Save DC content as BMP files, screenshots can also (ZT)

Hbitmap Copyscreentobitmap (lprect lprect)

Lprect represents the selected area

{

HDC HSCRDC, HMEMDC;

Screen and memory Device description table

Hbitmap Hbitmap, Holdbitmap;

Bitmap handle

int NX, NY, nX2, nY2;

Selected area coordinates

int nwidth, nheight;

Bitmap width and height

int XSCRN, YSCRN;

Screen resolution

Make sure the selection is not an empty rectangle

if (Isrectempty (lprect))

return NULL;

Create a Device Description table for the screen

HSCRDC = CreateDC ("DISPLAY", NULL, NULL, NULL);

To create a compatible memory device description table for the Screen device description table

HMEMDC = CreateCompatibleDC (HSCRDC);

Get the selected area coordinates

NX = lprect->left;

NY = lprect->top;

NX2 = lprect->right;

NY2 = lprect->bottom;

Get screen resolution

XSCRN = GetDeviceCaps (HSCRDC, horzres);

YSCRN = GetDeviceCaps (HSCRDC, vertres);

Make sure the selected area is visible

if (NX < 0)

NX = 0;

if (NY < 0)

NY = 0;

if (NX2 > Xscrn)

nX2 = XSCRN;

if (NY2 > Yscrn)

nY2 = YSCRN;

nwidth = Nx2-nx;

nheight = Ny2-ny;

Create a bitmap that is compatible with the Screen Device description table

Hbitmap = CreateCompatibleBitmap

(HSCRDC, nwidth, nheight);

Select the new bitmap in the Memory Device description table

Holdbitmap = (hbitmap) SelectObject (HMEMDC, HBITMAP);

Copy the screen Device description table to the Memory Device description table

BitBlt (HMEMDC, 0, 0, nwidth, nheight,

HSCRDC, NX, NY, srccopy);

Get the handle to the screen bitmap

Hbitmap = (hbitmap) SelectObject (HMEMDC, holdbitmap);//This time you can get the handle to the Savebitmaptofile save to the file, I continue to lazy write here

 //Clear
 bitmapinfoheader BiH;
 bih.bisize =sizeof (Bitmapinfoheader);
 bih.biwidth = 800;
 bih.biheight = 600;
 bih.biplanes = 1;
 bih.bibitcount= 8;//8bit bitmap
 bih.bicompression = Bi_rgb;
 bih.bisizeimage = 0;
 bih.bixpelspermeter = 0;
 bih.biypelspermeter = 0;
 bih.biclrused = 0;
 bih.biclrimportant = 0;
 dword DWBMBITSSIZE=800*600*8/8;
 handle Hdib=globalalloc (ghnd,dwbmbitssize+256*sizeof (Rgbquad) +sizeof (Bitmapinfoheader));//Allocate memory, GlobalAlloc allocating memory can share allocated memory with DLL programs (can be released by non-C + + compiled DLLs), malloc words can only have C + + themselves know how to release the

The assigned content includes Bitmapinfoheader + PALETTE (palette) + bitmap content
LPVOID ptr= (LPVOID) GlobalLock (HDIB);
* (bitmapinfoheader*) ptr=bih;//save that Bitmapinfoheader to the memory we allocate
HDC Xdc=getdc (NULL);
Hpalette hpal= (Hpalette) getstockobject (Default_palette);
Hpalette holdpal= (Hpalette) SelectPalette (Xdc,hpal,false);
RealizePalette (XDC);
if (! GetDIBits (hscrdc,hbitmap,0,600,
(LPSTR) ptr+sizeof (bitmapinfoheader) +256*sizeof (Rgbquad),
(Bitmapinfo *) PTR,
dib_rgb_colors))

The parameters describe the DC from which (must have the correct palette), the bitmap handle, from which line (scanline), how many rows, save the bitmap content, a save bitmapinfo structure (GetDIBits will help us perfect the damned palette), Color of the way, to get BMP must be dib_rgb_colors

{
Return hbitmap;//If GetDIBits returns 0, then it fails ...
}
HANDLE fh = CreateFile ("C://b.bmp", Generic_write,

0, NULL, Create_always,

File_attribute_normal | File_flag_sequential_scan,
NULL);

if (fh = INVALID_HANDLE_VALUE)

return FALSE;

Set Bitmap file Headers
Bitmapfileheader Bmfhdr;
Bmfhdr.bftype = 0x4d42; "BM"

DWORD dwdibsize = sizeof (Bitmapfileheader)

+ sizeof (Bitmapinfoheader)

+ 256*sizeof (rgbquad) + dwbmbitssize;

Bmfhdr.bfsize = dwdibsize;

bmfhdr.bfreserved1 = 0;

Bmfhdr.bfreserved2 = 0;

Bmfhdr.bfoffbits = (DWORD) sizeof

(Bitmapfileheader)

+ (DWORD) sizeof (Bitmapinfoheader)

+ 256*sizeof (Rgbquad);

