<?php
include "php/classes/imagecreatefrombmp.php";

class canvas{

  private $file, $image, $temp_image;

  private $width, $height, $new_width, $new_height, $html_size;

  private $format, $extension, $size, $basename, $dirname;

  private $rgb = array(255, 255, 255);
  
  private $quality = 100;

  private $crop_coordinates;

  private $error = "";
  
  private $image_formats = array(
    "jpeg" => 2,
    "jpg" => 2,
    "gif" => 1,
    "png" => 3,
    "bmp" => 6
  );

  function __construct($file = null){
    if($file){
      $this->file = $file;
      $this->image_info();
    } 
  }

  function load($file){
    $this->file = $file;
    $this->image_info();
    if(!$this->error)
      return $this;
    else
      return false;
  }
  
  function load_url($url){
    $this->file = $url;
    $this->file_info();
    if(!$this->format){
      $this->error = "Invalid image URL.";
      return false;
    }else{
      $this->create_image();
      $this->update_dimensions();
      return $this;
    }
  }

  private function image_info(){
    if(is_file($this->file)){
      $this->file_info();
      if(!$this->is_image())
        $this->error = "Invalid file. {$this->file} is not an image file.";
      else
        $this->create_image();
    }else{
      $this->error = "File not accessible/found.";
    }
  }

  private function dimensions(){
    list($this->width, $this->height, $this->html_size, $this->format) = getimagesize($this->file);
    return $this; 
  }
  
  private function update_dimensions(){
    $this->width = imagesx($this->image);
    $this->height = imagesy($this->image);
    return $this;
  }

  private function file_info(){
    $pathinfo = pathinfo($this->file);
    $this->extension = strtolower($pathinfo["extension"]);
    $this->basename = $pathinfo["basename"];
    $this->dirname = $pathinfo["dirname"];
    $this->format = (isset($this->image_formats[$this->extension]) ? $this->image_formats[$this->extension] : null);
  }

  private function is_image(){
    $this->dimensions();
    if(!$this->format)
      return false;
    else
      return true;
  }

  function create_empty_image($width, $height, $extension = "jpg", $alpha = false){
    if(!$width || !$height) return false;
    $this->width = $width;
    $this->height = $height;
    $this->image = imagecreatetruecolor($this->width, $this->height);
    if($alpha){
      imagealphablending($this->image, false); 
      imagesavealpha($this->image, true);
      $background_color = imagecolorallocatealpha($this->image, $this->rgb[0], $this->rgb[1], $this->rgb[2], $alpha);
    }else{
      $background_color = imagecolorallocate($this->image, $this->rgb[0], $this->rgb[1], $this->rgb[2]);
    }
    imagefill($this->image, 0, 0, $background_color);
    $this->extension = $extension;
    return $this;
  }

  private function create_image(){
    $extension = ($this->extension == "jpg" ? "jpeg" : $this->extension);
    $function_name = "imagecreatefrom{$extension}";

    if(function_exists($function_name))
      $this->image = $function_name($this->file);
    else
      $this->error = "Invalid image file or imagecreate function not enabled.";

    return $this;
  }

  function set_rgb($rgb){
    if(is_array($rgb)){ 
      $this->rgb = $rgb;
      return $this;
    }elseif($this->hex_to_rgb($rgb)){
      return $this;
    }else{
      return false;
    }
  }

  private function hex_to_rgb($hex_color){
    $hex_color = str_replace( "#", "", $hex_color );
    if(strlen($hex_color) == 3) // #fff, #000 etc. 
      $hex_color .= $hex_color;
    if(strlen($hex_color) != 6)
      return false;
    $this->rgb = array(
      hexdec(substr($hex_color, 0, 2)),
      hexdec(substr($hex_color, 2, 2)),
      hexdec(substr($hex_color, 4, 2))
    );
    return $this;
  }

  function set_crop_coordinates($x, $y){
    $this->crop_coordinates = array($x, $y, $this->width, $this->height);
    return $this;
  }

  function resize($new_width = null, $new_height = null, $method = null){
    if(!$new_width && !$new_height){
      $this->error = "Inform a new width and/or a new height.";
      return false;
    }elseif(!is_resource($this->image)){
      return false;
    }

