下面提供三款生成缩代码，兼容性都相当的不错，也可以自定高度与宽度哦。
function imageresize($srcfile,$tow,$toh,$tofile="") { if($tofile==""){ $tofile = $srcfile; } $info = ""; $data = getimagesize($srcfile,$info); switch ($data[2]) { case 1: if(!function_exists("imagecreatefromgif")){ echo "你的gd库不能使用gif格式的图片，请使用jpeg或png格式！返回"; exit(); } $im = imagecreatefromgif($srcfile); break; case 2: if(!function_exists("imagecreatefromjpeg")){ echo "你的gd库不能使用jpeg格式的图片，请使用其它格式的图片！返回"; exit(); } $im = imagecreatefromjpeg($srcfile); break; case 3: $im = imagecreatefrompng($srcfile); break; } $srcw=imagesx($im); $srch=imagesy($im); $towh=$tow/$toh; $srcwh=$srcw/$srch; if($towh$tow||$srch>$toh) { if(function_exists("imagecreatetruecolor")){ @$ni = imagecreatetruecolor($ftow,$ftoh); if($ni) imagecopyresampled($ni,$im,0,0,0,0,$ftow,$ftoh,$srcw,$srch); else{ $ni=imagecreate($ftow,$ftoh); imagecopyresized($ni,$im,0,0,0,0,$ftow,$ftoh,$srcw,$srch); } }else{ $ni=imagecreate($ftow,$ftoh); imagecopyresized($ni,$im,0,0,0,0,$ftow,$ftoh,$srcw,$srch); } if(function_exists('imagejpeg')) imagejpeg($ni,$tofile); else imagepng($ni,$tofile); imagedestroy($ni); } imagedestroy($im); }
实例代码二
/*构造函数-生成缩略图+水印,参数说明:
$srcfile-图片文件名,
$dstfile-另存文件名,
$markwords-水印文字,
$markimage-水印图片,
$dstw-图片保存宽度,
$dsth-图片保存高度,
$rate-图片保存品质*/
makethumb("a.jpg","b.jpg","50","50");
function makethumb($srcfile,$dstfile,$dstw,$dsth,$rate=100,$markwords=null,$markimage=null)
{
$data = getimagesize($srcfile);
switch($data[2])
{
case 1:
$im=@imagecreatefromgif($srcfile);
break;
case 2:
$im=@imagecreatefromjpeg($srcfile);
break;
case 3:
$im=@imagecreatefrompng($srcfile);
break;
}
if(!$im) return false;
$srcw=imagesx($im);
$srch=imagesy($im);
$dstx=0;
$dsty=0;
if ($srcw*$dsth>$srch*$dstw)
{
$fdsth = round($srch*$dstw/$srcw);
$dsty = floor(($dsth-$fdsth)/2);
$fdstw = $dstw;
}
else
{
$fdstw = round($srcw*$dsth/$srch);
$dstx = floor(($dstw-$fdstw)/2);
$fdsth = $dsth;
}
$ni=imagecreatetruecolor($dstw,$dsth);
$dstx=($dstx $dsty=($dstx $dstx=($dstx>($dstw/2))?floor($dstw/2):$dstx;
$dsty=($dsty>($dsth/2))?floor($dsth/s):$dsty;
$white = imagecolorallocate($ni,255,255,255);
$black = imagecolorallocate($ni,0,0,0);
imagefilledrectangle($ni,0,0,$dstw,$dsth,$white);// 填充背景色
imagecopyresized($ni,$im,$dstx,$dsty,0,0,$fdstw,$fdsth,$srcw,$srch);
if($markwords!=null)
{
$markwords=iconv("gb2312","utf-8",$markwords);
//转换文字编码
imagettftext($ni,20,30,450,560,$black,"simhei.ttf",$markwords); //写入文字水印
//参数依次为，文字大小|偏转度|横坐标|纵坐标|文字颜色|文字类型|文字内容
}
elseif($markimage!=null)
{
$wimage_data = getimagesize($markimage);
switch($wimage_data[2])
{
case 1:
$wimage=@imagecreatefromgif($markimage);
break;
case 2:
$wimage=@imagecreatefromjpeg($markimage);
break;
case 3:
$wimage=@imagecreatefrompng($markimage);
break;
}
imagecopy($ni,$wimage,500,560,0,0,88,31); //写入图片水印,水印图片大小默认为88*31
imagedestroy($wimage);
}
imagejpeg($ni,$dstfile,$rate);
imagejpeg($ni,$srcfile,$rate);
imagedestroy($im);
imagedestroy($ni);
}
?>
支持图片上传代码
$pic_name=date("dmyhis");
立即学习“PHP免费学习笔记（深入）”；
// 生成图片的宽度
$pic_width=$_post['width'];// 生成图片的高度
$pic_height=$_post['length'];function resizeimage($im,$maxwidth,$maxheight,$name){
//取得当前图片大小
$width = imagesx($im);
$height = imagesy($im);
//生成缩略图的大小
if(($width > $maxwidth) || ($height > $maxheight)){
$widthratio = $maxwidth/$width;
$heightratio = $maxheight/$height;
if($widthratio $ratio = $widthratio;
}else{
$ratio = $heightratio;
}
$newwidth = $width * $ratio;
$newheight = $height * $ratio;
if(function_exists("imagecopyresampled")){
$newim = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}else{
$newim = imagecreate($newwidth, $newheight);
imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}
imagejpeg ($newim,$name . ".jpg");
imagedestroy ($newim);
}else{
imagejpeg ($im,$name . ".jpg");
}
}if($_files['image']['size']){
//echo $_files['image']['type'];
if($_files['image']['type'] == "image/pjpeg"||$_files['image']['type'] == "image/jpg"||$_files['image']['type'] == "image/jpeg"){
$im = imagecreatefromjpeg($_files['image']['tmp_name']);
}elseif($_files['image']['type'] == "image/x-png"){
$im = imagecreatefrompng($_files['image']['tmp_name']);
}elseif($_files['image']['type'] == "image/gif"){
$im = imagecreatefromgif($_files['image']['tmp_name']);
}
if($im){
if(file_exists($pic_name.'.jpg')){
unlink($pic_name.'.jpg');
}
resizeimage($im,$pic_width,$pic_height,$pic_name);
imagedestroy ($im);
}
}
?>
