PHP實現圖片裁剪與縮放的幾種方法

方法一

代碼如下

複製代碼

圖片裁剪縮放函數，支援方位裁剪和自訂座標裁剪     /**      * 圖片裁剪函數，支援指定定點裁剪和方位裁剪兩種裁剪模式      * @param <string>  $src_file       原圖片路徑      * @param <int>     $new_width      裁剪後圖片寬度（當寬度超過原圖片寬度時，去原圖片寬度）      * @param <int>     $new_height     裁剪後圖片高度（當寬度超過原圖片寬度時，去原圖片高度）      * @param <int>     $type           裁剪方式，1-方位元模式裁剪；0-定點模式裁剪。      * @param <int>     $pos            方位元模式裁剪時的起始方位（當選定點模式裁剪時，此參數不起作用）      *                                      1為頂端居左，2為頂端置中，3為頂端居右；      *                                      4為中部居左，5為中部置中，6為中部居右；      *                                      7為底端居左，8為底端置中，9為底端居右；      * @param <int>     $start_x        起始位置X （當選定方位元模式裁剪時，此參數不起作用）      * @param <int>     $start_y        起始位置Y（當選定方位元模式裁剪時，此參數不起作用）      * @return <string>                 裁剪圖片儲存路徑      */     function thumb($src_file, $new_width, $new_height, $type = 1, $pos = 5, $start_x = 0, $start_y = 0) {         $pathinfo = pathinfo($src_file);         $dst_file = $pathinfo['dirname'] . '/' . $pathinfo['filename'] .'_'. $new_width . 'x' . $new_height . '.' . $pathinfo['extension'];         if (!file_exists($dst_file)) {             if ($new_width < 1 || $new_height < 1) {                 echo "params width or height error !";                 exit();             }             if (!file_exists($src_file)) {                 echo $src_file . " is not exists !";                 exit();             }             // 映像類型             $img_type = exif_imagetype($src_file);             $support_type = array(IMAGETYPE_JPEG, IMAGETYPE_PNG, IMAGETYPE_GIF);             if (!in_array($img_type, $support_type, true)) {                 echo "只支援jpg、png、gif格式圖片裁剪";                 exit();             }             /* 載入映像 */             switch ($img_type) {                 case IMAGETYPE_JPEG :                     $src_img = imagecreatefromjpeg($src_file);                     break;                 case IMAGETYPE_PNG :                     $src_img = imagecreatefrompng($src_file);                     break;                 case IMAGETYPE_GIF :                     $src_img = imagecreatefromgif($src_file);                     break;                 default:                 echo "載入映像錯誤!";                 exit();             }             /* 擷取源圖片的寬度和高度 */             $src_width = imagesx($src_img);             $src_height = imagesy($src_img);             /* 計算剪下圖片的寬度和高度 */             $mid_width = ($src_width < $new_width) ? $src_width : $new_width;             $mid_height = ($src_height < $new_height) ? $src_height : $new_height;             /* 初始化源圖片剪下裁剪的起始位置座標 */             switch ($pos * $type) {                 case 1://1為頂端居左                     $start_x = 0;                     $start_y = 0;                     break;                 case 2://2為頂端置中                     $start_x = ($src_width - $mid_width) / 2;                     $start_y = 0;                     break;                 case 3://3為頂端居右                     $start_x = $src_width - $mid_width;                     $start_y = 0;                     break;                 case 4://4為中部居左                     $start_x = 0;                     $start_y = ($src_height - $mid_height) / 2;                     break;                 case 5://5為中部置中                     $start_x = ($src_width - $mid_width) / 2;                     $start_y = ($src_height - $mid_height) / 2;                     break;                 case 6://6為中部居右                     $start_x = $src_width - $mid_width;                     $start_y = ($src_height - $mid_height) / 2;                     break;                 case 7://7為底端居左                     $start_x = 0;                     $start_y = $src_height - $mid_height;                     break;                 case 8://8為底端置中                     $start_x = ($src_width - $mid_width) / 2;                     $start_y = $src_height - $mid_height;                     break;                 case 9://9為底端居右                     $start_x = $src_width - $mid_width;                     $start_y = $src_height - $mid_height;                     break;                 default://隨機                     break;             }             // 為剪下映像建立背景畫板             $mid_img = imagecreatetruecolor($mid_width, $mid_height);             //拷貝剪下的映像資料到畫板，產生剪下映像             imagecopy($mid_img, $src_img, 0, 0, $start_x, $start_y, $mid_width, $mid_height);             // 為裁剪映像建立背景畫板             $new_img = imagecreatetruecolor($new_width, $new_height);             //拷貝剪下映像到背景畫板，並按比例裁剪             imagecopyresampled($new_img, $mid_img, 0, 0, 0, 0, $new_width, $new_height, $mid_width, $mid_height);             /* 按格式儲存為圖片 */             switch ($img_type) {                 case IMAGETYPE_JPEG :                     imagejpeg($new_img, $dst_file, 100);                     break;                 case IMAGETYPE_PNG :                     imagepng($new_img, $dst_file, 9);                     break;                 case IMAGETYPE_GIF :                     imagegif($new_img, $dst_file, 100);                     break;                 default:                     break;             }         }         return ltrim($dst_file, '.');     }

附件是一個有範例圖片的測試demo。
不過，這個函數不支援動態gif圖片的裁剪縮放。

方法二，

代碼如下

複製代碼

<?php list($src_w,$src_h)=getimagesize($src_img);  // 擷取原圖尺寸 $dst_scale = $dst_h/$dst_w; //靶心圖表像長寬比 $src_scale = $src_h/$src_w; // 原圖長寬比 if($src_scale>=$dst_scale) {   // 過高  $w = intval($src_w);  $h = intval($dst_scale*$w);  $x = 0;  $y = ($src_h - $h)/3; } else { // 過寬  $h = intval($src_h);  $w = intval($h/$dst_scale);  $x = ($src_w - $w)/2;  $y = 0; } // 剪裁 $source=imagecreatefromjpeg($src_img); $croped=imagecreatetruecolor($w, $h); imagecopy($croped,$source,0,0,$x,$y,$src_w,$src_h); // 縮放 $scale = $dst_w/$w; $target = imagecreatetruecolor($dst_w, $dst_h); $final_w = intval($w*$scale); $final_h = intval($h*$scale); imagecopysampled($target,$croped,0,0,0,0,$final_w,$final_h,$w,$h); // 儲存 $timestamp = time(); imagejpeg($target, "$timestamp.jpg"); imagedestroy($target); ?>

方法三

根據自訂的靶心圖表, 按靶心圖表高寬比裁剪、縮放源圖.

傳入參數:

代碼如下

複製代碼

$source_path string 源圖路徑 $target_width integer 靶心圖表寬度 $target_height integer 靶心圖表高度 支援圖片類型: image/gif, image/jpeg, image/png. function imagecropper($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 - $cropped_height) / 2;  }  // 源圖過寬  elseif ($source_ratio < $target_ratio)  {   $cropped_width  = $source_height / $target_ratio;   $cropped_height = $source_height;   $source_x = ($source_width - $cropped_width) / 2;   $source_y = 0;  }  // 源圖適中  else  {   $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, $cropped_height);  header('Content-Type: image/jpeg');  imagejpeg($target_image);  imagedestroy($source_image);  imagedestroy($target_image);  imagedestroy($cropped_image); }