Question

我正在尝试创建一个应用程序，用户每3次点击一次绘制角度。每次点击都会创建角度点并连接它们。

这很简单。然而，现在我正试图使这些角度可编辑，并且变得更加困难。当我完成我的3次点击并触及touchesEnded时，我将这三个点添加到一个名为segment的NSObject子类中，该子类有三个属性，firstPoint，secondPoint和thirdPoint，它精确地存储了它。

然后我将'segment'对象添加到数组中。每当touchesBegan被调用时，我都会进入我的数组的for循环。如果水龙头在“段”对象的3个CGPoint中的任何一个的25px范围内，那么我不会绘制新的角度，我会编辑该角度。

据我所知，在这一点上，感谢你们，没有任何问题或错误！我只是检查一般的改进/简化，保持我正在使用的当前方法。我希望我能把这笔钱给大家，因为你们都非常乐于助人！

这是我迄今为止最大的项目，我非常感谢一些见解。如果你想要它并且可以处理它，这是一个非常好的挑战。任何帮助都是 IMMENSELY 赞赏。如果您能想出更好的方法来处理我想要完成的事情，请务必告诉我们！

注意：要绘制，只需点击/点击屏幕即可。

以下是最相关的代码：

drawingsubclass.m

#import "SegmentDraw.h"
#import <QuartzCore/QuartzCore.h>

BOOL editing1 = FALSE;
BOOL editing2 = FALSE;
BOOL editing3 = FALSE;
BOOL erased = FALSE;
int radius = 35;
int handleSize = 20;

@implementation SegmentDraw {
    UIImage *incrementalImage;
}
@synthesize first;
@synthesize second;
@synthesize third;

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

        first = CGPointZero;
        second = CGPointZero;
        third = CGPointZero;
    }
    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView:self];

    for (Segment *currentSegment in self.tapArray) {

        int xDistance = abs(point.x - currentSegment.firstPoint.x);
        int yDistance = abs(point.y - currentSegment.firstPoint.y);
        int firstDistance = sqrtf(xDistance * xDistance + yDistance * yDistance);

        int xDistance2 = abs(point.x - currentSegment.secondPoint.x);
        int yDistance2 = abs(point.y - currentSegment.secondPoint.y);
        int secondDistance = sqrtf(xDistance2 * xDistance2 + yDistance2 * yDistance2);

        int xDistance3 = abs(point.x - currentSegment.thirdPoint.x);
        int yDistance3 = abs(point.y - currentSegment.thirdPoint.y);
        int thirdDistance = sqrtf(xDistance3 * xDistance3 + yDistance3 * yDistance3);

        if (firstDistance <= radius) {
            NSLog(@"First point matches");
            editing1 = TRUE;
            editing2 = FALSE;
            editing3 = FALSE;
            first = point;
            second = currentSegment.secondPoint;
            third = currentSegment.thirdPoint;
            self.segmentBeingEdited = currentSegment;
            [self setNeedsDisplay];
            [self drawBitmap];
            erased = FALSE;
            return;
        }
        else if (secondDistance <= radius) {
            NSLog(@"Second point matches");
            editing2 = TRUE;
            editing1 = FALSE;
            editing3 = FALSE;
            first = currentSegment.firstPoint;
            second = point;
            third = currentSegment.thirdPoint;
            self.segmentBeingEdited = currentSegment;
            [self setNeedsDisplay];
            [self drawBitmap];
            erased = FALSE;
            return;
        }
        else if (thirdDistance <= radius) {
            NSLog(@"Third point matches");
            editing3 = TRUE;
            editing1 = FALSE;
            editing2 = FALSE;
            first = currentSegment.firstPoint;
            second = currentSegment.secondPoint;
            third = point;
            self.segmentBeingEdited = currentSegment;
            [self setNeedsDisplay];
            [self drawBitmap];
            erased = FALSE;
            return;
        }
        else {
            editing1 = FALSE;
            editing2 = FALSE;
            editing3 = FALSE;
        }
    }

    if (CGPointEqualToPoint(first, CGPointZero)) {
        first = [touch locationInView:self];
    }
    else if (!CGPointEqualToPoint(first, CGPointZero) && CGPointEqualToPoint(second, CGPointZero)) {
        second = [touch locationInView:self];
    }
    else if (!CGPointEqualToPoint(first, CGPointZero) && !(CGPointEqualToPoint(second, CGPointZero)) && CGPointEqualToPoint(third, CGPointZero)) {
        third = [touch locationInView:self];
    }
    else {
        //[self drawBitmap];
        first = [touch locationInView:self];
        second = CGPointZero;
        third = CGPointZero;
    }

