PHP全功能无变形图片裁剪操作类与用法示例

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jpg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jpg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 : $this->sImage=imagecreatefromjpg($this->src_file); $this->ext='jpg'; break; case IMAGETYPE_PNG : $this->sImage=imagecreatefromjpg($this->src_file); $this->ext='jpg'; break; case IMAGETYPE_GIF : $this->sImage=imagecreatefromjpg($this->src_file); $this->ext='jpg'; break; default: exit(); } } function SaveImage($fileName='') { $this->dst_file=$fileName ? $fileName : $this->dst_file; switch($this->src_type) { case IMAGETYPE_JPEG : imagejpg($this->dImage,$this->dst_file,100); break; case IMAGETYPE_PNG : imagejpg($this->dImage,$this->dst_file); break; case IMAGETYPE_GIF : imagejpg($this->dImage,$this->dst_file); break; default: break; } } function OutImage() { switch($this->src_type) { case IMAGETYPE_JPEG : header('Content-type: image/jpg'); imagejpg($this->dImage); break; case IMAGETYPE_PNG : header('Content-type: image/jpg'); imagejpg($this->dImage); break; case IMAGETYPE_GIF : header('Content-type: image/jpg'); imagejpg($this->dImage); break; default: break; } } function SaveAlpha($fileName='') { $this->dst_file=$fileName ? $fileName . '.jpg' : $this->dst_file .'.jpg'; imagesavealpha($this->dImage, true); imagejpg($this->dImage,$this->dst_file); } function OutAlpha() { imagesavealpha($this->dImage, true); header('Content-type: image/jpg'); imagejpg($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 } ?>

 

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