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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
! y* C% C$ }( H) Q* U - $FILENAME="image.thumb";
& B( a5 Z( y. [& t, b( J - // 生成图片的宽度 ( q1 p$ b: W: S' K1 n* n
- $RESIZEWIDTH=400;
* r9 O& z8 ^: P4 i - // 生成图片的高度 7 R( G$ y/ P& {, g3 \
- $RESIZEHEIGHT=400;) A/ H% q8 c* ~) S
- % R: r1 H9 c* c. t+ v
- function ResizeImage($im,$maxwidth,$maxheight,$name){
, u4 X: e: G0 a, ~1 T) |; K/ V' N" r - $width = imagesx($im); / B, l* d2 d; b/ R7 m) j$ l# _
- $height = imagesy($im);
- }6 B* j+ a! U - if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
# b1 C) J1 t/ O" Y2 j9 n - if($maxwidth && $width > $maxwidth){
. _+ X" ?7 n8 f - $widthratio = $maxwidth/$width; 8 ^( J( f6 `8 J
- $RESIZEWIDTH=true; $ F0 X9 w! P4 b3 e' ] _8 P
- } & M! y4 D4 U8 \7 U6 g
- if($maxheight && $height > $maxheight){ $ i2 W% v j9 c0 e {
- $heightratio = $maxheight/$height; |: r6 O+ T6 n+ C/ F% H- F
- $RESIZEHEIGHT=true; # ^7 U2 I! X# I d% i
- }
# s/ D |. B3 y M. G4 _ H - if($RESIZEWIDTH && $RESIZEHEIGHT){
2 b$ x* P& P9 S2 _6 ?, G - if($widthratio < $heightratio){ ( R* b2 k: u. k: n i/ |
- $ratio = $widthratio;
) }1 p! f' M; W( G - }else{
0 \+ N% @1 w3 I( }- e' B7 h7 H- F2 u3 i - $ratio = $heightratio;
6 [8 L# [: s, H v' r& ] - }
' o: c/ ] `6 L - }elseif($RESIZEWIDTH){ " g/ k" V' R8 Y* Q; N+ `& u* F* T
- $ratio = $widthratio; & G8 U2 B. k3 d, _! ~( G
- }elseif($RESIZEHEIGHT){ 9 Z+ V9 |" |1 K; ]! [0 M7 a9 _- l
- $ratio = $heightratio; q- t$ F8 k4 T& a
- }
8 H& a" K3 b! Y) G# ~- ` - $newwidth = $width * $ratio;
' T7 P U: m( z& d- W( Q - $newheight = $height * $ratio; 2 e4 N5 B" W }8 E
- if(function_exists("imagecopyresampled")){ . ^1 {: [/ @! n
- $newim = imagecreatetruecolor($newwidth, $newheight); % G8 r. J; b8 Z
- imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); : `8 K. Z! z% P3 |
- }else{
: \' J) a7 h6 n. b' F% p! p - $newim = imagecreate($newwidth, $newheight); $ `% q; r9 o3 E* I) a% c) Y# S
- imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); ' T& H2 y4 N/ C) x
- } ; G- M# b* p/ {& a
- ImageJpeg ($newim,$name . ".jpg");
: N- h3 U$ \" y/ \. U - ImageDestroy ($newim);
, w( r) `/ }$ [6 N - }else{ + Y9 [, L. H* K" O7 T
- ImageJpeg ($im,$name . ".jpg"); " Z H- t7 l# ?/ Q
- }
3 a5 N8 e0 e1 M. j, Z' J) T - }
* y* t5 [2 D+ [% a - . `" S8 [' A7 D2 q& }# r
- if($_FILES['image']['size']){
; O1 y1 A3 I6 ?9 K - if($_FILES['image']['type'] == "image/pjpeg"){
9 V6 m, y; m7 m+ A; k+ c$ H2 a0 M - $im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
I2 s( P; f/ D. H0 l - }elseif($_FILES['image']['type'] == "image/x-png"){
3 }* g- c6 A: l2 X - $im = imagecreatefrompng($_FILES['image']['tmp_name']); * R4 ]1 g7 _, j6 n% V( _2 a' U) E
- }elseif($_FILES['image']['type'] == "image/gif"){
8 A$ \8 ? o, r- ^$ e! Y - $im = imagecreatefromgif($_FILES['image']['tmp_name']); ; L1 Z- y t! @7 @9 Y7 r3 H
- } 28810641510 s8 E( `* J2 I
- if($im){
6 @! e6 y; O D5 K2 T6 Q - if(file_exists("$FILENAME.jpg")){ ; ?% h Q3 ]/ w) @# \* G% @/ v
- unlink("$FILENAME.jpg");
9 n- [- Y7 k7 K% X7 B5 ^8 |6 ?# m8 z/ e - }
& s! y, B) [8 r8 k% u - ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME); : }; b, S9 X% a8 ]8 f
- ImageDestroy ($im); ' E @* l! q( f+ d1 @; E$ W* D6 h
- }
( Z$ ~1 W' }: |7 _ - }
- R( @8 H6 \) g/ F* n* a/ \- r1 r - ?>
复制代码 以下是测试代码(demo.php) - P8 }6 K; N. p7 Z" I
2 w; J& v: G: J) R
代码如下:
/ g! t3 Z$ Z4 P& ]% K, _2 f0 k. |6 s( I9 g* t
- <?php 1 x3 `" a% K8 ]1 G( q1 G
- include('ResizeImage.php');
/ J5 }+ w0 W$ w - if(!empty($_POST)){
3 q" X$ K$ T b X - echo($FILENAME.".jpg?cache=".rand(0,999999));
4 X8 n3 }+ D4 ~ - }
0 M% q4 @2 [$ v: y% ~' J - ?>
& v1 d o0 G% f0 K) a - <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
( _0 Y+ l0 k5 t4 \* G& M0 b* O' k - <input type="file" name="image" size="50" value="浏览"><p> . p+ G" v: [6 F" b
- <input type="submit" value="上传图片"> - G6 |; A7 ]7 _3 Z& W5 G
- </form>
复制代码 - X& G' N" e6 W1 U3 a* V( M, E
; ^, s5 X% X' K1 F& Q
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