通过TCP发送的图像被翻转
问题描述:
我创建了一个客户端,它通过TCP向服务器发送屏幕截图。图像发送成功。然而,在接收时,图像是颠倒的(我知道这是由结构的一个属性中的负高度设置的)。 我在互联网上搜索的方式,但我找不到一个正确的方式来实现这一点。所以,如果有更好的方式做到这一点,请纠正我。通过TCP发送的图像被翻转
这是我送的截图(客户端):
HDC ScreenDC = GetDC(0);
HDC hMemory = CreateCompatibleDC(ScreenDC);
POINT ScreenSize = { GetDeviceCaps(ScreenDC, HORZRES),GetDeviceCaps(ScreenDC, VERTRES)};
// fill the hbitmap wtih the screenshot
HBITMAP hBitmap = CreateCompatibleBitmap(ScreenDC, ScreenSize.x, ScreenSize.y);
HGDIOBJ hOldBitmap = SelectObject(hMemory, hBitmap);
BITMAPINFO bmpInfo = { 0 };
bmpInfo.bmiHeader.biSize = sizeof(bmpInfo.bmiHeader);
GetDIBits(ScreenDC , hBitmap, 0, 0, NULL, &bmpInfo, DIB_RGB_COLORS); // fill bmpInfo with info about the hBitmap
char * dataBuffer = new char[bmpInfo.bmiHeader.biSizeImage];
// adjust the header for our needs
bmpInfo.bmiHeader.biBitCount = 32;
bmpInfo.bmiHeader.biCompression = BI_RGB; // no compression -> easier to use
bmpInfo.bmiHeader.biHeight = abs(bmpInfo.bmiHeader.biHeight);
BitBlt(hMemory, 0, 0, ScreenSize.x, ScreenSize.y, ScreenDC, 0, 0, SRCCOPY); // take a screenshot
GetDIBits(ScreenDC, hBitmap, 0, bmpInfo.bmiHeader.biHeight, dataBuffer, &bmpInfo, DIB_RGB_COLORS); // fill dataBuffer with raw image data
// send first the bmpInfo.bmiHeader struct
// send raw data : dataBuffer
//.....
我相信正在发送的消息,因为我已经实现了一个协议,用于分离packets.This正确接收是没有问题的。
这是接收器(服务器):
// data is the entire sent : structure + dataBuffer
HDC hDc = GetDC(windowHwnd);
HDC tCpyHdc = CreateCompatibleDC(hDc);
BITMAPINFOHEADER bmpHeader = *(BITMAPINFOHEADER*)data;
BITMAP bmp;
bmp.bmType = 0;
bmp.bmWidth = bmpHeader.biWidth;
bmp.bmHeight = abs(bmpHeader.biHeight);
bmp.bmPlanes = bmpHeader.biPlanes;
bmp.bmWidthBytes = bmpHeader.biWidth * 4;
bmp.bmBitsPixel = bmpHeader.biBitCount;
bmp.bmBits = (char*)(data + sizeof(BITMAPINFOHEADER));
HBITMAP hB = CreateBitmapIndirect(&bmp);
HBITMAP oldBmp = (HBITMAP)SelectObject(tCpyHdc, hB);
StretchBlt(hDc, 0, 0, width - 20, height - 40, tCpyHdc, 0, 0, bmp.bmWidth, bmp.bmHeight, SRCCOPY);
的图像是上下颠倒我。如何解决这个问题?
答
感谢@Igor Tandetnik我解决了这个问题。这是最后的代码:
在客户端我送BITMAPINFO而不是BITMAPINFOHEADER:
//...
// send first the bmpInfo struct
// send raw data : dataBuffer
//.....
服务器端(我用CreateDIBSection代替CreateBitmapIndirect的):
// data is the entire sent : structure + dataBuffer
HDC hDc = GetDC(windowHwnd);
HDC tCpyHdc = CreateCompatibleDC(hDc);
BITMAPINFO bmpInfo = *(BITMAPINFO*)data;
BITMAP bmp;
bmp.bmType = 0;
bmp.bmWidth = bmpInfo.bmiHeader.biWidth;
bmp.bmHeight = -abs(bmpInfo.bmiHeader.biHeight);
bmp.bmPlanes = bmpInfo.bmiHeader.biPlanes;
bmp.bmWidthBytes = bmpInfo.bmiHeader.biWidth * 4;
bmp.bmBitsPixel = bmpInfo.bmiHeader.biBitCount;
bmp.bmBits = (char*)(data + sizeof(BITMAPINFO));
char* dibarr = NULL;
HBITMAP hB = CreateDIBSection(windowData.tCpyHdc, &bmpInfo, DIB_RGB_COLORS, (void**)&dibarr, 0, 0);
memcpy((void*)dibarr, (void*)bmp.bmBits, inf.packetsz - sizeof(BITMAPINFO));
HBITMAP oldBmp = (HBITMAP)SelectObject(tCpyHdc, hB);
StretchBlt(hDc, 0, 0, width - 20, height - 40, tCpyHdc, 0, 0, bmp.bmWidth, bmp.bmHeight, SRCCOPY);
在发送端使用设备无关位图(通过'GetDIBits'),但在接收端使用与设备相关的位图(通过'CreateBi tmapIndirect')。我建议你也在接收端使用DIB,例如通过'CreateDIBSection' –
我会测试它并回复它是否工作。谢谢 –
你的意思是CreateDIBitmap也许?因为我可以看到CreateDIBSection不会从数组中返回一个HBITMAP。我相信,基于HDC,它提供了一个阵列和一个HBITMAP。这不是我想要的服务器上。 –