Question

亲爱的朋友们，我需要你们的帮助。

我需要将.bmp文件发送到另一个进程（对话框）并使用MMF（内存映射文件）将其显示在那里但问题是图像以反色和颠倒的方式显示。

这是源代码：

在第一个应用程序中，我从HDD打开图片并将其链接到命名的MMF“Gigabyte_picture”

HANDLE hFile = CreateFile("123.bmp", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, "Gigabyte_picture");

在第二个应用程序中，我打开映射的bmp文件，最后我使用SendMessage函数在静态组件上显示m_HBitmap。

HANDLE hMappedFile = OpenFileMapping(FILE_MAP_READ, FALSE, "Gigabyte_picture");
PBYTE pbData = (PBYTE) MapViewOfFile(hMappedFile, FILE_MAP_READ, 0, 0, 0); 

BITMAPINFO bmpInfo = { 0 };
LONG lBmpSize = 60608; // size of the bmp file in bytes

bmpInfo.bmiHeader.biBitCount = 32;
bmpInfo.bmiHeader.biHeight = 174;
bmpInfo.bmiHeader.biWidth = 87;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biSizeImage = lBmpSize;
bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);               

UINT * pPixels = 0;    
HDC hDC = CreateCompatibleDC(NULL);

HBITMAP m_HBitmap = CreateDIBSection(hDC, &bmpInfo, DIB_RGB_COLORS, (void **)& pPixels, NULL, 0);                               
SetBitmapBits(m_HBitmap, lBmpSize, pbData);
SendMessage(gStaticBox, STM_SETIMAGE, (WPARAM)IMAGE_BITMAP,(LPARAM)m_HBitmap);
/////////////
HWND gStaticBox = CreateWindowEx(0, "STATIC","",
SS_CENTERIMAGE | SS_REALSIZEIMAGE | SS_BITMAP | WS_CHILD | WS_VISIBLE,
10,10,380, 380, myDialog, (HMENU)-1,NULL,NULL);

Answer 1

pbData指向位图数据的开头，指向位图标题。将SetBitmapBits指针指向原始数据：pbData + header size + optional pallete。

Answer 2

我编辑了代码，现在工作正常（图片颜色正确，图片不是颠倒的）

SetBitmapBits(m_HBitmap, lBmpSize, pbFile + 54);

BITMAP bm;              
GetObject(m_HBitmap, sizeof(BITMAP), (LPSTR)&bm);

// this code rotate picture on 180 degrees on Y axis
HDC TempHDC = ::CreateCompatibleDC(NULL);
HBITMAP hOldBitmap2 = (HBITMAP)SelectObject(TempHDC, m_HBitmap);

::StretchBlt(TempHDC,0,0, bm.bmWidth, bm.bmHeight, TempHDC,  0,  bm.bmHeight-1, bm.bmWidth,-bm.bmHeight, SRCCOPY ); 
SelectObject(TempHDC,hOldBitmap2);
DeleteDC(TempHDC);

// as before
SendMessage(gStaticBox, STM_SETIMAGE, (WPARAM)IMAGE_BITMAP,(LPARAM)m_HBitmap);

如何正确地重新创建以前由CreateFileMapping（）共享的BITMAP？

2 个答案: