Tag: gd
Nabin Nepal (Starx) apache gd imagemagick laravel php
September 18, 2012

How to ensure JPEG image is valid and can be handled by PHP?

Question by Nyxynyx

NyxynyxNyxynyx

I have this JPEG that has been giving problems to the function imagesx($this->image) from the Resizer library that I am using. I am able to view the image using the browser, and when attempting to resize, I get the error:

imagesx() expects parameter 1 to be resource, boolean given

It is OK for me to not handle this file if it is going to throw an error. How can I use PHP to check whether this image can be handled properly by PHP’s image functions?

Code that calls the Library

// Download the photo
$img_content = file_get_contents($url);
if($img_content !== FALSE) {
    file_put_contents($img_documentroot . $img_subpath . $img_filename . '_tmp.jpg',
     $img_content);
}

echo $url . '<br>';
echo $img_documentroot . $img_subpath . $img_filename . '_tmp.jpg<br>';
ob_flush();
flush();

// Resize photo
Resizer::open( $img_documentroot . $img_subpath . $img_filename . '_tmp.jpg' )
->resize(300, 300, 'landscape' )
->save($img_documentroot . $img_subpath . $img_filename . '.jpg' , 90 );

// Thumbnail photo
Resizer::open( $img_documentroot . $img_subpath . $img_filename . '_tmp.jpg' )
->resize(100, 100, 'crop' )
->save($img_documentroot . $img_subpath . $img_filename . '.jpg' , 90 );

Output

I also echoed out the full path of the image being resized.

http://www.ApartmentsInAllstonMA.com/Images/Apts/132847_kn1.jpg
/home/photos/public_html/2012/0917/2516539_7_tmp.jpg
resource(127) of type (gd)
resource(130) of type (gd)
http://www.ApartmentsInMedford.com/Images/Apts/132847_lv2.jpg
/home/photos/public_html/2012/0917/2516539_11_tmp.jpg
resource(163) of type (gd)
resource(166) of type (gd)
http://www.AllstonApartmentX.com/images/agents/61.jpg
/home/photos/public_html/2012/0917/2516539_12_tmp.jpg
bool(false)

UPDATE

This is the code snippet that is causing the library to return a false value.

private function open_image( $file )
{

    // If $file isn't an array, we'll turn it into one
    if ( !is_array($file) ) {
        $file = array(
            'type'      => File::mime( strtolower(File::extension($file)) ),
            'tmp_name'  => $file
        );
    }

    $mime = $file['type'];
    $file_path = $file['tmp_name'];

    switch ( $mime )
    {
        case 'image/pjpeg': // IE6
        case File::mime('jpg'): $img = @imagecreatefromjpeg( $file_path );  break;
        case File::mime('gif'): $img = @imagecreatefromgif( $file_path );   break;
        case File::mime('png'): $img = @imagecreatefrompng( $file_path );   break;
        default:                $img = false;                               break;
    }

    return $img;
}

Answer by Starx

StarxStarx

Checking for the mime type is a very good method to ensure the validity of JPEG image. Here is how you can do this.

$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type
$type = finfo_file($finfo, $filename) . "n";  
if($type == "image/jpeg") { 
     //Valid JPEG Image
}
finfo_close($finfo);

According to your errors, you are sending boolean value instead of image resource.

Nabin Nepal (Starx) gd php
April 16, 2012

PHP detect if ImageCreateFromString fail

Question by Jerome Ansia

Jerome AnsiaJerome Ansia

I would like to be able to detect when i launch this function if it’s fail or not due to the memory size limit

ImageCreateFromString();

http://php.net/manual/en/function.imagecreatefromstring.php

Answer by rauchmelder

rauchmelderrauchmelder

In the PHP-Manual which you’ve linked there is the solution already written:

Return Values

An image resource will be returned on success. FALSE is returned if the image type is unsupported, the data is not in a recognised format, or the image is corrupt and cannot be loaded.

Answer by Starx

StarxStarx

If you had read the manual you linked in your question, there is an answer already.

An image resource will be returned on success. FALSE is returned if the image type is unsupported, the data is not in a recognised format, or the image is corrupt and cannot be loaded.

There is an example for that

$im = imagecreatefromstring($data);
if ($im !== false) {
    // OK
}
else {
    echo 'An error occurred.';
}
Nabin Nepal (Starx) gd php
February 27, 2012

Why does my Image stretch when I crop it?

Question by Starx

StarxStarx

I am using the following code snippet in order to crop a image?

   function crop($width,$height) {
       $new_image = imagecreatetruecolor($width, $height);
       imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $this->getWidth(), $this->getHeight(), $width, $height );
       $this->image = $new_image;
   }

Here, $this->image is the original image $this->getWidth() and $this->getHeight() holds the original dimensions of the picture, where as $width and $height, is the crop area.

But for some reason, the crop image is resized(we can almost say it is resized).

How to fix this?

Answer by Starx

StarxStarx

Well, the problem is giving the source dimensions. Giving the dimensions of entire image will re size instead of cropping.

This should solve the problem

   function crop($width,$height) {
       $new_image = imagecreatetruecolor($width, $height);
       imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $width, $height );
       $this->image = $new_image;
   }
...

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