PHP & Optimizing Images

[MisterX]

How would you go about making an image optimizer using PHP ?

I usually use Resizr for image optimization and it does a great job, but I'll need to make my own code to deal with user uploaded pictures.

So far I've been looking at imagejpeg. Any other suggestions ?

 

[Houdas]

I recommend using ImageMagick PHP extension, because when working with native GD functions, you run into memory problems quite easily, especially when working with larger images (like 2000x1600 pixels), since PHP scripts have usually allocated only 8MB for data.

ImageMagick v6 Examples

 

[Juicify]

Also looking for resizing and cropping? This is my own code that does it all.

function cropResize(&$gdSource, $newWidth, $newHeight, $mode, $left=false,$top=false,$alpha = false){
// $mode: 1=resize, keep aspect ratio, width & height as max values, 
// $mode: 2=resize the relative smallest side, + crop the bigger side if needed, keep aspect ratio
// $mode: 3=resize to desired, NOT keeping aspect ratio
// $mode: 4=just crop, $left and $top needed
    // list($oldWidth,$oldHeight) = getimagesize($gdSource); // Get the original dimensions

    $oldWidth = imagesx($gdSource);
    $oldHeight = imagesy($gdSource);

    if ($mode == '1'){// $mode = 1
        if (($oldWidth <= $newWidth) && ($oldHeight <= $newHeight)){
            return $gdSource;
        }
        if (($oldWidth <= $newWidth) || ($oldHeight <= $newHeight)){
            $finalHeight = $oldHeight;
            $finalWidth = $oldWidth;
        }
        if (($oldHeight > $newHeight) || ($oldWidth > $newWidth)) {
            $multiplier = $oldWidth/$oldHeight;
            if ($oldHeight/$newHeight > $oldWidth/$newWidth){
                $finalHeight = $newHeight;
                $finalWidth = $finalHeight*$multiplier;
            }
            else {
                $finalWidth = $newWidth;
                $finalHeight = $finalWidth/$multiplier;
            }
        }
    }

    if (!$finalHeight){
        $finalHeight = $newHeight;
    }
    if (!$finalWidth){
        $finalWidth = $newWidth;
    }
    
    if ((($oldWidth/$oldHeight) !== ($newWidth/$newHeight)) && ($mode == '2')){ // $mode = 2
        $multiplier = $newWidth/$newHeight;
        if (($oldWidth/$oldHeight) < ($newWidth/$newHeight)){
            $cropHeight = $oldHeight/$multiplier;
            $cropWidth = $oldWidth;
        }
        elseif (($oldWidth/$oldHeight) > ($newWidth/$newHeight)){
            $cropHeight = $oldHeight;
            $cropWidth = $oldHeight*$multiplier;
        }
    }
    elseif ($mode == '4'){
        $cropHeight = $newHeight;
        $cropWidth = $newWidth;
    }
    else { // $mode = 3 or if can be used by 1 or 2
        $cropHeight = $oldHeight;
        $cropWidth = $oldWidth;
    }
    
    if ($left !== false && $mode == '4'){
        $cropLeft = $left;
    }
    elseif ($cropWidth < $oldWidth && ($mode == '2')){
        $cropLeft = ($oldWidth-$cropWidth)/2;
    }
    else {
        $cropLeft = 0;
    }
    
    if ($top !== false && $mode == '4'){
        $cropTop = $top;
    }
    elseif ($cropHeight < $oldHeight && ($mode == '2')){
        $cropTop = ($oldHeight-$cropHeight)/2;
    }
    else {
        $cropTop = 0;
    }
    
    $cropLeft = round($cropLeft);
    $cropTop = round($cropTop);
    $cropWidth = round($cropWidth);
    $cropHeight = round($cropHeight);
    
    $gdOutput = imagecreatetruecolor($finalWidth,$finalHeight);
    if ($alpha === true){
        $background = imagecolorallocate($gdOutput, 0, 0, 0);
        imagecolortransparent($gdOutput, $background); // make the new temp image all transparent
        imagealphablending($gdOutput, false); // turn off the alpha blending to keep the alpha channel
         imagesavealpha ( $gdOutput, true ); // Save full alpha
    }
    
    imagecopyresampled($gdOutput, $gdSource, 0,0, $cropLeft, $cropTop, $finalWidth, $finalHeight, $cropWidth, $cropHeight);
    imagedestroy($gdSource);
    return $gdOutput;
}

 

[MisterX]

I recommend using ImageMagick PHP extension, because when working with native GD functions, you run into memory problems quite easily, especially when working with larger images (like 2000x1600 pixels), since PHP scripts have usually allocated only 8MB for data.

ImageMagick v6 Examples

Thanks for the info, it wouldn't have crossed my mind! After a day of testing, I'm using GD, but limiting the size & dimensions of pictures (I needed to do that anyhow) to 300KB & 1024 pixels.

Also looking for resizing and cropping? This is my own code that does it all.

Thanks, I think I'll find a use for it. I have resizing covered, but still need to do some thumbnail cropping, although I still haven't decided which parts I'll want to crop.