是否可以从 uiview 获取所有 uibezerpath？答案

【问题标题】：Is it possible to get all uibezerpath from uiview?是否可以从 uiview 获取所有 uibezerpath？
【发布时间】：2015-08-20 02:53:32
【问题描述】：

我一直在研究，没有找到答案。

如果我使用 CGGontext 将其绘制到视图中，是否可以从 UIView 中获取所有 UIBezierPath？（如果是，你能给我一个想法吗？） UIBezierPath 来自用户输入，所以如果用户绘制了很多 UIBezierPath，我需要所有这些路径并将其保存到 .svg 文件中。

【问题讨论】：

没有。您应该在用户绘图时将路径（或触摸位置或其他东西）保存在内存中。

标签： ios objective-c cgcontext uibezierpath

【解决方案1】：

这是一个更好的工作示例，在测试了我在评论中给出的一些答案之后，这将返回一组 shapelayer 或图层，具体取决于您要查找的内容：

CAShapeLayer * firstNameCorners = [CAShapeLayer layer];
[firstNameCorners setPath:[UIBezierPath bezierPathWithRoundedRect:CGRectMake(100, 100, 196.75, 44.0) byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerTopLeft cornerRadii:(CGSize){2.5, 2.5}].CGPath];
[[self.view layer] addSublayer:firstNameCorners];

NSMutableArray *this = [[NSMutableArray alloc] init];

for (CALayer * rd in self.view.layer.sublayers) {
    if ([rd isKindOfClass:[CAShapeLayer class]]) {
        [this addObject:rd];
        NSLog(@"this is a layer: %@", rd);
    }
}
NSLog(@"this is an Array of Shapes: %@", this);

CAShapeLayer 也可以只存储一条线，不管这条线有多复杂，如果它来自 UIBezierPath 并且你将它存储在你正在绘制的 UIView 的子层中，这个对象可以存储它。事实上，为了进一步扩展这一点，为了您的目的，请参阅以下内容，这将返回 CGPath，根据您的问题，这就是您想要的：

CAShapeLayer * firstNameCorners = [CAShapeLayer layer];
[firstNameCorners setPath:[UIBezierPath bezierPathWithRoundedRect:CGRectMake(100, 100, 96.75, 44.0) byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerTopLeft cornerRadii:(CGSize){2.5, 2.5}].CGPath];
[[self.view layer] addSublayer:firstNameCorners];

NSMutableArray *this = [[NSMutableArray alloc] init];

for (CALayer * rd in self.view.layer.sublayers) {
    if ([rd isKindOfClass:[CAShapeLayer class]]) {
        [this addObject:rd];
        CAShapeLayer * rf = (CAShapeLayer*)rd;
        NSLog(@"this is a layer: %@", rf.path);
        CGRect pathBounds = CGPathGetBoundingBox(rf.path);
        NSLog(@"this is this boundingBox: origin.X: %f, origin.X: %f, size.Width: %f, size.Height: %f", pathBounds.origin.x, pathBounds.origin.y, pathBounds.size.width, pathBounds.size.height);
    }
}
NSLog(@"this is an Array of Shapes: %@", this);

而且，如果你想走得更远，那么这可以存储 CGRect 坐标，而且，这将向你展示如何检索和使用这些坐标：

CAShapeLayer * firstNameCorners = [CAShapeLayer layer];
[firstNameCorners setPath:[UIBezierPath bezierPathWithRoundedRect:CGRectMake(100, 100, 196.75, 44.0) byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerTopLeft cornerRadii:(CGSize){2.5, 2.5}].CGPath];
[[self.view layer] addSublayer:firstNameCorners];

NSMutableArray *this = [[NSMutableArray alloc] init];

NSMutableArray *that = [[NSMutableArray alloc] init];

for (CALayer * rd in self.view.layer.sublayers) {
    if ([rd isKindOfClass:[CAShapeLayer class]]) {
        [this addObject:rd];
        CAShapeLayer * rf = (CAShapeLayer*)rd;
        NSLog(@"this is a layer: %@", rf.path);
        CGRect pathBounds = CGPathGetBoundingBox(rf.path);
        [that addObject:[NSValue valueWithCGRect:pathBounds]];
        NSLog(@"this is this boundingBox: origin.X: %f, origin.X: %f, size.Width: %f, size.Height: %f", pathBounds.origin.x, pathBounds.origin.y, pathBounds.size.width, pathBounds.size.height);
    }
}

现在，结束，这是对https://github.com/erica/iOS-6-Cookbook 的改编，这是为了展示我对 UIBezierPath 的绘制的完全解开：

#define VALUE(_INDEX_) [NSValue valueWithCGPoint:points[_INDEX_]]

-(void)showPaths
{
    CAShapeLayer * firstNameCorners = [CAShapeLayer layer];
    [firstNameCorners setPath:[UIBezierPath bezierPathWithRoundedRect:CGRectMake(100, 100, 196.75, 44.0) byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerTopLeft cornerRadii:(CGSize){2.5, 2.5}].CGPath];
    [[self.view layer] addSublayer:firstNameCorners];

    NSMutableArray *this = [[NSMutableArray alloc] init];

