Catmull-Rom算法
根據(jù)四個(gè)點(diǎn)計(jì)算中間
前后兩個(gè)點(diǎn)位輔助點(diǎn)
-(CGPoint)getPoint:(CGFloat)t p:(CGPoint)p p1:(CGPoint)p1 p2:(CGPoint)p2 p3:(CGPoint)p3{
CGFloat t2 = t*t;
CGFloat t3 = t2*t;
CGFloat f = -0.5*t3 + t2 - 0.5*t;
CGFloat f1 = 1.5*t3 + -2.5*t2 + 1.0;
CGFloat f2 = -1.5*t3 + 2.0*t2 + 0.5*t;
CGFloat f3 = 0.5*t3 - 0.5*t2;
CGFloat x = p.x*f + p1.x*f1 + p2.x*f2 + p3.x*f3;
CGFloat y = p.y*f + p1.y*f1 + p2.y*f2 + p3.y*f3;
return CGPointMake(x,y);
}
pointArray:點(diǎn)的數(shù)組
pointCount:曲線之間由count-1個(gè)小點(diǎn)組成枚赡，當(dāng)為0時(shí)顯示為最初與最末兩點(diǎn)的連線厚宰，1為原始折線
isSame:添加的輔助點(diǎn)跟初始點(diǎn)是否一致,不一致的只能用NO
#define P(p) [(NSValue *)[points objectAtIndex:p] CGPointValue]
- (void)getCurvePathWithPoint:(NSArray *)pointArray pointCount:(NSInteger)pointCount isSame:(BOOL)isSame{
NSMutableArray *points = [pointArray mutableCopy];
UIBezierPath *path = [UIBezierPath bezierPath];
CAShapeLayer *layer = [CAShapeLayer layer];
layer.strokeColor = [UIColor blackColor].CGColor;
layer.fillColor = [UIColor clearColor].CGColor;
//添加兩個(gè)輔助點(diǎn)
[points insertObject:[points firstObject] atIndex:0];
[points addObject:[points lastObject]];
//添加的點(diǎn)與初始的點(diǎn)是否一致
if (isSame) {
[path moveToPoint:P(0)];
}else{
[path moveToPoint:P(1)];
}
for (int i = 0; i < points.count-3; i++) {
CGPoint p0 = P(i);
CGPoint p1 = P(i+1);
CGPoint p2 = P(i+2);
CGPoint p3 = P(i+3);
for (int j = 0 ; j < pointCount; j++) {
CGFloat t = 1.0 * j / pointCount;
CGPoint point = [self getPoint:t p:p0 p1:p1 p2:p2 p3:p3];
[path addLineToPoint:point];
}
}
//添加最后一個(gè)點(diǎn)
[path addLineToPoint:P(points.count-1)];
layer.path = path.CGPath;
[self.view.layer addSublayer:layer];
}
畫表格的測(cè)試
-(void)backgroundTable:(CGRect)frame{
//下面距離20上面距離10戴涝，顯示范圍在frame內(nèi)各減少20
width = frame.size.width;
height = frame.size.height;
UIBezierPath *path = [[UIBezierPath alloc] init];
[path moveToPoint:CGPointMake(20, 10)];
[path addLineToPoint:CGPointMake(20, height-20)];
[path addLineToPoint:CGPointMake(width-10, height-20)];
[path moveToPoint:CGPointMake(16, 18)];
[path addLineToPoint:CGPointMake(20, 10)];
[path addLineToPoint:CGPointMake(24, 18)];
[path moveToPoint:CGPointMake(width-18, height-16)];
[path addLineToPoint:CGPointMake(width-10, height-20)];
[path addLineToPoint:CGPointMake(width-18, height-24)];
CAShapeLayer *layer = [CAShapeLayer layer];
layer.strokeColor = [UIColor blackColor].CGColor;
layer.fillColor = [UIColor clearColor].CGColor;
layer.path = path.CGPath;
[self.view.layer addSublayer:layer];
}
-(void)ContrastFigure{
NSMutableArray *a = [_arr mutableCopy];
NSMutableArray *points = [NSMutableArray array];
for (int i = 0; i<a.count; i++) {
CGPoint p = CGPointMake(20+i*((width-40)/a.count), 20 + (10-[[_arr objectAtIndex:i] floatValue])*(height-40)/10);
[points addObject:[NSValue valueWithCGPoint:p]];
}
NSLog(@"%@",a);
[self getCurvePathWithPoint:points pointCount:100 isSame:NO];
UIBezierPath *path1 = [[UIBezierPath alloc] init];
CAShapeLayer *layer1 = [CAShapeLayer layer];
layer1.strokeColor = [UIColor redColor].CGColor;
layer1.fillColor = [UIColor clearColor].CGColor;
for (int i = 0; i < _arr.count; i++) {
if (i == 0) {
[path1 moveToPoint:CGPointMake(20+i*((width-40)/_arr.count),20+(10-[[_arr objectAtIndex:i] floatValue])*(height-40)/10)];
}else{
[path1 addLineToPoint:CGPointMake(20+i*(width-40)/_arr.count,20+(10-[[_arr objectAtIndex:i] floatValue])*(height-40)/10)];
}
}
layer1.path = path1.CGPath;
[self.view.layer addSublayer:layer1];
}
viewDidLoad調(diào)用
[self backgroundTable:CGRectMake(0, 0, self.view.frame.size.width, 200)];
_arr = @[@0,@10,@3,@8,@6,@9,@1,@2,@1,@2];
[self ContrastFigure];
NSArray *arr = [NSArray arrayWithObjects:[NSValue valueWithCGPoint:CGPointMake(30, 350)],[NSValue valueWithCGPoint:CGPointMake(130, 250)],[NSValue valueWithCGPoint:CGPointMake(180, 250)],[NSValue valueWithCGPoint:CGPointMake(230, 450)],[NSValue valueWithCGPoint:CGPointMake(280, 400)], nil];
[self getCurvePathWithPoint:arr pointCount:100 isSame:YES];
圖片.png
