Resize PNG image in PHP - php

Question

I'm getting a no image display when resizing PNG however the following code works for JPEG.
list($width_orig, $height_orig) = getimagesize( $fileName );
$ratio_orig = $width_orig/$height_orig;
if ($width/$height > $ratio_orig) {
$width = $height*$ratio_orig;
} else {
$height = $width/$ratio_orig;
}
// Resample
$image_p = imagecreatetruecolor($width, $height);
if( $type )){
switch( $type ){
case 'image/jpeg':
$image = imagecreatefromjpeg($fileName);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);
imagejpeg($image_p, null, 100);
break;
case 'image/png':
imagealphablending( $image_p, false );
imagesavealpha( $image_p, true );
$image = imagecreatefrompng( $fileName );
imagecopyresampled( $image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);
imagepng($image_p, null, 100);
break;
}
}
I've put the headers in but for some reason I'm doing something wrong for png images.

Answer 1

Last argument in imagepng($image_p, null, 100) should be between 0 and 9.

Answer 2

try this:
$image = imagecreatefrompng ( $filename );
$new_image = imagecreatetruecolor ( $width, $height ); // new wigth and height
imagealphablending($new_image , false);
imagesavealpha($new_image , true);
imagecopyresampled ( $new_image, $image, 0, 0, 0, 0, $width, $height, imagesx ( $image ), imagesy ( $image ) );
$image = $new_image;
// saving
imagealphablending($image , false);
imagesavealpha($image , true);
imagepng ( $image, $filename );

Answer 3

see if this works
#upload de image
public function upImagem($imagem, $dir, $res, $id, $tam){
$arquivo = $imagem;
$arq_nome = $arquivo['name'];
$ext = $arquivo['type'];
$nome=$this->RenImg($arquivo, $dir, $id, $tam);
$imagem = $arquivo['tmp_name'];
if($ext=='image/jpeg'){
$img = imagecreatefromjpeg($imagem);
}
elseif($ext=='image/png'){
$img = imagecreatefrompng($imagem);
}
elseif($ext=='image/gif'){
$img = imagecreatefromgif($imagem);
}
if(($ext=='image/png') or ($ext=='image/gif')){
list($x, $y) = getimagesize($arquivo['tmp_name']);
}
elseif($ext=='image/jpeg'){
$x = imagesx($img);//original height
$y = imagesy($img);//original width
}
$altura = $res[1];
$largura = $res[0];
$nova = imagecreatetruecolor($largura,$altura);
$preto = imagecolorallocate($nova, 0, 0, 0);
if(($ext=='image/png') or ($ext=='image/gif')){
imagealphablending($nova , false);
imagesavealpha($nova , true);
}
if($ext=='image/png'){
imagecolortransparent ($nova, $preto);
imagecopymerge($img, $nova, 0, 0, 0, 0, imagesx($nova), imagesy($nova), 100);
imagecopyresized($nova,$img,0,0,0,0,$largura,$altura, $x, $y );
}
else {
imagecopyresampled($nova,$img,0,0,0,0,$largura,$altura,$x,$y);
}
if($ext=='image/jpeg'){
imagejpeg($nova,$nome,99);
}
elseif($ext=='image/gif'){
imagealphablending($nova , false);
imagesavealpha($nova , true);
imagegif($nova,$nome,99);
}
elseif($ext=='image/png'){
imagealphablending($nova , false);
imagesavealpha($nova , true);
imagepng($nova,$nome);
}
imagedestroy($img);
imagedestroy($nova);
}
#renames the image
public function RenImg($arq,$dir,$id,$tam){
$arq_nome = $arq['name'];
$arq_nome2=str_replace('.jpg','',$arq['name']);//renomeia o arquivo
$arq_nome2=str_replace('.png','',$arq_nome2);//renomeia o arquivo
$arq_nome2=str_replace('.gif','',$arq_nome2);//renomeia o arquivo
//$new_name = md5($arq_nome);
$ext = $this->getExt($arq_nome);
$nome = $dir.$id.$tam.'.jpg';//.'.'.$ext
return $nome;
}
#capture the file extension
public function getExt($arq){
$ext = pathinfo($arq, PATHINFO_EXTENSION);
return $ext;
}

Answer 4

This is a code i use for JPG/PNG rezise.
$imagename = "default";
if (isset ($_FILES['arquivo'])) {
$imagename = $imagename . ".jpg";
$source = $_FILES['arquivo']['tmp_name'];
$target = "images/tmp/" . $imagename;
$type = $_FILES["arquivo"]["type"];
//JPG or JPEG
if ($type == "image/jpeg" || $type == "image/jpg") {
move_uploaded_file($source, $target);
$imagepath = $imagename;
$save = "images/" . $imagepath; //Path to save the image
$file = "images/tmp/" . $imagepath; //path to orginal size image
list($width, $height) = getimagesize($file);
$modwidth = 1920;
$diff = $width / $modwidth; // Use $modheight = $idff to mantain aspect ratio
$modheight = 1080;
$tn = imagecreatetruecolor($modwidth, $modheight);
$image = imagecreatefromjpeg($file);
imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height);
echo "<center><b><h5>Image was updated!</h5></b>";
imagejpeg($tn, $save, 100);
} elseif ($type == "image/png") { //PNG
move_uploaded_file($source, $target);
$imagepath = $imagename;
$save = "images/" . $imagepath; //Path to save the image
$file = "images/tmp/" . $imagepath; //path to orginal size image
list($width, $height) = getimagesize($file);
$modwidth = 1920;
$diff = $width / $modwidth; // Use $modheight = $idff to mantain aspect ratio
$modheight = 1080;
$tn = imagecreatetruecolor($modwidth, $modheight);
imagealphablending($tn, false);
imagesavealpha($tn, true);
$image = imagecreatefrompng($file);
imagecopyresampled($tn, $image, 0, 0, 0, 0, $modwidth, $modheight, $width, $height);
echo "Image was updated!";
imagepng($tn, $save, 9);
} else {
echo "Error!";
}
}