Win32 SDK显示图像(GDI+)

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转载自：http://www.cnblogs.com/nbsofer/archive/2012/05/12/2497109.html

刚学了GDI+, 发现显示图片很方便, 以前用OleLoadPicture+IPicture接口显示, 别提有多
悲剧了, 现在学了GDI+, 太方便友好了, 哈哈~

　　提供一个GDI+显示图片的示例供那些不知道怎么用Win32SDK显示图片的新手程序猿们一快速简单的方法.

　　程序工作方式, 程序启动后, 任意拖动一张图片到窗口即可显示图像, 格式包括但不限于JPG,BMP,PNG,...

　　预览:
　　

　　程序代码:　　

#include <windows.h>#include <gdiplus.h>#pragma comment(lib,"gdiplus")using namespace Gdiplus;//根据图片的宽度和高度更新窗口客户区的大小void set_window_size(HWND hWnd,int width,int height){    RECT rcWindow,rcClient;    int border_width,border_height;    GetWindowRect(hWnd,&rcWindow);    GetClientRect(hWnd,&rcClient);    border_width = (rcWindow.right-rcWindow.left) - (rcClient.right-rcClient.left);    border_height = (rcWindow.bottom-rcWindow.top) - (rcClient.bottom-rcClient.top);    SetWindowPos(hWnd,0,0,0,border_width+width,border_height+height,SWP_NOMOVE|SWP_NOZORDER);}void draw_image(HWND hWnd,wchar_t* file){    HDC hdc;    int width,height;    //加载图像    Image image(file);    if(image.GetLastStatus() != Status::Ok){        MessageBox(hWnd,"图片无效!",NULL,MB_OK);        return;    }        //取得宽度和高度    width = image.GetWidth();    height = image.GetHeight();    //更新窗口大小    set_window_size(hWnd,width,height);    hdc = GetDC(hWnd);    //绘图    Graphics graphics(hdc);    graphics.DrawImage(&image,0,0,width,height);    ReleaseDC(hWnd,hdc);    return;}LRESULT CALLBACK WndProc(HWND hWnd,UINT uMsg,WPARAM wParam,LPARAM lParam){    switch(uMsg)    {    case WM_DROPFILES://拖动图片文件时进行图像显示        {            wchar_t file[MAX_PATH];            DragQueryFileW((HDROP)wParam,0,file,sizeof(file)/sizeof(*file));            draw_image(hWnd,file);            DragFinish((HDROP)wParam);            return 0;        }    case WM_LBUTTONDOWN://左键单击时拖动窗体        SendMessage(hWnd,WM_NCLBUTTONDOWN,HTCAPTION,0);        return 0;    case WM_CREATE:        return 0;    case WM_DESTROY:        PostQuitMessage(0);        return 0;    }    return DefWindowProc(hWnd,uMsg,wParam,lParam);}int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nShowCmd){    MSG msg;    WNDCLASSEX wce={0};    HWND hWnd;    wce.cbSize = sizeof(wce);    wce.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);    wce.hCursor = LoadCursor(NULL,IDC_ARROW);    wce.hIcon = LoadIcon(NULL,IDI_APPLICATION);    wce.hInstance = hInstance;    wce.lpfnWndProc = WndProc;    wce.lpszClassName = "MyClassName";    wce.style = CS_HREDRAW|CS_VREDRAW;    if(!RegisterClassEx(&wce))        return 1;    char* title = "Win32SDK GDI+ 图像显示示例程序(拖动图片文件到窗口以显示)";    hWnd = CreateWindowEx(0,"MyClassName",title,WS_OVERLAPPEDWINDOW,        CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,        NULL,NULL,hInstance,NULL);    if(hWnd == NULL)        return 1;    //GdiPlus初始化    ULONG_PTR gdiplusToken;    GdiplusStartupInput gdiplusInput;    GdiplusStartup(&gdiplusToken,&gdiplusInput,NULL);    //窗口接收文件拖放    DragAcceptFiles(hWnd,TRUE);    ShowWindow(hWnd,nShowCmd);    UpdateWindow(hWnd);    while(GetMessage(&msg,NULL,0,0)){        TranslateMessage(&msg);        DispatchMessage(&msg);    }    //GdiPlus 取消初始化    GdiplusShutdown(gdiplusToken);    return msg.wParam;}

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