php生成缩略图类_PHP教程

生成缩略图是当我们要上传图片时如果图片较大我们需要生成一张指定大小的小图以在列表页面显示，这样可节省资源也是现在常用的做法，下面我来分享一个php生成缩略图类，支持自定义高和宽。还支持按高和宽截图代码如下复制代码class resizeimage{//图片类型var $type;//实际宽度var $width;//实际高度var $height;//改变后的宽度var $resize_width;//改变后的高度var $resize_height;//是否裁图var $cut;//源图象var $srcimg;//目标图象地址var $dstimg;//临时创建的图象var $im;function resizeimage($img, $wid, $hei,$c,$dstpath){$this->srcimg = $img;$this->resize_width = $wid;$this->resize_height = $hei;$this->cut = $c;//图片的类型$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));//初始化图象$this->initi_img();//目标图象地址$this -> dst_img($dstpath);//--$this->width = imagesx($this->im);$this->height = imagesy($this->im);//生成图象$this->newimg();ImageDestroy ($this->im);}function newimg(){//改变后的图象的比例$resize_ratio = ($this->resize_width)/($this->resize_height);//实际图象的比例$ratio = ($this->width)/($this->height);if(($this->cut)=="1")//裁图{if($ratio>=$resize_ratio)//高度优先{$newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height);ImageJpeg ($newimg,$this->dstimg);}if($ratio//宽度优先{$newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio));ImageJpeg ($newimg,$this->dstimg);}}else//不裁图{if($ratio>=$resize_ratio){$newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this->height);ImageJpeg ($newimg,$this->dstimg);}if($ratio{$newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height);ImageJpeg ($newimg,$this->dstimg);}}}//初始化图象function initi_img(){if($this->type=="jpg"){$this->im = imagecreatefromjpeg($this->srcimg);}if($this->type=="gif"){$this->im = imagecreatefromgif($this->srcimg);}if($this->type=="png"){$this->im = imagecreatefrompng($this->srcimg);}}//图象目标地址function dst_img($dstpath){$full_length  = strlen($this->srcimg);$type_length  = strlen($this->type);$name_length  = $full_length-$type_length;$name         = substr($this->srcimg,0,$name_length-1);$this->dstimg = $dstpath;//echo $this->dstimg;}}$resizeimage = new resizeimage("11.jpg", "200", "150", "1","17.jpg");?>实例二代码如下复制代码PHP 8.5.5PHP 8.5.5 是 PHP 8.5 分支的维护更新版本。该版本延续了“小步快跑”的迭代逻辑，通过深度错误修复、底层性能微调以及安全加固，旨在为开发者提供一个更健壮、更高效的运行环境。该版本严格遵守语义化版本规范，不包含破坏性变更。下载/*** 生成缩略图* @author yangzhiguo0903@163.com* @param string     源图绝对完整地址{带文件名及后缀名}* @param string     目标图绝对完整地址{带文件名及后缀名}* @param int        缩略图宽{0:此时目标高度不能为0，目标宽度为源图宽*(目标高度/源图高)}* @param int        缩略图高{0:此时目标宽度不能为0，目标高度为源图高*(目标宽度/源图宽)}* @param int        是否裁切{宽,高必须非0}* @param int/float  缩放{0:不缩放, 0* @return boolean*/function img2thumb($src_img, $dst_img, $width = 75, $height = 75, $cut = 0, $proportion = 0){if(!is_file($src_img)){return false;}$ot = fileext($dst_img);$otfunc = 'image' . ($ot == 'jpg' ? 'jpeg' : $ot);$srcinfo = getimagesize($src_img);$src_w = $srcinfo[0];$src_h = $srcinfo[1];$type  = strtolower(substr(image_type_to_extension($srcinfo[2]), 1));$createfun = 'imagecreatefrom' . ($type == 'jpg' ? 'jpeg' : $type);$dst_h = $height;$dst_w = $width;$x = $y = 0;/*** 缩略图不超过源图尺寸（前提是宽或高只有一个）*/if(($width> $src_w && $height> $src_h) || ($height> $src_h && $width == 0) || ($width> $src_w && $height == 0)){$proportion = 1;}if($width> $src_w){$dst_w = $width = $src_w;}if($height> $src_h){$dst_h = $height = $src_h;}if(!$width && !$height && !$proportion){return false;}if(!$proportion){if($cut == 0){if($dst_w && $dst_h){if($dst_w/$src_w> $dst_h/$src_h){$dst_w = $src_w * ($dst_h / $src_h);$x = 0 - ($dst_w - $width) / 2;}else{$dst_h = $src_h * ($dst_w / $src_w);$y = 0 - ($dst_h - $height) / 2;}}else if($dst_w xor $dst_h){if($dst_w && !$dst_h)  //有宽无高{$propor = $dst_w / $src_w;$height = $dst_h  = $src_h * $propor;}else if(!$dst_w && $dst_h)  //有高无宽{$propor = $dst_h / $src_h;$width  = $dst_w = $src_w * $propor;}}}else{if(!$dst_h)  //裁剪时无高{$height = $dst_h = $dst_w;}if(!$dst_w)  //裁剪时无宽{$width = $dst_w = $dst_h;}$propor = min(max($dst_w / $src_w, $dst_h / $src_h), 1);$dst_w = (int)round($src_w * $propor);$dst_h = (int)round($src_h * $propor);$x = ($width - $dst_w) / 2;$y = ($height - $dst_h) / 2;}}else{$proportion = min($proportion, 1);$height = $dst_h = $src_h * $proportion;$width  = $dst_w = $src_w * $proportion;}$src = $createfun($src_img);$dst = imagecreatetruecolor($width ? $width : $dst_w, $height ? $height : $dst_h);$white = imagecolorallocate($dst, 255, 255, 255);imagefill($dst, 0, 0, $white);if(function_exists('imagecopyresampled')){imagecopyresampled($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);}else{imagecopyresized($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);}$otfunc($dst, $dst_img);imagedestroy($dst);imagedestroy($src);return true;}使用方法代码如下复制代码$src_img = "./ROSI_050_002.JPG";$dst_img = "./ROSI_050_002_thumb.jpg";$stat = img2thumb($src_img, $dst_img, $width = 200, $height = 300, $cut = 0, $proportion = 0);if($stat){echo 'Resize Image Success!';echo '@@##@@';}else{echo 'Resize Image Fail!';}http://www.bkjia.com/PHPjc/632963.html www.bkjia.com true http://www.bkjia.com/PHPjc/632963.html TechArticle生成缩略图是当我们要上传图片时如果图片较大我们需要生成一张指定大小的小图以在列表页面显示，这样可节省资源也是现在常用的做法...