Image Manipulation

anortrup

I am currently writing an application where my client has images that go along with every record in the database (likely to be well around a million when all is said and done), these images however are to large to fit into the printable area of the screen in their original format but if rotated 90 degrees they will fit. What I have read suggests that you should include a file that will return headers to indicate an image this include file would look like this:

<?
Header("Content-type: image/jpeg");
 $filename = "/tmp/" . $img_name;
 $img_size = GetImageSize($filename);
 $x = $img_size[0];
 $y = $img_size[1];
 $src_img = ImageCreateFromJpeg($filename);
 $dst_img = ImageCreateTrueColor($width,$height);

ImageCopyResized($dst_img,$src_img,0,0,0,0,$x,$y,$x,$y);
 $degrees = "180";
 $rotated_img = ImageRotate($dst_img,$degrees,0);
ImageJpeg($rotated_img); 
?>

The problem with this however is that the image is inserted well into the page when headers can no longer be output.

Is there something that I'm missing?

-Andy

Weedpacket

You wouldn't imbed it into the page anyway; even if you delayed the output long enough to send out the headers you'd get a big wodge of gibberish while the client tries to render binary image data as HTML. You can't use the output of ImageJpeg as the src of an img tag if that's what you're thinking.

What you can have, though, is an img src that contains the URL of a PHP script containing the code you've posted, with the name to render in the URL's querystring ("image.php?image_name=foo"). Put in image.php a bit of code that will make sure that $_GET['image_name'] contains the name of a valid image, and if it does, build the full filename from it and carry on as you are.

Of course, it would probably make better sense to rotate the images when you upload them (if you're uploading them via PHP) - because then you only need to rotate them once - not every time they're requested.

coreyp_1

The type of script you are talking about should indeed give out a jpg, but that is all. It is not something that is included inside another script.

Let me try to explain it this way...

In writing in HTML, you would include an image using the <img> tag, and point it to a picture file (jpg, gif, png, etc.).

Well, the script you are talking about here takes the place of the image file. In fact, it IS an image, created dynamically by php.

You see, when the browser attempts to access this script, the headers tell the browser that the information it is about to receive is a jpg, and then the php creates the graphical data. If the script is called "rotate.php", then your HTML might look something like this:

Where id is a reference in a database that includes the path to the original picture, etc. The PHP takes the request and creates a jpg, which it then sends back to the browser to be displayed.

I have used this same method to stream pdf's without disclosing their actual directory on the server (to protect from outside linking). This method can also be used to only allow registered members of a site to access a file, etc., because you can do any PHP processing that you want (like access a database and validate information), as long as the only information you output is the graphical information.

This is the same general concept behind counters, in that they dynamically create an image based on the number that they are trying to display at that particular moment.

In short, the script will output only ONE type of file, in this case a jpg, which a browser can access just as it would any other picture.

HTH

[EDIT: Drat! I type too slow! Oh, well, you got two people's answer rather than just one.]