这篇文章主要讲解了“php实现等比例缩放图片及剪切图片”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“php实现等比例缩放图片及剪切图片”吧！
php等比例缩放图片及剪切图片代码分享
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/**
* 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);
}感谢各位的阅读，以上就是“php实现等比例缩放图片及剪切图片”的内容了，经过本文的学习后，相信大家对php实现等比例缩放图片及剪切图片这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是亿速云，小编将为大家推送更多相关知识点的文章，欢迎关注！
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