    $this->new_width = $new_width;
    $this->new_height = $new_height;
    
    $this->calculate_new_dimensions();
    
    if($method) $method = "resize_with_{$method}";
    
    if(!method_exists($this, $method))
      $method = "resize_with_no_method";
    
    $this->$method()->update_dimensions();
    return $this;
  }
  
  private function calculate_new_dimensions(){
    $this->check_for_percentages();
    if(!$this->new_width)
      $this->new_width = $this->width/($this->height/$this->new_height);
    elseif(!$this->new_height)
      $this->new_height = $this->height/($this->width/$this->new_width);
  }
  
  private function check_for_percentages(){
    if(strpos($this->new_width, "%"))
      $this->new_width = round($this->width*(preg_replace("/[^0-9]/", "", $this->new_width)/100)); 
    if(strpos($this->new_height, "%"))
      $this->new_height = round($this->height*(preg_replace("/[^0-9]/", "", $this->new_height)/100));
  }

  private function resize_with_no_method(){
    $this->temp_image = imagecreatetruecolor($this->new_width, $this->new_height);
    imagecopyresampled($this->temp_image, $this->image, 0, 0, 0, 0, 
                       $this->new_width, $this->new_height, $this->width, $this->height);
    $this->image = $this->temp_image;
    return $this;
  }

  private function fill(){
    imagefill($this->temp_image, 0, 0, 
              imagecolorallocate($this->temp_image, $this->rgb[0], $this->rgb[1], $this->rgb[2]));
  }

  private function resize_with_fill(){
    $this->temp_image = imagecreatetruecolor($this->new_width, $this->new_height);
    $this->fill();

    // centers image into the filled image area
    // by width
    if(($this->width/$this->height) >= ($this->new_width/$this->new_height)){
        $dif_w = $this->new_width;
        $dif_h = $this->height*($this->new_width/$this->width);
        $dif_x = 0;
        $dif_y = round(($this->new_height-$dif_h)/2);
    // by height
    }else{
        $dif_w = $this->width*($this->new_height/$this->height);
        $dif_h = $this->new_height;
        $dif_x = round(($this->new_width-$dif_w)/2);
        $dif_y = 0;
    }
    
    imagecopyresampled($this->temp_image, $this->image, $dif_x, $dif_y, 0, 0, $dif_w, $dif_h, $this->width, $this->height);
    $this->image = $this->temp_image;
    return $this;
  }

  private function resize_with_crop(){
    if(!is_array($this->crop_coordinates))
      $this->crop_coordinates = array(0, 0, $this->width, $this->height);
      
    $this->temp_image = imagecreatetruecolor($this->new_width, $this->new_height);

    $this->fill();

    imagecopyresampled($this->temp_image, $this->image, $this->crop_coordinates[0], 
                       $this->crop_coordinates[1], 0, 0, $this->crop_coordinates[2], 
                       $this->crop_coordinates[3], $this->width, $this->height);

    $this->image = $this->temp_image;
    return $this;
  }

  function flip($orientation = "horizontal"){
    $orientation = strtolower($orientation);
    if($orientation != "horizontal" && $orientation != "vertical")
      return false;

    $w = imagesx($this->image);
    $h = imagesy($this->image);
    $this->temp_image = imagecreatetruecolor($w, $h);
    $method = "flip_{$orientation}";
    $this->$method($w, $h);

    $this->image = $this->temp_image;
    return $this;
  }
  
  private function flip_horizontal($w, $h){
    for($x = 0; $x < $w; $x++)
      imagecopy($this->temp_image, $this->image, $x, 0, $w - $x - 1, 0, 1, $h);
  }
  
  private function flip_vertical($w, $h){
    for($y = 0; $y < $h; $y++)
      imagecopy($this->temp_image, $this->image, 0, $y, 0, ($h - $y - 1), $w, 1);
  }

  function rotate($degrees){
    $background_color = imagecolorallocate($this->image, $this->rgb[0], $this->rgb[1], $this->rgb[2]);
    
