如何从 ushort[] 创建 FreeImageBitmap 只制作一个像素数据副本？

Question

我正在使用 FreeImageNET 在 .NET 下编写单通道 16 位 PNG，因为此功能不适用于 System.Drawing.Bitmap。

我从相机获取 16 位数据作为 ushort[]。我将此数据保存到文件中，如下所示：

public void SavePngGray16(ushort[] data, string fname)
{
    // Create bitmap object to manage image: one 16-bit channel (true monochrome)
    Bitmap bmp16 = new Bitmap(ImageSize.Width, ImageSize.Height, PixelFormat.Format16bppGrayScale);

    // Copy received data into bitmap
    Rectangle rc = new Rectangle(Point.Empty, ImageSize);
    BitmapData data16 = bmp16.LockBits(rc, ImageLockMode.WriteOnly, bmp16.PixelFormat);
    // intermediary to enable casting in the Copy() call;
    // casting required because Copy() doesn't have a ushort[] flavor.
    Array ax = data;
    Marshal.Copy((short[])ax, 0, data16.Scan0, data.Length);
    bmp16.UnlockBits(data16);

    // 16-bit support, for real
    // Instantiate a FreeImage bitmap from the System.Drawing bitmap we just built
    //## this causes a full copy of the image data...
    //##   but FreeImageBitmap.LockBits() is UNIMPLEMENTED, so can't just build-and-fill
    //##   as above with a FreeImageBitmap instance
    FreeImageBitmap fbmp = new FreeImageBitmap(bmp16);
    // And save that as a 16-bit grayscale PNG
    fbmp.Save(fname, FREE_IMAGE_FORMAT.FIF_PNG, FREE_IMAGE_SAVE_FLAGS.PNG_Z_DEFAULT_COMPRESSION);
}

我想避免复制数据两次（一次将数据放入 Bitmap，一次将数据放入 FreeImageBitmap）。这可能吗？

Answer 1

您可以使用此构造函数：

public FreeImageBitmap(int width, int height, int stride, PixelFormat format, IntPtr scan0)

您有 width 和 height。 stride 你可以放 0（它是图像行之间的填充）。 format 是 PixelFormat.Format16bppGrayScale。您通过固定 ushort[] 获得 scan0 （如果您查看源文件，最后您传递的数组将被固定...）

GCHandle handle = default(GCHandle);

try
{
    handle = GCHandle.Alloc(data, GCHandleType.Pinned);
    FreeImageBitmap fbmp = new FreeImageBitmap(width, height, 0, PixelFormat.Format16bppGrayScale, handle.AddrOfPinnedObject());
}
finally
{
    if (handle.IsAllocated)
    {
        handle.Free();
    }
}

如何从 ushort[] 创建 FreeImageBitmap 只制作一个像素数据副本？

How to create FreeImageBitmap from ushort[] making only one copy of the pixel data?

c#

freeimage