Creating a 128x128 thumbnail

[pek]

Hello, I have a simple question which I can't figure out:
I want to create a thumbnail of an image, but I want to make sure that
the output is exactly 128x128.. The resized thumbnail has to be
centered.
Can you please help me?

Thank you very much,
Panagiotis

[pek]

Oops, I kinda rushed and posted it without further explaining. Anyway,
to create this 128x128, I meant not the image will be resized at
128x128 (distorting the perspective), but it would be resized with
maximum width or height at 128, and the space that's left (on top/
bottom or left/right) will be filled with transparent background. I
hope I made my self clear.

Sorry for my bad English.

[macca]

function createthumb($name,$filename,$new_w,$new_h){
$system=explode('.',$name);
if (preg_match('/jpg|jpeg|JPG|JPEG/',$system[1])){
$src_img=imagecreatefromjpeg($name);
}
if (preg_match('/png|PNG/',$system[1])){
$src_img=imagecreatefrompng($name);
}

$old_x=imageSX($src_img);
$old_y=imageSY($src_img);
if ($old_x $old_y) {
$thumb_w=$new_w;
$thumb_h=$old_y*($new_h/$old_x);
}
if ($old_x < $old_y) {
$thumb_w=$old_x*($new_w/$old_y);
$thumb_h=$new_h;
}
if ($old_x == $old_y) {
$thumb_w=$new_w;
$thumb_h=$new_h;
}

$dst_img=ImageCreateTrueColor($thumb_w,$thumb_h);
imagecopyresampled($dst_img,$src_img,0,0,0,0,$thum b_w,$thumb_h,
$old_x,$old_y);


if (preg_match("/png/",$system[1]))
{
imagepng($dst_img,$filename);
} else {
imagejpeg($dst_img,$filename);
}
imagedestroy($dst_img);
imagedestroy($src_img);
}
//call the function with this:
//createthumb('test.jpg','tn_apple.jpg',150,150);

[Michael Fesser]

..oO(macca)

Some little hints:

>function createthumb($name,$filename,$new_w,$new_h){
$system=explode('.',$name);

What about image names containing a dot? Better use pathinfo():

$ext = pathinfo($name, PATHINFO_EXTENSION);

if (preg_match('/jpg|jpeg|JPG|JPEG/',$system[1])){

Make use of the power of regular expressions:

if (preg_match('/jpe?g/i', $ext)) {

$src_img=imagecreatefromjpeg($name);
}
if (preg_match('/png|PNG/',$system[1])){

if (preg_match('/png/i', $ext)) {

$src_img=imagecreatefrompng($name);
}

$old_x=imageSX($src_img);
$old_y=imageSY($src_img);
if ($old_x $old_y) {
$thumb_w=$new_w;
$thumb_h=$old_y*($new_h/$old_x);
}
if ($old_x < $old_y) {
$thumb_w=$old_x*($new_w/$old_y);
$thumb_h=$new_h;
}
if ($old_x == $old_y) {
$thumb_w=$new_w;
$thumb_h=$new_h;
}

You can drop the last part. Just add the equalness to one of the
previous operations (<= or >=). Keeps the code a bit shorter.

>if (preg_match("/png/",$system[1]))

With your original code this part will fail if the extension is PNG. At
the beginning of the function you checked for both lower- and uppercase,
here you don't. Better:

if (preg_match('/png/i', $ext)) {

To avoid this preg_match() call, you could also set a variable at the
beginning, which file format to use. Then it would be as simple as

if ($mode == 'png') {

Micha

[macca]

A few improvements there thanks :-)

[Michael Fesser]

..oO(macca)

>A few improvements there thanks :-)

You're welcome.

Micha