<?php
function open_image ($file) {
        $file = str_replace("%20"," ", $file);
        
        # JPEG:
        $im = @imagecreatefromjpeg($file);
        if ($im !== false) { return $im; }

        # GIF:
        $im = @imagecreatefromgif($file);
        if ($im !== false) { return $im; }

        # PNG:
        $im = @imagecreatefrompng($file);
        if ($im !== false) { return $im; }

        # GD File:
        $im = @imagecreatefromgd($file);
        if ($im !== false) { return $im; }

        # GD2 File:
        $im = @imagecreatefromgd2($file);
        if ($im !== false) { return $im; }

        # WBMP:
        $im = @imagecreatefromwbmp($file);
        if ($im !== false) { return $im; }

        # XBM:
        $im = @imagecreatefromxbm($file);
        if ($im !== false) { return $im; }

        # XPM:
        $im = @imagecreatefromxpm($file);
        if ($im !== false) { return $im; }

        # Try and load from string:
        $im = @imagecreatefromstring(file_get_contents($file));
        if ($im !== false) { return $im; }

        return false;
}

function gray_it($imin, $xin, $yin){
	$rgb = imagecolorat($imin, $xin, $yin);
	$r = (($rgb >> 16) & 0xFF)*.3;
	$g = (($rgb >> 8) & 0xFF)*.59;
	$b = ($rgb & 0xFF)*.11;
	return $r+$g+$b;
}

$image = open_image($_GET['image']);
if ($image === false) {
        die ('Unable to open image');
}

$x = 0;
$y = 0;
$z = 2;

$gerber  = "G0 X$x Y$y Z$z F60\n";
$gerber .= "G1 Z$z F40\n\n";

$step = .0078;
$max_depth = -0.005;

$width = imagesx($image);
$height = imagesy($image);

$d = 1;
$y_count = 0;

for ($w = 0; $w < $width; $w++){
	if ($d == 0) {$d=1;}else{$d=0;}
	

	for ($h = 0; $h < $height; $h++){
		$adj_h = abs($d*($height-1)-$h);
		
		$new_x = $w*$step;
		$new_y = $adj_h*$step;
		$new_z = number_format(gray_it($image, $w, $adj_h)/255*$max_depth-$max_depth, 5, '.', '');
		
		$x_gerber = $y_gerber = $z_gerber = "";

		if ($new_x != $x){
			$x = $new_x;
			$x_gerber = "X$x";
		}
		
		if ($new_y != $y){
			$y = $new_y;
			$y_gerber = "Y$y";
		}
		
		if ($new_z != $z){
		
			$z = $new_z;
			$z_gerber = "Z$z";
		}
		
		$pregerb = $x_gerber.$y_gerber.$z_gerber;
		$gerber .= $pregerb;
		if ($pregerb != ""){$gerber .= "\n";}
	}

		
/*		if ($new_x != $x){
			$x = $new_x;
			$x_gerber = "X$x";
		}
		
		if ($new_y != $y){
			$prev_y = $y;
			$y = $new_y;
			$y_gerber = "Y$y";
		}
		
		if ($new_z != $z){
			if ($y_count > 0){
				$gerber .= $prev_y."\n";
			}
			
			$z = $new_z;
			$z_gerber = "Z$z";
			
			$y_count = 0;
		}else{
			$y_gerber = "";
			$y_count++;
		}
		
		$pregerb = $x_gerber.$y_gerber.$z_gerber;
		$gerber .= $pregerb;
		if ($pregerb != ""){$gerber .= "\n";}
	}*/
	
	
	
	
	
	$gerber .= "\n\n";
}

$gerber .= "G00 Z1\nG00 X0Y0\nM30";
//header('Content-Type: text');
//header('Content-Type: application/force-download');
//header('Content-Length: '.strlen($gerber));
header('Content-type: text/plain');
//header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename=image.cnc');  
echo $gerber;
?>