php 生成缩略图 3种模式
2017-04-14
后端
1、把大图缩略到缩略图指定的范围内,可能有留白(原图细节不丢失)
2、把大图缩略到缩略图指定的范围内,不留白(原图会居中缩放,把超出的部分裁剪掉)
3、把大图缩略到缩略图指定的范围内,不留白(原图会剪切掉不符合比例的右边和下边)
thumb_stand.php
<?php
// http://localhost/exa5/thumb_image/thumb_stand.php?w=200&h=200
// 把大图缩略到缩略图指定的范围内,可能有留白(原图细节不丢失)
$w = $_GET['w']?$_GET['w']:200;
$h = $_GET['h']?$_GET['h']:200;
$filename = "stand_test_".$w."_".$h.".jpg";
image_resize( 'test.jpg',$filename, $w, $h);
header("content-type:image/png");//设定生成图片格式
echo file_get_contents($filename);
function image_resize($f, $t, $tw, $th)
{
// 按指定大小生成缩略图,而且不变形,缩略图函数
$temp = array(1=>'gif', 2=>'jpeg', 3=>'png');
list($fw, $fh, $tmp) = getimagesize($f);
if(!$temp[$tmp])
return false;
$tmp = $temp[$tmp];
$infunc = 'imagecreatefrom' . $tmp;
$outfunc = 'image'. $tmp;
$fimg = $infunc($f);
// 使缩略后的图片不变形,并且限制在 缩略图宽高范围内
if(($fw / $tw) > ($fh / $th))
$th = $tw * ($fh / $fw);
else
$tw = $th * ($fw / $fh);
$timg = imagecreatetruecolor($tw, $th);
imagecopyresampled($timg, $fimg, 0,0, 0,0, $tw, $th, $fw, $fh);
if($outfunc($timg, $t))
return true;
else
return false; }
?>
thumb_cut.php
<?php
// http://localhost/exa5/thumb_image/thumb_cut.php?w=200&h=200
// 把大图缩略到缩略图指定的范围内,不留白(原图会居中缩放,把超出的部分裁剪掉)
$w = $_GET['w']?$_GET['w']:200;
$h = $_GET['h']?$_GET['h']:200;
$filename = "cut_test_".$w."_".$h.".jpg";
image_resize( 'test.jpg',$filename, $w, $h);
header("content-type:image/png");//设定生成 图片 格式
echo file_get_contents($filename);
// 按指定大小生成缩略图,而且不变形,缩略图函数
function image_resize($f, $t, $tw, $th){
$temp = array(1=>'gif', 2=>'jpeg', 3=>'png');
list($fw, $fh, $tmp) = getimagesize($f);
if(!$temp[$tmp]){
return false;
}
$tmp = $temp[$tmp];
$infunc = "imagecreatefrom$tmp";
$outfunc = "image$tmp";
$fimg = $infunc($f);
// $fw = 10;
// $fh = 4;
// $tw = 4;
// $th = 2;
// 把图片铺满要缩放的区域
if($fw/$tw > $fh/$th){
$zh = $th;
$zw = $zh*($fw/$fh);
$_zw = ($zw-$tw)/2;
}else{
$zw = $tw;
$zh = $zw*($fh/$fw);
$_zh = ($zh-$th)/2;
}
// echo $zw."<br>";
// echo $zh."<br>";
// echo $_zw."<br>";
// echo $_zh."<br>";
// exit;
$zimg = imagecreatetruecolor($zw, $zh);
// 先把图像放满区域
imagecopyresampled($zimg, $fimg, 0,0, 0,0, $zw,$zh, $fw,$fh);
// 再截取到指定的宽高度
$timg = imagecreatetruecolor($tw, $th);
imagecopyresampled($timg, $zimg, 0,0, 0+$_zw,0+$_zh, $tw,$th, $zw-$_zw*2,$zh-$_zh*2);
//
if($outfunc($timg, $t)){
return true;
}else{
return false;
}
}
?>
thumb_strict.php
<?php
// http://localhost/exa5/thumb_image/thumb_strict.php?w=200&h=200
// 把大图缩略到缩略图指定的范围内,不留白(原图会剪切掉不符合比例的右边和下边)
$w = $_GET['w']?$_GET['w']:200;
$h = $_GET['h']?$_GET['h']:200;
$filename = "strict_test_".$w."_".$h.".jpg";
image_resize( 'test.jpg',$filename, $w, $h);
header("content-type:image/png");//设定生成图片格式
echo file_get_contents($filename);
function image_resize($f, $t, $tw, $th){
// 按指定大小生成缩略图,而且不变形,缩略图函数
$temp = array(1=>'gif', 2=>'jpeg', 3=>'png');
list($fw, $fh, $tmp) = getimagesize($f);
if(!$temp[$tmp]){
return false;
}
$tmp = $temp[$tmp];
$infunc = "imagecreatefrom$tmp";
$outfunc = "image$tmp";
$fimg = $infunc($f);
if($fw/$tw > $fh/$th){
$fw = $tw * ($fh/$th);
}else{
$fh = $th * ($fw/$tw);
}
$timg = imagecreatetruecolor($tw, $th);
imagecopyresampled($timg, $fimg, 0,0, 0,0, $tw,$th, $fw,$fh);
if($outfunc($timg, $t)){
return true;
}else{
return false;
}
}