MFC technology accumulation--the things that are based on MFC dialog box Class 4

3.3.4 with compatible DC Loading DIB Bitmap

Create a DC that is compatible with the device environment by temporarily importing the bitmap to a compatible DC and then drawing the bitmap into the device environment using the CDC::BITBLT or Cdc::stretchblt function.

The sample code is as follows:

voidCfdlg::onloadbitmap () {//Todo:add your control notification handler code hereHbitmap hbitmap;    BITMAP Bitmapinfo;    CBitmap CBitmap;    RECT RC; //Gets the window pointer for the specified ID numbercwnd* Mywnd =GetDlgItem (Idc_bitmaparea); //defines a device environment (DC) associated with a specified windowcclientdc DC (Mywnd); //defines a DC-to-compatible memory DCCDC MEMDC; //gets the size of the specified windowMywnd->getclientrect (&RC); //Import Bitmap HandleHbitmap = (HBITMAP):: LoadImage (NULL,"d:\\wanghui1.bmp", Image_bitmap,0,0, Lr_loadfromfile); //Attaching a bitmap handle to a bitmap class objectCBitmap.    Attach (HBITMAP); //get bitmap information, including bitmap width, high parameterCBitmap. Getbitmap (&bitmapinfo); //creates a memory DC that is compatible with the specified window DCMEMDC. CreateCompatibleDC (&DC); //to load a bitmap into a memory DCCBitmap *oldbitmap = MEMDC. SelectObject (&CBitmap); //import a bitmap from a memory DC into the actual DC in the specified window//DC. StretchBlt (0, 0, (Rc.right-rc.left), (rc.bottom-rc.top), &MEMDC, 0, 0, bitmapinfo.bmwidth, Bitmapinfo.bmheight, srccopy);dc. BITBLT (0,0, (Rc.right-rc.left), (rc.bottom-rc.top), &MEMDC,0,0, srccopy); //to remove a bitmap from the memory DCMEMDC.    SelectObject (OLDBITMAP); //Deletes a bitmap handle, and the bitmap class object calls its destructor after the program ends to free memoryCBitmap. DeleteObject ();}

For the above example code, several functions are explained in detail:

HANDLE LoadImage (

hinstance hinst      , //Handle of the instance containing the image

LPCTSTR LpszName ,       //Name or identifier of image

UINT Utype ,             //Type of image

int cxdesired ,          //Desired width

int cydesired ,          //Desired height

UINT fuload //Load Flags

);

This function can import an icon, a cursor, and a bitmap.

Hinst: Point to an instance of an application that can be obtained through the AfxGetInstanceHandle () function,

LpszName: Refers to the file name or resource identifier of the image, and when Fuload=lr_loadfromfile, LpszName points to the file name, hinst the value null.

Utype: Image type, values are:

Value meaning

Image_bitmap Importing bitmaps

Image_cursor Import Cursor

Image_icon Import icon

Cxdesired, cydesired: The width and height of the cursor or icon, in pixels.

Fuload: When fuload = Lr_loadfromfile , indicates that the image is loaded from a file pointed to by Lpszname, and if Lr_loadfromfile is unspecified, lpszname points to the resource name.

3.3.5 Use SetDIBitsToDevice to load the bitmap

first explain the SetDIBitsToDevice:  

int SetDIBitsToDevice (

HDC hdc, //Handle to device context

int xdest, //X-coordinate of Upper-left corner of dest. Rect .

int ydest, //Y-coordinate of Upper-left corner of dest. Rect .

DWORD dwwidth, //Source Rectangle width

DWORD dwheight, //source Rectangle height

int XSRC, //X-coordinate of Lower-left corner of source rect.

int YSRC, //Y-coordinate of Lower-left corner of source rect.

UINT Ustartscan, //First scan line in array

UINT Cscanlines, //number of scan lines

CONST VOID *lpvbits, //Address of array with DIB bits

CONST bitmapinfo *lpbmi, //address of structure with bitmap info.

UINT fucoloruse //RGB or palette indexes

);

Example code:

voidCfdlg::onloadbitmap () {
unsignedChar* imagebuffer=NULL; unsignedChar* ImageData =NULL;    Bitmapfileheader M_bitmapfileheader; Bitmapinfoheader*Infoheader; Rgbquad*Palette; Bitmapinfo*BMI;; FILE*ImageFile; unsignedintBytessize=0; if(null== (Imagefile=fopen ("d:\\wanghui1.bmp","RB")) {printf ("can not open the image file!"); return ; }    Else    {        //Read Bitmap file headerFread (&m_bitmapfileheader,sizeof(Bitmapfileheader),1, ImageFile); //opening up memory for bitmap information headers and palettesImagebuffer =NewUnsignedChar[m_bitmapfileheader.bfoffbits-sizeof(Bitmapfileheader)]; //reading header and palette data blocksFread (imagebuffer,m_bitmapfileheader.bfoffbits-sizeof(Bitmapfileheader),1, ImageFile); //force Imagebuffer to the Bitmapinfo type, and then point the information header and palette pointers to the corresponding address locationBMI = (bitmapinfo*) Imagebuffer; Infoheader= & (bmi->Bmiheader); Palette= bmi->bmicolors; //calculating the size of a graph data byteBytessize = (Infoheader->biwidth * infoheader->biheight * (infoheader->bibitcount/8)); //Open Bitmap data memory blockImageData =NewUnsignedChar[Bytessize]; //reading bitmap data blocksFread (Imagedata,bytessize,1, ImageFile); //gets the specified windowcwnd* Mywnd =GetDlgItem (Idc_bitmaparea); //creates the DC associated with the specified windowcclientdc DC (Mywnd);                RECT RC; //gets the size of the specified window areaMywnd->getclientrect (&RC); //draws a bitmap to the DC on the specified windowSetDIBitsToDevice (DC.M_HDC,0,0, Infoheader->biwidth, Infoheader->biheight,0,0,0, infoheader->Biheight, ImageData, BMI, dib_rgb_colors); }    //releasing dynamically opened memorydelete[] Imagebuffer; Delete[] ImageData;}

MFC technology accumulation--the things that are based on MFC dialog box Class 4