    [self setNeedsDisplay];
}

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

    CGPoint point = [touch locationInView:self];

    for (Segment *currentSegment in self.tapArray) {
        if (editing1) {
            editing2 = FALSE;
            editing3 = FALSE;
            first = point;
            second = self.segmentBeingEdited.secondPoint;
            third = self.segmentBeingEdited.thirdPoint;
            //self.segmentBeingEdited = currentSegment;
            if (erased == FALSE) {
                [self drawBitmap];
                //      NSLog(@"YOU NEED TO ERASE.");
            }
            [self setNeedsDisplay];
            return;
        }
        else if (editing2) {
            editing1 = FALSE;
            editing3 = FALSE;
            first = self.segmentBeingEdited.firstPoint;
            second = point;
            third = self.segmentBeingEdited.thirdPoint;
            //self.segmentBeingEdited = currentSegment;
            if (erased == FALSE) {
                [self drawBitmap];
                //    NSLog(@"YOU NEED TO ERASE.");
            }
            [self setNeedsDisplay];
            return;
        }
        else if (editing3) {
            //       NSLog(@"It's editing time, yo");
            editing1 = FALSE;
            editing2 = FALSE;
            first = self.segmentBeingEdited.firstPoint;
            second = self.segmentBeingEdited.secondPoint;
            third = point;
            //self.segmentBeingEdited = currentSegment;
            if (erased == FALSE) {
                [self drawBitmap];
                //             NSLog(@"YOU NEED TO ERASE.");
            }
            [self setNeedsDisplay];
            return;
        }
        else {
            editing1 = FALSE;
            editing2 = FALSE;
            editing3 = FALSE;
        }
    }

    if (!CGPointEqualToPoint(first, CGPointZero) && CGPointEqualToPoint(second, CGPointZero)) {
        first = [touch locationInView:self];
    }
    else if (!CGPointEqualToPoint(first, CGPointZero) && !(CGPointEqualToPoint(second, CGPointZero)) && CGPointEqualToPoint(third, CGPointZero)) {
        second = [touch locationInView:self];
    }
    else if (!CGPointEqualToPoint(first, CGPointZero) && !(CGPointEqualToPoint(second, CGPointZero)) && !(CGPointEqualToPoint(third, CGPointZero))) {
        third = [touch locationInView:self];
    }
    else {
        first = [touch locationInView:self];
        second = CGPointZero;
        third = CGPointZero;
    }

    [self setNeedsDisplay];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSUInteger index;
    if (editing1 || editing2 || editing3) {
        index = [self.tapArray indexOfObject:self.segmentBeingEdited];
        Segment *datSegment = [self.tapArray objectAtIndex:index];
        datSegment.firstPoint = first;
        datSegment.secondPoint = second;
        datSegment.thirdPoint = third;
    }


    if (!CGPointEqualToPoint(third, CGPointZero) && editing1 == FALSE && editing2 == FALSE && editing3 == FALSE) {
        Segment *segment = [[Segment alloc] init];
        segment.firstPoint = first;
        segment.secondPoint = second;
        segment.thirdPoint = third;

        if (self.tapArray == nil) {
            self.tapArray = [[NSMutableArray alloc] init];
        }

        [self.tapArray addObject:segment];
    }

    editing1 = FALSE;
    editing2 = FALSE;
    editing3 = FALSE;
    erased = FALSE;

