Question

我在绘图矩形中做一些特定的绘图。这些绘图是动态的, 以视图宽度和高度为基础。然后, 包含此图的视图对它进行旋转转换。但是这种转换似乎调整了我视图框的值, 从而影响我的绘图矩形。

NSLog (@ 之前的 :%f,%f,%f,%f,%f" "button. frame. button. blood. hindow.x, button.frame.stext.y, button.ference.width.widdth, button.ference.hleight); NSLog (@ 之前的 :%f,%f,%f,%f,%f,%f,%f,%f", button. frame. buton. blate.x,button. frame. instate.y.y, button.framef.

    CGAffineTransform currentTransform = button.transform;
    CGAffineTransform transformRotate = CGAffineTransformMakeRotation(degreesToRadians);
    button.transform = transformRotate;

    NSLog(@"after:%f,%f,%f,%f",button.frame.origin.x,button.frame.origin.y,button.frame.size.width,button.frame.size.height);

以下是输出 :

before:50.000000,100.000000,150.000000,50.000000 after:65.849365,47.548096,118.301262,154.903809

这是正确的行为吗? 还是我应用变换错误了?

Answer 1

见“http:// developmenter.apple.com/library/ios/#documentation/uikit/reference/uiview_gle/uiview/uiview.html>UIViews框架属性的参考文件;

框架

The frame rectangle, which describes the view’s location and size in its superview’s coordinate system.

@property(nonatomic) CGRect frame

<强 > 警告

If the transform property is not the identity transform, the value of this property is undefined and therefore should be ignored.

Despite that warning, things work as intended. Once a transformation (other that identity) is applied, the frame usually results into the projection rectangle of the original view. But then again, you should not ignore that warning if you really want to find out about the frame with the applied transformation and use CGRectApplyAffineTransform for properly getting it.

友情链接