<?php
/* PHP script to generate rounded corner images using the Portable Network Graphic (PNG) format
 * Created by Iain Campbell <iain@theapothecaryscat.com> on Fri Sep 22, 2006
 * 
 * Kudos to Ulrich Mierendorff for the ImageSmoothArc subroutine, which has been incorporated 
 * into this script (see http://icewind.ic.funpic.de/index.php?content=ellipse)
 *
 * Use as you would an image URL, with query string parameters as follows:
 *
 * location
 *    the location of this corner. For brevity, use TL, TR, BR, BL. For clarity, use any 
 *    combination of UPPER, TOP, LOWER, BOTTOM and LEFT, RIGHT. Alternatively, create four
 *    symlinks to this script, using the same rules to define symlink basenames (they
 *    should retain the .php filetype), and call those instead of always having to specify
 *    the location parameter.
 * background (default CCCCCC)
 *    the background colour (i.e. the background colour of the region bounded by this set
 *    of rounded corners. Specified as 6-character hex triplets (NO leading # symbol).
 * outside (default FFFFFF)
 *    the colour of the region outside your rectangle. Specified as 6-character hex triplets.
 * border
 *    the colour of the border (if one exists). Specified as 6-character hex triplets.
 * borderwidth (default 0)
 *    the width of the border (px). Should be +ve non-zero value if borders are important
 *    to you.
 * radius (default 10)
 *    the radius (px) of the corner.
 * smooth
 *    Specified with any value (or none) if anti-aliasing is required.
 *
 * Examples:
 *
 *    roundedcorner.php?location=upper-left&radius=15&borderwidth=2&border=000000&background=F0F0F0&outside=FFFFFF
 *
 *    upper-left.php?outside=FFFFFF&background=FFFFFF&borderwidth=1&border=000000&smooth
 */
 
   if ( array_key_exists('location', $_GET) ) {
      if ( isset($_GET['location']) ) $location = $_GET['location'];
   }

   if ( !isset($location) ) {
      preg_match('/([^\/\\:]+)\.\w+$/i', $_SERVER['PHP_SELF'], $match);
      $location = $match[1];
   }

   if ( preg_match('/^TL|LT|UL$/i', $location) ) $arc_start = 180;
   else if ( preg_match('/^TR|RT|UR$/i', $location) ) $arc_start = 270;
   else if ( preg_match('/^BL|LB|LL$/i', $location) ) $arc_start = 90;
   else if ( preg_match('/^BR|RB|LR$/i', $location) ) $arc_start = 0;
   else {
      if ( preg_match('/UPPER|TOP/i', $location) ) {
         if ( preg_match('/LEFT/i', $location) ) $arc_start = 180;
         else if ( preg_match('/RIGHT/i', $location) ) $arc_start = 270;
      }
      else if ( preg_match('/LOWER|BOTTOM/i', $location) ) {
         if ( preg_match('/LEFT/i', $location) ) $arc_start = 90;
         else if ( preg_match('/RIGHT/i', $location) ) $arc_start = 0;
      }
   }

   if ( array_key_exists('radius', $_GET) ) {
      if ( isset($_GET['radius']) ) $radius = $_GET['radius'];
   }
   isset($radius) or $radius = 10;
      
   if ( isset($arc_start) ) {
      $arc_finish = $arc_start + 90;
      
      if ( array_key_exists('background', $_GET) ) {
         if ( isset($_GET['background']) ) $background['x'] = $_GET['background'];
      }
      isset($background['x']) or $background['x'] = 'cccccc';
      hex2rgb($background);
      
      if ( array_key_exists('outside', $_GET) ) {
         if ( isset($_GET['outside']) ) $outside['x'] = $_GET['outside'];
      }
      isset($outside['x']) or $outside['x'] = 'ffffff';
      hex2rgb($outside);
      
      if ( array_key_exists('border', $_GET) ) {
         if ( isset($_GET['border']) ) $border['x'] = $_GET['border'];
      }
      isset($border['x']) or $border['x'] = '000000';
      hex2rgb($border);
      
      if ( array_key_exists('borderwidth', $_GET) ) {
         if ( isset($_GET['borderwidth']) ) $borderwidth = $_GET['borderwidth'];
      }
      isset($borderwidth) or $borderwidth = 0;
      
