UIImage 在 UIScrollView 上缩放时的 UIButton 位置

Question

我有一个场景，我需要实现一个离线地图概念，为此我使用 UIScrollView 上的地图图像，放大 PinchGesture，效果很好。

问题

我在地图上有一个UIButton。缩放时，按钮不会跟踪其相对于正在缩放的​​UIImageView 的位置。我可以在不影响其大小的情况下重新构建按钮。但立场不对。

TLDR， 我需要在UIScrollView 上用UIImage 重现ma​​pView with annotation kinda concept。有人可以帮忙吗？

提前致谢:)

Answer 1

我已经找到了答案。我最初将按钮值存储在 CGRect initialButtonFrame 中。然后我使用滚动视图委托更新了按钮框架（仅来源，而不是按钮大小的大小，因为我希望按钮不像图像那样缩放，即；我的按钮不应该缩放）

- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
{
   [self manageImageOnScrollView];//here i managed the image's coordinates and zoom
   [self manageButtonCoordinatesWithRespectToImageWithScale:scale];
}

-(void)manageButtonCoordinatesWithRespectToImageWithScale:(float)scaleFactor
{

//initialButtonFrame is frame of button 
   self.button.frame = CGRectMake((initialButtonFrame.origin.x * scaleFactor),
                                  (initialButtonFrame.origin.y * scaleFactor),
                                           initialButtonFrame.size.width,
                                           initialButtonFrame.size.height);

   [self.scrollView addSubview:self.button];// I removed the button from superview while zooming and later added with updated button coordinates which I got here
 }

Answer 2

如果您知道地图的当前偏移和缩放，您应该能够计算按钮的位置：

//Assuming your map image has its origin at 0, 0
CGPoint mapOffsetX, mapOffsetY; // these would come from your map as you calculated it.
CGPoint mapZoomFactor; // 1.0 means not zoomed, 3.0 means zooming in 3x, etc
CGPoint buttonAnchorPosition; //the position of your button on your map at 1.0 zoom

CGFloat buttonX = buttonAnchorPosition.x * mapZoomFactor + mapOffsetX;
CGFloat buttonY = buttonAnchorPosition.y * mapZoomFactor + mapOffsetY;

CGPoint buttonPosition = CGPointMake(buttonX, buttonY);

button.position = buttonPosition;

试试看，祝你好运