    [self drawBitmap];
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
}

- (void)drawRect:(CGRect)rect {
    [incrementalImage drawInRect:rect];
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
    CGContextSetLineWidth(context, 5.0);
    CGContextSetLineCap(context, kCGLineCapRound);
    CGContextSetLineJoin(context, kCGLineJoinRound);

    if (!CGPointEqualToPoint(first, CGPointZero)) {
        CGRect rectangle = CGRectMake(first.x - 10, first.y - 10, handleSize, handleSize);
        CGContextAddEllipseInRect(context, rectangle);
        CGContextMoveToPoint(context, first.x, first.y);

        if (!CGPointEqualToPoint(second, CGPointZero)) {
            CGContextAddLineToPoint(context, second.x, second.y);
            CGRect rectangle2 = CGRectMake(second.x - 10, second.y - 10, handleSize, handleSize);
            CGContextAddEllipseInRect(context, rectangle2);
            CGContextMoveToPoint(context, second.x, second.y);
        }

        if (!CGPointEqualToPoint(third, CGPointZero)) {
            CGContextAddLineToPoint(context, third.x, third.y);
            CGRect rectangle3 = CGRectMake(third.x - 10, third.y - 10, handleSize, handleSize);
            CGContextAddEllipseInRect(context, rectangle3);
        }

        CGContextStrokePath(context);
    }
}

- (void)drawBitmap {
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0.0);

    if (!incrementalImage) { // first draw;
        UIBezierPath *rectpath = [UIBezierPath bezierPathWithRect:self.bounds]; // enclosing bitmap by a rectangle defined by another UIBezierPath object
        [[UIColor clearColor] setFill];
        [rectpath fill]; // fill it
    }
    [incrementalImage drawAtPoint:CGPointZero];

    CGContextRef context = UIGraphicsGetCurrentContext();


    CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
    CGContextSetLineWidth(context, 5.0);
    CGContextSetLineCap(context, kCGLineCapRound);
    CGContextSetLineJoin(context, kCGLineJoinRound);

    if (editing1 || editing2 || editing3) {
        //    CGContextBeginTransparencyLayer(context, NULL);
        CGContextSetBlendMode(context, kCGBlendModeClear);
        CGContextSetLineWidth(context, 6.0);
        //CGContextSetBlendMode(context, kCGBlendModeColor);

        if (!CGPointEqualToPoint(self.segmentBeingEdited.firstPoint, CGPointZero)) {
            CGContextMoveToPoint(context, self.segmentBeingEdited.firstPoint.x, self.segmentBeingEdited.firstPoint.y);

            if (!CGPointEqualToPoint(self.segmentBeingEdited.secondPoint, CGPointZero)) {
                CGContextAddLineToPoint(context, self.segmentBeingEdited.secondPoint.x, self.segmentBeingEdited.secondPoint.y);
            }

            if (!CGPointEqualToPoint(self.segmentBeingEdited.thirdPoint, CGPointZero)) {
                CGContextAddLineToPoint(context, self.segmentBeingEdited.thirdPoint.x, self.segmentBeingEdited.thirdPoint.y);
            }

            CGContextStrokePath(context);
            //      CGContextEndTransparencyLayer(context);
        }

        incrementalImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        erased = TRUE;
        return;
    }

    CGContextSetBlendMode(context, kCGBlendModeNormal);


    if (!CGPointEqualToPoint(first, CGPointZero)) {
        CGContextMoveToPoint(context, first.x, first.y);

        if (!CGPointEqualToPoint(second, CGPointZero)) {
            CGContextAddLineToPoint(context, second.x, second.y);
        }

        if (!CGPointEqualToPoint(third, CGPointZero)) {
            CGContextAddLineToPoint(context, third.x, third.y);
        }

        CGContextStrokePath(context);
    }

    incrementalImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
}

@end

回顾一下，我想绘制一堆角度，然后能够通过点击我想要编辑的角度的3个点中的任何一个来编辑它们中的任何一个。然后通过拖动，编辑角度以扩展到水龙头当前所在的位置。只是想让它变得更好/更简单。任何评论/见解欢迎！

Answer 1

好的 - 这可能不是您想要的......我创建了一个可编辑的角度UI，我认为这是一个很好的方式来组合您想要做的事情。（我喜欢这样的项目）

有一个画布，视图控制器，角度视图和角度视图视图。记录画布上的点击。当3次点击发生时，会创建一个角度视图（其中有手柄）。点击现有角度选择它（显示句柄和选择UI）

该项目位于github。

修改

我没有使用手势识别器，但这可能是一个不错的选择。

Answer 2

您没有正确处理编辑标记。你打电话给touchesBegan:

        if(yDistance2 <= 25 || editing){
            NSLog(@"It's editing time, yo");
            editing = TRUE; // Here's your problem

