Re: get image size from binary data

james.gauth@googlemail.com wrote:
> On 26 Jun, 08:31, Christoph Burschka <christoph.bursc...@rwth-
> aachen.de> wrote:
>> Is there some way to get the dimensions of an image, given the binary
>> data of the image, without having to write it to a temporary file?
>>
>> It seems that getimagesize() will only take a filename, but since I have
>> to download the image from a remote URL with fsockopen(), I have it
>> stored as a binary string.
>>
>> I've had a cursory glance at the data, but predictably the size is not
>> stored in decimal format anywhere...
>>
>> --
>> cb
>
> If the image format is supported by your GD Library, you can use the
> following:
>
> <?php
>
> $binary_data = file_get_contents('http://www.google.co.uk/intl/en_uk/
> images/logo.gif');
>
> $im = imagecreatefromstring($binary_data);
>
> $width = imagesx($im);
> $height = imagesy($im);
>
> print "width: $width\n";
> print "height: $height\n";
>
> ?>
>

Someone correct me if I am wrong, but whenever you open an image/file to
read (even if you want to read the headers) you are storing it to some
temporary buffer/space on your machine!
Maybe the GD solution above is the best!

Armand

Armand Brahaj wrote:
> james.gauth@googlemail.com wrote:
>> On 26 Jun, 08:31, Christoph Burschka <christoph.bursc...@rwth-
>> aachen.de> wrote:
>>> Is there some way to get the dimensions of an image, given the binary
>>> data of the image, without having to write it to a temporary file?
>>>
>>> It seems that getimagesize() will only take a filename, but since I have
>>> to download the image from a remote URL with fsockopen(), I have it
>>> stored as a binary string.
>>>
>>> I've had a cursory glance at the data, but predictably the size is not
>>> stored in decimal format anywhere...
>>>
>>> --
>>> cb
>>
>> If the image format is supported by your GD Library, you can use the
>> following:
>>
>> <?php
>>
>> $binary_data = file_get_contents('http://www.google.co.uk/intl/en_uk/
>> images/logo.gif');
>>
>> $im = imagecreatefromstring($binary_data);
>>
>> $width = imagesx($im);
>> $height = imagesy($im);
>>
>> print "width: $width\n";
>> print "height: $height\n";
>>
>> ?>
>>
>
> Someone correct me if I am wrong, but whenever you open an image/file to
> read (even if you want to read the headers) you are storing it to some
> temporary buffer/space on your machine!
> Maybe the GD solution above is the best!
>
> Armand

Yeah, so I'd be downloading the image data, saving it to a temporary
file, reading the temp file into the buffer and getting the header. Not
exactly efficient.

Thanks for imagecreatefromstring(); that was exactly the function I was
looking for!

--
cb

> Yeah, so I'd be downloading the image data, saving it to a temporary
> file, reading the temp file into the buffer and getting the header. Not
> exactly efficient.
>
> Thanks for imagecreatefromstring(); that was exactly the function I was
> looking for!

How else do you expect a system to know details of files on other systems
without downloading them?

I have a book beside me how many pages has it got, what is the author and
what is the title? This is basically what you are wanting your script to do.

peter schrieb:
>>Yeah, so I'd be downloading the image data, saving it to a temporary
>>file, reading the temp file into the buffer and getting the header. Not
>>exactly efficient.
>>
>>Thanks for imagecreatefromstring(); that was exactly the function I was
>>looking for!
>
>
> How else do you expect a system to know details of files on other systems
> without downloading them?
>
> I have a book beside me how many pages has it got, what is the author and
> what is the title? This is basically what you are wanting your script to do.
>
>

To complete the analogy, you open the book and count the pages. You do
not xerox the book page by page, then open the copy. ;)

It doesn't matter if fsockopen(url) -> imagecreatefromstring() ->
imagesx() uses temporary files (a process I can't influence anyway),
fsockopen() -> fwrite() -> getimagesize() is likely to use one more.

Even if they are equally efficient, the first method handles it in the
background without making me juggle files in my own code, removing a
frequent source of bugs.

--
cb