PHP图像裁剪缩略裁切类源码及使用方法


            最近在做网页拖拽验证码的开源项目，需要在服务端生成图片对应的可移动的色块，但是网上的资源都是做缩略图，对整个图片进行缩放的，所以自己动手，完成了对图片进行裁剪小块的工具





<?php

namespace App\Libs;

/**

* 2016-01-07 15:54:58

* Lixiaoyu

* 

* mode 1 : 强制裁剪，生成图片严格按照需要，不足放大，超过裁剪，图片始终铺满

* mode 2 : 和1类似，但不足的时候 不放大 会产生补白，可以用png消除。

* mode 3 : 只缩放，不裁剪，保留全部图片信息，会产生补白，

* mode 4 : 只缩放，不裁剪，保留全部图片信息，生成图片大小为最终缩放后的图片有效信息的实际大小，不产生补白

* 默认补白为白色，如果要使补白成透明像素，请使用SaveAlpha()方法代替SaveImage()方法

*/

class ImageCrop{

var $sImage;

var $dImage;

var $src_file;

var $dst_file;

var $src_width;

var $src_height;

var $src_ext;

var $src_type;

function __construct($src_file,$dst_file=''){

$this->src_file=$src_file;

$this->dst_file=$dst_file;

$this->LoadImage();

}

function SetSrcFile($src_file){

$this->src_file=$src_file;

}

function SetDstFile($dst_file){

$this->dst_file=$dst_file;

}

function LoadImage(){

list($this->src_width, $this->src_height, $this->src_type) = getimagesize($this->src_file);

switch($this->src_type) {

case IMAGETYPE_JPEG :

$this->sImage=imagecreatefromjpeg($this->src_file);

$this->ext='jpg';

break;

case IMAGETYPE_PNG :

$this->sImage=imagecreatefrompng($this->src_file);

$this->ext='png';

break;

case IMAGETYPE_GIF :

$this->sImage=imagecreatefromgif($this->src_file);

$this->ext='gif';

break;

default:

exit();

}

}

function SaveImage($fileName=''){

$this->dst_file=$fileName ? $fileName : $this->dst_file;

switch($this->src_type) {

case IMAGETYPE_JPEG :

imagejpeg($this->dImage,$this->dst_file,100);

break;

case IMAGETYPE_PNG :

imagepng($this->dImage,$this->dst_file);

break;

case IMAGETYPE_GIF :

imagegif($this->dImage,$this->dst_file);

break;

default:

break;

}

}

function OutImage(){

switch($this->src_type) {

case IMAGETYPE_JPEG :

header('Content-type: image/jpeg');

imagejpeg($this->dImage);

break;

case IMAGETYPE_PNG :

header('Content-type: image/png');

imagepng($this->dImage);

break;

case IMAGETYPE_GIF :

header('Content-type: image/gif');

imagegif($this->dImage);

break;

default:

break;

}

}

function SaveAlpha($fileName=''){

$this->dst_file=$fileName ? $fileName . '.png' : $this->dst_file .'.png';

imagesavealpha($this->dImage, true);

imagepng($this->dImage,$this->dst_file);

}

function OutAlpha(){

imagesavealpha($this->dImage, true);

header('Content-type: image/png');

imagepng($this->dImage);

}

function destory(){

imagedestroy($this->sImage);

imagedestroy($this->dImage);

}

function Crop($dst_width,$dst_height,$mode=1,$dst_file=''){

if($dst_file) $this->dst_file=$dst_file;

$this->dImage = imagecreatetruecolor($dst_width,$dst_height);

$bg = imagecolorallocatealpha($this->dImage,255,255,255,127);

imagefill($this->dImage, 0, 0, $bg);

imagecolortransparent($this->dImage,$bg);

$ratio_w=1.0 * $dst_width / $this->src_width;

$ratio_h=1.0 * $dst_height / $this->src_height;

$ratio=1.0;

switch($mode){

case 1: // always crop

if( ($ratio_w < 1 && $ratio_h < 1) || ($ratio_w > 1 && $ratio_h > 1)){

$ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

$tmp_w = (int)($dst_width / $ratio);

$tmp_h = (int)($dst_height / $ratio);

$tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);

$src_x = (int) (($this->src_width-$tmp_w)/2) ;

$src_y = (int) (($this->src_height-$tmp_h)/2) ;

imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);

imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);

imagedestroy($tmp_img);

}else{

$ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

$tmp_w = (int)($this->src_width * $ratio);

$tmp_h = (int)($this->src_height * $ratio);

$tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);

imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

$src_x = (int)($tmp_w - $dst_width) / 2 ;

$src_y = (int)($tmp_h - $dst_height) / 2 ;

imagecopy($this->dImage, $tmp_img, 0,0,$src_x,$src_y,$dst_width,$dst_height);

imagedestroy($tmp_img);

}

break;

case 2: // only small

if($ratio_w < 1 && $ratio_h < 1){

$ratio = $ratio_w < $ratio_h ? $ratio_h : $ratio_w;

$tmp_w = (int)($dst_width / $ratio);

$tmp_h = (int)($dst_height / $ratio);

$tmp_img=imagecreatetruecolor($tmp_w , $tmp_h);

$src_x = (int) ($this->src_width-$tmp_w)/2 ;

$src_y = (int) ($this->src_height-$tmp_h)/2 ;

imagecopy($tmp_img, $this->sImage, 0,0,$src_x,$src_y,$tmp_w,$tmp_h);

imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h);

imagedestroy($tmp_img);

