PHP实现对png图像进行缩放的方法(支持透明背景)
发布:smiling 来源: PHP粉丝网 添加日期:2021-06-12 19:47:28 浏览: 评论:0
这篇文章主要介绍了PHP实现对png图像进行缩放的方法(支持透明背景),可实现php针对png图像的缩放功能,且支持透明背景,具有一定参考借鉴价值,需要的朋友可以参考下。
本文实例讲述了PHP实现对png图像进行缩放的方法,分享给大家供大家参考,具体实现方法如下:
- function smart_resize_image( $file, $width = 0, $height = 0, $proportional = false, $output = 'file', $delete_original = true, $use_linux_commands = false )
- {
- if ( $height <= 0 && $width <= 0 ) {
- return false;
- }
- $info = getimagesize($file);
- $image = '';
- $final_width = 0;
- $final_height = 0;
- list($width_old, $height_old) = $info;
- if ($proportional) {
- if ($width == 0) $factor = $height/$height_old;
- elseif ($height == 0) $factor = $width/$width_old;
- else $factor = min ( $width / $width_old, $height / $height_old);
- $final_width = round ($width_old * $factor);
- $final_height = round ($height_old * $factor);
- }
- else {
- $final_width = ( $width <= 0 ) ? $width_old : $width;
- $final_height = ( $height <= 0 ) ? $height_old : $height;
- }
- switch ($info[2] ) {
- case IMAGETYPE_GIF:
- $image = imagecreatefromgif($file);
- break;
- case IMAGETYPE_JPEG:
- $image = imagecreatefromjpeg($file);
- break;
- case IMAGETYPE_PNG:
- $image = imagecreatefrompng($file);
- break;
- default:
- return false;
- }
- $image_resized = imagecreatetruecolor( $final_width, $final_height );
- if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) {
- $trnprt_indx = imagecolortransparent($image);
- // If we have a specific transparent color
- if ($trnprt_indx >= 0) {
- // Get the original image's transparent color's RGB values
- $trnprt_color = imagecolorsforindex($image, $trnprt_indx);
- // Allocate the same color in the new image resource
- $trnprt_indx = imagecolorallocate($image_resized, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
- // Completely fill the background of the new image with allocated color.
- imagefill($image_resized, 0, 0, $trnprt_indx);
- // Set the background color for new image to transparent
- imagecolortransparent($image_resized, $trnprt_indx);
- }
- // Always make a transparent background color for PNGs that don't have one allocated already
- elseif ($info[2] == IMAGETYPE_PNG) {
- // Turn off transparency blending (temporarily)
- imagealphablending($image_resized, false);
- // Create a new transparent color for image
- $color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);
- // Completely fill the background of the new image with allocated color.
- imagefill($image_resized, 0, 0, $color);
- // Restore transparency blending
- imagesavealpha($image_resized, true);
- }
- }
- imagecopyresampled($image_resized, $image, 0, 0, 0, 0, $final_width, $final_height, $width_old, $height_old);
- if ( $delete_original ) {
- if ( $use_linux_commands )
- exec('rm '.$file);
- else
- @unlink($file);
- }
- switch ( strtolower($output) ) {
- case 'browser':
- $mime = image_type_to_mime_type($info[2]);
- header("Content-type: $mime");
- $output = NULL;
- break;
- case 'file':
- $output = $file;
- break;
- case 'return':
- return $image_resized;
- break;
- default:
- break;
- }
- switch ($info[2] ) {
- case IMAGETYPE_GIF:
- imagegif($image_resized, $output);
- break;
- case IMAGETYPE_JPEG:
- imagejpeg($image_resized, $output);
- break;
- case IMAGETYPE_PNG:
- imagepng($image_resized, $output);
- break;
- default:
- return false;
- }
- return true;
- }
希望本文所述对大家的php程序设计有所帮助。
Tags: png图像缩放
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