平滑滚动文本（如突发新闻...） [英] Smoothly scroll text (like breaking news...)

问题描述

注意：创建这个问题是为了帮助其他人找到我找不到的东西，说过欢迎任何人提出比我想出的更好的解决方案。

Note: This question is created to help others find what I could not find, having said that anyone is welcome to propose a better solution than I came up with.

我的挑战是在Windows窗体应用程序上生成平滑的滚动文本流，此外，在窗体上绘制了其他项目，因此我必须避免在此过程中销毁它们。

My challenge was to produce a smooth scrolling text stream on a windows form application, in addition the form had other items drawn on it so I had to avoid destroying them in the process.

我尝试使用计时器和 do ... loops 等移动文本框来递增它，等等，还尝试使用 Graphics.DrawString 再次增加位置。
他们所有人都产生了一个生涩的输出，并且随着文本的移动而闪烁。

I tried moving a text box incrementing it with timers and do...loops and so on, also tried using Graphics.DrawString again incrementing the position. All of them produced a jerky output with the text flashing as it moved.

我花了几个小时在谷歌上搜索和浏览大约50种建议的解决方案

I Spent several hours googling and browsing probably in the region of 50 different proposed solutions including many in other languages in the hope I might get a clue!

我无法确定是哪一个给了我线索，但是我看到了一些对<$ c $的引用c> Doublebuffer ，所以我用谷歌搜索了一下（没有成功就尝试了！），最后从此处是一个手动缓冲区，因此我最终得到了...。（请参见下面的答案）

I can't identify which one gave me the clue but I saw several references to Doublebuffer so I googled that (and tried it without sucess!) and finally came up with the idea from here of a manual buffer so I ended up with....(see answer below)

推荐答案

Do
        Dim currentContext As BufferedGraphicsContext
        Dim myBuffer As BufferedGraphics
        ' Gets a reference to the current BufferedGraphicsContext.
        currentContext = BufferedGraphicsManager.Current
        ' Creates a BufferedGraphics instance associated with Form1, and with 
        ' dimensions the same size as the drawing surface of Form1.
        myBuffer = currentContext.Allocate(BNP1.CreateGraphics, BNP1.DisplayRectangle)
        'update test
        With myBuffer
            .Graphics.Clear(Panel.BackColor)
            .Graphics.DrawString("Some Text", [Your Font], Brushes.Blue, xpos, ypos)
        End With
        myBuffer.Render()
        myBuffer.Dispose()
        'This bit will need adjusting to suit your layout!
        If xpos + Panel.Width < Panel.Left Then xpos = Panel.Right Else xpos -= 1
        Thread.Sleep(1)
Loop

使用睡眠时间和xpos减少功能，可以实现完全平滑的滚动速度和完全可调的滚动速度。

This produced a perfectly smooth scroll with a fully adjustable scroll speed using the sleep time and xpos reduction.

您可能会注意到我做了在单独的线程中使用 Do ... Loop 也可以在计时器中使用，但是由于某些原因（有人可能会解释），滚动速度要慢得多。

As you will probably notice I did this with a Do...Loop in a separate thread it also works in a timer but the scroll speed for some reason (someone can probably explain) is much slower.

免责声明：我不是专业的编码人员，所以如果有人对我所做的工作有所改进，我将不胜感激（避免使用诸如 Option Strict之类的泛型-已经开启！）

Disclaimer: I am not a professional coder so if anyone has suggestions to improve what I have done I will greatly appreciate it (avoid generics such as Option Strict - already on!)

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