封閉的三次貝塞爾曲線的填充

接上一篇博文，記載一下怎樣將封閉的貝塞爾曲線填充顏色。
設計師要求的效果圖如下：

我的步驟是先描點，然後將其組成一個封閉區間，最後上色。上代碼：（代碼可能寫的不怎麼樣，以後儘量追求優質代碼。）

//根據points中的點畫出曲線
- (void)drawCurveChartWithPoints:(NSMutableArray *)points
{
    UIBezierPath* path1 = [UIBezierPath bezierPath];
    [path1 moveToPoint:[[points objectAtIndex:0] CGPointValue]];//這一步很重要
    //遍歷各個點，畫曲線
    for(int i=0; i<[points count]-1; i++){
        CGPoint startPoint = [[points objectAtIndex:i] CGPointValue];
        CGPoint endPoint = [[points objectAtIndex:i+1] CGPointValue];
        [UIView animateWithDuration:.1 animations:^(){
            [path1 addCurveToPoint:endPoint controlPoint1:CGPointMake((endPoint.x-startPoint.x)/2+startPoint.x, startPoint.y) controlPoint2:CGPointMake((endPoint.x-startPoint.x)/2+startPoint.x, endPoint.y)];
        }];
    }
    CGPoint firstPoint = [[points firstObject] CGPointValue];
    CGPoint lastPoint = [[points lastObject] CGPointValue];
    CGPoint secondPoint = CGPointMake(lastPoint.x+2, lastPoint.y);
    CGPoint thirdPoint = CGPointMake(secondPoint.x, ViewHeight(self)+1);
    CGPoint forthPoint = CGPointMake(firstPoint.x-1, thirdPoint.y);
    CGPoint fifthPoint = CGPointMake(forthPoint.x, firstPoint.y);

    //把曲線封閉起來
    [path1 addLineToPoint:secondPoint];
    [path1 addLineToPoint:thirdPoint];
    [path1 addLineToPoint:forthPoint];
    [path1 addLineToPoint:fifthPoint];
    [path1 addLineToPoint:firstPoint];

    [path1 closePath];
    [[UIColor colorWithRed:80.0/255.0 green:187.0/255.0 blue:255/255.0 alpha:0.5] setFill];
    [path1 fill];

    [self.lineColor set];       //設置畫筆顏色
    [path1 setLineWidth:2];     //設置畫筆寬度
    path1.lineCapStyle = kCGLineCapRound;
    [path1 strokeWithBlendMode:kCGBlendModeNormal alpha:1];
}

代碼裏面本來只要將首位端點拉下來，然後相連就行的。我這裏因爲當時設計的原因，所以連到了外界區域。

之後添加點後的圖如下：

基本完成了設計師的要求。
（看過後覺得有什麼地方可以更正或者改進的地方，請給我回復，謝謝。。）