.NET 真彩色图形转换为索引格式的图形

最新推荐文章于 2023-08-22 10:15:27 发布

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#图形 #.net #byte #components #null #tree

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本文介绍了一种将真彩色图像转换为1位、4位或8位索引彩色图像的方法，并提供了完整的C#实现代码。该方法首先将图像转换为24位RGB格式，再通过颜色量化和抖动处理生成指定格式的索引图像。

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.NET的Graphics不能绘制其他索引格式的图形,可以先绘制一个真彩的图形然后转换成索引的图形例如 1位 4位 8位色的图形
效果图

使用方法

pictureBox1.Image = Image.FromFile(@"c:/temp/1.jpg");

            pictureBox2.Image = Zgke.MyImage.Panit.MyConvert.Convert((Bitmap)pictureBox1.Image, PixelFormat.Format8bppIndexed, true);
            pictureBox3.Image = Zgke.MyImage.Panit.MyConvert.Convert((Bitmap)pictureBox1.Image, PixelFormat.Format4bppIndexed, true);
            pictureBox4.Image = Zgke.MyImage.Panit.MyConvert.Convert((Bitmap)pictureBox1.Image, PixelFormat.Format1bppIndexed, true);

下面是全部的类

using System; using System.Collections.Generic; using System.Text; using System.Drawing; using System.Drawing.Imaging; using System.Runtime.InteropServices; namespace Zgke.MyImage.Panit { /// <summary> /// 图形转换 /// zgke@sina.com qq:116149 /// </summary> public class MyConvert { /// <summary> /// 转换图片为彩色转换索引色成可以绘制的图形 /// </summary> /// <param name="p_Image"></param> /// <returns></returns> public static Bitmap ConvertToRGB(Bitmap p_Image) { Bitmap newImage = new Bitmap(p_Image.Width, p_Image.Height, PixelFormat.Format32bppArgb); newImage.SetResolution(p_Image.HorizontalResolution, p_Image.VerticalResolution); Graphics g = Graphics.FromImage(newImage); g.DrawImageUnscaled(p_Image, 0, 0); g.Dispose(); return newImage; } /// <summary> /// Convet图形为索引图形 /// </summary> /// <param name="p_SourceImage">原始图形</param> /// <param name="p_PixelFormat">格式之支持 Format4bppIndexed Format1bppIndexed Format8bppIndexed</param> /// <param name="p_Dithering">原始图形</param> /// <returns>图形</returns> public static Bitmap Convert(Bitmap p_SourceImage, PixelFormat p_PixelFormat, bool p_Dithering) { int _Width = p_SourceImage.Width; int _Height = p_SourceImage.Height; PixelFormat _SetPixFormat = PixelFormat.Format1bppIndexed; if (p_PixelFormat == PixelFormat.Format4bppIndexed || p_PixelFormat == PixelFormat.Format1bppIndexed || p_PixelFormat == PixelFormat.Format8bppIndexed) _SetPixFormat = p_PixelFormat; //创建颜色索引表为2个颜色 Bitmap _NewBitmap = new Bitmap(_Width, _Height, _SetPixFormat); ColorPalette _Palette = null; switch (_SetPixFormat) { case PixelFormat.Format1bppIndexed: _Palette = _NewBitmap.Palette; _Palette.Entries[0] = Color.FromArgb(255, 0, 0, 0); _Palette.Entries[1] = Color.FromArgb(255, 255, 255, 255); _NewBitmap.Palette = _Palette; break; case PixelFormat.Format4bppIndexed: _Palette = SetColorPalette.CreatePalette(p_SourceImage, 16, 4); _NewBitmap.Palette = _Palette; break; case PixelFormat.Format8bppIndexed: _Palette = SetColorPalette.CreatePalette(p_SourceImage, 256, 8); _NewBitmap.Palette = _Palette; break; } //重新获取一个原始图形色彩设置为24色 R G B Bitmap _Source = new Bitmap(_Width, _Height, PixelFormat.Format24bppRgb); Graphics _Graphics = Graphics.FromImage(_Source); _Graphics.DrawImage(p_SourceImage, 0, 0, _Width, _Height); _Graphics.Dispose(); //获取两个图形的数据 BitmapData _SourceData = _Source.LockBits(new Rectangle(0, 