在DirectShow预览窗口上写文本 [英] Write Text on DirectShow Preview Window

问题描述

我想在预览窗口上写一个文字或标签，使用directshow显示网络摄像头预览。

- >当屏幕上有预览或帧时，文本将显示在窗口上。

这里是否有人对此有所了解，怎么做？



谢谢！

I want to write a text or a label on Preview Window that is showing the webcam preview using directshow.
-> Text will be on window when there will be preview or frames on screen.
Is here anyone having idea about this, how to do it?

Thanks!

推荐答案

你通常做的是在视频上叠加文字 - 你不需要添加标签。

有一些过滤器可以让你这样做，例如 C＃中的纯.NET DirectShow过滤器 [ ^ ]描述了一个添加文本的过滤器视频。

What you normally do is overlay text on a video - you don''t need to add a label.
There are some filters that would allow you to do this for e.g. Pure .NET DirectShow Filters in C#[^] describes a filter that adds text to a video.

另一个选项是将视频和文本渲染到纹理，SDK中包含如何将视频渲染到纹理的示例：

来源：（SDK root）\ Samples \ C ++ \DirectShow \Players\Texture3D [ ^ ]



要渲染文本，你可以这样做：



启用透明度：

Another option is to render bot the video and the text to a texture, and an example on how to render the video to a texture is included with the SDK:
Source: (SDK root)\Samples\C++\DirectShow\Players\Texture3D[^]

To render the text you do something like this:

Enable transparency:

device.RenderState.AlphaTestEnable = true;
device.RenderState.AlphaFunction = Compare.Greater;
device.RenderState.ReferenceAlpha = 0;

创建字体和精灵：

Create font and sprite:

D3DX10CreateFont(device, 16, 0, FW_BOLD, 0, FALSE, 
           DEFAULT_CHARSET, OUT_TT_ONLY_PRECIS, ANTIALIASED_QUALITY, 
           DEFAULT_PITCH | FF_DONTCARE, L"Verdana", &font);

D3DX10CreateSprite(device, 256, &sprite);

渲染：

Render:

hr = sprite->Begin(0);
std::wstring left = L"Hurray, text on a sprite!";

RECT r;
r.top = 0;
r.bottom = window->height;
r.left = 0;
r.right = window->width;

hr = font->DrawTextW(sprite, left.c_str(), -1, &r, 
              DT_LEFT | DT_TOP, D3DXCOLOR(0.0f, 1.0f, 0.0f, 1.0f));
hr = sprite->End();

祝你好运

Espen Harlinn

Best regards
Espen Harlinn

请看我对这个问题的评论。



你能简单地对视频进行标签控制吗？不花哨，但很简单。



否则，挖掘DirectX;但它需要时间和神经......

-SA

Please see my comment to the question.

Could you simply place a label control over the video? Not fancy, but simple.

Otherwise, dig in DirectX; but it will need time and nerve…

—SA

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