本文实例讲述了PHP全功能无变形图片裁剪操作类与用法。分享给大家供大家参考，具体如下：
如果需要图片裁剪，或生成缩略图，这个基本上没有问题，全部需要的功能都在里面，全部都是无变形的。
这里我们划分为四种模式：
1. 任意图片裁剪到指定大小，超过的，剧中裁剪，并且最大化缩放，不够的拉伸，
2. 超过的剧中裁剪，而不足的，不拉伸，即只缩小，不放大裁剪，会产生补白，可以用png透明度来消除
3. 保留全部图片信息。不裁剪，只缩放，不足的补白。
4. 保留全部图片信息。不裁剪，只缩放，不足的不补白，产生的图片为实际有效像素大小，例如有个图片是600X600 现在要生成 120X100 那么缩放后的实际有效像素为100X100，所以只生成100X100的图片，而第三种模式则生成120X100的大小，并且有补白
代码如下
<?php
/**
* Author : smallchicken
* 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
*
* 调用方法：
*
* $ic=new ImageCrop('old.jpg','afterCrop.jpg');
* $ic->Crop(120,80,2);
* $ic->SaveImage();
* //$ic->SaveAlpha();将补白变成透明像素保存
* $ic->destory();
*
*
*/
class ImageCrop {
var $sImage;
var $dImage;
var $src_file;
var $dst_file;
var $src_width;
var $src_height;
var $src_ext;
var $src_type;
function ImageCrop($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
}
?>希望本文所述对大家PHP程序设计有所帮助。
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