1 = $x1;
$this->y1 = $y1;
}
/**
* 生成截图
* 根据图片的格式，生成不同的截图
*/
private function generate_shot() {
switch ($this->ext) {
case 'jpg':
return $this->generate_jpg();
break;
case 'png':
return $this->generate_png();
break;
case 'gif':
return $this->generate_gif();
break;
default:
return false;
}
}
/**
* 得到生成的截图的文件名
*
*/
private function get_shot_name() {
$pathinfo = pathinfo($this->filename);
$filename = $this->dst_name . "_" . $pathinfo['basename'];
return $pathinfo['dirname'] . '/' . $filename;
}
/**
* 生成jpg格式的图片
*
*/
private function generate_jpg() {
$shot_name = $this->get_shot_name();
$img_r = imagecreatefromjpeg($this->filename);
$dst_r = ImageCreateTrueColor($this->width, $this->height);
imagecopyresampled($dst_r, $img_r, 0, 0, $this->x, $this->y,
$this->width, $this->height, $this->x1, $this->y1);
imagejpeg($dst_r, $shot_name, $this->jpeg_quality);
return $shot_name;
}
/**
* 生成gif格式的图片
*
*/
private function generate_gif() {
$shot_name = $this->get_shot_name();
$img_r = imagecreatefromgif($this->filename);
$dst_r = ImageCreateTrueColor($this->width, $this->height);
imagecopyresampled($dst_r, $img_r, 0, 0, $this->x, $this->y,
$this->width, $this->height, $this->x1, $this->y1);
imagegif($dst_r, $shot_name);
return $shot_name;
}
/**
* 生成png格式的图片
*
*/
private function generate_png() {
$shot_name = $this->get_shot_name();
$img_r = imagecreatefrompng($this->filename);
$dst_r = ImageCreateTrueColor($this->width, $this->height);
imagecopyresampled($dst_r, $img_r, 0, 0, $this->x, $this->y,
$this->width, $this->height, $this->x1, $this->y1);
imagepng($dst_r, $shot_name);
return $shot_name;
}
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