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PHP用GD库生成高质量的缩略图片,PHP一般情况下生成的缩略图都比较不理想。今天试用PHP,GD库来生成缩略图。虽然并不100%完美。可是也应该可以满足缩略图的要求了。- <?php 4 \5 B) c* _& {0 X
- $FILENAME="image.thumb"; 7 e) \1 g& e2 N3 g7 z6 @5 Y% |
- // 生成图片的宽度
7 O1 h+ Z7 S& {+ u# M. j - $RESIZEWIDTH=400; 6 Z# r. x4 b3 E% l6 W' |1 h
- // 生成图片的高度
6 ~. W- l# H) [( T! r$ V% ~ - $RESIZEHEIGHT=400;
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' q9 k, @: }, F- u) t3 }9 k- function ResizeImage($im,$maxwidth,$maxheight,$name){
2 j/ a4 A; _- v G - $width = imagesx($im);
* j& `/ K! N G% p( d - $height = imagesy($im);
$ j d; S2 ?' _9 L% v3 M5 \3 c - if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
; q7 @2 Y! H1 c) i9 b# H - if($maxwidth && $width > $maxwidth){ ' y8 S) g; g/ z5 h, v. R
- $widthratio = $maxwidth/$width;
4 A W2 L5 R7 `+ F( j" b. e" [+ r - $RESIZEWIDTH=true; 1 I1 v4 D2 w# M J, b3 N' c V
- } . c/ f, k" o+ X
- if($maxheight && $height > $maxheight){
- x/ D8 p* P, _3 r7 l; c( m - $heightratio = $maxheight/$height;
3 m) R! r" L/ V% h9 [ - $RESIZEHEIGHT=true;
, _$ o7 j6 U' `9 J% U* [7 A1 a6 ^ - }
, F! S3 B" o& G: n3 q1 [6 {$ J! {2 { - if($RESIZEWIDTH && $RESIZEHEIGHT){
- N2 ^3 g/ v- z' }( D - if($widthratio < $heightratio){
" g1 S; O6 j% n' G% m1 f4 i - $ratio = $widthratio; 3 h& o1 U9 z7 i# Y) s! b3 B, t
- }else{
t" I2 j6 E# F/ S3 {5 c# g: c - $ratio = $heightratio;
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- }elseif($RESIZEWIDTH){ ' h8 M" Q6 q" w
- $ratio = $widthratio; % i8 W9 A, x1 N
- }elseif($RESIZEHEIGHT){ ' J+ }7 @. w' Y: b
- $ratio = $heightratio; 3 |) _$ ?) G0 Z5 G: f
- }
- d( j* x) r, ?; H2 U4 v) e4 g, c$ e - $newwidth = $width * $ratio;
8 N( t, x. {0 m0 o Z - $newheight = $height * $ratio;
! x1 Z* |* G: O - if(function_exists("imagecopyresampled")){ . F8 M0 q. g% S. k
- $newim = imagecreatetruecolor($newwidth, $newheight);
" ?2 N' Q/ M+ F. j - imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); $ D5 q- i8 m% C1 [8 [% ~
- }else{
) f0 k' `5 w: A2 n1 e8 ^" a* U$ G - $newim = imagecreate($newwidth, $newheight);
7 a+ }7 ^2 q% L( @ q) t* J - imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); ) H3 B3 H$ n: P! }0 ], u7 y. g
- }
3 b# ^, s; {3 C7 G1 P' b1 j; P - ImageJpeg ($newim,$name . ".jpg"); - F4 z- E- S3 E0 H
- ImageDestroy ($newim); 3 `: Q/ [8 z0 e. j
- }else{ 9 }! t( l6 h' h. H7 [2 G
- ImageJpeg ($im,$name . ".jpg");
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- 8 B3 H) R" v& A) ^
- if($_FILES['image']['size']){ & o) }8 X0 B8 B0 H6 _2 e+ o) C X+ l
- if($_FILES['image']['type'] == "image/pjpeg"){
" a1 H/ A$ u2 q1 `* P6 |. H7 k - $im = imagecreatefromjpeg($_FILES['image']['tmp_name']); * [! T1 R3 ]% D2 Y2 W+ a
- }elseif($_FILES['image']['type'] == "image/x-png"){
4 s V( f) V7 B! o O- b# | - $im = imagecreatefrompng($_FILES['image']['tmp_name']); ( i N9 ^, E4 G ?+ p' S
- }elseif($_FILES['image']['type'] == "image/gif"){
5 n8 C D- Y& ` z$ U# N( R - $im = imagecreatefromgif($_FILES['image']['tmp_name']);
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- if($im){
1 }4 L" U, m0 [+ @ A - if(file_exists("$FILENAME.jpg")){ ' D4 v1 ]) M ?6 H% t' b+ n3 S
- unlink("$FILENAME.jpg");
) K; \$ K: g* z% ` - }
) T8 p/ g* x) M' ^6 Q - ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME); $ C+ z7 V9 B8 a
- ImageDestroy ($im);
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- } 1 _, g( Y9 Z, N6 `' f
- ?>
复制代码 以下是测试代码(demo.php)
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# q7 a+ K, L" J1 ]! [: n代码如下:
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* z# X; R& D( y/ C2 y8 l# F% x- <?php ' Y: h5 L {7 m/ q8 z
- include('ResizeImage.php');
3 o- [8 I5 r1 E8 p3 g4 O: f - if(!empty($_POST)){ # E" s# G) p9 V0 Z1 o2 J7 s+ {
- echo($FILENAME.".jpg?cache=".rand(0,999999));
: z% ^2 K4 B: }" T2 I+ f% Y- x - }
( O' y3 U$ {6 ~6 n - ?>
5 P) ]& @7 V7 s - <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" > ; F" x% x, w- ^+ s
- <input type="file" name="image" size="50" value="浏览"><p>
, i( A0 |0 I: B# m - <input type="submit" value="上传图片"> 3 d3 U2 m2 o/ e- V) F c
- </form>
复制代码
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