diff --git a/App/Processor/Imaging/BitmapHelper.cs b/App/Processor/Imaging/BitmapHelper.cs index 1e56e3a..a901cd9 100644 --- a/App/Processor/Imaging/BitmapHelper.cs +++ b/App/Processor/Imaging/BitmapHelper.cs @@ -136,6 +136,14 @@ namespace PDFPatcher.Processor.Imaging /// 染色后的新颜色。 public static Color Tint(this Color color, Color tint) { return Color.FromArgb(color.A, mul255(color.R, tint.R), mul255(color.G, tint.G), mul255(color.B, tint.B)); + + // MuPDF: pixmap.c + static int mul255(int a, int b) { + /* see Jim Blinn's book "Dirty Pixels" for how this works */ + int x = a * b + 128; + x += x >> 8; + return x >> 8; + } } unsafe public static Bitmap ToIndexImage(this Bitmap source, Color[] pallette) { @@ -187,10 +195,6 @@ namespace PDFPatcher.Processor.Imaging return result; } - public static Bitmap ToMonochrome(this Bitmap bitmap) { - return CopyToBpp(bitmap, 1); - } - /// 将图像转换为黑白图像。 /// 需要转换的图像。 /// 转换后的图像。 @@ -259,9 +263,9 @@ namespace PDFPatcher.Processor.Imaging return destination; } - const int threshold = 255 * 3 / 2; - public static byte[] SimpleThresholdBW(byte[] sourceBuffer, int width, int height, int srcStride, int dstStride) { + const int THRESHOLD = 255 * 3 / 2; + byte[] destinationBuffer = new byte[dstStride * height]; int srcIx = 0; int dstIx = 0; @@ -281,7 +285,7 @@ namespace PDFPatcher.Processor.Imaging // Compute pixel brightness (i.e. total of Red, Green, and Blue values) newPixel = sourceBuffer[i] + sourceBuffer[i + 1] + sourceBuffer[i + 2]; - if (newPixel > threshold) + if (newPixel > THRESHOLD) pix8 |= bit; if (bit == 1) { destinationBuffer[j++] = pix8; @@ -296,139 +300,5 @@ namespace PDFPatcher.Processor.Imaging } // all lines finished return destinationBuffer; } - - /// - /// Copies a bitmap into a 1bpp/8bpp bitmap of the same dimensions, fast - /// - /// original bitmap - /// 1 or 8, target bpp - /// a 1bpp copy of the bitmap - /// http://www.wischik.com/lu/programmer/1bpp.html - static Bitmap CopyToBpp(Bitmap b, int bpp) { - if (bpp != 1 && bpp != 8) throw new ArgumentException("1 or 8", "bpp"); - - // Plan: built into Windows GDI is the ability to convert - // bitmaps from one format to another. Most of the time, this - // job is actually done by the graphics hardware accelerator card - // and so is extremely fast. The rest of the time, the job is done by - // very fast native code. - // We will call into this GDI functionality from C#. Our plan: - // (1) Convert our Bitmap into a GDI hbitmap (ie. copy unmanaged->managed) - // (2) Create a GDI monochrome hbitmap - // (3) Use GDI "BitBlt" function to copy from hbitmap into monochrome (as above) - // (4) Convert the monochrone hbitmap into a Bitmap (ie. copy unmanaged->managed) - - int w = b.Width, h = b.Height; - var hbm = b.GetHbitmap(); // this is step (1) - // - // Step (2): create the monochrome bitmap. - // "BITMAPINFO" is an interop-struct which we define below. - // In GDI terms, it's a BITMAPHEADERINFO followed by an array of two RGBQUADs - var bmi = new NativeMethods.BITMAPINFO { - biSize = 40, // the size of the BITMAPHEADERINFO struct - biWidth = w, - biHeight = h, - biPlanes = 1, // "planes" are confusing. We always use just 1. Read MSDN for more info. - biBitCount = (short)bpp, // ie. 1bpp or 8bpp - biCompression = NativeMethods.BI_RGB, // ie. the pixels in our RGBQUAD table are stored as RGBs, not palette indexes - biSizeImage = (uint)(((w + 7) & 0xFFFFFFF8) * h / 8), - biXPelsPerMeter = 1000000, // not really important - biYPelsPerMeter = 1000000 // not really important - }; - // Now for the colour table. - uint ncols = (uint)1 << bpp; // 2 colours for 1bpp; 256 colours for 8bpp - bmi.biClrUsed = ncols; - bmi.biClrImportant = ncols; - bmi.cols = new uint[256]; // The