public static IconHolder BitmapToIconHolder(Bitmap b) { var bmp = new BitmapHolder(); using (var stream = new MemoryStream()) { b.Save(stream, ImageFormat.Bmp); stream.Position = 0; bmp.Open(stream); } return BitmapToIconHolder(bmp); }
public static IconHolder BitmapToIconHolder(BitmapHolder bmp) { var mapColors = (bmp.Info.InfoHeader.BiBitCount <= 24); //Hashtable uniqueColors = new Hashtable(maximumColors); // actual colors is probably nowhere near maximum, so dont try to initialize the hashtable var uniqueColors = new Hashtable(); int sourcePosition = 0; int numPixels = bmp.Info.InfoHeader.BiHeight*bmp.Info.InfoHeader.BiWidth; var indexedImage = new byte[numPixels]; byte colorIndex; if (mapColors) { for (var i = 0; i < indexedImage.Length; i++) { //TODO: currently assumes source bitmap is 24bit color //read 3 bytes, convert to color var pixel = new byte[3]; Array.Copy(bmp.ImageData, sourcePosition, pixel, 0, 3); sourcePosition += 3; var color = new RGBQUAD(pixel); if (uniqueColors.Contains(color)) { colorIndex = Convert.ToByte(uniqueColors[color]); } else { if (uniqueColors.Count > byte.MaxValue) { throw new NotSupportedException( String.Format("The source image contains more than {0} colors.", byte.MaxValue)); } colorIndex = Convert.ToByte(uniqueColors.Count); uniqueColors.Add(color, colorIndex); } // store pixel as an index into the color table indexedImage[i] = colorIndex; } } else { // added by Pavel Janda on 14/11/2006 if (bmp.Info.InfoHeader.BiBitCount == 32) { for (var i = 0; i < indexedImage.Length; i++) { //TODO: currently assumes source bitmap is 32bit color with alpha set to zero //ignore first byte, read another 3 bytes, convert to color var pixel = new byte[4]; Array.Copy(bmp.ImageData, sourcePosition, pixel, 0, 4); sourcePosition += 4; var color = new RGBQUAD(pixel[0], pixel[1], pixel[2], pixel[3]); if (uniqueColors.Contains(color)) { colorIndex = Convert.ToByte(uniqueColors[color]); } else { if (uniqueColors.Count > byte.MaxValue) { throw new NotSupportedException( String.Format("The source image contains more than {0} colors.", byte.MaxValue)); } colorIndex = Convert.ToByte(uniqueColors.Count); uniqueColors.Add(color, colorIndex); } // store pixel as an index into the color table indexedImage[i] = colorIndex; } // end of addition } else { //TODO: implement converting an indexed bitmap throw new NotImplementedException("Unable to convert indexed bitmaps."); } } ushort bitCount = GetBitCount(uniqueColors.Count); // *** Build Icon *** var ico = new IconHolder {IconDirectory = {Entries = new IconDirEntry[1]}}; //TODO: is it really safe to assume the bitmap width/height are bytes? ico.IconDirectory.Entries[0].Width = (byte) bmp.Info.InfoHeader.BiWidth; ico.IconDirectory.Entries[0].Height = (byte) bmp.Info.InfoHeader.BiHeight; ico.IconDirectory.Entries[0].BitCount = bitCount; // maybe 0? ico.IconDirectory.Entries[0].ColorCount = (uniqueColors.Count > byte.MaxValue) ? (byte) 0 : (byte) uniqueColors.Count; //HACK: safe to assume that the first imageoffset is always 22 ico.IconDirectory.Entries[0].ImageOffset = 22; ico.IconDirectory.Entries[0].Planes = 0; ico.IconImages[0].Header.BiBitCount = bitCount; ico.IconImages[0].Header.BiWidth = ico.IconDirectory.Entries[0].Width; // height is doubled in header, to account for XOR and AND ico.IconImages[0].Header.BiHeight = ico.IconDirectory.Entries[0].Height << 1; ico.IconImages[0].XOR = new byte[ico.IconImages[0].NumBytesInXor()]; ico.IconImages[0].AND = new byte[ico.IconImages[0].NumBytesInAnd()]; ico.IconImages[0].Header.BiSize = 40; // always ico.IconImages[0].Header.BiSizeImage = (uint) ico.IconImages[0].XOR.Length; ico.IconImages[0].Header.BiPlanes = 1; ico.IconImages[0].Colors = BuildColorTable(uniqueColors, bitCount); //BytesInRes = biSize + colors * 4 + XOR + AND ico.IconDirectory.Entries[0].BytesInRes = (uint) (ico.IconImages[0].Header.BiSize + (ico.IconImages[0].Colors.Length*4) + ico.IconImages[0].XOR.Length + ico.IconImages[0].AND.Length); // copy image data var bytePosXOR = 0; var bytePosAND = 0; byte transparentIndex = indexedImage[0]; //initialize AND ico.IconImages[0].AND[0] = byte.MaxValue; int pixelsPerByte; int[] shiftCounts; switch (bitCount) { case 1: pixelsPerByte = 8; shiftCounts = new[] {7, 6, 5, 4, 3, 2, 1, 0}; break; case 4: pixelsPerByte = 2; shiftCounts = new[] {4, 0}; break; case 8: pixelsPerByte = 1; shiftCounts = new[] {0}; break; default: throw new NotSupportedException("Bits per pixel must be 1, 4, or 8"); } int bytesPerRow = ico.IconDirectory.Entries[0].Width/pixelsPerByte; int padBytes = bytesPerRow%4; if (padBytes > 0) padBytes = 4 - padBytes; sourcePosition = 0; for (var row = 0; row < ico.IconDirectory.Entries[0].Height; ++row) { for (var rowByte = 0; rowByte < bytesPerRow; ++rowByte) { byte currentByte = 0; for (var pixel = 0; pixel < pixelsPerByte; ++pixel) { byte index = indexedImage[sourcePosition++]; var shiftedIndex = (byte) (index << shiftCounts[pixel]); currentByte |= shiftedIndex; } ico.IconImages[0].XOR[bytePosXOR] = currentByte; ++bytePosXOR; } // make sure each scan line ends on a long boundary bytePosXOR += padBytes; } for (var i = 0; i < indexedImage.Length; i++) { var index = indexedImage[i]; var bitPosAND = 128 >> (i%8); if (index != transparentIndex) ico.IconImages[0].AND[bytePosAND] ^= (byte) bitPosAND; if (bitPosAND == 1) { // need to start another byte for next pixel if (bytePosAND%2 == 1) { //TODO: fix assumption that icon is 16px wide //skip some bytes so that scanline ends on a long barrier bytePosAND += 3; } else { bytePosAND += 1; } if (bytePosAND < ico.IconImages[0].AND.Length) ico.IconImages[0].AND[bytePosAND] = byte.MaxValue; } } return ico; }