    NSMutableArray *that = [[NSMutableArray alloc] init];

    for (CALayer * rd in self.view.layer.sublayers) {
        if ([rd isKindOfClass:[CAShapeLayer class]]) {
            [this addObject:rd];
            CAShapeLayer * rf = (CAShapeLayer*)rd;
            NSLog(@"this is a layer: %@", rf.path);
            CGRect pathBounds = CGPathGetBoundingBox(rf.path);
            [that addObject:[NSValue valueWithCGRect:pathBounds]];

            CGMutablePathRef p3 = CGPathCreateMutableCopy(rf.path);
            NSArray *p3points = [self pointsFromCGPath:p3];
            for (NSValue *point in p3points) {
                NSLog(@"path element in p3: %@", NSStringFromCGPoint(point.CGPointValue));
            }
            NSLog(@"this is this boundingBox: origin.X: %f, origin.X: %f, size.Width: %f, size.Height: %f", pathBounds.origin.x, pathBounds.origin.y, pathBounds.size.width, pathBounds.size.height);
        }
    }
}

void getPointsFromBezier(void *info, const CGPathElement *element)
{
    NSMutableArray *bezierPoints = (__bridge NSMutableArray *)info;

    // Retrieve the path element type and its points
    CGPathElementType type = element->type;
    CGPoint *points = element->points;

    switch (type) {
        case kCGPathElementMoveToPoint:
            NSLog(@"MoveToPoint (%3.2f, %3.2f", points->x, points->y);
            break;
        case kCGPathElementAddLineToPoint:
            NSLog(@"AddLineToPoint (%3.2f, %3.2f)", points->x, points->y);
            break;
        case kCGPathElementAddQuadCurveToPoint:
            NSLog(@"AddQuadCurveToPoint (%3.2f, %3.2f), (%3.2f, %3.2f)", points->x, points->y, points[1].x, points[1].y);
            break;
        case kCGPathElementAddCurveToPoint:
            NSLog(@"AddCurveToPoint (%3.2f, %3.2f), (%3.2f, %3.2f), (%3.2f, %3.2f)", points->x, points->y, points[1].x, points[1].y, points[2].x, points[2].y);
            break;
        case kCGPathElementCloseSubpath:
            NSLog(@"CloseSubpath (%3.2f, %3.2f)", points->x, points->y);
            break;
        default:
            NSLog(@"unknown");
            break;
    }

    // Add the points if they're available (per type)
    if (type != kCGPathElementCloseSubpath)
    {
        [bezierPoints addObject:VALUE(0)];
        if ((type != kCGPathElementAddLineToPoint) &&
            (type != kCGPathElementMoveToPoint))
            [bezierPoints addObject:VALUE(1)];
    }
    if (type == kCGPathElementAddCurveToPoint)
        [bezierPoints addObject:VALUE(2)];
}

- (NSArray *)pointsFromCGPath:(CGPathRef)path
{
    NSMutableArray *points = [NSMutableArray array];
    CGPathApply(path, (__bridge void *)points, getPointsFromBezier);
    return points;
}

输出将记录到控制台，我们开始时存储在 CAShapeLayer 中的所有路径，输出太大太乱，无法在此处发布，但它的开头是这样的：

[30146:2680987] 移动到点 (103.82, 100.00

[30146:2680987] AddLineToPoint (296.75, 100.00)

[30146:2680987] AddLineToPoint (296.75, 144.00)

[30146:2680987] AddLineToPoint (103.82, 144.00)

[30146:2680987] AddCurveToPoint (102.72, 144.00), (102.17, 144.00), (101.67, 143.84)

[30146:2680987] AddLineToPoint (101.58, 143.81)

[30146:2680987] AddCurveToPoint (100.93, 143.58), (100.42, 143.07), (100.19, 142.42)

[30146:2680987] AddCurveToPoint (100.00, 141.83), (100.00, 141.28), (100.00, 140.18)

[30146:2680987] AddLineToPoint (100.00, 103.82)

[30146:2680987] AddCurveToPoint (100.00, 102.72), (100.00, 102.17), (100.16, 101.67)

[30146:2680987] AddLineToPoint (100.19, 101.58)

[30146:2680987] AddCurveToPoint (100.42, 100.93), (100.93, 100.42), (101.58, 100.19)

[30146:2680987] AddCurveToPoint (102.17, 100.00), (102.72, 100.00), (103.82, 100.00)

[30146:2680987] AddLineToPoint (103.82, 100.00)

[30146:2680987] p3 中的路径元素：{103.8216625, 100}

[30146:2680987] p3 中的路径元素：{296.75, 100}

[30146:2680987] p3 中的路径元素：{296.75, 144}

[30146:2680987] p3 中的路径元素：{103.8216625, 144}

[30146:2680987] p3 中的路径元素：{102.72123239404632, 144}

[30146:2680987] p3 中的路径元素：{102.17101736015751, 144}

【讨论】：

哇，感谢您的努力，如果这是经过测试的，那么我只需要将它合并到我的代码中。我仍然很惊讶有人努力回答我的问题...... :) 非常感谢 Larcerax！
没问题，我这样做是为了帮助，也是为了学习，直到你问这个问题我才知道我能走这么远！！

【解决方案2】：

如果您使用 Core Graphics 绘制路径，您可能有一些模型支持 drawRect 用于绘制所有路径的视图。如果您不这样做（即您只是更新位图），您应该简单地重构该代码以捕获并保存表示路径所需的信息。

【讨论】：