图像在PHP中调整大小

I am very new to Resize image in php.Basically i wanted to make thumbnail image using uploaded image. i have used below code but its not working, can anybody help me?.. Thanks in Advance...

$source_image = $path.$row->photosfolder;
$size = getimagesize($source_image);
$w = $size[0];
$h = $size[1];
$simg = imagecreatefromjpeg($source_image);
$dimg = imagecreatetruecolor(150, 225);
$wm = $w / 150;
$hm = $h / 225;
$h_height = 225 / 2;
$w_height = 150 / 2;

if ($w > $h) {
    $temp = imagecopyresampled($dimg, $simg, 0, 0, 0, 0, 150, 225, $w, $h);
}
elseif (($w < $h) || ($w == $h)) {
    $temp = imagecopyresampled($dimg, $simg, 0, 0, 0, 0, 150, 225, $w, $h);
}
else {
    $temp = imagecopyresampled($dimg, $simg, 0, 0, 0, 0, 150, 225, $w, $h);
}

$thumb_image = imagejpeg($dimg, $simg, 100);

check timthumb.php is easy to use and you can find the code full educational

If you want to resize an image, you should do it on client side because PHP image manipulation takes a lot of memory and CPU time, and it doesn't have to be done on server side (there are no access to db, no access to session, etc).

If you still want to do it on PHP, you can use that functions to get the right sizes :

list($realW, $realH) = getimagesize($source_image);

$realR = $realW / $realH;
$thumbR = $thumbW / $thumbH;

// If you want your resize image to fit inside the max thumb size :

if($realR > $thumbR) // Real image if flatter than thumb
{
    $newW = $thumbW;
    $newH = $newW / $realR;
}
else
{
    $newH = $thumbH;
    $newW = $newH * $realR;
}

// Or if you want your resize image to be as small as possible but
// not smaller than your thumb. This can be helpful in some cases.

if($realR < $thumbR)
{
    // Same code
}

And then use copy resampled as you did (read php manual if you can't get it to work, there are examples below the synopsis of the function).

If you want to resize an image using javascript, you can use the <canvas> :

var canvas = document.createElement('canvas');
var image = document.getElementById('image');
var context = canvas.getContext('2d');
context.save();
context.drawImage(image, /* Here you put the right values using the algorithms above */);
context.restore();
var thumb = document.createElement('image');
thumb.src = canvas.toDataUrl();

Or something like that. You may change a few things depending on your specific case.

Please try with below code, It will resize image and create new thumbnail. New size is defined 100 X 100. This example will also keep aspected ratio of image. Note:

1.Image path will be directory path if want to set full path. 2. In example we consider for jpg file, you can use for PGN & GIF file with imagecreatefrompng, imagecreatefromgif. 3.This will create PNG file.

$_imagePath = 'somefile.jpg';
$im = imagecreatefromjpeg($_imagePath);

imagealphablending($im, true);

$_orgWidth = imagesx($im);
$_orgHeight =  imagesy($im);

$_newWidth = 100;
$_newHeight = 100;

$_finalHeight = $_orgHeight * ( $_newWidth/ $_orgWidth);
    if($_finalHeight > $_newHeight){
        $_newWidth = $_orgWidth * ($_newHeight / $_orgHeight);
    }else{
        $_newHeight = $_finalHeight ;
    }


$_thumb = imagecreatetruecolor($_newWidth, $_newHeight);
imagealphablending($_thumb, true);
imagesavealpha($_thumb, true);

imagecopyresampled($_thumb, $im, 0, 0, 0, 0, $_newWidth, $_newHeight, $_orgWidth , $_orgHeight  );

imagepng($_thumb, 'newname.png');
imagedestroy($_thumb);