/**该方法用来绘制一个有填充色的圆角矩形 
 *@param cxt:canvas的上下文环境 
 *@param x:左上角x轴坐标 
 *@param y:左上角y轴坐标 
 *@param width:矩形的宽度 
 *@param height:矩形的高度 
 *@param radius:圆的半径 
 *@param fillColor:填充颜色 
 **/
export function fillRoundRect(cxt, x, y, width, height, radius, /*optional*/ fillColor) {
	//圆的直径必然要小于矩形的宽高          
	if (2 * radius > width || 2 * radius > height) { return false; }

	cxt.save();
	cxt.translate(x, y);
	//绘制圆角矩形的各个边  
	drawRoundRectPath(cxt, width, height, radius);
	cxt.fillStyle = fillColor || "#000"; //若是给定了值就用给定的值否则给予默认值  
	cxt.fill();
	cxt.restore();
}


/**该方法用来绘制圆角矩形 
 *@param cxt:canvas的上下文环境 
 *@param x:左上角x轴坐标 
 *@param y:左上角y轴坐标 
 *@param width:矩形的宽度 
 *@param height:矩形的高度 
 *@param radius:圆的半径 
 *@param lineWidth:线条粗细 
 *@param strokeColor:线条颜色 
 **/
export function strokeRoundRect(cxt, x, y, width, height, radius, /*optional*/ lineWidth, /*optional*/ strokeColor) {
	//圆的直径必然要小于矩形的宽高          
	if (2 * radius > width || 2 * radius > height) { return false; }

	cxt.save();
	cxt.translate(x, y);
	//绘制圆角矩形的各个边  
	drawRoundRectPath(cxt, width, height, radius);
	cxt.lineWidth = lineWidth || 2; //若是给定了值就用给定的值否则给予默认值2  
	cxt.strokeStyle = strokeColor || "#000";
	cxt.stroke();
	cxt.restore();
}

export function drawRoundRectPath(cxt, width, height, radius) {
	cxt.beginPath(0);
	//从右下角顺时针绘制，弧度从0到1/2PI  
	cxt.arc(width - radius, height - radius, radius, 0, Math.PI / 2);

	//矩形下边线  
	cxt.lineTo(radius, height);

	//左下角圆弧，弧度从1/2PI到PI  
	cxt.arc(radius, height - radius, radius, Math.PI / 2, Math.PI);

	//矩形左边线  
	cxt.lineTo(0, radius);

	//左上角圆弧，弧度从PI到3/2PI  
	cxt.arc(radius, radius, radius, Math.PI, Math.PI * 3 / 2);

	//上边线  
	cxt.lineTo(width - radius, 0);

	//右上角圆弧  
	cxt.arc(width - radius, radius, radius, Math.PI * 3 / 2, Math.PI * 2);

	//右边线  
	cxt.lineTo(width, height - radius);
	cxt.closePath();
}

export default {
	fillRoundRect,
	strokeRoundRect,
	drawRoundRectPath
}