      $canvas = ImageCreateTrueColor($radius, $radius);
			ImageAlphaBlending($canvas, false);
      $color['background'] = ImageColorAllocateAlpha($canvas, $background['r'], $background['g'], $background['b'], 127);
      $color['border'] = ImageColorAllocateAlpha($canvas, $border['r'], $border['g'], $border['b'], 0);
      $color['outside'] = ImageColorAllocateAlpha($canvas, $outside['r'], $outside['g'], $outside['b'], 0);
			ImageAlphaBlending($canvas, true);
      
      ImageFilledRectangle($canvas, 0, 0, $radius, $radius, $color['outside']);
      if ( array_key_exists('smooth', $_GET) ) {
         if ( $arc_start == 0 ) { // BR
            $x = -1;
            $y = -2;
            $arc_start = 270;
         }
         else if ( $arc_start == 90 ) { // BL
            $x = $radius;
            $y = -2;
            $arc_start = 180;
         }
         else if ( $arc_start == 180 ) { // TL
            $x = $radius;
            $y = $radius;
            $arc_start = 90;
         }
         else if ( $arc_start == 270 ) { // TR
            $x = -1;
            $y = $radius;
            $arc_start = 0;
         }

         $arc_finish = deg2rad($arc_start + 90);
         $arc_start = deg2rad($arc_start);

         if ( $borderwidth > 0 ) {
            ImageSmoothArc($canvas, $x, $y, $radius * 2, $radius * 2, array($border['r'], $border['g'], $border['b']), $arc_start, $arc_finish);
            ImageSmoothArc($canvas, $x, $y, ($radius - $borderwidth) * 2, ($radius - $borderwidth) * 2, array($background['r'], $background['g'], $background['b']), $arc_start, $arc_finish);
         }
         else {
            ImageSmoothArc($canvas, $x, $y, $radius * 2, $radius * 2, array($background['r'], $background['g'], $background['b']), $arc_start, $arc_finish);
         }
      }
      else {
         if ( $arc_start == 0 ) { // BR
            $x = 0;
            $y = 0;
         }
         else if ( $arc_start == 90 ) { // BL
            $x = $radius - 1;
            $y = 0;
         }
         else if ( $arc_start == 180 ) { // TL
            $x = $radius - 1;
            $y = $radius - 1;
         }
         else if ( $arc_start == 270 ) { // TR
            $x = 0;
            $y = $radius - 1;
         }

         if ( $borderwidth > 0 ) {
            for ( $n = 0; $n < $borderwidth; ++$n ) {
               ImageArc($canvas, $x, $y, ($radius - $n) * 2, ($radius - $n) * 2, $arc_start, $arc_finish, $color['border']);
            }
            ImageFillToBorder($canvas, $x, $y, $color['border'], $color['background']);
         }
         else {
            ImageArc($canvas, $x, $y, $radius * 2, $radius * 2, $arc_start, $arc_finish, $color['background']);
            ImageFillToBorder($canvas, $x, $y, $color['background'], $color['background']);
         }
      }
   }
   else {
      $canvas = ImageCreateTrueColor($radius, $radius);
      $color['background'] = ImageColorAllocate($canvas, 255, 0, 0);
      ImageFilledRectangle($canvas, 0, 0, $radius, $radius, $color['background']);
   }

   ImageSaveAlpha($canvas, true);
   header('Content-Type: image/png');
   ImagePNG($canvas);
   
   function hex2rgb(&$arr, $hex = '') 
   {
      if ( $hex == '' ) $hex = $arr['x'];
      $arr['r'] = hexdec(substr($hex, 0, 2));
      $arr['g'] = hexdec(substr($hex, 2, 2));
      $arr['b'] = hexdec(substr($hex, 4, 2));
   }
   
