php等比例缩放图片及剪切图片代码分享

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);

}

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