[PHP] Draw a rectangle with rounded corners

imageroundedrectangle.php

<?php
/**
 * Draw a rectangle with rounded corners.
 * @param ressource &$img An image resource
 * @param int $x1 Upper left x coordinate
 * @param int $y1 Upper left y coordinate
 * @param int $x2 Bottom right x coordinate
 * @param int $y2 Bottom right y coordinate
 * @param int $r Corners radius
 * @param int $color A color identifier created with imagecolorallocate()
 * @return true
 */
function imageroundedrectangle(&$img, $x1, $y1, $x2, $y2, $r, $color)
{
  $r = min($r, floor(min(($x2-$x1)/2, ($y2-$y1)/2)));
    
  // top border
  imageline($img, $x1+$r, $y1, $x2-$r, $y1, $color);
  // right border
  imageline($img, $x2, $y1+$r, $x2, $y2-$r, $color);
  // bottom border
  imageline($img, $x1+$r, $y2, $x2-$r, $y2, $color);
  // left border
  imageline($img, $x1, $y1+$r, $x1, $y2-$r, $color);
  
  // top-left arc
  imagearc($img, $x1+$r, $y1+$r, $r*2, $r*2, 180, 270, $color);
  // top-right arc
  imagearc($img, $x2-$r, $y1+$r, $r*2, $r*2, 270, 0, $color);
  // bottom-right arc
  imagearc($img, $x2-$r, $y2-$r, $r*2, $r*2, 0, 90, $color);
  // bottom-left arc
  imagearc($img, $x1+$r, $y2-$r, $r*2, $r*2, 90, 180, $color);
  
  return true;
}

Nice work. I made some additions incase you want a filled rounded corner rectangle.

<?php
function imageroundedrectangle(&$img, $x1, $y1, $x2, $y2, $r, $color)
{
    $r = min($r, floor(min(($x2 - $x1) / 2, ($y2 - $y1) / 2)));

    // top border
    imageline($img, $x1 + $r, $y1, $x2 - $r, $y1, $color);
    // right border
    imageline($img, $x2, $y1 + $r, $x2, $y2 - $r, $color);
    // bottom border
    imageline($img, $x1 + $r, $y2, $x2 - $r, $y2, $color);
    // left border
    imageline($img, $x1, $y1 + $r, $x1, $y2 - $r, $color);

    // top-left arc
    imagefilledarc($img, $x1 + $r, $y1 + $r, $r * 2, $r * 2, 180, 270, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x1 + 1.5, $y1 + 1.5, 200, 150, 0, 90, $color, IMG_ARC_PIE);

    // top-right arc
    imagefilledarc($img, $x2 - $r, $y1 + $r, $r * 2, $r * 2, 270, 0, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x2 - 0.5, $y1 + 1.5, 200, 150, 90, 180, $color, IMG_ARC_PIE);

    // bottom-right arc
    imagefilledarc($img, $x2 - $r, $y2 - $r, $r * 2, $r * 2, 0, 90, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x2 - 0.5, $y2 - 0.5, 200, 150, 180, 270, $color, IMG_ARC_PIE);

    // bottom-left arc
    imagefilledarc($img, $x1 + $r, $y2 - $r, $r * 2, $r * 2, 0, 180, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x1 + 1.5, $y2 - 0.5, 200, 150, 270, 360, $color, IMG_ARC_PIE);

    return true;
}

cheamsteads function didn't work properly for me, revised if anyone wants to try this version

function imageroundedrectangle(&$img, $x1, $y1, $x2, $y2, $r, $color){
    $r = min($r, floor(min(($x2 - $x1) / 2, ($y2 - $y1) / 2)));
    // render corners
    imagefilledarc($img, $x1 + $r, $y1 + $r, $r * 2, $r * 2, 180, 270, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x2 - $r, $y1 + $r, $r * 2, $r * 2, 270, 0, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x2 - $r, $y2 - $r, $r * 2, $r * 2, 0, 90, $color, IMG_ARC_PIE);
    imagefilledarc($img, $x1 + $r, $y2 - $r, $r * 2, $r * 2, 0, 180, $color, IMG_ARC_PIE);
    // middle fill, left fill, right fill
    imagefilledrectangle($img, $x1+$r, $y1, $x2-$r, $y2, $color);
    imagefilledrectangle($img, $x1, $y1+$r, $x1+$r, $y2-$r, $color);
    imagefilledrectangle($img, $x2-$r, $y1+$r, $x2, $y2-$r, $color);
    return true;
}

I used the solution to make a filled rounded rectangle. It works very well, however if you want to make a semi transparent rounded rectangle then you need to have a +1 and -1 on the "// middle fill, left fill, right fill" otherwise the overlaps create a darkened line. None the less KUDOS for this solution(s).