转载自：http://www.cnblogs.com/xiashengwang/p/4225848.html
2015-01-15 11:38 by xiashengwang, 585 阅读, 0 评论, 收藏, 编辑
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。
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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; }} |
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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; }} |