php生成縮略圖的兩種方法

　　在php中如果要生成縮略圖有什麼辦法呢？以下是小編整理的兩種方法，希望對大家有用，更多消息請關注應屆畢業生網。　　核心代碼如下　　public function getImage(){　　// create instance　　$basePath = base_path('public/');　　$md5 = 'b8c3bf0b10a81c5b6a98c527868a0000';　　$sub1 = substr($md5, 0, 1);　　$sub2 = substr($md5, 1, 2);　　$subPath = sprintf("image/%s/%s/%s%s.jpg", $sub1, $sub2, $md5, '300x300');　　$sourcePath = sprintf("image/%s/%s/%s.jpg", $sub1, $sub2, $md5);　　//截成100x80的縮略圖　　//$image = $this->getCropper($basePath.$sourcePath,$basePath.$subPath, 300, 300);　　$image = $this->getCrops($basePath.$sourcePath,$basePath.$subPath, 300, 300);　　}　　//生成縮略圖　　function getCropper($source_path,$NewImagePath, $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, $cropped_height);　　// 圖片裁剪　　imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);　　// 圖片縮放　　imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);　　header('Content-Type: image/jpeg');　　imagejpeg($target_image,$NewImagePath,100);　　imagedestroy($source_image);　　imagedestroy($target_image);　　imagedestroy($cropped_image);　　}　　//生成縮略圖，填充白邊　　function getCrops($src_path,$NewImagePath,$width,$height){　　//源圖對象　　$src_image = imagecreatefromstring(file_get_contents($src_path));　　$source_info = getimagesize($src_path);　　$source_mime = $source_info['mime'];　　$src_width = imagesx($src_image);　　$src_height = imagesy($src_image);　　switch ($source_mime)　　{　　case 'image/gif':　　$src_image = imagecreatefromgif($src_path);　　break;　　case 'image/jpeg':　　$src_image = imagecreatefromjpeg($src_path);　　break;　　case 'image/png':　　$src_image = imagecreatefrompng($src_path);　　break;　　default:　　return false;　　break;　　}　　//生成等比例的縮略圖　　//$tmp_image_width = 0;　　//$tmp_image_height = 0;　　if ($src_width / $src_height >= $width / $height) {　　$tmp_image_width = $width;　　$tmp_image_height = round($tmp_image_width * $src_height / $src_width);　　} else {　　$tmp_image_height = $height;　　$tmp_image_width = round($tmp_image_height * $src_width / $src_height);　　}　　$tmpImage = imagecreatetruecolor($tmp_image_width, $tmp_image_height);　　imagecopyresampled($tmpImage, $src_image, 0, 0, 0, 0, $tmp_image_width, $tmp_image_height, $src_width, $src_height);　　//添加白邊　　$final_image = imagecreatetruecolor($width, $height);　　$color = imagecolorallocate($final_image, 255, 255, 255);　　imagefill($final_image, 0, 0, $color);　　$x = round(($width - $tmp_image_width) / 2);　　$y = round(($height - $tmp_image_height) / 2);　　imagecopy($final_image, $tmpImage, $x, $y, 0, 0, $tmp_image_width, $tmp_image_height);　　//輸出圖片　　header('Content-Type: image/jpeg');　　imagejpeg($final_image,$NewImagePath,100);　　imagedestroy($src_image);　　imagedestroy($final_image);　　}