转载自：http://www.cnblogs.com/xiashengwang/p/4225848.html
2015-01-15 11:38 by xiashengwang, 585 阅读, 0 评论, ,
用Bitmap.GetPixel和Bitmap.SetPixel访问像素点实在是太慢了，必须要用LockBits的方式访问内存才能改善，这里贴一个快速访问Bitmap每个像素点的包装类，是国外一个老外写的，感觉很好用。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | public class LockBitmap { Bitmap source = null ; IntPtr Iptr = IntPtr.Zero; BitmapData bitmapData = null ; public byte [] Pixels { get ; set ; } public int Depth { get ; private set ; } public int Width { get ; private set ; } public int Height { get ; private set ; } public LockBitmap(Bitmap source) { this .source = source; } /// <summary> /// Lock bitmap data /// </summary> public void LockBits() { try { // Get width and height of bitmap Width = source.Width; Height = source.Height; // get total locked pixels count int PixelCount = Width * Height; // Create rectangle to lock System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, Width, Height); // get source bitmap pixel format size Depth = System.Drawing.Bitmap.GetPixelFormatSize(source.PixelFormat); // Check if bpp (Bits Per Pixel) is 8, 24, or 32 if (Depth != 8 && Depth != 24 && Depth != 32) { throw new ArgumentException( "Only 8, 24 and 32 bpp images are supported." ); } // Lock bitmap and return bitmap data bitmapData = source.LockBits(rect, ImageLockMode.ReadWrite, source.PixelFormat); // create byte array to copy pixel values int step = Depth / 8; Pixels = new byte [PixelCount * step]; Iptr = bitmapData.Scan0; // Copy data from pointer to array Marshal.Copy(Iptr, Pixels, 0, Pixels.Length); } catch (Exception ex) { throw ex; } } /// <summary> /// Unlock bitmap data /// </summary> public void UnlockBits() { try { // Copy data from byte array to pointer Marshal.Copy(Pixels, 0, Iptr, Pixels.Length); // Unlock bitmap data source.UnlockBits(bitmapData); } catch (Exception ex) { throw ex; } } /// <summary> /// Get the color of the specified pixel /// </summary> /// <param name="x"></param> /// <param name="y"></param> /// <returns></returns> public Color GetPixel( int x, int y) { Color clr = Color.Empty; // Get color components count int cCount = Depth / 8; // Get start index of the specified pixel int i = ((y * Width) + x) * cCount; if (i > Pixels.Length - cCount) throw new IndexOutOfRangeException(); if (Depth == 32) // For 32 bpp get Red, Green, Blue and Alpha { byte b = Pixels[i]; byte g = Pixels[i + 1]; byte r = Pixels[i + 2]; byte a = Pixels[i + 3]; // a clr = Color.FromArgb(a, r, g, b); } if (Depth == 24) // For 24 bpp get Red, Green and Blue { byte b = Pixels[i]; byte g = Pixels[i + 1]; byte r = Pixels[i + 2]; clr = Color.FromArgb(r, g, b); } if (Depth == 8) // For 8 bpp get color value (Red, Green and Blue values are the same) { byte c = Pixels[i]; clr = Color.FromArgb(c, c, c); } return clr; } /// <summary> /// Set the color of the specified pixel /// </summary> /// <param name="x"></param> /// <param name="y"></param> /// <param name="color"></param> public void SetPixel( int x, int y, Color color) { // Get color components count int cCount = Depth / 8; // Get start index of the specified pixel int i = ((y * Width) + x) * cCount; if (Depth == 32) // For 32 bpp set Red, Green, Blue and Alpha { Pixels[i] = color.B; Pixels[i + 1] = color.G; Pixels[i + 2] = color.R; Pixels[i + 3] = color.A; } if (Depth == 24) // For 24 bpp set Red, Green and Blue { Pixels[i] = color.B; Pixels[i + 1] = color.G; Pixels[i + 2] = color.R; } if (Depth == 8) // For 8 bpp set color value (Red, Green and Blue values are the same) { Pixels[i] = color.B; } } public bool IsValidCoordinate( int x, int y) { return x >= 0 && x < this .Width && y > 0 && y < this .Height; } } |
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | public class Benchmark { private static DateTime startDate = DateTime.MinValue; private static DateTime endDate = DateTime.MinValue; public static TimeSpan Span { get { return endDate.Subtract(startDate); } } public static void Start() { startDate = DateTime.Now; } public static void End() { endDate = DateTime.Now; } public static double GetSeconds() { if (endDate == DateTime.MinValue) return 0.0; else return Span.TotalSeconds; } } |