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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 0 z! i8 i8 @0 s& B h
- $FILENAME="image.thumb"; 3 o9 u2 j$ V, L3 D7 M& T
- // 生成图片的宽度 5 A# E' P U$ [/ s0 c0 Y
- $RESIZEWIDTH=400; * e' b$ }9 R$ }. O: i% @3 I! X
- // 生成图片的高度
8 r& I+ w. d/ l0 r - $RESIZEHEIGHT=400;( B8 h: g# c1 M9 J% d
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- function ResizeImage($im,$maxwidth,$maxheight,$name){ . W8 s: K1 p! M! K) _5 a
- $width = imagesx($im); + i3 T# M8 U) i( y7 I
- $height = imagesy($im);
! r5 m0 \' ?! }4 F; v) g7 | - if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){ i/ n) t* x9 Y! H
- if($maxwidth && $width > $maxwidth){ 7 b3 h) w, ?. R6 ~& R" Q
- $widthratio = $maxwidth/$width;
0 j. K5 U. b2 U2 Y9 D - $RESIZEWIDTH=true; % \# W3 J' j6 ?1 ^' I: G
- } " L$ R# |5 l; x, E
- if($maxheight && $height > $maxheight){ 6 {' t) `* |; N& F
- $heightratio = $maxheight/$height;
3 g8 v e8 C3 S2 Q - $RESIZEHEIGHT=true; . y/ v+ E2 _# P5 o- v
- }
% e. u; e1 U7 R( J- ~8 C - if($RESIZEWIDTH && $RESIZEHEIGHT){
. l" X5 }0 e4 J, e7 D1 W$ D" g - if($widthratio < $heightratio){
) Y# v8 W2 x# G( j. C - $ratio = $widthratio;
* k0 n4 \8 a6 h6 l3 e - }else{ . E, t# L3 f! k5 }8 ]
- $ratio = $heightratio; / v! U0 F* Y: C7 m' c) P& f
- }
. Y" t( Z5 }; E2 M7 F; b0 V - }elseif($RESIZEWIDTH){ ! W0 p V% Z3 P! t5 Y5 p% _
- $ratio = $widthratio; " L, E7 v! ]9 X Z3 M/ _4 {
- }elseif($RESIZEHEIGHT){
5 T! n$ S& ~) D0 b - $ratio = $heightratio; ; b6 n9 r& z: R' D/ Q
- } + s$ F" E3 w0 z( Z/ e7 |
- $newwidth = $width * $ratio; ; ]" L& l# d& O- r, |" r' n( d
- $newheight = $height * $ratio;
6 N9 {# P& C! l1 |0 ]' G - if(function_exists("imagecopyresampled")){ 1 L# Q& j% y" H" r5 f& ?" n/ w
- $newim = imagecreatetruecolor($newwidth, $newheight);
* l0 u- F( }8 o - imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 2 q1 D6 Q! p# o
- }else{
/ [; F1 Z: e$ W - $newim = imagecreate($newwidth, $newheight); 7 M; H( G/ H, P# Y$ P) e
- imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
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- ImageJpeg ($newim,$name . ".jpg");
4 N* d2 ^3 y! j, L, [2 H - ImageDestroy ($newim); 0 S6 W7 _& R/ ^1 g2 d, _
- }else{
7 v$ l6 Z& u2 n0 y0 P/ y - ImageJpeg ($im,$name . ".jpg"); 2 p$ g+ b+ [( k/ p. g# Y* h A* u
- }
7 K+ x0 f5 F* q - }/ |( H4 T8 f0 O% g
- $ M+ M; k6 `: O ^- |
- if($_FILES['image']['size']){ 5 W# s; u6 z# J* A
- if($_FILES['image']['type'] == "image/pjpeg"){
6 j1 n! R& R, Q - $im = imagecreatefromjpeg($_FILES['image']['tmp_name']); # {# m/ F+ C2 L( ?- T
- }elseif($_FILES['image']['type'] == "image/x-png"){
: V5 E, t" D& U! ~9 k, e8 Y - $im = imagecreatefrompng($_FILES['image']['tmp_name']); 4 h4 C+ \7 B# E7 L: A( c# d
- }elseif($_FILES['image']['type'] == "image/gif"){
, e8 F5 F" l- N9 V - $im = imagecreatefromgif($_FILES['image']['tmp_name']);
' m' j0 n. [0 L, Y( o$ s: J - } 2881064151
9 J! Z9 J. M$ {5 q5 w0 x" I/ f# q - if($im){ % U1 R) Y w& G
- if(file_exists("$FILENAME.jpg")){ 1 I4 P% V7 G* O2 ~
- unlink("$FILENAME.jpg"); & U2 n( I, g- f. A- A& [
- } 5 H% Z" b/ x- d0 C% G# k6 s# [2 B
- ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
5 N3 k* {2 n3 e5 @ G0 A - ImageDestroy ($im); " \, _# C; Y$ q7 R& P5 M5 s
- }
- y( w" F# c: W n8 s - } * L0 U2 T# u! ]6 ^' k8 C. p
- ?>
复制代码 以下是测试代码(demo.php)
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代码如下:& `' {9 F: ]7 X5 `* y) Q
. l* o: T1 }3 c& }6 d+ S6 F- <?php ; Z( K: [: V4 v! I2 F
- include('ResizeImage.php');
# o1 i- U8 n1 C' J - if(!empty($_POST)){
( ?" M/ l" {* o8 s - echo($FILENAME.".jpg?cache=".rand(0,999999)); 4 R+ g+ ^( e6 A$ S. b: F: h
- } 1 e5 q5 H+ M0 H: f' j0 ?
- ?>
$ x* h2 I% q, K; t - <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
2 g3 Y/ V! |; S) }+ k' Y - <input type="file" name="image" size="50" value="浏览"><p>
$ [" ^! R0 ~5 u6 Z3 _/ D1 ] - <input type="submit" value="上传图片"> 6 E9 B# x8 E$ W1 A! }: Y7 ~
- </form>
复制代码 8 [* E( R1 ]2 q# E. z
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