PHP Image resize function - Tilted Forum Project Discussion Community

frogza · 05-24-2007, 07:34 AM

I have the GD library installed and running. I can't get this script to work, any suggestions? The picture displays, but not at the size I want.

Quote:

<?php

function imageResize($width, $height, $target) {

//the math to resize the picture maintaining ratio

if ($width > $height) {
$percentage = ($target / $width);
} else {
$percentage = ($target / $height);
}

//gets the new value and applies the percentage, then rounds the value
$width = round($width * $percentage);
$height = round($height * $percentage);

//returns the new sizes in html image tag format

return "width=\"$width\" height=\"$height\"";

}

?>

<?php

//get the image size of the picture
$thumbpic = getimagesize("admin/photos/321-30853-Turpin.JPG");

?>

img src="admin/photos/321-30853-Turpin.JPG" <?php imageResize($thumbpic[0], $thumbpic[1],150); ?>>

the image tag here is missing the opening bracket to help it display properly, in my script it is there.

ratbastid · 05-24-2007, 08:32 AM

I don't really understand what this function is supposed to do, but... Try viewing the source. Are your width and height values getting set correctly in the img tag? That's the place to start.

Jinn · 05-24-2007, 09:18 AM

Two things:

1) I see the function declaration, but where is the actual call? Do you have a separate block of code which calls it? I don't see you passing a height, width, target to imageResize. You get it with getimagesize, but never pass that value to the function? Also, without a function call, where is that return value going? It's going nowhere at the moment.

It looks like you're trying to accomplish something like:

PHP Code:


			
<img src="imgfilename" <?php imageResize($height, $width, $target); ?>>

2) You're not actually resizing the picture with this code. You are in the effect that you're causing the browser to render the picture at a shrunken size, but someone viewing the page still had to download the full size image, and then their browser shrunk it down. Changing HTML height and width tags only changes rendered size, not actual size.

seretogis · 05-24-2007, 09:25 AM

This is some old code I used to generate a thumbnail from an uploaded image, which may help.

For reference, check out the PHP image function documentation.

Code:

$fullsize = $user_id . "_" . time() . "_" . $_FILES['shot']['name'];
$thumb = "thumb_" . $user_id . "_" . time() . "_" . $_FILES['shot']['name'];

move_uploaded_file( $_FILES['shot']['tmp_name'], $shot_directory . "/" . $fullsize );

list( $width, $height, $type, $attr ) = getimagesize( $shot_directory . "/" . $fullsize );

if ( $type == 1 )
    $src = imagecreatefromgif( $shot_directory . "/" . $fullsize );
else if ( $type == 2 )
    $src = imagecreatefromjpeg( $shot_directory . "/" . $fullsize );
else
    return "ERROR: This gallery only supports JPG and GIF file formats";

// creating a thumbnail ----------------------------------------------------------

$multiplier = 160 / $width;

$new_width = 160;
$new_height = round( $height * $multiplier );

if ( $new_height > 160 ) {
    $multiplier = 0;
    $new_height = 0;
    $new_width = 0;

    $multiplier = 160 / $height;

    $new_height = 160;
    $new_width = round( $width * $multiplier );
}

$dest = imagecreatetruecolor( $new_width, $new_height );

imageCopyResampled( $dest, $src, 0, 0, 0, 0, $new_width, $new_height, $width, $height );

imagejpeg( $dest, $shot_directory . "/" . $thumb );

frogza · 05-27-2007, 06:32 AM

Thanks for the help

05-24-2007, 09:18 AM	#3 (permalink)
Jinn Lover - Protector - Teacher Location: Seattle, WA	Two things: 1) I see the function declaration, but where is the actual call? Do you have a separate block of code which calls it? I don't see you passing a height, width, target to imageResize. You get it with getimagesize, but never pass that value to the function? Also, without a function call, where is that return value going? It's going nowhere at the moment. It looks like you're trying to accomplish something like: PHP Code: `<img src="imgfilename" <?php imageResize($height, $width, $target); ?>>` 2) You're not actually resizing the picture with this code. You are in the effect that you're causing the browser to render the picture at a shrunken size, but someone viewing the page still had to download the full size image, and then their browser shrunk it down. Changing HTML height and width tags only changes rendered size, not actual size. __________________ "I'm typing on a computer of science, which is being sent by science wires to a little science server where you can access it. I'm not typing on a computer of philosophy or religion or whatever other thing you think can be used to understand the universe because they're a poor substitute in the role of understanding the universe which exists independent from ourselves." - Willravel Last edited by Jinn; 05-24-2007 at 09:22 AM..

05-24-2007, 08:32 AM	#2 (permalink)
ratbastid Darth Papa Location: Yonder	I don't really understand what this function is supposed to do, but... Try viewing the source. Are your width and height values getting set correctly in the img tag? That's the place to start.

05-27-2007, 06:32 AM	#5 (permalink)
frogza Registered User Location: Right Here	Thanks for the help