可能重复：
将图片大小调整为固定大小
我正在使用以下 php 代码调整大小（宽度）并保存图像，代码运行没有错误，但图像没有调整大小。
<?php
$old_path = "users_images/".$name.".".$type;
$new_path = "main_images/".$name.".".$type;
$image_size = getimagesize($new_path);
if($image_size['0'] > 700){
$image_size['0'] = 700;
}
rename($old_path, $new_path);// save image
?>
基本上如果图像宽度大于 700 我想将其设置为 700 ？我做错了什么？
该变量$image_size['0']不是对实际图像大小的引用。
您需要计算尺寸的比率，然后使用调整图像大小的适当函数调整它的大小，可能在GD 库中。
首先，您必须加载图像。我会让你选择类型是什么：
$image = imagecreatefromjpeg($new_path);
$image = imagecreatefromgif($new_path);
$image = imagecreatefrompng($new_path);
现在计算比率：
$ratio = 700 / imagesx($image); // 700 for the width you want...
// imagesx() to determine the current width
获取缩放高度：
$height = imagesy($image) * $ratio; // imagesy() to determine the current height
进行实际调整大小：
$new_image = imagecreatetruecolor($width, $height);
imagecopyresampled($new_image, $image, 0, 0, 0, 0, $width, $height, imagesx($image), imagesy($image));
$image = $new_image; // $image has now been replaced with the resized one.
我找到了一个用于调整图像大小的简单类。为了防止链接腐烂，我在这里重新创建了它：
<?php
/*
* File: SimpleImage.php
* Author: Simon Jarvis
* Copyright: 2006 Simon Jarvis
* Date: 08/11/06
* Link: http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details:
* http://www.gnu.org/licenses/gpl.html
*
*/
class SimpleImage {
var $image;
var $image_type;
function load($filename) {
$image_info = getimagesize($filename);
$this->image_type = $image_info[2];
if( $this->image_type == IMAGETYPE_JPEG ) {
$this->image = imagecreatefromjpeg($filename);
} elseif( $this->image_type == IMAGETYPE_GIF ) {
$this->image = imagecreatefromgif($filename);
} elseif( $this->image_type == IMAGETYPE_PNG ) {
$this->image = imagecreatefrompng($filename);
}
}
function save($filename, $image_type=IMAGETYPE_JPEG, $compression=75, $permissions=null) {
if( $image_type == IMAGETYPE_JPEG ) {
imagejpeg($this->image,$filename,$compression);
} elseif( $image_type == IMAGETYPE_GIF ) {
imagegif($this->image,$filename);
} elseif( $image_type == IMAGETYPE_PNG ) {
imagepng($this->image,$filename);
}
if( $permissions != null) {
chmod($filename,$permissions);
}
}
function output($image_type=IMAGETYPE_JPEG) {
if( $image_type == IMAGETYPE_JPEG ) {
imagejpeg($this->image);
} elseif( $image_type == IMAGETYPE_GIF ) {
imagegif($this->image);
} elseif( $image_type == IMAGETYPE_PNG ) {
imagepng($this->image);
}
}
function getWidth() {
return imagesx($this->image);
}
function getHeight() {
return imagesy($this->image);
}
function resizeToHeight($height) {
$ratio = $height / $this->getHeight();
$width = $this->getWidth() * $ratio;
$this->resize($width,$height);
}
function resizeToWidth($width) {
$ratio = $width / $this->getWidth();
$height = $this->getheight() * $ratio;
$this->resize($width,$height);
}
function scale($scale) {
$width = $this->getWidth() * $scale/100;
$height = $this->getheight() * $scale/100;
$this->resize($width,$height);
}
function resize($width,$height) {
$new_image = imagecreatetruecolor($width, $height);
imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
$this->image = $new_image;
}
}
?>
您正在设置一个变量，而不是调整图像大小。我挖了一些旧功能，您需要传递图像对象，保存路径，图像名称，最大高度，最大宽度和质量。这不是最好的功能，但它可以完成工作。
function resizeImage($imgObject, $savePath, $imgName, $imgMaxWidth, $imgMaxHeight, $imgQuality)
{
$source = imagecreatefromjpeg($imgObject['tmp_name']);
list($imgWidth, $imgHeight) = getimagesize($imgObject['tmp_name']);
$imgAspectRatio = $imgWidth / $imgHeight;
if ($imgMaxWidth / $imgMaxHeight > $imgAspectRatio)
{
$imgMaxWidth = $imgMaxHeight * $imgAspectRatio;
}
else
{
$imgMaxHeight = $imgMaxWidth / $imgAspectRatio;
}
$image_p = imagecreatetruecolor($imgMaxWidth, $imgMaxHeight);
$image = imagecreatefromjpeg($imgObject['tmp_name']);
imagecopyresampled($image_p, $source, 0, 0, 0, 0, $imgMaxWidth, $imgMaxHeight, $imgWidth, $imgHeight);
imagejpeg($image_p, $savePath . $imgName, $imgQuality);
unset($imgObject);
unset($source);
unset($image_p);
unset($image);
}
您应该使用作为 GD 扩展的一部分的imagecopyresampled函数来复制/移动图像。