php - 创建 png 文件

Question

我制作了一个函数来处理 jpg 和 png 文件，但在尝试上传 png 文件时出现错误。

这是函数:

function createImg ($type, $src, $dst, $width, $height, $quality) {

$newImage = imagecreatetruecolor($width,$height);
if ($type == "jpg/jpeg") {  
    //imagecreatefromjpeg() returns an image identifier representing the image obtained from the given filename.
    $source = imagecreatefromjpeg($src);
}
else if ($type == "png") {
    //imagecreatefrompng() returns an image identifier representing the image obtained from the given filename.
    $source = imagecreatefrompng($src);
}
imagecopyresampled($newImage,$source,0,0,0,0,$width,$height,getWidth($src),getHeight($src));
if ($type == "jpg/jpeg") {
    //imagejpeg() creates a JPEG file from the given image. 
    imagejpeg($newImage,$dst,$quality); 
}
else if ($type == "png") {
    //imagepng() creates a PNG file from the given image. 
    imagepng($newImage,$dst,$quality);      
}
return $dst;

可以正常使用 jpg，但使用 png 我会收到此错误消息:

警告:imagepng() [function.imagepng]: gd-png: fatal libpng error: zlib failed to initialize compressor -- stream error in E:...\php\functions.upload.php on line 48

警告:imagepng() [function.imagepng]:gd-png 错误:setjmp 在第 48 行的 E:...\php\functions.upload.php 中返回错误条件

编辑:

我刚刚更改删除了 imagepng();并且只使用 imagejpeg 并且它像这样工作，我只想保存 jpg 文件。谢谢!

Answer 1

问题是因为 imagejpeg 质量最高可达 100，而 imagepng 最高质量为 9。试试这个

 else if ($type == "png") {
//imagepng() creates a PNG file from the given image. 
$q=9/100;
$quality*=$q;
imagepng($newImage,$dst,$quality);      
}