请问DC怎么转成内存？？
本帖最后由 u011911734 于 2013-08-31 23:31:40 编辑 我用 GetDC(NULL); 取得屏幕DC后，想放到缓冲区内，用Socket送出去
用Bitmap 或JPG 都太麻烦了，还要处理文件头，其实我只是要把DC用StretchBlt() 显示在用户端的视窗上，文件头跟本是不必要的，如果能够直接把DC 转到内存再送出去就太方便了，不过前提是要能再转回DC...
有什么好方法？ ？
[解决办法]
BOOL SaveBitmapToFile(LPCTSTR lpszFilePath, HBITMAP hBm)
{
// 定义位图文件表头
BITMAPFILEHEADER bmfh;
// 定义位图信息表头
BITMAPINFOHEADER bmih;
// 调色板长度
int nColorLen = 0;
// 调色表大小
DWORD dwRgbQuadSize = 0;
// 位图大小
DWORD dwBmSize = 0;
// 分配内存的指针
HGLOBAL hMem = NULL;
LPBITMAPINFOHEADER lpbi;
BITMAP bm;
HDC hDC;
HANDLE hFile = NULL;
DWORD dwWritten;
GetObject(hBm, sizeof(BITMAP), &bm);
bmih.biSize = sizeof(BITMAPINFOHEADER); // 本结构所占的字节
bmih.biWidth = bm.bmWidth; // 位图宽
bmih.biHeight = bm.bmHeight; // 位图高
bmih.biPlanes = 1;
bmih.biBitCount = bm.bmBitsPixel; // 每一图素的位数
bmih.biCompression = BI_RGB; // 不压缩
bmih.biSizeImage = 0; // 位图大小
bmih.biXPelsPerMeter = 0;
bmih.biYPelsPerMeter = 0;
bmih.biClrUsed = 0;
bmih.biClrImportant = 0;
// 计算位图图素数据区大小
dwBmSize = 4 * ((bm.bmWidth * bmih.biBitCount + 31) / 32) * bm.bmHeight;
// 如果图素位 <= 8bit，则有调色板
if (bmih.biBitCount <= 8)
{
nColorLen = (1 << bm.bmBitsPixel);
}
// 计算调色板大小
dwRgbQuadSize = nColorLen * sizeof(RGBQUAD);
// 分配内存
hMem = GlobalAlloc(GHND, dwBmSize + dwRgbQuadSize + sizeof(BITMAPINFOHEADER));
if (NULL == hMem)
{
return FALSE;
}
// 锁定内存
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hMem);
// 将bmih中的内容写入分配的内存中
*lpbi = bmih;
hDC= GetDC(NULL);
// 将位图中的数据以bits的形式放入lpData中。
GetDIBits(hDC, hBm, 0, (DWORD)bmih.biHeight, (LPSTR)lpbi+sizeof(BITMAPINFOHEADER)+dwRgbQuadSize, (BITMAPINFO *)lpbi, (DWORD)DIB_RGB_COLORS);
bmfh.bfType = 0x4D42; // 位图文件类型：BM
bmfh.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwRgbQuadSize + dwBmSize; // 位图大小
bmfh.bfReserved1 = 0;
bmfh.bfReserved2 = 0;
bmfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwRgbQuadSize; // 位图数据与文件头部的偏移量
// 把上面的数据写入文件中
hFile = CreateFile(lpszFilePath, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL
------解决方案--------------------
FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (INVALID_HANDLE_VALUE == hFile)
{
return FALSE;
}
// 写入位图文件头
WriteFile(hFile, (LPSTR)&bmfh, sizeof(BITMAPFILEHEADER), (DWORD *)&dwWritten, NULL);
// 写入位图数据
WriteFile(hFile, (LPBITMAPINFOHEADER)lpbi, bmfh.bfSize - sizeof(BITMAPFILEHEADER), (DWORD *)&dwWritten, NULL);
GlobalFree(hMem);
CloseHandle(hFile);
return TRUE;
}
#pragma comment(lib,"gdi32")
