php如何使用等比例縮放圖片執行個體代碼

主要介紹了如何使用php等比例縮放圖片,可以對原圖片提出縮放要求的寬度、縮放的長度.

本文介紹了PHP實現圖片壓縮方法，讀者可以根據具體應用參考或加以改進，直接上代碼，imgzip($src,$newwid,$newhei)這個函數帶進去的分別是原圖片、縮放要求的寬度、縮放的長度。

<?php //壓縮圖片 縮圖$src= "xiezheng.jpg";$newwid=640;$newhei= 480;function imgzip($src,$newwid,$newhei){ $imgInfo = getimagesize($src); $imgType = image_type_to_extension($imgInfo[2], false); $fun = "imagecreatefrom{$imgType}";//聲明圖片 開啟圖片 在記憶體中 $image = $fun($src);//方便配置長度寬度、高度，設定框為變數wid,高度為hei $wid=$imgInfo[0]; $hei=$imgInfo[1];//判斷長度和寬度，以方便等比縮放,規格按照500, 320 if($wid>$hei){ $wid=$newwid; $hei=$newwid/($wid/$hei); }else { $wid = $newhei * ($wid / $hei); $hei = $newhei; }//在記憶體中建立一張圖片 $images2 = imagecreatetruecolor($newwid, $newhei); //建立一個500*320的圖片//將原圖複製到建立圖片中//imagecopyresampled($dst_image, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h) imagecopyresampled($images2, $image, 0, 0, 0, 0, $wid,$hei, $imgInfo[0],$imgInfo[1]);//銷毀原始圖片 imagedestroy($image);//直接輸出圖片檔案 header("Content-type: ".$imgInfo['mime']); imagejpeg($images2);//儲存圖片 到新檔案 imagejpeg($images2, 'new.jpg', 100); //10代碼輸出圖片的品質 0-100 100品質最高//銷毀 imagedestroy($images2);}imgzip($src,$newwid,$newhei);?>

下面這篇文章給大家分享的是使用php實現的等比例縮放圖片及剪下圖片的代碼，非常的簡單實用，附上用法，有需要的小夥伴可以參考下。

php等比例縮放圖片及剪下圖片代碼分享

/** * 圖片縮放函數（可設定高度固定，寬度固定或者最大寬高，支援gif/jpg/png三種類型） * Author : Specs * * @param string $source_path 源圖片 * @param int $target_width 目標寬度 * @param int $target_height 目標高度 * @param string $fixed_orig 鎖定寬高（選擇性參數 width、height或者空值） * @return string */function myImageResize($source_path, $target_width = 200, $target_height = 200, $fixed_orig = ''){  $source_info = getimagesize($source_path);  $source_width = $source_info[0];  $source_height = $source_info[1];  $source_mime = $source_info['mime'];  $ratio_orig = $source_width / $source_height;  if ($fixed_orig == 'width'){    //寬度固定    $target_height = $target_width / $ratio_orig;  }elseif ($fixed_orig == 'height'){    //高度固定    $target_width = $target_height * $ratio_orig;  }else{    //最大寬或最大高    if ($target_width / $target_height > $ratio_orig){      $target_width = $target_height * $ratio_orig;    }else{      $target_height = $target_width / $ratio_orig;    }  }  switch ($source_mime){    case 'image/gif':      $source_image = imagecreatefromgif($source_path);      break;         case 'image/jpeg':      $source_image = imagecreatefromjpeg($source_path);      break;         case 'image/png':      $source_image = imagecreatefrompng($source_path);      break;         default:      return false;      break;  }  $target_image = imagecreatetruecolor($target_width, $target_height);  imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $target_width, $target_height, $source_width, $source_height);  //header('Content-type: image/jpeg');  $imgArr = explode('.', $source_path);  $target_path = $imgArr[0] . '_new.' . $imgArr[1];  imagejpeg($target_image, $target_path, 100);}

用法：

myImageResize($filename, 200, 200); //最大寬高

myImageResize($filename, 200, 200, 'width'); //寬度固定

myImageResize($filename, 200, 200, 'height'); //高度固定

剪下圖片為固定大小：

function imagecropper($source_path, $target_width, $target_height){  $source_info = getimagesize($source_path);  $source_width = $source_info[0];  $source_height = $source_info[1];  $source_mime = $source_info['mime'];  $source_ratio = $source_height / $source_width;  $target_ratio = $target_height / $target_width;     // 源圖過高  if ($source_ratio > $target_ratio){    $cropped_width = $source_width;    $cropped_height = $source_width * $target_ratio;    $source_x = 0;    $source_y = ($source_height - $cropped_height) / 2;  }elseif ($source_ratio < $target_ratio){ // 源圖過寬    $cropped_width = $source_height / $target_ratio;    $cropped_height = $source_height;    $source_x = ($source_width - $cropped_width) / 2;    $source_y = 0;  }else{ // 源圖適中    $cropped_width = $source_width;    $cropped_height = $source_height;    $source_x = 0;    $source_y = 0;  }     switch ($source_mime){    case 'image/gif':      $source_image = imagecreatefromgif($source_path);      break;         case 'image/jpeg':      $source_image = imagecreatefromjpeg($source_path);      break;         case 'image/png':      $source_image = imagecreatefrompng($source_path);      break;         default:      return false;      break;  }     $target_image = imagecreatetruecolor($target_width, $target_height);  $cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);     // 裁剪  imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);  // 縮放  imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);  $dotpos = strrpos($source_path, '.');  $imgName = substr($source_path, 0, $dotpos);  $suffix = substr($source_path, $dotpos);  $imgNew = $imgName . '_small' . $suffix;  imagejpeg($target_image, $imgNew, 100);  imagedestroy($source_image);  imagedestroy($target_image);  imagedestroy($cropped_image);}