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Core Graphicsを使用して矢印を描画するにはどうすればよいですか？

Drawアプリで端に矢印のある線を引く必要があります。私は三角法が苦手なので、この問題を解決することはできません。

ユーザーは画面に指を置き、任意の方向に線を引きます。したがって、矢印は行末に表示されます。

objective-cioscore-graphicsquartz-2d
36
Sasha Prent

Swift私の古いObjective-Cコードのバージョンです。Swift 3.2以降のバージョンで動作するはずです。

extension UIBezierPath {

    static func arrow(from start: CGPoint, to end: CGPoint, tailWidth: CGFloat, headWidth: CGFloat, headLength: CGFloat) -> UIBezierPath {
        let length = hypot(end.x - start.x, end.y - start.y)
        let tailLength = length - headLength

        func p(_ x: CGFloat, _ y: CGFloat) -> CGPoint { return CGPoint(x: x, y: y) }
        let points: [CGPoint] = [
            p(0, tailWidth / 2),
            p(tailLength, tailWidth / 2),
            p(tailLength, headWidth / 2),
            p(length, 0),
            p(tailLength, -headWidth / 2),
            p(tailLength, -tailWidth / 2),
            p(0, -tailWidth / 2)
        ]

        let cosine = (end.x - start.x) / length
        let sine = (end.y - start.y) / length
        let transform = CGAffineTransform(a: cosine, b: sine, c: -sine, d: cosine, tx: start.x, ty: start.y)

        let path = CGMutablePath()
        path.addLines(between: points, transform: transform)
        path.closeSubpath()

        return self.init(cgPath: path)
    }

}

呼び出し方法の例を次に示します。

let arrow = UIBezierPath.arrow(from: CGPoint(x: 50, y: 100), to: CGPoint(x: 200, y: 50),
        tailWidth: 10, headWidth: 25, headLength: 40)
15
rob mayoff
//This is the integration into the view of the previous exemple
//Attach the following class to your view in the xib file

#import <UIKit/UIKit.h>

@interface Arrow : UIView

@end

#import "Arrow.h"
#import "UIBezierPath+dqd_arrowhead.h"

@implementation Arrow
{
    CGPoint startPoint;
    CGPoint endPoint;
    CGFloat tailWidth;
    CGFloat headWidth;
    CGFloat headLength;
    UIBezierPath *path;

}


- (id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super initWithCoder:aDecoder])
    {
        [self setMultipleTouchEnabled:NO];
        [self setBackgroundColor:[UIColor whiteColor]];

    }
    return self;
}

- (void)drawRect:(CGRect)rect {

    [[UIColor redColor] setStroke];
    tailWidth = 4;
    headWidth = 8;
    headLength = 8;
    path = [UIBezierPath dqd_bezierPathWithArrowFromPoint:(CGPoint)startPoint
                                                  toPoint:(CGPoint)endPoint
                                                tailWidth:(CGFloat)tailWidth
                                                headWidth:(CGFloat)headWidth
                                               headLength:(CGFloat)headLength];
    [path setLineWidth:2.0];

    [path stroke];

}
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
    UITouch* touchPoint = [touches anyObject];
    startPoint = [touchPoint locationInView:self];
    endPoint = [touchPoint locationInView:self];


    [self setNeedsDisplay];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch* touch = [touches anyObject];
    endPoint=[touch locationInView:self];
    [self setNeedsDisplay];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch* touch = [touches anyObject];
    endPoint = [touch locationInView:self];
    [self setNeedsDisplay];
}


@end
7
copter244

Swift 3.0では、これを達成することができます

extension UIBezierPath {

class func arrow(from start: CGPoint, to end: CGPoint, tailWidth: CGFloat, headWidth: CGFloat, headLength: CGFloat) -> Self {
    let length = hypot(end.x - start.x, end.y - start.y)
    let tailLength = length - headLength

    func p(_ x: CGFloat, _ y: CGFloat) -> CGPoint { return CGPoint(x: x, y: y) }
    var points: [CGPoint] = [
        p(0, tailWidth / 2),
        p(tailLength, tailWidth / 2),
        p(tailLength, headWidth / 2),
        p(length, 0),
        p(tailLength, -headWidth / 2),
        p(tailLength, -tailWidth / 2),
        p(0, -tailWidth / 2)
    ]

    let cosine = (end.x - start.x) / length
    let sine = (end.y - start.y) / length
    var transform = CGAffineTransform(a: cosine, b: sine, c: -sine, d: cosine, tx: start.x, ty: start.y)        
    let path = CGMutablePath()
    path.addLines(between: points, transform: transform)
    path.closeSubpath()
    return self.init(cgPath: path)
}

}
1
Sujatha Girijala