怎么才能把当前屏幕的图像截下来，并存成JPG文件，请各位大侠指教

[Lo]

知道的，能给出个例子吗？本人将不慎感缴。

[Searph]

以下是抓屏并保存为BMP的代码，其中第二个函数是抓取当前最前面的窗口，你还要改一下，忘了限制不要超出当前屏幕大小，存成jpg就自己想办法吧：
HBITMAP CopyScreenToBitmap()
{
HDC hScrDC, hMemDC;
HBITMAP hBitmap, hOldBitmap;
int nX, nY, nX2, nY2;
int nWidth, nHeight;
hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
hMemDC = CreateCompatibleDC(hScrDC);
nX = 0;
nY = 0;
nX2 = GetDeviceCaps(hScrDC, HORZRES);
nY2 = GetDeviceCaps(hScrDC, VERTRES);
nWidth = nX2 - nX;
nHeight = nY2 - nY;
// 创建一个与屏幕设备描述表兼容的位图
hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight);
// 把新位图选到内存设备描述表中
hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
// 把屏幕设备描述表拷贝到内存设备描述表中
BitBlt(hMemDC, 0, 0, nWidth, nHeight, hScrDC, nX, nY, SRCCOPY);
//得到屏幕位图的句柄
hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
//清除
DeleteDC(hScrDC);
DeleteDC(hMemDC);
// 返回位图句柄
return hBitmap;
}
HBITMAP CopyWindowToBitmap()
{
HDC hScrDC, hMemDC;
HBITMAP hBitmap, hOldBitmap;
int nX, nY, nX2, nY2;
int nWidth, nHeight;
HWND hWndCurrent = GetForegroundWindow();
RECT rect;
GetWindowRect(hWndCurrent, &rect);
hScrDC = GetWindowDC(hWndCurrent);
hMemDC = CreateCompatibleDC(hScrDC);
nX = rect.left;
nY = rect.top;
nX2 = rect.right;
nY2 = rect.bottom;
nWidth = nX2 - nX;
nHeight = nY2 - nY;
// 创建一个与屏幕设备描述表兼容的位图
hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight);
// 把新位图选到内存设备描述表中
hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
// 把屏幕设备描述表拷贝到内存设备描述表中
BitBlt(hMemDC, 0, 0, nWidth, nHeight, hScrDC, 0, 0, SRCCOPY);
//得到屏幕位图的句柄
hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
//清除
DeleteDC(hScrDC);
DeleteDC(hMemDC);
// 返回位图句柄
return hBitmap;
}

int SaveBitmapToFile(HBITMAP hBitmap, LPSTR lpFileName) //hBitmap 为刚才的屏幕位图句柄
{ //lpFileName 为位图文件名
HDC hDC;
//设备描述表
int iBits;
//当前显示分辨率下每个像素所占字节数
WORD wBitCount;
//位图中每个像素所占字节数
//定义调色板大小， 位图中像素字节大小 ， 位图文件大小 ， 写入文件字节数
DWORD dwPaletteSize=0,
dwBmBitsSize,
dwDIBSize, dwWritten;
BITMAP Bitmap;
//位图属性结构
BITMAPFILEHEADER bmfHdr;
//位图文件头结构
BITMAPINFOHEADER bi;
//位图信息头结构
LPBITMAPINFOHEADER lpbi;
//指向位图信息头结构
HANDLE fh, hDib, hPal,hOldPal=NULL;
//定义文件，分配内存句柄，调色板句柄

//计算位图文件每个像素所占字节数
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 if (iBits <= 24)
wBitCount = 24;
else if(iBits <= 32)
wBitCount = 32;
//计算调色板大小
if (wBitCount <= 8)
dwPaletteSize = (1 << wBitCount) * sizeof(RGBQUAD);

//设置位图信息头结构
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 ;
//为位图内容分配内存
hDib = GlobalAlloc(GHND, dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;
// 处理调色板
hPal = GetStockObject(DEFAULT_PALETTE);
if(hPal)
{
hDC = GetDC(NULL);
hOldPal = SelectPalette(hDC, (HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}
// 获取该调色板下新的像素值
GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
+ dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);
//恢复调色板
if(hOldPal)
{
SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
RealizePalette(hDC);
ReleaseDC(NULL, hDC);
}
//创建位图文件
fh = CreateFile(lpFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if(fh == INVALID_HANDLE_VALUE)
return FALSE;
// 设置位图文件头
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;
// 写入位图文件头
WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
// 写入位图文件其余内容
WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
//清除
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);
return dwWritten;
}

[BCB]

// 下面简单有效
#include "jpeg.hpp"
void SaveDesktop(char *jpeg)
{
RECT r;
GetWindowRect(GetDesktopWindow(),&r);
TCanvas *Canvas0=new TCanvas;
Canvas0->Handle=GetDC(0);
Graphics::TBitmap *bitmap=new Graphics::TBitmap();
bitmap->Height=r.bottom;
bitmap->Width=r.right;
bitmap->Canvas->CopyRect(r,Canvas0,r);
TJPEGImage *j=new TJPEGImage();
j->CompressionQuality=50; // 失真度
j->Assign(bitmap);
j->SaveToFile(jpeg);
delete j;
delete bitmap;
delete Canvas0;
}
void __fastcall TForm1::Button1Click(TObject *Sender)
{
SaveDesktop("c:\\test.jpg");
}
//---------------------------------------------------------------------------

[BCB]

// 下面简单有效
#include "jpeg.hpp"
void SaveDesktop(char *jpeg)
{
RECT r;
GetWindowRect(GetDesktopWindow( ),&r);
TCanvas *Canvas0=new TCanvas;
Canvas0->Handle=GetDC(0);
Graphics::TBitmap *bitmap=new Graphics::TBitmap( );
bitmap->Height=r.bottom;
bitmap->Width=r.right;
bitmap->Canvas->CopyRect(r,Canvas0,r);
TJPEGImage *j=new TJPEGImage();
j->CompressionQuality=50; // 失真度
j->Assign(bitmap);
j->SaveToFile(jpeg);
delete j;
delete bitmap;
delete Canvas0;
}
void __fastcall TForm1::Button1Click(TObject *Sender)
{
SaveDesktop("c:\\test.jpg");
}
//---------------------------------------------------------------------------

[BCB]

C++BUILDER比VC++简单就在这里。
C++BUILDER只要10几行。

[BCB]

要求C++BUILDER 5.0或DELPHI5.0;
4.0未试过，可能要安装jpeg有关库

[Lo]

BCB，谢谢！
能告诉我你的联系方式吗？OICQ、Email。以后有机会请你多多指教！

[BCB]

ok!
鼠标移到带 下画线的别名下面就直接看到了EMAIL。