Just mucking about, tell me what you think:

http://www.richardlyon.co.uk/tree/tree.php

 

It generates a tree-like structure based on a few rules... lots of random numbers, plugging them into logs with a bit of trig thrown in for good measure... I might add some leaf-spawning shortly..

 

For the code-junkies out there...

<?php

// create and fill canvas
$width = 800;
$height = 1000;
$image = imagecreatetruecolor( $width, $height );
$sky = imagecolorallocate( $image, 170, 210, 230 );
imagefill( $image, 0, 0, $sky );


// root color
$root    =    imagecolorallocate( $image, 70, 56, 28 );
$leaf    =    imagecolorallocate( $image, 75, 135,55 );

// root function
function root( $image, $x1, $y1, $width, $step, $limit, $angle = false )
{
   global $root; // color

   $step++;

   if( $step > $limit ) return;

   // randomly prune
   if( rand( 0, 20 ) > 19 ) return;

   // should the branch diverge?
   $diverge = ( rand( 0, $width * 4 ) / $width > log( $width ) );

   // should the width shrink?
   $shrink_limit = $diverge ? 1: 0;
   if( $width > 1 && rand( 0, 10 ) > $shrink_limit )
   {
       $width--;
   }

   /* make new length    */

   $length = rand( $width * 2, log($width) * 50 ) / 2;

   // calculate angle
   /* width is between 1 and 20... 180 - ( w * 8 ) gives between 172 and 20 */
   /* if it is diverging, one branch has forced angle.. */
   if( isset( $angle ) || !$angle )
   {
       $angle_dif = 180 - ( $width * 8 );
       $angle_mid = 180;

       $angle_min = $angle_mid - $angle_dif;
       $angle_max = $angle_mid + $angle_dif;

       $angle = rand( $angle_min, $angle_max );
   }

   /* calculate new positions from angle, length and x1,x2 */
   $mod_x = $length * sin( deg2rad( $angle ) );
   $mod_y = $length * cos( deg2rad( $angle ) );

   $x2 = $x1 + $mod_x;
   $y2 = $y1 + $mod_y;

   if( $width == 1 && rand( 0, 10 ) > 5 )
   {
       spawn_leaf(     $image, $x2, $y2 );
   }

   // set thickness
   imagesetthickness( $image, $width / 2 );

   // draw line
   imageline( $image, $x1, $y1, $x2, $y2, $root );

   // draw new branch(es)
   if( $diverge )
   {
       root( $image, $x2, $y2, $width, $step, $limit );
   }

   $pm = ( rand(0,10) > 5 ) ? 1 : -1;

   $angle = $angle + ( $pm * 10 );

   root( $image, $x2, $y2, $width, $step, $limit, $angle );

   return $image;
}

function spawn_leaf( $image, $cx, $cy )
{
   global $leaf; // color

   // random size between 1 and 10 wide * high
   $width = rand( 1, 10 );
   $height = rand( 1, 10 );

   return imagefilledellipse  ( $image, $cx  , $cy  , $width  , $height  , $leaf  );

}

// make first root
$x = $width/2;
$y = $height;

$image = root( $image, $x, $y, 20, 1, 30 );







// output
header('Content-type: image/png');
imagepng( $image );
imagedestroy( $image );

 

EDIT: LEAFINESS ADDED

It's very cool!

 

Needs a little work on it - I got quite a few bare little twigs and once or twice:

 

"The image “http://www.richardlyon.co.uk/tree/tree.php” cannot be displayed, because it contains errors."

 

But I love the concept and it works many more times than it doesn't!

the bare little twigs is due to the random pruning 1/20 times... the chance of one section and then failure is possible, as is 2 or 3 sections and so on... once it gets past the 4th tube its probably diverged and so failure falls to 1/400+

 

The "cannot be displayed" is probably a division by zero somewhere, but i cba figuring it out right now...

It's genius!

I really must get my head down and learn how to program one day