/**
	 * 處理成圓圖片,如果圖片不是正方形就取最小邊的圓半徑,從左邊開始剪下成圓形
	 * @param  string $imgpath [description]
	 * @return [type]          [description]
	 */
	function yj_img($imgpath = './yj.jpg') {
		$ext     = pathinfo($imgpath);
		$src_img = null;
		switch ($ext['extension']) {
		case 'jpg':
			$src_img = imagecreatefromjpeg($imgpath);
			break;
		case 'png':
			$src_img = imagecreatefrompng($imgpath);
			break;
		}
		$wh  = getimagesize($imgpath);
		$w   = $wh[0];
		$h   = $wh[1];
		$w   = min($w, $h);
		$h   = $w;
		$img = imagecreatetruecolor($w, $h);
		//這一句一定要有
		imagesavealpha($img, true);
		//拾取一個完全透明的顏色,最後一個引數127為全透明
		$bg = imagecolorallocatealpha($img, 255, 255, 255, 127);
		imagefill($img, 0, 0, $bg);
		$r   = $w / 2; //圓半徑
		$y_x = $r; //圓心X座標
		$y_y = $r; //圓心Y座標
		for ($x = 0; $x < $w; $x++) {
			for ($y = 0; $y < $h; $y++) {
				$rgbColor = imagecolorat($src_img, $x, $y);
				if (((($x - $r) * ($x - $r) + ($y - $r) * ($y - $r)) < ($r * $r))) {
					imagesetpixel($img, $x, $y, $rgbColor);
				}
			}
		}
		return $img;
	}