这意味着touchesMoved，当你点击：

if(xDistance <= 25 || editing) // Note the "Or editing"

editing等于true，这意味着它将移动第1点，因为它首先命中if语句，无论哪个点设置为。

<强>结论

您需要为每个点使用特定的编辑标志。不是共享的。至少没有进行or检查。或者更好的是，处理touchesMoved更好一点。您无需从touchesBegan

几乎完全复制代码

旁注

虽然与您的问题没有完全相关，但我相信您也在if语句中交换point2和point3。检查xDistance2：

else if(xDistance2 <= 25 || editing){
            NSLog(@"X is pretty close");
            if(yDistance2 <= 25 || editing){
                NSLog(@"It's editing time, yo");
                editing = TRUE;
                first = currentSegment.firstPoint;
                second = currentSegment.secondPoint;
                third = point; // <- Why are you setting third to point and not second to point.
                self.segmentBeingEdited = currentSegment;
                [self setNeedsDisplay];
                return;
            }
    }

检查XDistance3时同样如此。你设置第二个点而不是第三个。

Answer 3

你的代码中有一个明显的和一个非显而易见的错误。

显而易见的一点是，在您的touchesBegan方法中，您错误地设置了second和third的值 - 当您接近第二点时，您正在分配触摸将值指向third变量，反之亦然。

不明显的一个是你有一个全局变量editing，它在touchesBegan中设置为你正在编辑的任何一个点，然后在or条件下使用touchesMoved，意思是只要你拖动任何东西，它就会立即落到数组中第一个项目的第一个点。

你的touchesMoved方法已经太多了。您应该在touchesBegan中确定正在编辑哪个分段的哪个点，然后在touchesMoved中仅在编辑特定点时执行任何操作 - 不要尝试再次计算出您正在编辑的内容。您也不需要维护所有单独的状态 - 您有一个segmentBeingEdited属性，只需使用它，并使用一个标志来说明您正在编辑哪个点，并在拖动时直接更新值

通过在日志消息中包含一些上下文，这几乎是显而易见的 - 复制粘贴相同的日志消息到处都会让您最终感到困惑。

以下是touchesXX方法的改编版本。我删除了很多不必要的代码并为您说明。它仍然不能正常工作 - 绘制已编辑的段有问题。在某些时候，您需要添加代码以进行完全重绘，或者将每个图像分开并删除不需要的图像，但希望我正在解释的原则将是直截了当的。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    self.segmentBeingEdited = nil;
    pointBeingEdited = 0;

    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView:self];

    // Are we editing an existing segment?
    for(int i = 0;i<self.tapArray.count;i++){
        Segment *currentSegment = [self.tapArray objectAtIndex:i];

        int xDistance = abs(point.x - currentSegment.firstPoint.x);
        int yDistance = abs(point.y - currentSegment.firstPoint.y);
        int xDistance2 = abs(point.x - currentSegment.secondPoint.x);
        int yDistance2 = abs(point.y - currentSegment.secondPoint.y);
        int xDistance3 = abs(point.x - currentSegment.thirdPoint.x);
        int yDistance3 = abs(point.y - currentSegment.thirdPoint.y);

        if(xDistance <= 25){
            if(yDistance <= 25){
                pointBeingEdited = 1;
            }
        }
        else if(xDistance2 <= 25 ){
            if(yDistance2 <= 25){
                pointBeingEdited = 2;
            }
        }
        else if(xDistance3 <= 25){
            if(yDistance3 <= 25){
                pointBeingEdited = 3;
            }
        }

        if (pointBeingEdited != 0)
        {
            NSLog(@"editing point %d",pointBeingEdited);
            self.segmentBeingEdited = currentSegment;
            return;
        }
    }

