调整大小并保存图像 - resize and save an image?

可能的重复项：
将图片大小调整为固定大小

我正在使用以下 php 代码来调整大小（宽度）并保存图像，代码工作没有错误，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？

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例，然后使用适当的函数调整其大小，该函数可以调整图像大小，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

执行实际大小调整：

$new_image = imagecreatetruecolor($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.

我找到了一个简单的类来调整图像大小。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;
   }      
}
?>

您正在设置变量，而不是调整图像大小。我挖了一些旧函数，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 imagecopyresampled 函数复制/移动图像，这是 GD 扩展的一部分。