/* ImageSmoothArc() created by Ulrich Mierendorff, Jun 2006
 */
 
   function ImageSmoothArc( &$img, $cx, $cy, $w, $h, $color, $start, $stop) 
   {
       $fillColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 0 );
       $w /= 2;
       $h /= 2;
       $cdx = $w * cos(M_PI/4);
       $cdy = $h * sin(M_PI/4);

       $xStart = $w * cos($start);
       $yStart = $h * sin($start);
       $xStop = $w * cos(min(M_PI,$stop));
       $yStop = $h * sin(min(M_PI,$stop));
       if ( $start < M_PI/2 ) {
           $yy = 0;
           for ( $x = 0; $x <= $xStart; $x += 1 ) {
               if ( $x < $xStop ) {
                   $y1 = $x/$xStop*$yStop;
               } else {
                   $y1 = $h * sqrt( 1 - pow( $x,2 ) / pow( $w,2 ) );
               }
               $y2 = $x/$xStart*$yStart;
               $d1 = $y1 - floor($y1);
               $d2 = $y2 - floor($y2);
               $y1 = floor($y1);
               $y2 = floor($y2);
               imageLine($img, $cx + $x, $cy - $y1, $cx + $x, $cy - $y2, $fillColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
               imageSetPixel($img, $cx + $x, $cy - $y1 - 1, $diffColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d2*100 );
               imageSetPixel($img, $cx + $x, $cy - $y2 + 1, $diffColor);
               for ( $yy; $yy <= $y1; $yy += 1 ) {
                   if ( $yy < $yStart ) {
                       $x1 = $yy/$yStart*$xStart;
                   } else {
                       $x1 = $w * sqrt( 1 - pow( $yy,2 ) / pow( $h,2 ) );
                   }
                   $d1 = $x1 - floor($x1);
                   $x1 = floor($x1);
                   $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
                   imageSetPixel($img, $cx + $x1 + 1, $cy - $yy, $diffColor);
                   if ($stop < M_PI/2) {
                       $x2 = $yy/$yStop*$xStop;
                       $d2 = $x2 - floor($x2);
                       $x2 = floor($x2);
                       $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d2*100 );
                       imageSetPixel($img, $cx + $x2, $cy - $yy, $diffColor);
                   }
               }
           }
       }
       if ( $start < M_PI && $stop > M_PI/2 ) {
           $yy = 0;
           for ( $x = 0; $x >= $xStop; $x -= 1 ) {
               if ( $x > $xStart ) {
                   $y1 = $x/$xStart*$yStart;
               } else {
                   $y1 = $h * sqrt( 1 - pow( $x,2 ) / pow( $w,2 ) );
               }
               $y2 = $x/$xStop*$yStop;
               $d1 = $y1 - floor($y1);
               $d2 = $y2 - floor($y2);
               $y1 = floor($y1);
               $y2 = floor($y2);
               imageLine($img, $cx + $x, $cy - $y1, $cx + $x, $cy - $y2, $fillColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
               imageSetPixel($img, $cx + $x, $cy - $y1 - 1, $diffColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d2*100 );
               imageSetPixel($img, $cx + $x, $cy - $y2 + 1, $diffColor);
               for ( $yy; $yy <= $y1; $yy += 1 ) {
                   if ( $yy < $yStop ) {
                       $x1 = -$yy/$yStop*$xStop;
                   } else {
                       $x1 = $w * sqrt( 1 - pow( $yy,2 ) / pow( $h,2 ) );
                   }
                   $d1 = $x1 - floor($x1);
                   $x1 = floor($x1);
                   $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
                   imageSetPixel($img, $cx - $x1 - 1, $cy - $yy, $diffColor);
                   if ( $start > M_PI/2 ) {
                       $x2 = $yy/$yStart*$xStart;
                       $d2 = $x2 - floor($x2);
                       $x2 = floor($x2);
                       $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d2*100 );
                       imageSetPixel($img, $cx + $x2, $cy - $yy, $diffColor);
                   }
               }
           }
       }

