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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
+ ]2 o9 h/ r- ]' Y1 B% T - $FILENAME="image.thumb"; 0 N, b( x# y0 y0 y
- // 生成图片的宽度
7 U' @* f; U& i: ` - $RESIZEWIDTH=400; * d4 k4 a/ o* D& P" L, }& R
- // 生成图片的高度
+ V/ P% }" f9 h: k ?$ Z - $RESIZEHEIGHT=400;
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( x" G/ l J; d# k: H- function ResizeImage($im,$maxwidth,$maxheight,$name){
0 l/ j- G" y" e& b! O& u R! G - $width = imagesx($im);
# i+ h7 z( P# E/ B7 n - $height = imagesy($im);
3 `2 r8 z4 W$ Z - if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){ ) D% \9 S( n4 A. o* i& W2 N
- if($maxwidth && $width > $maxwidth){ / X: k! R' i3 H# G$ w. X
- $widthratio = $maxwidth/$width; ; v* o' d5 b' u- ~. j
- $RESIZEWIDTH=true;
+ [- X+ A, _ R% H( N - }
* m$ ` q" o% |- P - if($maxheight && $height > $maxheight){ . N( _, m4 z D* i
- $heightratio = $maxheight/$height; . H; q2 D) \3 N9 m. W
- $RESIZEHEIGHT=true; 5 r+ G$ f$ C3 s$ _1 E
- } 8 x; s% F3 M/ ?" Q
- if($RESIZEWIDTH && $RESIZEHEIGHT){
9 B2 P6 n+ i; F8 Y" l - if($widthratio < $heightratio){
( n. P, l& `9 n* p3 [8 X0 ~; n - $ratio = $widthratio; , q2 p, R3 e6 z% k. Q/ `: y
- }else{ 0 z) { Q1 w& y4 F) J# Q0 s
- $ratio = $heightratio; 7 }" Q% {! y9 ]' g3 {" `9 F0 e4 |
- } 1 Z; E8 ^% `# u; P1 f1 X
- }elseif($RESIZEWIDTH){ . n' j4 Z, g. O) i
- $ratio = $widthratio;
- H/ W6 \6 _+ L# q6 T3 a, p& n - }elseif($RESIZEHEIGHT){ 8 M- w0 L8 y0 k* X# }5 j" p
- $ratio = $heightratio;
: w4 I/ {5 X) V - }
/ o% ~; R5 S; p$ t - $newwidth = $width * $ratio;
- c- j# ]2 v! u' H5 H - $newheight = $height * $ratio;
6 O# F g! P! ?7 r3 }, ~! [3 ^8 ~ - if(function_exists("imagecopyresampled")){
/ A9 \$ t. R7 m) U4 P - $newim = imagecreatetruecolor($newwidth, $newheight); 9 J7 d9 [, v2 \& @* a' @
- imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
7 t6 S- D5 Z4 }' f. c8 C" ? - }else{ - r9 Q& ?4 k# H: x! B
- $newim = imagecreate($newwidth, $newheight); 4 |, u9 X/ g N2 R- A0 m4 u
- imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
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- ImageJpeg ($newim,$name . ".jpg"); 2 b2 g; |# k: G7 ^' C7 H
- ImageDestroy ($newim); ; F$ r/ M3 h6 P# G8 f5 M! U
- }else{ / O% {: p4 Q) t
- ImageJpeg ($im,$name . ".jpg"); $ z! R1 B7 r/ x/ o, @$ V0 S: r0 M
- }
7 h& n/ k. w9 S K4 I* S - }
9 g2 B0 I( H5 q7 l- }, b - 0 [* C& B& k( M6 ^" y
- if($_FILES['image']['size']){
! u* y/ _3 z% [1 M- ]4 q; u8 j8 r - if($_FILES['image']['type'] == "image/pjpeg"){
, j5 e i8 Q7 y, H1 a - $im = imagecreatefromjpeg($_FILES['image']['tmp_name']); ; H5 b7 m) c/ g, v/ f
- }elseif($_FILES['image']['type'] == "image/x-png"){
% k1 [% x& c0 N, w3 b' v1 o. X- _ - $im = imagecreatefrompng($_FILES['image']['tmp_name']);
& |- w& u+ f- f+ ?& U+ a - }elseif($_FILES['image']['type'] == "image/gif"){ 0 p: A4 n1 P2 X/ o0 x" ]+ B6 S
- $im = imagecreatefromgif($_FILES['image']['tmp_name']);
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- if($im){
) f( T# L5 @; F - if(file_exists("$FILENAME.jpg")){ * l0 E; R9 v# x% Q. P. F
- unlink("$FILENAME.jpg"); ' i: b: R" U1 R9 \& }5 n& D+ k6 h9 m
- } 5 |: j3 U- Z! d3 ^
- ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
: n5 }2 d/ @5 f1 U: a: J, Z/ n - ImageDestroy ($im); , a, w1 T' E D1 q
- } ' U4 k* h/ S* _ s& S2 O$ B' }
- }
0 M. `8 u! D, T/ X - ?>
复制代码 以下是测试代码(demo.php) ' e; h4 z) R* M# M) n9 ?8 Q; E
3 P- ^) L* \+ a' B# j代码如下:
7 k3 c- o6 G+ u1 v- t/ W" C$ ]! M1 r. \
- <?php 1 S H0 U# f- j
- include('ResizeImage.php');
; q, |) M5 ^- Q' h' y. h - if(!empty($_POST)){
2 \( X; _' H& d& m# V j - echo($FILENAME.".jpg?cache=".rand(0,999999)); $ E/ D) }/ w. P* L$ g2 h g
- }
' H% r$ h! }- j0 V- c1 @" } - ?> 7 {4 I1 X2 ~- i/ R0 h) L
- <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
3 w7 @' Q- F% p* [& }. ` - <input type="file" name="image" size="50" value="浏览"><p> ( u% F+ X D+ y) n* D$ P- N
- <input type="submit" value="上传图片">
r6 H$ T7 l" w# p! e, @% A - </form>
复制代码 ' ]3 X5 |4 f& \3 N y Q
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