提高c#位图操作的速度[抄袭之作]

众所周知，c#里 bitmap类里的getpixel和setpixel函数的效率很慢，一个解决办法是使用bitmapData对位图进行指针操作，

而在用指针在进行读取的时候，对于不用格式(PixelFormat)的位图，要进行区分。十分的麻烦。前几天无意中在codeproject上看到一篇文章，

对于bitmapData的进行了封装，相当的漂亮，所以就抄了过来，仅供参考，原文在这里。

代码如下：

 

  1 public class LockBitmap:IDisposable
  2 {
  3     Bitmap source = null;
  4     IntPtr Iptr = IntPtr.Zero;
  5     BitmapData bitmapData = null;
  6     int step=0;
  7     public byte[] Pixels { get; set; }
  8     public int Depth { get; private set; }
  9     public int Width { get; private set; }
 10     public int Height { get; private set; }
 11 
 12     public LockBitmap(Bitmap source)
 13     {
 14         this.source = source;
 15          LockBits();
 16     }
 17  
 18     ///<summary>
 19 /// Lock bitmap data
 20 ///</summary>
 21     private void LockBits()
 22     {
 23         try
 24         {
 25             // Get width and height of bitmap
 26             Width = source.Width;
 27             Height = source.Height;
 28  
 29             // get total locked pixels count
 30             int PixelCount = Width * Height;
 31  
 32             // Create rectangle to lock
 33             Rectangle rect = new Rectangle(0, 0, Width, Height);
 34  
 35             // get source bitmap pixel format size
 36             Depth = System.Drawing.Bitmap.GetPixelFormatSize(source.PixelFormat);
 37  
 38             // Check if bpp (Bits Per Pixel) is 8, 24, or 32
 39             if (Depth != 8 && Depth != 24 && Depth != 32)
 40             {
 41                 throw new ArgumentException("Only 8, 24 and 32 bpp images are supported.");
 42             }
 43  
 44             // Lock bitmap and return bitmap data
 45             bitmapData = source.LockBits(rect, ImageLockMode.ReadWrite, 
 46                                          source.PixelFormat);
 47  
 48             // create byte array to copy pixel values
 49             step = Depth / 8;
 50             Pixels = new byte[PixelCount * step];
 51             Iptr = bitmapData.Scan0;
 52  
 53             // Copy data from pointer to array
 54             Marshal.Copy(Iptr, Pixels, 0, Pixels.Length);
 55         }
 56         catch (Exception ex)
 57         {
 58             throw ex;
 59         }
 60     }
 61  
 62     ///<summary>
 63 /// Unlock bitmap data
 64 ///</summary>
 65     private void UnlockBits()
 66     {
 67         try
 68         {
 69             // Copy data from byte array to pointer
 70             Marshal.Copy(Pixels, 0, Iptr, Pixels.Length);
 71  
 72             // Unlock bitmap data
 73             source.UnlockBits(bitmapData);
 74         }
 75         catch (Exception ex)
 76         {
 77             throw ex;
 78         }
 79     }
 80     public void Dispose()
 81     {
 82        UnlockBits();
 83     }
 84     ///<summary>
 85 /// Get the color of the specified pixel
 86 ///</summary>
 87 ///<param name="x"></param>
 88 ///<param name="y"></param>
 89 ///<returns></returns>
 90     public Color GetPixel(int x, int y)
 91     {
 92         Color clr = Color.Empty;
 95  
 96 // Get start index of the specified pixel
 97         int i = ((y * Width) + x) * step;
 98  
 99         if (i > Pixels.Length - step)
100             throw new IndexOutOfRangeException();
101  
102         if (Depth == 32) // For 32 bpp get Red, Green, Blue and Alpha
103         {
104             byte b = Pixels[i];
105             byte g = Pixels[i + 1];
106             byte r = Pixels[i + 2];
107             byte a = Pixels[i + 3]; // a
108             clr = Color.FromArgb(a, r, g, b);
109         }
110         if (Depth == 24) // For 24 bpp get Red, Green and Blue
111         {
112             byte b = Pixels[i];
113             byte g = Pixels[i + 1];
114             byte r = Pixels[i + 2];
115             clr = Color.FromArgb(r, g, b);
116         }
117         if (Depth == 8)
118         // For 8 bpp get color value (Red, Green and Blue values are the same)
119         {
120             byte c = Pixels[i];
121             clr = Color.FromArgb(c, c, c);
122         }
123         return clr;
124     }
125  
126     ///<summary>
127 /// Set the color of the specified pixel
128 ///</summary>
129 ///<param name="x"></param>
130 ///<param name="y"></param>
131 ///<param name="color"></param>
132     public void SetPixel(int x, int y, Color color)
133     {
134         // Get start index of the specified pixel
135         int i = ((y * Width) + x) * step;
136  
137         if (Depth == 32) // For 32 bpp set Red, Green, Blue and Alpha
138         {
139             Pixels[i] = color.B;
140             Pixels[i + 1] = color.G;
141             Pixels[i + 2] = color.R;
142             Pixels[i + 3] = color.A;
143         }
144         if (Depth == 24) // For 24 bpp set Red, Green and Blue
145         {
146             Pixels[i] = color.B;
147             Pixels[i + 1] = color.G;
148             Pixels[i + 2] = color.R;
149         }
150         if (Depth == 8)
151         // For 8 bpp set color value (Red, Green and Blue values are the same)
152         {
153             Pixels[i] = color.B;
154         }
155     }
156 }