PHP一般情况下生成的缩略图都比较不理想

admin · 发表于 2018-7-7 23:52:53

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
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$FILENAME="image.thumb"; 1 s' Y: B- @% E
// 生成图片的宽度
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$RESIZEWIDTH=400;
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// 生成图片的高度
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$RESIZEHEIGHT=400;
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function ResizeImage($im,$maxwidth,$maxheight,$name){
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$width = imagesx($im); * }# ~0 _9 c% N" I A
$height = imagesy($im);
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if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){ + Y# t5 X. r! k2 D; ?1 F! S/ F
if($maxwidth && $width > $maxwidth){ - D4 M" e @% T# @
$widthratio = $maxwidth/$width; * t9 u$ ~, f8 J8 ]
$RESIZEWIDTH=true;
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}
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if($maxheight && $height > $maxheight){ 5 P& r% d8 T: e$ e
$heightratio = $maxheight/$height;
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$RESIZEHEIGHT=true; & a1 Z6 @3 E6 [" m) g; r
} / ]5 l+ a( K7 V7 p2 t4 l7 U, b
if($RESIZEWIDTH && $RESIZEHEIGHT){
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if($widthratio < $heightratio){ # I, g8 o5 s2 S& P
$ratio = $widthratio; 1 Q" B3 n6 J R! Q
}else{ " x( O) g/ H0 }$ S. U. c- c+ s
$ratio = $heightratio; 4 d: E5 h+ C3 u
}
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}elseif($RESIZEWIDTH){ 5 t' Z- p. H7 y2 e7 S1 @& l
$ratio = $widthratio;
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}elseif($RESIZEHEIGHT){ * D9 n/ V/ K# u7 G/ N2 f0 I: x
$ratio = $heightratio;
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} : Q0 j; p6 }3 `' _, N* H& a
$newwidth = $width * $ratio; ' [# x/ F3 w9 c- W) z
$newheight = $height * $ratio; 6 q" e0 W! w, N9 l: `
if(function_exists("imagecopyresampled")){ 7 f M+ |% V% P1 B/ ^0 C! S- \
$newim = imagecreatetruecolor($newwidth, $newheight);
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imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); * ^4 U3 K2 M9 f
}else{
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$newim = imagecreate($newwidth, $newheight); # B9 y8 f% e1 f8 j/ S
imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); * I4 T1 b/ p+ e
} ) J( ^$ X7 u$ x; _0 E3 J9 I
ImageJpeg ($newim,$name . ".jpg");
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ImageDestroy ($newim); 1 |% k, ?+ m: J
}else{ 9 G; ?6 C, C( K# z' h- U
ImageJpeg ($im,$name . ".jpg"); 3 ]. J9 H2 @# [* t6 e9 B4 K* i; c
}
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if($_FILES['image']['size']){ 8 C7 D4 r# D' y0 ?0 ]6 D
if($_FILES['image']['type'] == "image/pjpeg"){ 5 s) ?; I3 g( r4 V
$im = imagecreatefromjpeg($_FILES['image']['tmp_name']); % H1 j1 ?* j' U2 `6 |5 B) M6 }2 v
}elseif($_FILES['image']['type'] == "image/x-png"){ + [, s; ]! a5 a) Q
$im = imagecreatefrompng($_FILES['image']['tmp_name']); $ X! U3 v, Z& b7 R
}elseif($_FILES['image']['type'] == "image/gif"){ v; J: W1 ] @! Q
$im = imagecreatefromgif($_FILES['image']['tmp_name']);
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} 2881064151
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if($im){
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if(file_exists("$FILENAME.jpg")){ 5 ]* d( b0 i& ` G2 n
unlink("$FILENAME.jpg");
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}
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ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME); , U& ?4 e) D, g8 o7 A2 [
ImageDestroy ($im); 3 ?8 I6 Q6 G6 D5 E; q" s0 [
}
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}
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?>

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以下是测试代码(demo.php)

代码如下:

<?php
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include('ResizeImage.php');
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if(!empty($_POST)){
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echo($FILENAME.".jpg?cache=".rand(0,999999));
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} % m' F$ T0 q9 u, W
?> 2 N* n# o- N$ W4 W6 o) t' l( i
<form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
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<input type="file" name="image" size="50" value="浏览"><p> # V) J y/ }( X& A
<input type="submit" value="上传图片">
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</form>

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