    $this->image = imagerotate($this->image, $degrees, $background_color);

    imagealphablending($this->image, true);
    imagesavealpha($this->image, true);

    $this->update_dimensions();

    return $this; 
  }

  function text($text, $options = array()){
    if(!$text) return false;

    if(!isset($options["size"]))
      $options["size"] = 5;
    
    if(isset($options["color"]))
      $this->set_rgb($options["color"]);
      
    $text_color = imagecolorallocate($this->image, $this->rgb[0], $this->rgb[1], $this->rgb[2]); 
    $dimensions = $this->text_dimensions($text, $options);

    $options["x"] = isset($options["x"]) ? $options["x"] : 0;
    $options["y"] = isset($options["y"]) ? $options["y"] : 0;

    if(is_string($options["x"]) && is_string($options["y"]))
      list($options["x"], $options["y"]) = $this->calculate_position($options["x"], $options["y"], $dimensions["width"], $dimensions["height"]);
      
    if(isset($options["background_color"]) && $options["background_color"])
      $this->text_background_color($dimensions, $options);

    if(isset($options["truetype"]) && $options["truetype"])
      $this->add_truetype_text($text, $text_color, $options);
    else
      imagestring($this->image, $options["size"], $options["x"], $options["y"], $text, $text_color);

    return $this;
  }
  
  private function text_dimensions($text, $options){
    if(isset($options["truetype"]) && $options["truetype"]){
      $text_dimensions = imagettfbbox($options["size"], 0, $options["font"], $text);
      return array($text_dimensions[4], $options["size"]);
    }else{
      if($options["size"] > 5) 
        $options["size"] = 5;
      return array(
          "width" => imagefontwidth($options["size"])*strlen($text), 
          "height" => imagefontheight($options["size"])
      );
    }
  }

  private function calculate_position($x, $y, $width, $height){
    switch($y){
      case "top":
      default:
        $y = 0;
        break;
      case "bottom":
        $y = $this->height - $height;
        break;
      case "middle":
          switch($x){
            case "left":
            case "right":
              $y = ($this->height/2)-($height/2);
              break;
            case "center":
              $y = ($this->height-$height)/2;
              break;
          }
        break;
    }

    switch($x){
      case "left":
      default:
        $x = 0;
        break;
      case "center":
        $x = ($this->width-$width)/2;
        break;
      case "right":
        $x = $this->width - $width;
        break;
    }

    return array($x, $y);
  }
  
  private function text_background_color($dimensions, $options){
    $this->set_rgb($options["background_color"]);

    $this->temp_image = imagecreatetruecolor($dimensions["width"], $dimensions["height"]);
    $background_color = imagecolorallocate($this->temp_image, $this->rgb[0], $this->rgb[1], $this->rgb[2]);
    imagefill($this->temp_image, 0, 0, $background_color);
    imagecopy($this->image, $this->temp_image, $options["x"], $options["y"], 0, 0, $dimensions["width"], $dimensions["height"]);
  }

  private function add_truetype_text($text, $text_color, $options){
    imagettftext($this->image, $options["size"], 0, $options["x"], ($options["y"]+$options["size"]), $text_color, $options["font"], $text);
  }

  function merge($image, $position, $alpha = 100){
    if(!file_exists($image)){
      $this->error = "Invalid image.";
      return false;
    }
    list($w, $h) = getimagesize($image);

    if(is_string($position[0]) && is_string($position[1]))
      $position = $this->calculate_position($position[0], $position[1], $w, $h);