structure always has fixed size 256, even if we end up using fewer colours - if (bpp == 1) { bmi.cols[0] = MakeRgb(0, 0, 0); bmi.cols[1] = MakeRgb(255, 255, 255); } - else { for (int i = 0; i < ncols; i++) bmi.cols[i] = MakeRgb(i, i, i); } - // For 8bpp we've created an palette with just greyscale colours. - // You can set up any palette you want here. Here are some possibilities: - // greyscale: for (int i=0; i<256; i++) bmi.cols[i]=MAKERGB(i,i,i); - // rainbow: bmi.biClrUsed=216; bmi.biClrImportant=216; int[] colv=new int[6]{0,51,102,153,204,255}; - // for (int i=0; i<216; i++) bmi.cols[i]=MAKERGB(colv[i/36],colv[(i/6)%6],colv[i%6]); - // optimal: a difficult topic: http://en.wikipedia.org/wiki/Color_quantization - // - // Now create the indexed bitmap "hbm0" - IntPtr bits0; // not used for our purposes. It returns a pointer to the raw bits that make up the bitmap. - IntPtr hbm0 = NativeMethods.CreateDIBSection(IntPtr.Zero, ref bmi, NativeMethods.DIB_RGB_COLORS, out bits0, IntPtr.Zero, 0); - // - // Step (3): use GDI's BitBlt function to copy from original hbitmap into monocrhome bitmap - // GDI programming is kind of confusing... nb. The GDI equivalent of "Graphics" is called a "DC". - IntPtr sdc = NativeMethods.GetDC(IntPtr.Zero); // First we obtain the DC for the screen - // Next, create a DC for the original hbitmap - IntPtr hdc = NativeMethods.CreateCompatibleDC(sdc); - NativeMethods.SelectObject(hdc, hbm); - // and create a DC for the monochrome hbitmap - IntPtr hdc0 = NativeMethods.CreateCompatibleDC(sdc); - NativeMethods.SelectObject(hdc0, hbm0); - // Now we can do the BitBlt: - NativeMethods.BitBlt(hdc0, 0, 0, w, h, hdc, 0, 0, NativeMethods.SRCCOPY); - // Step (4): convert this monochrome hbitmap back into a Bitmap: - var b0 = Image.FromHbitmap(hbm0); - // - // Finally some cleanup. - NativeMethods.DeleteDC(hdc); - NativeMethods.DeleteDC(hdc0); - NativeMethods.ReleaseDC(IntPtr.Zero, sdc); - NativeMethods.DeleteObject(hbm); - NativeMethods.DeleteObject(hbm0); - // - return b0; - } - static uint MakeRgb(int r, int g, int b) { - return ((uint)(b & 255)) | ((uint)((g & 255) << 8)) | ((uint)((r & 255) << 16)); - } - - // MuPDF: pixmap.c - static int mul255(int a, int b) { - /* see Jim Blinn's book "Dirty Pixels" for how this works */ - int x = a * b + 128; - x += x >> 8; - return x >> 8; - } - - static class NativeMethods - { - public const uint BI_RGB = 0; - public const uint DIB_RGB_COLORS = 0; - public const int SRCCOPY = 0x00CC0020; - - [DllImport("gdi32.dll")] - public static extern int BitBlt(IntPtr hdcDst, int xDst, int yDst, int w, int h, IntPtr hdcSrc, int xSrc, int ySrc, int rop); - - [DllImport("gdi32.dll")] - public static extern IntPtr CreateCompatibleDC(IntPtr hdc); - - [DllImport("gdi32.dll")] - public static extern IntPtr CreateDIBSection(IntPtr hdc, ref BITMAPINFO bmi, uint Usage, out IntPtr bits, IntPtr hSection, uint dwOffset); - - [DllImport("gdi32.dll")] - public static extern int DeleteDC(IntPtr hdc); - - [DllImport("gdi32.dll")] - public static extern bool DeleteObject(IntPtr hObject); - - [DllImport("user32.dll")] - public static extern IntPtr GetDC(IntPtr hwnd); - - [DllImport("user32.dll")] - public static extern int ReleaseDC(IntPtr hwnd, IntPtr hdc); - - [DllImport("gdi32.dll")] - public static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj); - [StructLayout(LayoutKind.Sequential)] - public struct BITMAPINFO - { - public uint biSize; - public int biWidth, biHeight; - public short biPlanes, biBitCount; - public uint biCompression, biSizeImage; - public int biXPelsPerMeter, biYPelsPerMeter; - public uint biClrUsed, biClrImportant; - [MarshalAs(UnmanagedType.ByValArray, SizeConst = 256)] - public uint[] cols; - } - } } }