通过 UIElement.TranslatePoint 计算子元素中心偏离正确值

Posted 2023-04-01

【中文标题】通过 UIElement.TranslatePoint 计算子元素中心偏离正确值

【英文标题】：Calculation of childelement center via UIElement.TranslatePoint deviates from correct value

【发布时间】：2019-06-30 05:48:12

【问题描述】：

我有一个矩形，它周围有一些元素，用户可以通过鼠标旋转。这样的旋转适用于 RotateTransform，但旋转中心总是有轻微的偏移。 我这样计算中心：

this.rotationCenter = this.cornerA.CalculatePointOnLine(this.cornerC, 0.5);

CornerA 和 CornerC 是矩形的角，构成对角线。 现在我想设置所有 RotateTransforms 相对于相应元素的中心。

Logger.Logger.Write("coord.log", "center : " + this.rotationCenter.X + " ; " + this.rotationCenter.Y);
this.rotateSurroundingRectangle.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.suroundingRectangle).X;
this.rotateSurroundingRectangle.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.suroundingRectangle).Y;

Logger.Logger.Write("coord.log", "relative center : " + this.rotateSurroundingRectangle.CenterX + " ; " + this.rotateSurroundingRectangle.CenterY);

this.rotateResizeCorner1.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner1).X;
this.rotateResizeCorner1.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner1).Y;
this.rotateResizeCorner2.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner2).X;
this.rotateResizeCorner2.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner2).Y;
this.rotateResizeCorner3.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner3).X;
this.rotateResizeCorner3.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner3).Y;
this.rotateResizeCorner4.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner4).X;
this.rotateResizeCorner4.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.resizeCorner4).Y;
this.rotateRotationSign.CenterX = this.ParentLayer.TranslatePoint(this.rotationCenter, this.rotationSign).X;
this.rotateRotationSign.CenterY = this.ParentLayer.TranslatePoint(this.rotationCenter, this.rotationSign).Y;

根据角度，矩形周围所有元素的中心应该改变，但矩形本身的中心应该始终是 32,32。 但值存在偏差，X 和 Y 的值都在 29 到 35 之间。 我已经检查了rotationCenter的计算，它是正确的。 为什么会出现这种偏差，我该如何解决？ 谢谢...

【参考方案1】：

好的，由于似乎没有人知道，我决定绕过这个问题而不是实际解决它。所以现在我“手动”计算相对旋转中心。我不确定这是否会帮助任何人，但它对我有用。

this.rotateSurroundingRectangle.CenterX = (this.surroundingRectangle.Width * 0.5);
this.rotateSurroundingRectangle.CenterY = (this.surroundingRectangle.Height * 0.5);
this.rotateResizeCorner1.CenterX = this.rotationCenter.X - Canvas.GetLeft(this.resizeCornerA);
this.rotateResizeCorner1.CenterY = this.rotationCenter.Y - Canvas.GetTop(this.resizeCornerA);
this.rotateResizeCorner2.CenterX = this.rotationCenter.X - Canvas.GetLeft(this.resizeCornerB);
this.rotateResizeCorner2.CenterY = this.rotationCenter.Y - Canvas.GetTop(this.resizeCornerB);
this.rotateResizeCorner3.CenterX = this.rotationCenter.X - Canvas.GetLeft(this.resizeCornerC);
this.rotateResizeCorner3.CenterY = this.rotationCenter.Y - Canvas.GetTop(this.resizeCornerC);
this.rotateResizeCorner4.CenterX = this.rotationCenter.X - Canvas.GetLeft(this.resizeCornerD);
this.rotateResizeCorner4.CenterY = this.rotationCenter.Y - Canvas.GetTop(this.resizeCornerD);
this.rotateRotationSign.CenterX = this.rotationCenter.X - Canvas.GetLeft(this.rotationSign);
this.rotateRotationSign.CenterY = this.rotationCenter.Y - Canvas.GetTop(this.rotationSign);