Write Bitmap file headers
DWORD Dwwritten;
WriteFile (FH, (LPSTR) &BMFHDR, sizeof

(Bitmapfileheader), &dwwritten, NULL);

Write the rest of the bitmap file

WriteFile (FH, (LPSTR) PTR, dwdibsize,

&dwwritten, NULL);

DeleteDC (HSCRDC);

DeleteDC (HMEMDC);

return bitmap handle

return hbitmap;

}

int Savebitmaptofile (Hbitmap hbitmap,

LPSTR lpfilename)//hbitmap for just the screen bitmap handle

{//lpfilename is a bitmap file name

HDC HDC;

Device Description Table

int ibits;

The number of bytes per pixel at the current display resolution

WORD Wbitcount;

The number of bytes per pixel in the bitmap

Define palette size, pixel byte size in bitmap,

Bitmap file size, number of bytes written to file

DWORD dwpalettesize=0,

Dwbmbitssize,

Dwdibsize, Dwwritten;

BITMAP BITMAP;

Bitmap Property Structure

Bitmapfileheader Bmfhdr;

Bitmap File Header structure

Bitmapinfoheader bi;

Bitmap Information Header structure

Lpbitmapinfoheader LPBI;

Point to bitmap information header structure

HANDLE FH, Hdib;
Hpalette Hpal,holdpal=null;

Definition file, allocating memory handle, palette handle

Calculates the number of bytes per pixel in a bitmap file

HDC = CreateDC ("DISPLAY", null,null,null);

Ibits = GetDeviceCaps (HDC, Bitspixel) *

GetDeviceCaps (HDC, planes);

DeleteDC (HDC);

if (ibits <= 1)

Wbitcount = 1;

else if (ibits <= 4)

Wbitcount = 4;

else if (ibits <= 8)

Wbitcount = 8;

Else

Wbitcount = 24;

Calculate Palette Size
wbitcount=8;
if (Wbitcount <= 8)

Dwpalettesize = (1 << wbitcount) *

sizeof (RGBQUAD);

Set Bitmap information header structure

GetObject (hbitmap, sizeof (BITMAP), (LPSTR) &bitmap);

bi.bisize = sizeof (Bitmapinfoheader);

Bi.biwidth = Bitmap.bmwidth;

Bi.biheight = Bitmap.bmheight;

Bi.biplanes = 1;

Bi.bibitcount = Wbitcount;

Bi.bicompression = Bi_rgb;

bi.bisizeimage = 0;

Bi.bixpelspermeter = 0;

Bi.biypelspermeter = 0;

bi.biclrused = 0;

bi.biclrimportant = 0;

Dwbmbitssize = ((Bitmap.bmwidth *

WBITCOUNT+31)/32 * 4

*bitmap.bmheight;

allocating memory for bitmap content

Hdib = GlobalAlloc (ghnd,dwbmbitssize+

Dwpalettesize+sizeof (Bitmapinfoheader));

LPBI = (lpbitmapinfoheader) globallock (HDIB);

*LPBI = bi;

Working with palettes

Hpal = (Hpalette) getstockobject (Default_palette);

if (hpal)

{

HDC = GetDC (NULL);

Holdpal = SelectPalette (HDC, Hpal, FALSE);

RealizePalette (HDC);

}

Gets the new pixel value under the palette

GetDIBits (HDC, Hbitmap, 0, (UINT) Bitmap.bmheight,

(LPSTR) LPBI + sizeof (bitmapinfoheader)

+dwpalettesize,

(Bitmapinfo *) LPBI,
Dib_rgb_colors);

Restore Palette

if (Holdpal)

{

SelectPalette (HDC, Holdpal, TRUE);

RealizePalette (HDC);

ReleaseDC (NULL, HDC);

}

Create a bitmap file

FH = CreateFile (lpFileName, Generic_write,

0, NULL, Create_always,

File_attribute_normal | File_flag_sequential_scan
, NULL);

if (fh = INVALID_HANDLE_VALUE)

return FALSE;

Set Bitmap file Headers

Bmfhdr.bftype = 0x4d42; "BM"

dwdibsize = sizeof (Bitmapfileheader)

+ sizeof (Bitmapinfoheader)

+ Dwpalettesize + dwbmbitssize;

Bmfhdr.bfsize = dwdibsize;

bmfhdr.bfreserved1 = 0;

Bmfhdr.bfreserved2 = 0;

Bmfhdr.bfoffbits = (DWORD) sizeof

(Bitmapfileheader)

+ (DWORD) sizeof (Bitmapinfoheader)

+ dwpalettesize;

Write Bitmap file headers

WriteFile (FH, (LPSTR) &BMFHDR, sizeof

(Bitmapfileheader), &dwwritten, NULL);

Write the rest of the bitmap file

WriteFile (FH, (LPSTR) LPBI, Dwdibsize,

&dwwritten, NULL);

Clear

GlobalUnlock (HDIB);

GlobalFree (HDIB);

CloseHandle (FH);

}

I am also a half understand the state.