Why there is imageCreateFrom* if there is imageCreateFromString?

php image gd
dynamic picture dynamic · Jun 9, 2012 · Viewed 8k times · Source

I really can't understand why GD has different function for loading images such like:

imagecreatefromjpeg() 
imagecreatefrompng() 
imagecreatefromgif()

While there is a single function if the image is string?

imagecreatefromstring()

Indeed it's much better to read the image into the string and pass it to the function, something like:

$imgBlob = file_get_contents($imagePath);
imagecreatefromstring($imageBlob);
unset($imgBlob);  //> Free memory, but I am not interested in memory consumpation

? Or I am missing something ? This could led to potential confusion for new users

Maybe they just forgot to create a function imageCreateFromFile()?

Ps. Of course I am not interested about memory consumation using the file_get_contents method

Answer

Charlie Schliesser picture Charlie Schliesser · Dec 10, 2013

imagecreatefromstring() runs a switch against the passed image type, checks if your system has support for that image type, and then actually runs the correct imagecreatefrom* function.

You can check out the source code to see this: https://github.com/php/php-src/blob/master/ext/gd/gd.c?source=cc (line 2280 for the function, line 2301 where it switches on the image type and calls the correct function).

So, the imagecreatefromstring() function is really just a helper wrapper. You'll get a very slight benefit from not running _php_image_type (line 2217) if you call the actual image type function.

Related questions

Creating a thumbnail from an uploaded image

I'm wanting to create a thumbnail from a user uploaded image so the image doesn't look squashed. But also would like a copy of the original image.. So I would like the original image to send the original image to …

Read More
How to add text to an image with PHP GD library

I have image creation code in image_creator. <?php header("Content-Type: image/jpeg"); $im = ImageCreateFromGif("photo.gif"); $black = ImageColorAllocate($im, 255, 255, 255); $start_x = 10; $start_y = 20; Imagettftext($im, 12, 0, $start_x, $start_y, $black, 'verdana.ttf', "text to write"); Imagejpeg($im, '', 100); …

Read More
Efficient JPEG Image Resizing in PHP

What's the most efficient way to resize large images in PHP? I'm currently using the GD function imagecopyresampled to take high resolution images, and cleanly resize them down to a size for web viewing (roughly 700 pixels wide by 700 pixels tall). …

Read More