从字节数组创建 PNG

Question

我有一个一维字节数组，A、R、G 和 B 具有单独的值，并且我知道预期图像的高度和宽度。如何编码此数据并将其保存为 PNG？

Answer 1

您可以使用位图和 Bitmap.SetPixel()。

然后 save the Bitmap as png using ImageFormat.Png . Also, you might have to make sure that the Bitmap format maintains transparency .

（请参阅此处的其他答案以获得比 SetPixel 更快的方法。）

编辑

也许WPF可以直接使用数组。（我没有太多经验。）

Answer 2

这是使用 Unsafe pointers 和 LockBits

的更快解决方案

    public unsafe Bitmap Retreive(byte[] values)
    {
        Bitmap bmp = new Bitmap(Width, Height); //enter your width and height here.
        BitmapData bmData = bmp.LockBits(new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, bmp.PixelFormat);
        IntPtr scan0 = bmData.Scan0;
        int stride = bmData.Stride;
        int nWidth = bmp.Width;
        int nHeight = bmp.Height;

        for (int y = 0; y < nHeight; y++)
        {
            //define the pointers inside the first loop for parallelizing
            byte* p = (byte*)scan0.ToPointer();
            p += y * stride;

            for (int x = 0; x < nWidth; x++)
            {
                //fill as  the values stored in you byte array;
                p[0] = values[0];// R component.
                p[1] = values[1];// G component.
                p[2] = values[2];// B component.
                p[3] = values[3];// Alpha component.
                p += 4;
            }
        }

        bmp.UnlockBits(bmData);
        return bmp;
    }

只需填写 p[] 值，就像它们存储在您的数组中一样。

祝你好运。

Answer 3

byte[] data = new byte[] {
    255, 255, 000, 000,  255, 255, 255, 255,  255, 255, 255, 255,  255, 255, 255, 255,  255, 255, 000, 000, 
    255, 255, 255, 255,  255, 255, 000, 000,  255, 255, 255, 255,  255, 255, 000, 000,  255, 255, 255, 255, 
    255, 255, 255, 255,  255, 255, 255, 255,  255, 255, 000, 000,  255, 255, 255, 255,  255, 255, 255, 255, 
    255, 255, 255, 255,  255, 255, 000, 000,  255, 255, 255, 255,  255, 255, 000, 000,  255, 255, 255, 255, 
    255, 255, 000, 000,  255, 255, 255, 255,  255, 255, 255, 255,  255, 255, 255, 255,  255, 255, 000, 000 
  };

  Bitmap bmp = new Bitmap(5, 5);
  for (int y = 0; y < 5; ++y)
    for (int x = 0; x < 5; ++x)
    {
      int offset = y * 5 * 4 + x * 4;
      bmp.SetPixel(x, y, Color.FromArgb(data[offset], data[offset + 1], data[offset + 2], data[offset + 3]));
    }
  bmp.Save(@"c:\tmp.png");
}

如果数组中的值按此方式排序：B G R A B G R A B G R A ...您可以使用以下代码，它应该更快：

byte[] data = new byte[] {
  // B    G    R    A     B    G    R    A     B    G    R    A
      0,   0, 255, 255,    0,   0,   0, 255,    0, 255,   0, 255,
      0,   0,   0, 255,    0, 255,   0, 255,  255, 255, 255, 255,
      0, 255,   0, 255,    0,   0,   0, 255,  255,   0,   0, 255
  };
  int width = 3;
  int height = 3;

  Bitmap bmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
  var bitmapData = bmp.LockBits(new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height), System.Drawing.Imaging.ImageLockMode.WriteOnly, bmp.PixelFormat);
  Marshal.Copy(data, 0, bitmapData.Scan0, data.Length);
  bmp.UnlockBits(bitmapData);
  bmp.Save(@"c:\tmp.png");

这张图片应该是这样的：

从字节数组创建 PNG

Create a PNG from an array of bytes

.net

c#

png