旋转图像数学（C＃） [英] Rotate image math (C#)

问题描述

我有两个点的图像，排列是这样的：

I have an image with two points, aligned something like this:

|----------------|
|                |
|    .           |
|                |
|          .     |
|                |
|----------------|

我同时拥有X，Y为坐标的，我需要将图像旋转X度，所以它看起来是这样，而不是：

I have both X, Y coordinates for both points and I need to rotate the image X degrees so it looks like this instead:

|----------------|
|                |
|                |
|    .     .     |
|                |
|                |
|----------------|

基本上使他们对齐旁边的海誓山盟，什么是数学这个？ （在C＃A code例子会更好，但不是必需的）

Basically so they align next to eachother, what's the math for this? (A code example in C# would be even better but not required)

推荐答案

这取决于这一点要作为一个中心为循环使用。让我们把点到了，离开点A和一个右方和下方pointB。如果你想在A点周围旋转，使B点与它保持一致，计算弧度转角会是这样的：

It depends on which point you want to use as a "center" for your rotation. Let's call the point to the up and left pointA and the one to the right and below pointB. If you want to rotate around the point A so that point B aligns with it, calculating the rotation angle in radians would go like this:

double angle = Math.Atan2(pointB.Y - pointA.Y, pointB.X - pointA.X);

我不知道你是如何处理你的形象，因此，只有当你使用System.Drawing.Graphics适用：

I don't how you're handling your image, so the following applies only if you're using System.Drawing.Graphics:

myImage.TranslateTransform(-pointA.X, -pointA.Y);
myImage.RotateTransform((float) angle, MatrixOrder.Append);
myImage.TranslateTransform(pointA.X, pointA.Y, MatrixOrder.Append);

希望它帮助。

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