在.NET Format16bppGrayScale图像设置单个像素 [英] Set individual pixels in .NET Format16bppGrayScale image

问题描述

我试图呈现一个小位在内存中的.NET，需要为16位灰度。位图的格式设置为PixelFormat.Format16bppGrayScale。然而，Bitmap.SetPixel需要一个颜色参数。颜色反过来需要一个字节的每个R，B和G（和任选的A）。

I'm trying to render a small Bitmap in memory with .NET that needs to be 16 bit Grayscale. The bitmap's format is set to PixelFormat.Format16bppGrayScale. However, Bitmap.SetPixel takes a Color argument. Color in turn takes one byte for each of R, B, and G (and optionally A).

如何指定一个16位的灰度值，而不是一个8位的值绘制到我的位图的时候？

How do I specify a 16-bit gray scale value rather than an 8 bit value when drawing to my bitmap?

推荐答案

无论图像格式，与setPixel（）是残酷缓慢。我从来没有用它在实践中。

Regardless of the image format, SetPixel() is brutally slow. I never use it in practice.

您可以使用LockBits方法，它可以让您快速编组管理数据到非托管位字节快得多设置像素。

You can set pixels much faster using the LockBits method, which allows you to quickly marshal managed data to the unmanaged bitmap bytes.

下面是如何可能看一个例子：

Here is an example of how that might look:

Bitmap bitmap = // ...

// Lock the unmanaged bits for efficient writing.
var data = bitmap.LockBits(
    new Rectangle(0, 0, bitmap.Width, bitmap.Height),
    ImageLockMode.ReadWrite,
    bitmap.PixelFormat);

// Bulk copy pixel data from a byte array:
Marshal.Copy(byteArray, 0, data.Scan0, byteArray.Length);

// Or, for one pixel at a time:
Marshal.WriteInt16(data.Scan0, offsetInBytes, shortValue);

// When finished, unlock the unmanaged bits
bitmap.UnlockBits(data);

需要注意的是16bpp的灰度显示通过GDI +是不支持的，这意味着.NET不帮忙拯救一个16bpp的灰度位图文件或流。请参阅<一href="http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/10252c05-c4b6-49dc-b2a3-4c1396e2c3ab">http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/10252c05-c4b6-49dc-b2a3-4c1396e2c3ab

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