试图绘制螺旋线，只是画一条线

Question

我正在尝试仅使用文本标签在 UIView 中绘制螺旋线。代码如下：

//
//  ViewController.m
//  spiral
//
//  Created on 30/01/2015.
//  Copyright (c) 2015  All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (strong, nonatomic) IBOutlet UIView *canvas;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    //[self plotPoints:self.view.frame.size.width/2 andY:self.view.frame.size.height/2];

    // centerX-- X origin of the spiral.
    // centerY-- Y origin of the spiral.
    // radius--- Distance from origin to outer arm.
    // sides---- Number of points or sides along the spiral's arm.
    // coils---- Number of coils or full rotations. (Positive numbers spin clockwise, negative numbers spin counter-clockwise)
    // rotation- Overall rotation of the spiral. ('0'=no rotation, '1'=360 degrees, '180/360'=180 degrees)
    //

    [self spiral:170 andY:284 andRadius:100 withSides:20 andCoils:10 andRotation:0];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

-(void) spiral: (float)centerX andY:(float)centerY andRadius:(float)radius withSides: (float)sides andCoils:(float)coils andRotation:(float)rotation
{
    //
    // How far to step away from center for each side.
    float awayStep = radius/sides;
    //
    // How far to rotate around center for each side.
    float aroundStep = coils/sides;// 0 to 1 based.
    //
    // Convert aroundStep to radians.
    float aroundRadians = aroundStep * 2 * M_PI;
    //
    // Convert rotation to radians.
    rotation *= 2 * M_PI;
    //
    // For every side, step around and away from center.
    for(int i=1; i<=sides; i++){

        //
        // How far away from center
        float away = i * awayStep;
        //
        // How far around the center.
        float around = i * aroundRadians + rotation;
        //
        // Convert 'around' and 'away' to X and Y.
        float x = centerX + cos(around) * away;
        float y = centerY + sin(around) * away;
        //


        [self plotPoints:x andY:y];
    }
}


-(void)plotPoints: (float)x andY:(float) y {

    UILabel *point = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 22, 22)];

    point.font= [UIFont systemFontOfSize:19];

    point.text=@"*";
    point.center = CGPointMake(x, y);
    [self.canvas addSubview:point];
    point.hidden=NO;

}

@end

截图如下：

不确定为什么要这样做。在代码中一直使用浮点值可以吗？也许我正在失去一些东西。任何帮助，将不胜感激。谢谢！

编辑：查看 x,y 值：

2015-01-31 00:02:32.073 spiral[86741:6997860] x: 165.000000, y:284.000000
2015-01-31 00:02:32.075 spiral[86741:6997860] x: 180.000000, y:284.000000
2015-01-31 00:02:32.076 spiral[86741:6997860] x: 155.000000, y:284.000000
2015-01-31 00:02:32.076 spiral[86741:6997860] x: 190.000000, y:284.000000
2015-01-31 00:02:32.077 spiral[86741:6997860] x: 145.000000, y:283.999969
2015-01-31 00:02:32.077 spiral[86741:6997860] x: 200.000000, y:284.000000
2015-01-31 00:02:32.078 spiral[86741:6997860] x: 135.000000, y:283.999939
2015-01-31 00:02:32.078 spiral[86741:6997860] x: 210.000000, y:284.000031
2015-01-31 00:02:32.079 spiral[86741:6997860] x: 125.000000, y:284.000000
2015-01-31 00:02:32.079 spiral[86741:6997860] x: 220.000000, y:284.000061
2015-01-31 00:02:32.080 spiral[86741:6997860] x: 115.000000, y:283.999847
2015-01-31 00:02:32.080 spiral[86741:6997860] x: 230.000000, y:284.000000
2015-01-31 00:02:32.081 spiral[86741:6997860] x: 105.000000, y:283.999908
2015-01-31 00:02:32.081 spiral[86741:6997860] x: 240.000000, y:284.000183
2015-01-31 00:02:32.081 spiral[86741:6997860] x: 95.000000, y:284.000000
2015-01-31 00:02:32.082 spiral[86741:6997860] x: 250.000000, y:284.000122
2015-01-31 00:02:32.160 spiral[86741:6997860] x: 85.000000, y:283.999786
2015-01-31 00:02:32.160 spiral[86741:6997860] x: 260.000000, y:284.000000
2015-01-31 00:02:32.161 spiral[86741:6997860] x: 75.000000, y:283.999878
2015-01-31 00:02:32.161 spiral[86741:6997860] x: 270.000000, y:284.000275

似乎 y 值计算不正确..

固定图像：

Answer 1

如果您输入的角度是递减的，则正确转换为弧度是：

float radians = degrees * M_PI / 180.0f;

您对函数的输入似乎也是错误的。

float aroundStep = coils/sides;// 0 to 1 based.

此评论表明 coils < sides。您输入了10和5，使得aroundStep = 2；不在 0 和 1 之间。

试图绘制螺旋线，只是画一条线

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ios