调整 UIView 的大小以适合 CGPath

发布于 2024-10-22 06:22:47 字数 593 浏览 3 评论 0原文

我有一个 UIView 子类，用户可以在其上添加随机 CGPath。 CGPath是通过处理UIPanGestures添加的。

我想将 UIView 的大小调整为包含 CGPath 的最小矩形。在我的 UIView 子类中，我重写了 sizeThatFits 以返回最小尺寸，如下所示：

- (CGSize) sizeThatFits:(CGSize)size {
    CGRect box = CGPathGetBoundingBox(sigPath);
    return box.size;
}

这按预期工作，并且 UIView 的大小调整为返回的值，但 CGPath 也按比例“调整大小”，导致用户拥有的路径不同原来画的。例如，这是具有用户绘制的路径的视图：

Path asdrawn

这是具有以下内容的视图：调整大小后的路径：

在此处输入图像描述

如何调整 UIView 的大小而不是“调整”路径的大小？

原文

I have a UIView subclass on which the user can add a random CGPath. The CGPath is added by processing UIPanGestures.

I would like to resize the UIView to the minimal rect possible that contains the CGPath. In my UIView subclass, I have overridden sizeThatFits to return the minimal size as such:

- (CGSize) sizeThatFits:(CGSize)size {
    CGRect box = CGPathGetBoundingBox(sigPath);
    return box.size;
}

This works as expected and the UIView is resized to the value returned, but the CGPath is also "resized" proportionally resulting in a different path that what the user had originally drawn. As an example, this is the view with a path as drawn by the user:

Path as drawn

And this is the view with the path after resizing:

enter image description here

How can I resize my UIView and not "resize" the path?

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陌路终见情 2024-10-29 06:22:47

使用 CGPathGetBoundingBox。来自苹果文档：

返回包含图形路径中所有点的边界框。这
边界框是完全包围所有点的最小矩形
在路径中，包括贝塞尔曲线和二次曲线的控制点。

这里有一个小的概念验证的drawRect方法。希望对您有帮助！

- (void)drawRect:(CGRect)rect {

    //Get the CGContext from this view
    CGContextRef context = UIGraphicsGetCurrentContext();

    //Clear context rect
    CGContextClearRect(context, rect);

    //Set the stroke (pen) color
    CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);

    //Set the width of the pen mark
    CGContextSetLineWidth(context, 1.0);

    CGPoint startPoint = CGPointMake(50, 50);
    CGPoint arrowPoint = CGPointMake(60, 110);

    //Start at this point
    CGContextMoveToPoint(context, startPoint.x, startPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x+50, startPoint.y+90);
    CGContextAddLineToPoint(context, arrowPoint.x, arrowPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+40, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x, startPoint.y);

    //Draw it
    //CGContextStrokePath(context);

    CGPathRef aPathRef = CGContextCopyPath(context);

    // Close the path
    CGContextClosePath(context);

    CGRect boundingBox = CGPathGetBoundingBox(aPathRef);
    NSLog(@"your minimal enclosing rect: %.2f %.2f %.2f %.2f", boundingBox.origin.x, boundingBox.origin.y, boundingBox.size.width, boundingBox.size.height);
}

Use the CGPathGetBoundingBox. From Apple documentation:

Returns the bounding box containing all points in a graphics path. The
bounding box is the smallest rectangle completely enclosing all points
in the path, including control points for Bézier and quadratic curves.

Here a small proof-of-concept drawRect methods. Hope it helps you!

- (void)drawRect:(CGRect)rect {

    //Get the CGContext from this view
    CGContextRef context = UIGraphicsGetCurrentContext();

    //Clear context rect
    CGContextClearRect(context, rect);

    //Set the stroke (pen) color
    CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);

    //Set the width of the pen mark
    CGContextSetLineWidth(context, 1.0);

    CGPoint startPoint = CGPointMake(50, 50);
    CGPoint arrowPoint = CGPointMake(60, 110);

    //Start at this point
    CGContextMoveToPoint(context, startPoint.x, startPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x+50, startPoint.y+90);
    CGContextAddLineToPoint(context, arrowPoint.x, arrowPoint.y);
    CGContextAddLineToPoint(context, startPoint.x+40, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x, startPoint.y+90);
    CGContextAddLineToPoint(context, startPoint.x, startPoint.y);

    //Draw it
    //CGContextStrokePath(context);

    CGPathRef aPathRef = CGContextCopyPath(context);

    // Close the path
    CGContextClosePath(context);

    CGRect boundingBox = CGPathGetBoundingBox(aPathRef);
    NSLog(@"your minimal enclosing rect: %.2f %.2f %.2f %.2f", boundingBox.origin.x, boundingBox.origin.y, boundingBox.size.width, boundingBox.size.height);
}

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