右上方的对角线试图在UIView上画画

Question

我有一个名为Slate的平板电脑，我可以处理x，y点。我可以将这些x，y点传递给我的“drawShape”函数，相当于一个touchesMoved函数。我有一个为此目的而设计的自定义UIView类，具有4个主要功能。前三个是touchesbegan / move / ends，还有一个drawRect。

这是UIView子类的源代码......

//
//  DrawingLayerView.m
//
//
//  Created by Monica Kachlon on 12/3/17.
//

#import "DrawingLayerView.h"
#include "UIBezierPath+Interpolation.h"


@interface StrokeA : NSObject

@property (assign, nonatomic) CGPoint startPoint;

- (id)initWithStartPoint:(CGPoint)point;


@property (strong, nonatomic) NSMutableArray * points;

@end

@implementation StrokeA



- (id)initWithStartPoint:(CGPoint)point {
    self = [super init];
    self.startPoint = point;
    self.points = [NSMutableArray array];

    return self;
}


@end



@implementation DrawingLayerView

NSMutableArray * strokes;
NSMutableArray * points;


StrokeA * currentStroke;
UIBezierPath * currentPath;
UIBezierPath *path;
UIBezierPath *pathTwo;

UIBezierPath *Newpath;
CAShapeLayer * currentLayer;


- (void) noodlez
{
path = [UIBezierPath bezierPath];

   currentPath = [UIBezierPath bezierPath];

    pathTwo = [UIBezierPath bezierPath];

    Newpath = [UIBezierPath bezierPath];
     strokes = [NSMutableArray array];
     points = [NSMutableArray array];

}
- (void)startTouch: (CGPoint)point
{

    currentStroke = [[StrokeA alloc] initWithStartPoint:point];
    [strokes addObject:currentStroke];
}

- (UIBezierPath *)createPath {
    UIBezierPath * bezierPath = [UIBezierPath bezierPath];
    for (StrokeA * stroke in strokes) {
        [bezierPath moveToPoint:stroke.startPoint];
        for (NSValue * value in stroke.points) {
            [bezierPath addLineToPoint:[value CGPointValue]];
        }
    }
    return bezierPath;
}


- (void)endTouch: (CGPoint)point
{

    [points removeAllObjects];
    [self setNeedsDisplay];
}
- (void)drawShape: (CGPoint)point
{
    if (!currentStroke) {
        [self startTouch:point];
    }
    [currentStroke.points addObject:[NSValue valueWithCGPoint:point]];
    pathTwo = [self createPath];

    [self setNeedsDisplay];

}

- (void)drawRect:(CGRect)rect {
    [[UIColor blackColor] setStroke];
    [pathTwo stroke];
}


@end

这是截图。

我试着写“好吗？”只是为了说明这个问题。

Answer 1

尽管代码缺少一些细节并且问题措辞不当，但屏幕截图清楚地表明路径的初始点在每种情况下都是（0,0）。将路径中的点转移到控制台，您将看到它。弄清楚那些（0,0）是如何进入的，你将解决这个问题。