标签:php colors transparent png resize
我在使用PHP调整图片大小时遇到问题,特别是对于具有透明背景的PNG文件,而不是保持透明背景,它会变成黑色背景.我怎样才能解决这个问题?
这是用于调整大小的脚本:
<?php
class resize{
var $image;
var $image_type;
function load($filename) {
$image_info = getimagesize($filename);
$this->image_type = $image_info[2];
if( $this->image_type == IMAGETYPE_JPEG ) {
$this->image = imagecreatefromjpeg($filename);
} elseif( $this->image_type == IMAGETYPE_GIF ) {
$this->image = imagecreatefromgif($filename);
} elseif( $this->image_type == IMAGETYPE_PNG ) {
$this->image = imagecreatefrompng($filename);
}
}
function save($filename, $image_type=IMAGETYPE_JPEG, $compression=85, $permissions=null) {
if( $image_type == IMAGETYPE_JPEG ) {
imagejpeg($this->image,$filename,$compression);
} elseif( $image_type == IMAGETYPE_GIF ) {
imagegif($this->image,$filename);
} elseif( $image_type == IMAGETYPE_PNG ) {
imagepng($this->image,$filename);
}
if( $permissions != null) {
chmod($filename,$permissions);
}
}
function output($image_type=IMAGETYPE_JPEG) {
if( $image_type == IMAGETYPE_JPEG ) {
imagejpeg($this->image);
} elseif( $image_type == IMAGETYPE_GIF ) {
imagegif($this->image);
} elseif( $image_type == IMAGETYPE_PNG ) {
imagepng($this->image);
}
}
function getWidth() {
return imagesx($this->image);
}
function getHeight() {
return imagesy($this->image);
}
function resizeToHeight($height) {
$ratio = $height / $this->getHeight();
$width = $this->getWidth() * $ratio;
$this->resize($width,$height);
}
function resizeToWidth($width) {
$ratio = $width / $this->getWidth();
$height = $this->getheight() * $ratio;
$this->resize($width,$height);
}
function scale($scale) {
$width = $this->getWidth() * $scale/100;
$height = $this->getheight() * $scale/100;
$this->resize($width,$height);
}
function resize($width,$height) {
$new_image = imagecreatetruecolor($width, $height);
imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
$this->image = $new_image;
}
}
?>
这就是我所说的:
$picture_directory="images/" . $_FILES["file"]["name"];
include('arqinc/resizing.php');
$image = new resize();
$image->load($picture_directory);
$image->resize(660,780);
$image->save($picture_directory);
编辑:
香港专业教育学院改变了我的调整大小功能:
function resize($width,$height) {
$new_image = imagecreatetruecolor($width, $height);
$transparent=imagefill($new_image, 0, 0, imagecolorallocatealpha($new_image, 255, 255, 255, 127));
imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
$this->image = $new_image;
}
但现在它使背景保持白色,而不是透明.
编辑2:
解决了,这个调整大小的功能被破坏了,这个功能完美无缺:
http://mediumexposure.com/smart-image-resizing-while-preserving-transparency-php-and-gd-library/
谢谢
Tahir Yasin链接它:D
解决方法:
我发现另一个帖子有相同的问题,根据该帖子,下面的代码可以用来保持透明度.
imagealphablending( $targetImage, false );
imagesavealpha( $targetImage, true );
参考:Can PNG image transparency be preserved when using PHP’s GDlib imagecopyresampled?
如果有帮助,请投票.
标签:php,colors,transparent,png,resize 来源: https://codeday.me/bug/20190529/1181075.html
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