    // Creating a new segment. Update data.
    if (pointBeingAdded == 0)
    {
        first = [touch locationInView:self];
        second = CGPointZero;
        third = CGPointZero;
    }
    else if (pointBeingAdded == 1)
    {
        second = [touch locationInView:self];
    }
    else if (pointBeingAdded == 2)
    {
        third = [touch locationInView:self];
    }
    pointBeingAdded++;

    [self setNeedsDisplay];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

    if (!self.segmentBeingEdited)
        return;

    UITouch *touch = [touches anyObject];

    CGPoint point = [touch locationInView:self];
    if (pointBeingEdited == 1)
    {
        self.segmentBeingEdited.firstPoint = point;
    }
    else if (pointBeingEdited == 2)
    {
        self.segmentBeingEdited.secondPoint = point;
    }
    else if (pointBeingEdited == 3)
    {
        self.segmentBeingEdited.thirdPoint = point;
    }
    [self drawBitmap];
    [self setNeedsDisplay];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    if(self.segmentBeingEdited){
        first = CGPointZero;
        second = CGPointZero;
        third = CGPointZero;
    }

    if(pointBeingAdded == 3){
        // Add new segment
        Segment *segment = [[Segment alloc] init];
        segment.firstPoint = first;
        segment.secondPoint = second;
        segment.thirdPoint = third;

        if(self.tapArray == nil){
            self.tapArray = [[NSMutableArray alloc] init];
        }
        [self.tapArray addObject:segment];
        pointBeingAdded = 0;
    }
    [self drawBitmap];
    self.segmentBeingEdited = nil;
}

Answer 4

我想谈谈你代码的一些事情：

1-没有必要但是，您可以使用水龙头和平移手势识别器，我认为这会简化您的代码。

2-当你试图找到正在编辑的点时你重复了很多代码，你可以像这样迭代每个段的点：

- (void)tapAction:(UITapGestureRecognizer *)recognizer {
CGPoint point = [recognizer locationInView:self];
self.segmentBeingEdited = nil;
CGPoint currentPoint;
for (Segment *segment in self.tapArray) {
    for (NSInteger p = 0; p < 3; p++) {
        currentPoint = [segment pointAtIndex:p];
        CGFloat distance = fDistance(point, currentPoint);
        if (distance <= 25.0) {
            self.segmentBeingEdited = segment;
            self.pointBeingEdited = p;
            [self setNeedsDisplay];
            return;
        }
    }
}
Segment *segment = [self.tapArray lastObject];
if (!segment || segment.points == 3) {
    segment = [[Segment alloc] init];
    [self.tapArray addObject:segment];
}
[segment setPoint:point atIndex:segment.points];
segment.points = segment.points + 1;
[self setNeedsDisplay];

}

3- Segment类可以根据索引0,1,2和已添加的点数来获取和设置点的方法，我认为这会增加内聚力并简化代码。 / p>

4-用于确定从水龙头位置到某个点的距离是否小于25的算法......好吧，它可以工作但技术上不正确，你应该使用这样的东西：

static inline CGFloat fDistance(CGPoint point1, CGPoint point2) {
CGFloat dx = point1.x - point2.x;
CGFloat dy = point1.y - point2.y;
return sqrtf(dx * dx + dy * dy); }

5-我注意到你在某些if中使用CGPointEqualToPoint(point, CGPointZero)，再次，它有效，但有更好的方法，你可以用一个标志来找到下一个要添加的点。

最后，您可以使用平移手势识别器来编辑选定的点：

- (void)panAction:(UIPanGestureRecognizer *)recognizer {
CGPoint location = [recognizer locationInView:self];

switch (recognizer.state) {
    case UIGestureRecognizerStateBegan:
    {
        CGPoint point = [self.segmentBeingEdited pointAtIndex:self.pointBeingEdited];
        CGFloat distance = fDistance(location, point);
        if (distance > 25.0) {
            self.segmentBeingEdited = nil;
        }
        break;
    }
    case UIGestureRecognizerStateChanged:
    {
        if (self.segmentBeingEdited) {
            [self.segmentBeingEdited setPoint:location atIndex:self.pointBeingEdited];
            [self setNeedsDisplay];
        }
    }

    default:
        break;
}
}

我希望这可能有用。

使用drawRect绘制可编辑的角度？

4 个答案:

旁注