Change Image Size - PHP

Question

I have recently created an upload function, but I don\'t know how to change the width and height to 75px... I tried one code I found through Google, but I just got this erro

Answer 1

Simple solutions some times changed alfa (transparent png). For me forks only this (it's real, just copy-pasted code)

public static function resize($filename, $maxW, $maxH, $ext = null)
{
    if ($ext === null)
        $ext = strtolower(pathinfo($filename, PATHINFO_EXTENSION));
    else
        $ext = strtolower($ext);

    list($origW, $origH) = getimagesize($filename);

    $w = $origW;
    $h = $origH;

    # taller
    if ($h > $maxH) {
        $w = ($maxH / $h) * $w;
        $h = $maxH;
    }

    # wider
    if ($w > $maxW) {
        $h = ($maxW / $w) * $h;
        $w = $maxW;
    }


    $resource = imagecreatetruecolor($w, $h);
    # MUST IMPORTANT TWO ROWS
    imagesavealpha($resource, true);
    imagefill($resource, 0, 0, 0x7fffffff);

    if ($ext == 'jpeg' || $ext == 'jpg') {
        $image = imagecreatefromjpeg($filename);
    } else if ($ext == 'png') {
        $image = imagecreatefrompng($filename);
    } else {
        throw new Exception('Unsupported extension');
    }

    imagecopyresampled(
        $resource,
        $image, 0, 0, 0, 0,
        $w, $h, $origW, $origH
    );
    imagedestroy($image);

    return $resource;
}

Answer 2

The Imagick Class is not found, because it is a PHP extension you need to install on your server.

Read the following documentation to find instructions on how to use/install the extension. http://www.php.net/manual/en/book.imagick.php

Answer 3

You can also scale the image client-side, e.g. using plupload library (can resize JPEG and PNG).

Answer 4

I've successfully used GD to do this recently, specifically using the imagecopyresampled function.

---

To expand a little on that... Once I had the image uploaded (which I wont go into, because that is a whole other issue), I did something fairly simple like this:

$original_info = getimagesize($filename);
$original_w = $original_info[0];
$original_h = $original_info[1];
$original_img = imagecreatefromjpg($filename);
$thumb_w = 100;
$thumb_h = 100;
$thumb_img = imagecreatetruecolor($thumb_w, $thumb_h);
imagecopyresampled($thumb_img, $original_img,
                   0, 0,
                   0, 0,
                   $thumb_w, $thumb_h,
                   $original_w, $original_h);
imagejpeg($thumb_img, $thumb_filename);
imagedestroy($thumb_img);
imagedestroy($original_img);

Please note that I have not tested this code. It's just here to give you a basic idea of my method.

Answer 5

I use code like this:

$t = imagecreatefromjpeg($old_path);
$x = imagesx($t);
$y = imagesy($t);

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

imagecopyresampled($s, $t, 0, 0, 0, 0, $new_width, $new_height,
        $x, $y);

imagejpeg($s, $new_path);
chmod($new_path, 0644);