       $xStart = $w * cos(max(M_PI,$start));
       $yStart = $h * sin(max(M_PI,$start));
       $xStop = $w * cos($stop);
       $yStop = $h * sin($stop);
       if ( $start < 3*M_PI/2 && $stop > M_PI) {
           $yy = 0;
           for ( $x = 0; $x >= $xStart; $x -= 1 ) {
               if ( $x > $xStop) {
                   $y1 = $x/$xStop*$yStop;
               } else {
                   $y1 = -$h * sqrt( 1 - pow( $x,2 ) / pow( $w,2 ) );
               }
               $y2 = $x/$xStart*$yStart;
               $d1 = $y1 - floor($y1);
               $d2 = $y2 - floor($y2);
               $y1 = floor($y1);
               $y2 = floor($y2);
               imageLine($img, $cx + $x, $cy - $y1, $cx + $x, $cy - $y2, $fillColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d1*100 );
               imageSetPixel($img, $cx + $x, $cy - $y1 + 1, $diffColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d2*100 );
               imageSetPixel($img, $cx + $x, $cy - $y2 - 1, $diffColor);
               for ( $yy; $yy >= $y1; $yy -= 1 ) {
                   if ( $yy > $yStart ) {
                       $x1 = -$yy/$yStart*$xStart;
                   } else {
                       $x1 = $w * sqrt( 1 - pow( $yy,2 ) / pow( $h,2 ) );
                   }
                   $d1 = $x1 - floor($x1);
                   $x1 = floor($x1);
                   $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
                   imageSetPixel($img, $cx - $x1 - 1, $cy - $yy, $diffColor);
                   if ($stop < 3*M_PI/2) {
                       $x2 = $yy/$yStop*$xStop;
                       $d2 = $x2 - floor($x2);
                       $x2 = floor($x2);
                       $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d2*100 );
                       imageSetPixel($img, $cx + $x2 + 1, $cy - $yy, $diffColor);
                   }
               }
           }

       }
       if ( $start < 2*M_PI && $stop > 3*M_PI/2 ) {
           $yy = 0;
           for ( $x = 0; $x <= $xStop; $x += 1 ) {
               if ( $x < $xStart )  {
                   $y1 = $x/$xStart*$yStart;
               } else {
                   $y1 = -$h * sqrt( 1 - pow( $x,2 ) / pow( $w,2 ) );
               }
               $y2 = $x/$xStop*$yStop;
               $d1 = $y1 - floor($y1);
               $d2 = $y2 - floor($y2);
               $y1 = floor($y1);
               $y2 = floor($y2);
               imageLine($img, $cx + $x, $cy - $y1, $cx + $x, $cy - $y2, $fillColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d1*100 );
               imageSetPixel($img, $cx + $x, $cy - $y1 + 1, $diffColor);
               $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d2*100 );
               imageSetPixel($img, $cx + $x, $cy - $y2 - 1, $diffColor);
               for ( $yy; $yy >= $y1; $yy -= 1 ) {
                   if ( $yy > $yStop ) {
                       $x1 = $yy/$yStop*$xStop;
                   } else {
                       $x1 = $w * sqrt( 1 - pow( $yy,2 ) / pow( $h,2 ) );
                   }
                   $d1 = $x1 - floor($x1);
                   $x1 = floor($x1);
                   $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], 100 - $d1*100 );
                   imageSetPixel($img, $cx + $x1 + 1, $cy - $yy, $diffColor);
                   if ( $start > 3*M_PI/2 ) {
                       $x2 = $yy/$yStart*$xStart;
                       $d2 = $x2 - floor($x2);
                       $x2 = floor($x2);
                       $diffColor = imageColorExactAlpha( $img, $color[0], $color[1], $color[2], $d2*100 );
                       imageSetPixel($img, $cx + $x2 , $cy - $yy, $diffColor);
                   }
               }
           }
       }
   }
?>