php等比例缩放图片及剪切图片代码分享

/** * 图片缩放函数（可设置高度固定，宽度固定或者最大宽高，支持gif/jpg/png三种类型） * Author : Specs * * @param string $source_path 源图片 * @param int $target_width 目标宽度 * @param int $target_height 目标高度 * @param string $fixed_orig 锁定宽高（可选参数 width、height或者空值） * @return string */function myImageResize($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'){ //宽度固定 $target_height = $target_width / $ratio_orig; }elseif ($fixed_orig == 'height'){ //高度固定 $target_width = $target_height * $ratio_orig; }else{ //最大宽或最大高 if ($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); //最大宽高

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

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

剪切图片为固定大小：

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 - $cropped_height) / 2; }elseif ($source_ratio < $target_ratio){ // 源图过宽 $cropped_width = $source_height / $target_ratio; $cropped_height = $source_height; $source_x = ($source_width - $cropped_width) / 2; $source_y = 0; }else{ // 源图适中 $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, $cropped_height); // 缩放 imagecopyresampled($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);}