#include <windows.h>
#include <stdio.h>
int main() {
const DWORD uWidth = 18 + 17 * 256, uHeight = 18 + 17 * 128;
PBITMAPINFO pbmi = (PBITMAPINFO) LocalAlloc (LPTR, sizeof (BITMAPINFOHEADER) + sizeof (RGBQUAD) * 2);
pbmi->bmiHeader.biSize = sizeof (BITMAPINFOHEADER);
pbmi->bmiHeader.biWidth = uWidth;
pbmi->bmiHeader.biHeight = uHeight;
pbmi->bmiHeader.biPlanes = 1;
pbmi->bmiHeader.biBitCount = 1;
pbmi->bmiHeader.biSizeImage = ((uWidth + 31) & ~31) / 8 * uHeight;
pbmi->bmiColors[0].rgbBlue = 0;
pbmi->bmiColors[0].rgbGreen = 0;
pbmi->bmiColors[0].rgbRed = 0;
pbmi->bmiColors[1].rgbBlue = 255;
pbmi->bmiColors[1].rgbGreen = 255;
pbmi->bmiColors[1].rgbRed = 255;
HDC hDC = CreateCompatibleDC (0);
void * pvBits;
HBITMAP hBitmap = CreateDIBSection (hDC, pbmi, 0, &pvBits, NULL, 0);
SelectObject (hDC, hBitmap);
HFONT hFont = CreateFont (16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, "宋体");
// HFONT hFont = CreateFont (16, 0, 0, 0, 0, 0, 0, 0, SHIFTJIS_CHARSET, 0, 0, 0, 0, "宋体");
SelectObject (hDC, hFont);
BitBlt (hDC, 0, 0, uWidth, uHeight, NULL, 0, 0, WHITENESS);
char c[4];
int i, j;
for (i = 128; i < 256; i++) {
sprintf (c, "%02X", i);
TextOut (hDC, 1, (i - 127) * 17 + 1, c, 2);
}
for (j = 0; j < 256; j++) {
sprintf (c, "%02X", j);
TextOut (hDC, (j + 1)* 17 + 1, 1, c, 2);
}
for (i = 128; i < 256; i++) {
for (j = 0; j < 256; j++) {
c[0] = (char) i;
c[1] = (char) j;
TextOut (hDC, (j + 1) * 17 + 1, (i - 127) * 17 + 1, c, 2);
}
}
for (i = 0; i < 130; i++) {
MoveToEx (hDC, 0, i * 17, NULL);
LineTo (hDC, uWidth, i * 17);
}
for (j = 0; j < 258; j++) {
MoveToEx (hDC, j * 17, 0, NULL);
LineTo (hDC, j * 17, uHeight);
}
BITMAPFILEHEADER bmfh;
bmfh.bfType = *(PWORD) "BM";
bmfh.bfReserved1 = 0;
bmfh.bfReserved2 = 0;
bmfh.bfOffBits = sizeof (BITMAPFILEHEADER) + sizeof (BITMAPINFOHEADER) + sizeof (RGBQUAD) * 2;
bmfh.bfSize = bmfh.bfOffBits + pbmi->bmiHeader.biSizeImage;
HANDLE hFile = CreateFile ("goal.bmp", GENERIC_WRITE, 0, 0, CREATE_ALWAYS, 0, 0);
if (hFile != INVALID_HANDLE_VALUE) {
DWORD dwWritten;
WriteFile (hFile, &bmfh, sizeof (BITMAPFILEHEADER), &dwWritten, NULL);
WriteFile (hFile, pbmi, sizeof (BITMAPINFOHEADER) + sizeof (RGBQUAD) * 2, &dwWritten, NULL);
WriteFile (hFile, pvBits, pbmi->bmiHeader.biSizeImage, &dwWritten, NULL);
CloseHandle (hFile);
}
DeleteObject (hFont);
DeleteObject (hBitmap);
DeleteDC (hDC);
LocalFree (pbmi);
return 0;
}