}elseif($ratio_w > 1 && $ratio_h > 1){

$dst_x = (int) abs($dst_width - $this->src_width) / 2 ;

$dst_y = (int) abs($dst_height -$this->src_height) / 2;

imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,0,0,$this->src_width,$this->src_height);

}else{

$src_x=0;$dst_x=0;$src_y=0;$dst_y=0;

if(($dst_width - $this->src_width) < 0){

$src_x = (int) ($this->src_width - $dst_width)/2;

$dst_x =0;

}else{

$src_x =0;

$dst_x = (int) ($dst_width - $this->src_width)/2;

}

if( ($dst_height -$this->src_height) < 0){

$src_y = (int) ($this->src_height - $dst_height)/2;

$dst_y = 0;

}else{

$src_y = 0;

$dst_y = (int) ($dst_height - $this->src_height)/2;

}

imagecopy($this->dImage, $this->sImage,$dst_x,$dst_y,$src_x,$src_y,$this->src_width,$this->src_height);

}

break;

case 3: // keep all image size and create need size

if($ratio_w > 1 && $ratio_h > 1){

$dst_x = (int)(abs($dst_width - $this->src_width )/2) ;

$dst_y = (int)(abs($dst_height- $this->src_height)/2) ;

imagecopy($this->dImage, $this->sImage, $dst_x,$dst_y,0,0,$this->src_width,$this->src_height);

}else{

$ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;

$tmp_w = (int)($this->src_width * $ratio);

$tmp_h = (int)($this->src_height * $ratio);

$tmp_img=imagecreatetruecolor($tmp_w ,$tmp_h);

imagecopyresampled($tmp_img,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

$dst_x = (int)(abs($tmp_w -$dst_width )/2) ;

$dst_y = (int)(abs($tmp_h -$dst_height)/2) ;

imagecopy($this->dImage, $tmp_img, $dst_x,$dst_y,0,0,$tmp_w,$tmp_h);

imagedestroy($tmp_img);

}

break;

case 4: // keep all image but create actually size

if($ratio_w > 1 && $ratio_h > 1){

$this->dImage = imagecreatetruecolor($this->src_width,$this->src_height);

imagecopy($this->dImage, $this->sImage,0,0,0,0,$this->src_width,$this->src_height);

}else{

$ratio = $ratio_w > $ratio_h ? $ratio_h : $ratio_w;

$tmp_w = (int)($this->src_width * $ratio);

$tmp_h = (int)($this->src_height * $ratio);

$this->dImage = imagecreatetruecolor($tmp_w ,$tmp_h);

imagecopyresampled($this->dImage,$this->sImage,0,0,0,0,$tmp_w,$tmp_h,$this->src_width,$this->src_height);

}

break;

}

}// end Crop

/**

*

* 裁切方法

* 2016-01-07 15:05:44

* Lixiaoyu

*

* @param $dst_width 目标长

* @param $dst_height 目标高

* @param $dst_x 裁剪部分和原图左侧的距离

* @param $dst_y 裁剪部分和原图右侧的距离

* @param int $mode 模式

* @param string $dst_file 目标文件路径

*/

function Cut($dst_width,$dst_height,$dst_x,$dst_y,$dst_file='')

{

if ($dst_file) $this->dst_file = $dst_file; //设置目标文件位置

$this->dImage = imagecreatetruecolor($dst_width, $dst_height); //创建了目标文件的大小的画布

$bg = imagecolorallocatealpha($this->dImage, 255, 255, 255, 127); //给画布分配颜色

imagefill($this->dImage, 0, 0, $bg); //给图像用颜色进行填充

imagecolortransparent($this->dImage, $bg); //背景定义成透明色

$ratio_w = 1.0 * $dst_width / $this->src_width; //横向缩放的比例

$ratio_h = 1.0 * $dst_height / $this->src_height; //纵向缩放的比例

//var_dump($this);

//不进行缩放,直接对图像进行裁剪

$ratio = 1.0;

$tmp_w = (int)($dst_width / $ratio);

$tmp_h = (int)($dst_height / $ratio);

$tmp_img = imagecreatetruecolor($dst_width, $dst_height); //创建暂时保存的画布

imagecopy($tmp_img, $this->sImage, 0,0,$dst_x,$dst_y,$dst_width,$dst_height); //拷贝出图像的一部分,进行裁切

imagecopyresampled($this->dImage,$tmp_img,0,0,0,0,$dst_width,$dst_height,$tmp_w,$tmp_h); //把暂时缓存的图片,放到目标文件里面

imagedestroy($tmp_img);

}

}

?>



Use

裁剪图像





$ic=new ImageCrop($pathToFile,'./pic/afterCrop'.time().'.jpg');

$ic->Cut(40,30,120,130);

$ic->SaveImage();

//$ic->SaveAlpha();将补白变成透明像素保存

$ic->destory();



实现效果



原图





裁剪之后的图



缩放图像

原图



缩略图



本文重点在于使用图像处理函数 imagecopy 和 imagecopyresampled

bool imagecopy ( resource dstim,resourcesrc_im , int dstx,intdst_y , int srcx,intsrc_y , int srcw,intsrc_h ) 

将 src_im 图像中坐标从 src_x，src_y 开始，宽度为 src_w，高度为 src_h 的一部分拷贝到 dst_im 图像中坐标为 dst_x 和 dst_y 的位置上。