php生成缩略图的两种方法
在php中如果要生成缩略图有什么办法呢？以下是小编整理的两种方法，希望对大家有用，更多消息请关注应届毕业生网。核心代码如下 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, $md5; //截成100x80的缩略图 //$image = $this->getCropper$basePath.$sourcePath,$basePath.$subPath, 300, 300; $image = $this->getCrops$basePath.$sourcePath,$basePath.$subPath, 300, 300; //生成缩略图 function getCropper$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; // 源图过高 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; // 源图过宽 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; // 源图适中 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, $cropped_height; // 图片裁剪 imagecopy$cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height; // 图片缩放 imagecopyresampled$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; //生成缩略图，填充白边 function getCrops$src_path,$NewImagePath,$width,$height //源图对象 $src_image = imagecreatefromstringfile_get_contents$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; //生成等比例的缩略图 //$tmp_image_width = 0; //$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; //添加白边 $final_image = imagecreatetruecolor$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, $tmp_image_height; //输出图片 header'Content-Type: image/jpeg'; imagejpeg$final_image,$NewImagePath,100; imagedestroy$src_image; imagedestroy$final_image;