在Picturebox上绘制自定义形状

本文介绍了在Picturebox上绘制自定义形状的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试绘制一个特定的形状，我发现它令人难以置信。

我设法得到一个三角形，因为我理解它背后的数学。 ..至少排序。但是我不喜欢三角形的形状，因为我想用它 - 在图像上放置一个标记作为ROI（感兴趣的区域）

I am trying to draw a specific shape and I am finding it mind boggling.

I managed to get a triangle going because I understood the maths behind it... sort off at least. But I don't like the triangle shape for what I want to use it for - placing a marker on an image as a ROI (Region Of Interest)

'Traingle points - no need to change unless to increase / decrease size of Traingle
            Points(0) = New Point(StartX, StartY)
            Points(1) = New Point(StartX - 20, StartY - 12)
            Points(2) = New Point(StartX - 12, StartY - 20)

我想要的是更像这样的东西（请原谅我原始的ascii艺术技巧）

What I want is something more like this (forgive me for my primitive ascii artistic skills)

     ____
    /
o---

形状包括（1）填充特定颜色的圆，（2）与圆相交的线（中间），（3）与底部相交的45度线和（4））顶线。

帮助和指导将不胜感激。

T

The shape consists of (1) a circle filled with a specific colour, (2) a line intersecting with the circle (middle of), (3) a 45 degree line intersecting with the bottom and (4) top line.

Help and guidance will be appreciated.

T

推荐答案

Tino Fourie写道：

Tino Fourie wrote:

例如，有一条线以某个角度绘制，我需要查看Radiants（无论它叫什么）。

For example, having a line drawn at a certain angle I need to look into Radiants (whatever it is called).

你同时是对是错。如果忽略象限（我认为这是你所谓的辐射的正确名称），如果无限值，你将失去精度或NaN（不是数字）。但是你真的需要自己考虑这些象限吗？

我还要看象限，然后我意识到如果我使用正弦我只需要它和余弦函数。但是已经考虑到这个问题的函数已经存在： System.Math.Atan2 ：

[]。

在上面引用的MSDN帮助页面上查看此功能的注释;你会看到象限是如何在内部使用的。

-SA

You are right and wrong at the same time. If you ignore quadrants (I think this is a correct name for what you called "radiants"), you will get loss of precision or NaN (not a number) if infinite values. But do you actually need to consider those quadrants yourself?

I also though I have to look at quadrants, before I realized that I would only needed that if I uses sine and cosine functions. But the function which already takes this issue into account already exists: System.Math.Atan2:
http://msdn.microsoft.com/en-us/library/system.math.atan2%28v=vs.110%29.aspx[^].

Look at the notes to this function on the MSDN help page referenced above; and you will see how the quadrants are internally used.

—SA

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