<?php

class CRoundCorner{
	const TRANSPARENT = 127;
	
	const CORNER_TL = 0;
	const CORNER_TR = 1;
	const CORNER_BL = 2;
	const CORNER_BR = 3;
	
	private $color;
	private $colorOpacity;
	private $background;
	private $bgOpacity;
	private $width;
	private $height;
	private $image;
	private $corner;
	
	/*constructor
	* @param int $corner: the corner you want to generate (use class constant to indicate)
	* @param string $color: the color of the corner (format: RRGGBB)
	* @param string $background: the background color of the corner (format: RRGGBB or class constant TRANSPARENT)
	* @param int $radius: the radius of the corner
	* @param int $width: the width of the corner
	* @param int $height: the height of the corner
	* Note: If $radius is set, $width and $height can be omitted 
	*/
	public function __construct($corner = self::CORNER_TL, $color = "FFFFFF", $background = self::TRANSPARENT, $radius = 0, $width = 0, $height = 0){
		$this->setCorner($corner);
		$this->color = $color;
		$this->background = $background;
		$this->colorOpacity = 0;
		$this->bgOpacity = ($background == self::TRANSPARENT ? 127 : 0);
		$this->width = $width;
		$this->height = $height;
		if ($radius){
			$this->width = $radius;
			$this->height = $radius;
		}
	}
	private function hex2dec($str){
		$str = strtoupper($str);
		$search = array('A','B','C','D','E','F');
		$replace = array('10','11','12','13','14','15');
		$num = 0;
		$strLen = strlen($str);
		for ($i = ($strLen - 1); $i >=0; $i--){
			$n = str_replace($search, $replace, $str[$i]);
			$num += $n * pow(16,$strLen - $i - 1);
		}
		return $num;
	}
	
	/*setDimension: set the dimension
	* @param int $radius: the radius of the corner (if $height is passed also, this will be the width of the corner)
	* @param int $height: the height of the corner (can be omitted)
	*/
	public function setDimension($radius, $height = 0){
		$this->width = $radius;
		if ($height){
			$this->height = $height;
		}else{
			$this->height = $radius;
		}
	}
	/*setCorner: set the corner to be generated
	* @param int $corner: set the corner you want to generate (use class constants)
	*/
	public function setCorner($corner = self::CORNER_TL){
		$this->corner = CRoundCorner::CORNER_TL;
		if ($corner == CRoundCorner::CORNER_TL)
			$this->corner = CRoundCorner::CORNER_TL;
		if ($corner == CRoundCorner::CORNER_TR)
			$this->corner = CRoundCorner::CORNER_TR;
		if ($corner == CRoundCorner::CORNER_BL)
			$this->corner = CRoundCorner::CORNER_BL;
		if ($corner == CRoundCorner::CORNER_BR)
			$this->corner = CRoundCorner::CORNER_BR;
	}
	/*setColorOpacity: set the foreground(the corner) color opacity
	* @param int $opacity: the opacity of the corner (0 - 127)
	*/
	public function setColorOpacity($opacity){
		if ($opacity)
			$this->colorOpacity = (int) $opacity;
	}
	/*setBgOpacity: set the background color opacity
	* @param int $opacity: the opacity of the background (0 - 127)
	*/
	public function setBgOpacity($opacity){
		if ($opacity)
			$this->bgOpacity = (int) $opacity;
	}
	
	/*draw: draw the corner
	* @return resource: the image resource generated
	*/
	public function draw(){
		$this->image = imagecreate($this->width, $this->height);
		$rgb = str_split($this->background, 2);
		$bgColor = imagecolorallocatealpha($this->image,  (int) $this->hex2dec($rgb[0]), (int) $this->hex2dec($rgb[1]), (int) $this->hex2dec($rgb[2]), $this->bgOpacity);
		imagefill($this->image, 0,0, $bgColor);
		
		$rgb = str_split($this->color, 2);
		$color = imagecolorallocatealpha($this->image, $this->hex2dec($rgb[0]), $this->hex2dec($rgb[1]), $this->hex2dec($rgb[2]), $this->colorOpacity);
		$centerX = ($this->corner == CRoundCorner::CORNER_TR || $this->corner == CRoundCorner::CORNER_BR) ? 0 : $this->width;
		$centerY = ($this->corner == CRoundCorner::CORNER_BL || $this->corner == CRoundCorner::CORNER_BR) ? 0 : $this->height;
		imagefilledellipse($this->image, $centerX, $centerY, $this->width * 2, $this->height * 2, $color);
		
		return $this->image;
	}
	/*drawFlush: draw the corner and flush it to the browser
	*/
	public function drawFlush(){
		$image = $this->draw();
		header('Content-type: image/png');
		imagepng($image);
	}
	/*drawFile: draw the corner to a file
	* @param string $path: the path of the file to store the corner
	*/
	public function drawFile($path){
		$image = $this->draw();
		imagepng($image, $path);
	}
}

?>