    $pathinfo = pathinfo($image);
    $extension = strtolower($pathinfo["extension"]);
    $extension = ($extension == "jpg" ? "jpeg" : $extension);
    $function_name = "imagecreatefrom{$extension}";

    if(function_exists($function_name))
      $image_to_merge = $function_name($image);
    else
      $this->error = "Invalid image file or imagecreate function not enabled.";

    list($x, $y) = $position;
    if(is_numeric($alpha) && (($alpha > 0) && ($alpha < 100)))
      imagecopymerge($this->image, $image_to_merge, $x, $y, 0, 0, $w, $h, $alpha);
    else
      imagecopy($this->image, $image_to_merge, $x, $y, 0, 0, $w, $h);
    
    return $this;
  }
  
  function filter($filter, $ammount = 1, $args = array()){
    if(!function_exists("imagefilter"))
      return false;
    $filter = strtolower($filter);
    switch($filter){
      case "blur":
      case "gaussian_blur":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter( $this->image, IMG_FILTER_GAUSSIAN_BLUR );
        else
          imagefilter( $this->image, IMG_FILTER_GAUSSIAN_BLUR );
        break;
      case "selective_blur":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter( $this->image, IMG_FILTER_SELECTIVE_BLUR );
        else
          imagefilter( $this->image, IMG_FILTER_SELECTIVE_BLUR );
        break;
      case "brightness":
        imagefilter($this->image, IMG_FILTER_BRIGHTNESS, $args[0]);
        break;
      case "grayscale":
        imagefilter($this->image, IMG_FILTER_GRAYSCALE);
        break;
      case "colorize":
        imagefilter($this->image, IMG_FILTER_COLORIZE, $args[0], $args[1], $args[2], $args[3]);
        break;
      case "contrast":
        imagefilter($this->image, IMG_FILTER_CONTRAST, $args[0]);
        break;
      case "edge":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter($this->image, IMG_FILTER_EDGEDETECT);
        else
          imagefilter($this->image, IMG_FILTER_EDGEDETECT);
        break;
      case "emboss":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter($this->image, IMG_FILTER_EMBOSS);
        else
          imagefilter($this->image, IMG_FILTER_EMBOSS);
        break;
      case "negate":
        imagefilter($this->image, IMG_FILTER_NEGATE);
        break;
      case "noise":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter($this->image, IMG_FILTER_MEAN_REMOVAL);
        else
          imagefilter($this->image, IMG_FILTER_MEAN_REMOVAL);
        break;
      case "smooth":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter($this->image, IMG_FILTER_SMOOTH, $args[0]);
        else
          imagefilter($this->image, IMG_FILTER_SMOOTH, $args[0]);
        break;
      case "pixelate":
        if(is_numeric($ammount) && $ammount > 1)
          for($i = 1; $i <= $ammount; $i++)
            imagefilter($this->image, IMG_FILTER_PIXELATE, $args[0], $args[1]);
        else
          imagefilter($this->image, IMG_FILTER_PIXELATE, $args[0], $args[1]);
        break;
      default:
        return false;
        break;
    }
    return $this;
  }

  function set_quality($quality){
    $this->quality = $quality;
    return $this;
  }

  function save($destination){
    if(!is_dir(dirname($destination))){
      $this->error = "Invalid destination directory.";
      return false;
    }else{
      return $this->output_image($destination);  
    }
  }
  
  function show(){
    if(headers_sent()){
      $this->error = "Headers already sent.";
      return false;    
    }else{
      header("Content-type: image/{$this->extension}");
      $this->output_image();
      imagedestroy($this->image);
      exit;
    }
  }
  
  private function output_image($destination = null){
    $pathinfo = pathinfo($destination);
    $extension = ($pathinfo["extension"] ? strtolower($pathinfo["extension"]) : $this->extension);

    if($extension == "jpg" || $extension =="jpeg" || $extension == "bmp")
      imagejpeg($this->image, $destination, $this->quality);
    elseif($extension == "png")
      imagepng($this->image, $destination);
    elseif($extension == "gif")
      imagegif($this->image, $destination);
    else
      return false;
  }

  function error_message(){
    return $this->error;
  }

}?>