1.画直线
- (void)drawRect:(CGRect)rect
{
//获得处理的上下文
CGContextRef context = UIGraphicsGetCurrentContext();
//指定直线样式
CGContextSetLineCap(context, kCGLineCapSquare);
//直线宽度
CGContextSetLineWidth(context, 2.0);
//设置颜色
CGContextSetRGBStrokeColor(context,0.314, 0.486, 0.859, 1.0);
//开始绘制
CGContextBeginPath(context);
//画笔移动到点(31,170)
CGContextMoveToPoint(context,31, 70);
//下一点
CGContextAddLineToPoint(context,129, 148);
//下一点
CGContextAddLineToPoint(context,159, 148);
//绘制完成
CGContextStrokePath(context);
}
2.画折线图（曲线图）
CGContextRef ctx = UIGraphicsGetCurrentContext();
UIBezierPath *path = [[UIBezierPath alloc] init];
//初始点
CGPoint startPoint;
//移动到初始点
[path moveToPoint:startPoint];
//是否为曲线图
BOOL isCurve;
//点的集合
NSArray *pointArray;
//设置点之间的水平距离
CGFloat xInstance = 10;
for (int i = 0; i < pointArray.count; i++) {
CGPoint endPoint =CGPointMake(xInstance *i, [pointArray[i] floatValue]);
CGFloat centerX = (startPoint.x + endPoint.x)/2;
CGPoint crl1 = CGPointMake(centerX, startPoint.y);
CGPoint crl2 = CGPointMake(centerX, endPoint.y);
if (isCurve) {
//添加曲线路径，用于曲线图
[path addCurveToPoint:endPoint controlPoint1:crl1 controlPoint2:crl2];
startPoint = endPoint;
}
else
{
//添加直线路径，用于折线图
[path addLineToPoint:endPoint];
}
}
//线的颜色
[[UIColor yellowColor] set];
//线宽
CGContextSetLineWidth(ctx, 2);
// 将路径添加到图形上下文
CGContextAddPath(ctx, path.CGPath);
// 渲染
CGContextStrokePath(cox);
3.动态绘制曲线图
CGContextRef ctx = UIGraphicsGetCurrentContext();
UIBezierPath *path = [[UIBezierPath alloc] init];
//初始点
CGPoint startPoint;
//移动到初始点
[path moveToPoint:startPoint];
//是否为曲线图
BOOL isCurve;
//点的集合
NSArray *pointArray;
//设置点之间的水平距离
CGFloat xInstance = 10;
for (int i = 0; i < pointArray.count; i++) {
CGPoint endPoint =CGPointMake(xInstance *i, [pointArray[i] floatValue]);
CGFloat centerX = (startPoint.x + endPoint.x)/2;
CGPoint crl1 = CGPointMake(centerX, startPoint.y);
CGPoint crl2 = CGPointMake(centerX, endPoint.y);
if (isCurve) {
//添加曲线路径，用于曲线图
[path addCurveToPoint:endPoint controlPoint1:crl1 controlPoint2:crl2];
startPoint = endPoint;
}
else
{
//添加直线路径，用于折线图
[path addLineToPoint:endPoint];
}
}
CAShapeLayer *pathLayer = [CAShapeLayer layer];
pathLayer.frame = self.bounds;
pathLayer.path = path.CGPath;
//线的颜色
pathLayer.strokeColor = [plot.lineColor CGColor];
//线的填充色
pathLayer.fillColor = nil;
//线宽
pathLayer.lineWidth = 2;
pathLayer.lineJoin = kCALineJoinBevel;
[self.layer addSublayer:pathLayer];
//添加动画
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
//绘制时间
pathAnimation.duration = plot.pointArray.count * 0.3;
pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
[pathLayer addAnimation:pathAnimation forKey:@"strokeEnd"];