如何用 C# 实现图形绘制器
所以我正在写一个图形计算器。到目前为止，我有一个半功能的绘图仪，但是，我很难在准确的图表和平滑的曲线之间取得良好的平衡。
当前的实现（半伪代码）看起来像这样：
for (float i = GraphXMin; i <= GraphXMax; i++)
{
PointF P = new PointF(i, EvaluateFunction(Function, i)
ListOfPoints.Add(P)
}
Graphics.DrawCurve(ListOfPoints)
问题是因为它只在每个整数值处添加一个点，当它们的转折点不落在整数上时，图形最终会扭曲（例如 sin(x)^2)。
我尝试将 i 增加一些较小的值（例如 0.1），这是可行的，但是图表看起来非常粗糙。
我正在使用 C# 和 GDI+。我将 SmoothingMethod 设置为 AntiAlias，所以这不是问题，正如您从第一张图中看到的那样。绘制具有很多点的曲线是否存在某种问题？这些点是否应该精确定位在像素上？
我确信你们中的一些人以前做过非常类似的事情，所以有什么建议吗？当您这样做时，您对用渐近线绘制函数有什么建议吗？例如 1/x^
2我并不是在寻找一个可以完成所有这些工作的库 - 我想自己编写它。
So I'm writing a graphing calculator. So far I have a semi-functional grapher, however, I'm having a hard time getting a good balance between accurate graphs and smooth looking curves.
The current implementation (semi-pseudo-code) looks something like this:
for (float i = GraphXMin; i <= GraphXMax; i++)
{
PointF P = new PointF(i, EvaluateFunction(Function, i)
ListOfPoints.Add(P)
}
Graphics.DrawCurve(ListOfPoints)
The problem with this is since it only adds a point at every integer value, graphs end up distorted when their turning points don't fall on integers (e.g. sin(x)^2).
I tried incrementing i by something smaller (like 0.1), which works, but the graph looks very rough.
I am using C# and GDI+. I have SmoothingMethod set to AntiAlias, so that's not the problem, as you can see from the first graph. Is there some sort of issue with drawing curves with a lot of points? Should the points perhaps be positioned exactly on pixels?
I'm sure some of you have worked on something very similar before, so any suggestions? While you're at it, do you have any suggestions for graphing functions with asymptotes? e.g. 1/x^2
P.S. I'm not looking for a library that does all this - I want to write it myself.
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好的，我解决了问题。在绘图过程中的某个地方我使用了 int 而不是 float。
OK, I fixed the problem. Somewhere in the drawing process I was using int rather than float.
渲染图形时，您总是会出现舍入错误，因为位图是离散的，而图形不是。
有几种应对方法：
使用矢量 API（例如 WPF 或 Silverlight）可能会使事情更容易实现。
照顾渐近线是相当困难的。首先，您必须找到它们，然后跳过该值，以便您可以在图表中制作“洞”。
When rendering a graph you are always making rounding errors because a bitmap is discrete and the graph isn't.
There several ways of coping:
Using vector APIs such as WPF or Silverlight might make things easier to implement.
Taking care of asymptotes is pretty hard. First you have to find them and then skip the value so you can make the 'hole' in the graph.