【问题标题】:php - resize and save an image? [duplicate]php - 调整大小并保存图像? [复制]
【发布时间】:2012-06-26 22:10:59
【问题描述】:

可能重复:
Resize a picture to a fixed size

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 吗?我做错了什么?

【问题讨论】:

  • 您的代码没有做任何调整大小。您所做的只是覆盖 getimagesize 返回的计算值
  • 你只是改变了内存中的宽度值,实际上并没有对图像做任何事情(除了重命名它)。
  • 虽然是一个基本错误,但不值得一票否决

标签: php


【解决方案1】:

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,然后使用适当的调整图像大小的函数调整它的大小,可能在 GD library 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

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simple class for resizing images。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;
   }      

}
?>

【讨论】:

  • 将图像保持在 700x500 以内:$ratio=max(700/imagesx($image),500/imagesy($image));
  • 你的直觉是正确的,链接现在是 404 :)
  • 我可以验证这个类可以完美运行!谢谢
【解决方案2】:

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);
}

【讨论】:

  • 创建$image 有什么意义,因为它没有在其余代码中使用?之后你只能使用$image_p$source
  • 没有意义,你也不应该取消任何 IMO 设置。这是很久以前的事了,所以我不记得我为什么这样做了:)
  • 如果您已经将文件上传到服务器,则应将所有 $imgObject['tmp_name'] 代码更改为 $imgObject。这对我有用,非常感谢,你拯救了我的夜晚;)
【解决方案3】:

您应该使用 imagecopyresampled 函数复制/移动图像,该函数是 GD 扩展的一部分。

【讨论】:

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