PHP 8.3.4 Released!

imagecreatefrompng

(PHP 4, PHP 5, PHP 7, PHP 8)

imagecreatefrompngBir dosya veya URL'den yeni bir görüntü oluşturur.

Açıklama

imagecreatefrompng(string $dosyaismi): GdImage|false

imagecreatefrompng() işlevi dosya ismi verilen görüntüyü betimleyen bir görüntü tanıtıcısı döndürür.

İpucu

fopen sarmalayıcıları etkin kılınmışsa bu işlevde dosya ismi olarak bir URL belirtilebilir. Dosya isminin nasıl belirtilebileceği hakkında bilgi edinmek için fopen() işlevine bakılabilir. Sarmalayıcıların neler yapabildiği, kullanım bilgileri ve bunlar tarafından kullanılan öntanımlı değişkenler hakkında bilgi Desteklenen Protokoller ve Sarmalayıcılar bölümünde bulanabilir.

Bağımsız Değişkenler

dosyaismi

PNG görüntünün dosya yolu.

Dönen Değerler

Başarı durumunda görüntü nesnesi, hata durumunda false döner.

Sürüm Bilgisi

Sürüm: Açıklama
8.0.0 Başarı durumunda artık GDImage nesnesi dönüyor; evvelce, resourcetüründe bir değer dönerdi.

Örnekler

Örnek 1 - Bir PNG yüklerken oluşan bir hatanın ele alınması

<?php
function PNGyükle($ad)
{
/* Görüntüyü açmaya çalışalım */
$im = @imagecreatefrompng($ad);

/* Başarılı oldu mu bakalım */
if(!$im)
{
/* Boş bir görüntü oluşturalım */
$im = imagecreatetruecolor (20, 20);
$bgc = imagecolorallocate($im, 255, 255, 255);
$tc = imagecolorallocate($im, 0, 0, 0);

imagefilledrectangle($im, 0, 0, 10, 10, $bgc);

/* Hata iletisini çıktılayalım */
imagestring($im, 1, 5, 5, $ad . ' yüklenirken hata oluştu', $tc);
}

return
$im;
}

header('Content-Type: image/png');

$img = PNGyükle('bozuk.görüntü');

imagepng($img);
imagedestroy($img);
?>

Yukarıdaki örnek şuna benzer bir çıktı üretir:

imagecreatefrompng() örneği
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User Contributed Notes 7 notes

up
4
sageptr at gmail dot com
2 years ago
Because gd and imagick do not support animated PNG (at this moment), i wrote a simple function to determine if given PNG is APNG or not. It does not validate PNG, only checks whenever "acTL" chunk appears before "IDAT" like the specification says: https://wiki.mozilla.org/APNG_Specification

<?php

function is_apng(string $filename): bool
{
$f = new \SplFileObject($filename, 'rb');
$header = $f->fread(8);
if (
$header !== "\x89PNG\r\n\x1A\n") {
return
false;
}
while (!
$f->eof()) {
$bytes = $f->fread(4);
if (
strlen($bytes) < 4) {
return
false;
}
$length = unpack('N', $bytes)[1];
$chunkname = $f->fread(4);
switch (
$chunkname) {
case
'acTL':
return
true;
case
'IDAT':
return
false;
}
$f->fseek($length + 4, SEEK_CUR);
}
return
false;
}

?>
up
84
Anonymous
19 years ago
If you're trying to load a translucent png-24 image but are finding an absence of transparency (like it's black), you need to enable alpha channel AND save the setting. I'm new to GD and it took me almost two hours to figure this out.

<?php
$imgPng
= imageCreateFromPng($strImagePath);
imageAlphaBlending($imgPng, true);
imageSaveAlpha($imgPng, true);

/* Output image to browser */
header("Content-type: image/png");
imagePng($imgPng);
?>
up
11
marcos at assl-site dot net
17 years ago
I had the same problem as jboyd1189 at yahoo dot com but I solve d it allocating more memory dynamically.

Usually the memory_limit var on php.ini is set to 8M. Unfortunately, the required amount of memory to manage a PNG image about 1000x1000 could be bigger !

The approach I used to solve the problem is:

1-Calculate the memory required by the image
2-Set the new memory_limit value
3-Create the PNG image and thumbnail
4-Restore the original value

1-The following value works for me:
$required_memory = Round($width * $height * $size['bits']);

Note that for JPEG the requirements are not the same:
http://es2.php.net/manual/en/function.imagecreatefromjpeg.php#60241

2-Use somthing like:
$new_limit=memory_get_usage() + $required_memory;
ini_set("memory_limit", $new_limit);

4-ini_restore ("memory_limit");
up
0
admin at wdfa dot co dot uk
14 years ago
When using imagecreatepng with alpha blending you will lose the blending.

To over come this use something like the following
<?php
$dstimage
=imagecreatetruecolor($width,$height);
$srcimage=imagecreatefrompng($src);
imagecopyresampled($dstimage,$srcimage,0,0,0,0, $width,$height,$width,$height);
?>
Where $width and $height are the width and height of the $src image.

This will create a true colour image then copy the png image to this true colour image and retain alpha blending.
up
-6
Cyrille37
8 years ago
The image size (width x height) should not exceed INT_MAX ... It's still thrue on a 64 bits computer.
up
-13
katalin at knittedforyou dot com
6 years ago
I have this code:

if (exif_imagetype($this->img_name) == IMAGETYPE_PNG) {
try {

$this->image = imagecreatefrompng($this->img_name);
Error::log('It is a png: '.$this->img_name);
} catch (Exception $e) {
echo "The image file has some strange charachters. Probably not a png image?";
$this->image = '';
$this->img_name = '';
}
}

And I get this error in the error.log:
PHP Unknown error: imagecreatefrompng(): gd-png: fatal libpng error: Extra compressed data\n in Unknown on line 0

The file that I try to open is a generated .png image which I can open from gimp and Geeqie.

What is the problem? Could you please help me?
up
-30
jboyd1189 at yahoo dot com
17 years ago
I was having a terrible time with the imagecreatefrompng function as it was working perfectly for one image and not at all for another. After many hours of frustration, I discovered that the problem was the image size (number of pixels). It appears that the maximum number of pixels this function will process is 1,040,000. So, be sure that the pixel resolution of the image (eg. 1040 x 1000) does not exceed this value.
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