0, _Width, _Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); BitmapData _NewData = _NewBitmap.LockBits(new Rectangle(0, 0, _Width, _Height), ImageLockMode.WriteOnly, _SetPixFormat); //复制出图形数据的 byte[] _SourceByte = new byte[_SourceData.Stride * _Height]; byte[] _NewByte = new byte[_NewData.Stride * _Height]; Marshal.Copy(_SourceData.Scan0, _SourceByte, 0, _SourceByte.Length); Marshal.Copy(_NewData.Scan0, _NewByte, 0, _NewByte.Length); int _SourceIndex = 0; int _NewIndex = 0; //颜色表列 Dictionary<int, byte> _ColorTable = new Dictionary<int, byte>(); Color _SetColor; for (int i = 0; i != _Height; i++) { _NewIndex = i * _NewData.Stride; _SourceIndex = i * _SourceData.Stride; for (int z = 0; z != _Width; z++) { #region 获取色彩索引 //获取原始图形色彩 _SetColor = Color.FromArgb(0, _SourceByte[_SourceIndex + 2], _SourceByte[_SourceIndex + 1], _SourceByte[_SourceIndex]); _SourceIndex += 3; byte _TableIndex = 0; if (!(_ColorTable.TryGetValue(_SetColor.ToArgb(), out _TableIndex))) { //判断颜色是否在颜色表里 _TableIndex = (byte)ConvertTobppFindNearestColor(_SetColor, _Palette.Entries); _ColorTable.Add(_SetColor.ToArgb(), _TableIndex); } #endregion #region 填充新图形 switch (_SetPixFormat) { case PixelFormat.Format1bppIndexed: byte _Mask = (byte)(0x80 >> ((z - 1) & 0x7)); if (_TableIndex == 1) { _NewByte[_NewIndex] |= _Mask; } else { _NewByte[_NewIndex] &= (byte)(_Mask ^ 0xff); } if ((z % 8) == 0 && (z != 0)) _NewIndex++; break; case PixelFormat.Format4bppIndexed: int _SetIndex = z / 2; if ((z % 2) == 0) { _NewByte[_NewIndex + _SetIndex] = (byte)(_TableIndex << 4); } else { _NewByte[_NewIndex + _SetIndex] = (byte)(_NewByte[_NewIndex + _SetIndex] | _TableIndex); } break; case PixelFormat.Format8bppIndexed: _NewByte[_NewIndex + z] = _TableIndex; break; } #endregion #region 先获取右边然后获取下边获取下边的左变和右边的色彩设置数据 if (!p_Dithering) continue; int _R = _SetColor.R - _Palette.Entries[_TableIndex].R; int _G = _SetColor.G - _Palette.Entries[_TableIndex].G; int _B = _SetColor.B - _Palette.Entries[_TableIndex].B; int _StarIndex = i * _SourceData.Stride; int _SourceIndexRVA = 0; if (z + 1 < _Width) { _SourceIndexRVA = (_StarIndex) + ((z + 1) * 3); //_SourceIndexRVA = _SourceIndex; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_B * 7) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_G * 7) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_R * 7) >> 4); } if (i + 1 < _Height) { if (z - 1 > 0) { _SourceIndexRVA = (_StarIndex) + ((z - 1) * 3) + _SourceData.Stride; //_SourceIndexRVA = (_SourceIndex - 6) + _SourceData.Stride; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_B * 3) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_G * 3) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_R * 3) >> 4); } _SourceIndexRVA = (_StarIndex) + ((z + 0) * 3) + _SourceData.Stride; //_SourceIndexRVA = (_SourceIndex - 3) + _SourceData.Stride; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_B * 5) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_G * 5) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_R * 5) >> 4); if (z + 1 < _Width) { _SourceIndexRVA = (_StarIndex) + ((z + 1) * 3) + _SourceData.Stride; // _SourceIndexRVA = _SourceIndex + _SourceData.Stride; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_B * 1) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_G * 1) >> 4); _SourceIndexRVA++; _SourceByte[_SourceIndexRVA] = ConvertTobppLimits(_SourceByte[_SourceIndexRVA], (_R * 1) >> 4); } } #endregion } } _Source.UnlockBits(_SourceData); Marshal.Copy(_NewByte, 0, _NewData.Scan0, _NewByte.Length); _NewBitmap.UnlockBits(_NewData); return _NewBitmap; } private static int ConvertTobppFindNearestColor(Color p_SetColor, Color[] p_PaletteEntries) { int _MinDistanceSquared = 195076; // 255 * 255 + 255 * 255 + 255 * 255 + 1 int _BestIndex = 0; for (int i = 0; i < p_PaletteEntries.Length; i++) { int _ColorR = p_SetColor.R - p_PaletteEntries[i].R; int _ColorG = p_SetColor.G - p_PaletteEntries[i].G; int _ColorB = p_SetColor.B - p_PaletteEntries[i].B; int _DistanceSquared = _ColorR * _ColorR + _ColorG * _ColorG + _ColorB * _ColorB; if (_DistanceSquared < _MinDistanceSquared) { _MinDistanceSquared = _DistanceSquared; _BestIndex = i; } } return _BestIndex; } private static byte ConvertTobppLimits(int p_ColorA, int p_ColorB) { return (p_ColorA + p_ColorB) < 0 ? (byte)0 : (p_ColorA + p_ColorB) > 255 ? (byte)255 : (byte)(p_ColorA + p_ColorB); } /// <summary> /// 获取颜色索引表 /// </summary> public class SetColorPalette { public static ColorPalette CreatePalette(Bitmap p_Bitmap, int p_MaxColors, int p_BitsPerPixel) { ColorPalette _ReturnPalette; Node _Tree; int _LeafCount, _Index; Node[] _ReducibleNodes = new Node[9]; if (p_MaxColors > Math.Pow(2, p_BitsPerPixel)) return null; _Tree = null; _LeafCount = 0; if (p_BitsPerPixel > 8) return null; for (int i = 0; i <= (int)p_BitsPerPixel; i++) { _ReducibleNodes[i] = null; } Bitmap _SetBitmap = new Bitmap(p_Bitmap.Width, p_Bitmap.Height, PixelFormat.Format32bppArgb); Graphics _Graphcis = Graphics.FromImage(_SetBitmap); _Graphcis.DrawImage(p_Bitmap, 0, 0, p_Bitmap.Width, p_Bitmap.Height); _Graphcis.Dispose(); BitmapData _BitmapDataSource = _SetBitmap.LockBits(new Rectangle(0, 0, _SetBitmap.Width, _SetBitmap.Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb); int[] _DataInt = new int[_BitmapDataSource.Width * _BitmapDataSource.Height]; Marshal.Copy(_BitmapDataSource.Scan0, _DataInt, 0, _DataInt.Length); try { int _Pad = _BitmapDataSource.Stride - (((_SetBitmap.Width * Bitmap.GetPixelFormatSize(_SetBitmap.PixelFormat)) + 7) / 8); int _ReadIndex = 0; for (int i = 0; i < _SetBitmap.Height; i++) { for (int j = 0; j < _SetBitmap.Width; j++) { byte _ColorBlue = (byte)(((uint)_DataInt[_ReadIndex] & 0x000000FF) >> 0); byte _ColorGreen = (byte)(((uint)_DataInt[_ReadIndex] & 0x0000FF00) >> 8); byte _ColorRed = (byte)(((uint)_DataInt[_ReadIndex] & 0x00FF0000) >> 16); _ReadIndex++; AddColor(ref _Tree, _ColorRed, _ColorGreen, _ColorBlue, p_BitsPerPixel, 0, ref _LeafCount, ref _ReducibleNodes); while (_LeafCount > p_MaxColors) ReduceTree(p_BitsPerPixel, ref _LeafCount, ref _ReducibleNodes); } } if (_LeafCount > p_MaxColors) _Tree = null; Bitmap _Bmp = null; switch (p_BitsPerPixel) { case 1: _Bmp = new Bitmap(1, 1, PixelFormat.Format1bppIndexed); break; case 4: _Bmp = new Bitmap(1, 1, PixelFormat.Format4bppIndexed); break; case 8: _Bmp = new Bitmap(1, 1, PixelFormat.Format8bppIndexed); break; } _ReturnPalette = _Bmp.Palette; _Bmp.Dispose(); _Index = 0; GetPaletteColors(_Tree, ref _ReturnPalette, ref _Index); Color[] _EntriesList = _ReturnPalette.Entries; for (int i = _Index + 1; i < _EntriesList.Length; i++) { _EntriesList[i] = Color.FromArgb(0, 0, 0, 0); } } finally { if (_BitmapDataSource != null) _SetBitmap.UnlockBits(_BitmapDataSource); } return _ReturnPalette; } private static void GetPaletteColors(Node p_Tree, ref ColorPalette p_Entries, ref int p_Index) { Color[] _EntriesList = p_Entries.Entries; if (p_Tree.IsLeaf) { _EntriesList[p_Index] = Color.FromArgb( (byte)((p_Tree.RedSum) / (p_Tree.PixelCount)), (byte)((p_Tree.GreenSum) / (p_Tree.PixelCount)), (byte)((p_Tree.BlueSum) / (p_Tree.PixelCount))); p_Index++; } else { for (int i = 0; i < 8; i++) { if (p_Tree.Child[i] != null) GetPaletteColors(p_Tree.Child[i], ref p_Entries, ref p_Index); } } } private static void ReduceTree(int p_ColorBits, ref int p_LeafCount, ref Node[] p_ReducibleNodes) { int _i; Node _Node; uint _RedSum, _GreenSum, _BlueSum; int _Children; // Find the deepest level containing at least one reducible node for (_i = p_ColorBits - 1; (_i > 0) && (p_ReducibleNodes[_i] == null); _i--) ; // Reduce the node most recently added to the list at level i _Node = p_ReducibleNodes[_i]; p_ReducibleNodes[_i] = _Node.Next; _RedSum = _GreenSum = _BlueSum = 0; _Children = 0; for (_i = 0; _i < 8; _i++) { if (_Node.Child[_i] != null) { _RedSum += _Node.Child[_i].RedSum; _GreenSum += _Node.Child[_i].GreenSum; _BlueSum += _Node.Child[_i].BlueSum; _Node.PixelCount += _Node.Child[_i].PixelCount; _Node.Child[_i] = null; _Children++; } } _Node.IsLeaf = true; _Node.RedSum = _RedSum; _Node.GreenSum = _GreenSum; _Node.BlueSum = _BlueSum; p_LeafCount -= (_Children - 1); } private static void AddColor(ref Node p_Node, byte p_Red, byte p_Green, byte p_Blue, int p_ColorBits, int p_Level, ref int p_LeafCount, ref Node[] p_ReducibleNodes) { byte[] _Mask = new byte[8] { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 }; if (p_Node == null) { p_Node = CreateNode(p_Level, p_ColorBits, ref p_LeafCount, ref p_ReducibleNodes); } if (p_Node.IsLeaf) { p_Node.PixelCount++; p_Node.RedSum += p_Red; p_Node.GreenSum += p_Green; p_Node.BlueSum += p_Blue; } else { int _Shift = 7 - p_Level; int _Index = (((p_Red & _Mask[p_Level]) >> _Shift) << 2) | (((p_Green & _Mask[p_Level]) >> _Shift) << 1) | ((p_Blue & _Mask[p_Level]) >> _Shift); AddColor(ref p_Node.Child[_Index], p_Red, p_Green, p_Blue, p_ColorBits, p_Level + 1, ref p_LeafCount, ref p_ReducibleNodes); } } private static Node CreateNode(int p_Level, int p_ColorBits, ref int p_LeafCount, ref Node[] p_ReducibleNodes) { Node _Node = new Node(); _Node.IsLeaf = (p_Level == p_ColorBits); if (_Node.IsLeaf) p_LeafCount++; else { // Add the node to the reducible list for this level _Node.Next = p_ReducibleNodes[p_Level]; p_ReducibleNodes[p_Level] = _Node; } return _Node; } private class Node { public bool IsLeaf; // TRUE if node has no children public int PixelCount; // Number of pixels represented by this leaf public uint RedSum; // Sum of red components public uint GreenSum; // Sum of green components public uint BlueSum; // Sum of blue components public Node[] Child = new Node[8]; // Pointers to child nodes public Node Next; // Pointer to next reducible node } } } }