private void Realloc(int width, int height)
{
if (_gcHandle.IsAllocated)
{
_gcHandle.Free();
}
Width = width;
Height = height;
_pArray = new int[Width * Height];
_gcHandle = GCHandle.Alloc(_pArray, GCHandleType.Pinned);
_bi = new Bitmapinfo
{
biHeader =
{
bihBitCount = 32,
bihPlanes = 1,
bihSize = 40,
bihWidth = Width,
bihHeight = -Height,
bihSizeImage = (Width * Height) << 2
}
};
}
static extern IntPtr CreateDIBSection(
IntPtr hdc,
ref Bitmapinfo bmi,
uint usage,
out IntPtr bits,
IntPtr hSection,
uint dwOffset);
public static extern bool SendMessage(IntPtr hWnd, int wMsg, int wParam, ref Bitmapinfo lParam);
private static extern int SetDIBitsToDevice(HandleRef hDc, int xDest, int yDest, int dwWidth, int dwHeight,
int xSrc, int ySrc, int uStartScan, int cScanLines, ref int lpvBits, ref Bitmapinfo lpbmi, uint fuColorUse);
static extern IntPtr CreateDIBSection(
IntPtr hdc,
ref Bitmapinfo bmi,
uint usage,
out IntPtr bits,
IntPtr hSection,
uint dwOffset);
/// <summary>
/// Converts a bitmap into a 1 bpp bitmap of the same dimensions, fast.
/// Original source from: http://www.wischik.com/lu/programmer/1bpp.html
/// </summary>
/// <param name="source">The bitmap, which will be converted.</param>
/// <returns>A 1 or 8 bpp copy of the source bitmap.</returns>
public static Bitmap To1Bpp(Bitmap source)
{
// 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 = source.Width, h = source.Height;
IntPtr hbm = source.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
Bitmapinfo bmi = new Bitmapinfo();
bmi.biSize = 40; // the size of the BITMAPHEADERINFO struct
bmi.biWidth = w;
bmi.biHeight = h;
bmi.biPlanes = 1; // "planes" are confusing. We always use just 1. Read MSDN for more info.
bmi.biBitCount = 1;
bmi.biCompression = BI_RGB; // ie. the pixels in our RGBQUAD table are stored as RGBs, not palette indexes
bmi.biSizeImage = (uint)(((w + 7) & 0xFFFFFFF8) * h / 8);
bmi.biXPelsPerMeter = 1000000; // not really important
bmi.biYPelsPerMeter = 1000000; // not really important
// Now for the colour table.
const uint ncols = (uint)1 << 1;
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
bmi.cols[0] = MAKERGB(0, 0, 0);
bmi.cols[1] = MAKERGB(255, 255, 255);
// 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 = CreateDIBSection(IntPtr.Zero, ref bmi, 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 = GetDC(IntPtr.Zero); // First we obtain the DC for the screen
// Next, create a DC for the original hbitmap
IntPtr hdc = CreateCompatibleDC(sdc); SelectObject(hdc, hbm);
// and create a DC for the monochrome hbitmap
IntPtr hdc0 = CreateCompatibleDC(sdc); SelectObject(hdc0, hbm0);
// Now we can do the BitBlt:
BitBlt(hdc0, 0, 0, w, h, hdc, 0, 0, SRCCOPY);
// Step (4): convert this monochrome hbitmap back into a Bitmap:
Bitmap b0 = Image.FromHbitmap(hbm0);
//
// Finally some cleanup.
DeleteDC(hdc);
DeleteDC(hdc0);
ReleaseDC(IntPtr.Zero, sdc);
DeleteObject(hbm);
DeleteObject(hbm0);
//
return b0;
}
/// <summary>
/// Converts a bitmap into a 1 bpp bitmap of the same dimensions, fast.
/// Original source from: http://www.wischik.com/lu/programmer/1bpp.html
/// </summary>
/// <param name="source">The bitmap, which will be converted.</param>
/// <returns>A 1 or 8 bpp copy of the source bitmap.</returns>
public static Bitmap To1Bpp(Bitmap source)
{
// 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 = source.Width, h = source.Height;
IntPtr hbm = source.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
Bitmapinfo bmi = new Bitmapinfo();
bmi.biSize = 40; // the size of the BITMAPHEADERINFO struct
bmi.biWidth = w;
bmi.biHeight = h;
bmi.biPlanes = 1; // "planes" are confusing. We always use just 1. Read MSDN for more info.
bmi.biBitCount = 1;
bmi.biCompression = BI_RGB; // ie. the pixels in our RGBQUAD table are stored as RGBs, not palette indexes
bmi.biSizeImage = (uint)(((w + 7) & 0xFFFFFFF8) * h / 8);
bmi.biXPelsPerMeter = 1000000; // not really important
bmi.biYPelsPerMeter = 1000000; // not really important
// Now for the colour table.
const uint ncols = (uint)1 << 1;
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
bmi.cols[0] = MAKERGB(0, 0, 0);
bmi.cols[1] = MAKERGB(255, 255, 255);
// 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 = CreateDIBSection(IntPtr.Zero, ref bmi, 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 = GetDC(IntPtr.Zero); // First we obtain the DC for the screen
// Next, create a DC for the original hbitmap
IntPtr hdc = CreateCompatibleDC(sdc); SelectObject(hdc, hbm);
// and create a DC for the monochrome hbitmap
IntPtr hdc0 = CreateCompatibleDC(sdc); SelectObject(hdc0, hbm0);
// Now we can do the BitBlt:
BitBlt(hdc0, 0, 0, w, h, hdc, 0, 0, SRCCOPY);
// Step (4): convert this monochrome hbitmap back into a Bitmap:
Bitmap b0 = Image.FromHbitmap(hbm0);
//
// Finally some cleanup.
DeleteDC(hdc);
DeleteDC(hdc0);
ReleaseDC(IntPtr.Zero, sdc);
DeleteObject(hbm);
DeleteObject(hbm0);
//
return(b0);
}
