apps/tests/stretchblt/stretchblt.cpp

   1
   2 // ------------------------------------------------------------------
   3 // Windows 2000 Graphics API Black Book
   4 // Chapter 1 - Listing 1.5 (StretchBlt Zooming Demo)
   5 //
   6 // Created by Damon Chandler <dmc27@ee.cornell.edu>
   7 // Updates can be downloaded at: <www.coriolis.com>
   8 //
   9 // Please do not hesistate to e-mail me at dmc27@ee.cornell.edu
  10 // if you have any questions about this code.
  11 // ------------------------------------------------------------------
  12
  13
  14 //>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  15 #include <windows.h>
  16 //<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  17
  18
  19 HWND HListBox = NULL;
  20 const int ID_LISTBOX = 101;
  21
  22 HINSTANCE HInst;
  23 const char* WndClassName = "GMainWnd";
  24 LRESULT CALLBACK MainWndProc(HWND HWnd, UINT Msg, WPARAM WParam,
  25    LPARAM LParam);
  26
  27
  28 int APIENTRY WinMain(HINSTANCE HInstance, HINSTANCE HPrevInstance,
  29     LPTSTR lpCmdLine, int nCmdShow)
  30 {
  31    HInst = HInstance;
  32
  33    WNDCLASS wc;
  34    memset(&wc, 0, sizeof(WNDCLASS));
  35
  36    wc.style = CS_VREDRAW | CS_HREDRAW | CS_DBLCLKS;
  37    wc.lpfnWndProc = MainWndProc;
  38    wc.hInstance = HInstance;
  39    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
  40    wc.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_BTNFACE + 1);
  41    wc.lpszClassName = WndClassName;
  42
  43    if (RegisterClass(&wc))
  44    {
  45       HWND HWnd =
  46          CreateWindow(WndClassName, TEXT("StretchBlt Zooming Demo"),
  47                       WS_OVERLAPPEDWINDOW | WS_CAPTION |
  48                       WS_VISIBLE | WS_CLIPSIBLINGS,
  49                       0, 0, 675, 560,
  50                       NULL, NULL, HInst, NULL);
  51
  52       if (HWnd)
  53       {
  54          HListBox =
  55             CreateWindowEx(WS_EX_CLIENTEDGE, "LISTBOX", "",
  56                            LBS_NOTIFY | WS_CHILD | WS_VISIBLE,
  57                            530, 5, 130, 150, HWnd,
  58                            reinterpret_cast<HMENU>(ID_LISTBOX),
  59                            HInst, NULL);
  60          if (HListBox)
  61          {
  62             SNDMSG(HListBox, LB_ADDSTRING, 0,
  63                    reinterpret_cast<LPARAM>("Zoom 25%"));
  64             SNDMSG(HListBox, LB_ADDSTRING, 0,
  65                    reinterpret_cast<LPARAM>("Zoom 50%"));
  66             SNDMSG(HListBox, LB_ADDSTRING, 0,
  67                    reinterpret_cast<LPARAM>("Zoom 75%"));
  68             SNDMSG(HListBox, LB_ADDSTRING, 0,
  69                    reinterpret_cast<LPARAM>("Zoom 100%"));
  70             SNDMSG(HListBox, LB_ADDSTRING, 0,
  71                    reinterpret_cast<LPARAM>("Zoom 125%"));
  72             SNDMSG(HListBox, LB_ADDSTRING, 0,
  73                    reinterpret_cast<LPARAM>("Zoom 150%"));
  74             SNDMSG(HListBox, LB_ADDSTRING, 0,
  75                    reinterpret_cast<LPARAM>("Zoom 200%"));
  76             SNDMSG(HListBox, LB_ADDSTRING, 0,
  77                    reinterpret_cast<LPARAM>("Zoom 300%"));
  78          }
  79
  80          ShowWindow(HWnd, nCmdShow);
  81          UpdateWindow(HWnd);
  82
  83          MSG msg;
  84          while (GetMessage(&msg, NULL, 0, 0))
  85          {
  86              TranslateMessage(&msg);
  87              DispatchMessage(&msg);
  88          }
  89       }
  90     }
  91     return 0;
  92 }
  93 //------------------------------------------------------------------
  94
  95
  96 // image related
  97 BITMAP bmp;
  98 const char* filename = "LENA.BMP";
  99 HDC HMemDC = NULL;
 100 HBITMAP HOldBmp = NULL;
 101
 102 // zooming related
 103 float zoom_factor = 0.5;
 104 RECT RDest = {5, 5, 0, 0};
 105 enum {ID_ZOOM25, ID_ZOOM50, ID_ZOOM75, ID_ZOOM100,
 106       ID_ZOOM125, ID_ZOOM150, ID_ZOOM200, ID_ZOOM300};
 107
 108 LRESULT CALLBACK MainWndProc(HWND HWnd, UINT Msg, WPARAM WParam,
 109    LPARAM LParam)
 110 {
 111    switch (Msg)
 112    {
 113       case WM_CREATE:
 114       {
 115          // create a memory DC
 116          HMemDC = CreateCompatibleDC(NULL);
 117          if (HMemDC)
 118          {
 119             // load a bitmap from file
 120             HBITMAP HBmp =
 121                static_cast<HBITMAP>(
 122                   LoadImage(HInst, filename, IMAGE_BITMAP,
 123                             0, 0, LR_LOADFROMFILE)
 124                             );
 125             if (HBmp)
 126             {
 127                // extract dimensions of the bitmap
 128                GetObject(HBmp, sizeof(BITMAP), &bmp);
 129
 130                // associate the bitmap with the memory DC
 131                HOldBmp = static_cast<HBITMAP>(
 132                   SelectObject(HMemDC, HBmp)
 133                   );
 134             }
 135          }
 136       }
 137       case WM_COMMAND:
 138       {
 139          if (WParam == MAKEWPARAM(ID_LISTBOX, LBN_SELCHANGE))
 140          {
 141             switch (SNDMSG(HListBox, LB_GETCURSEL, 0, 0))
 142             {
 143                case ID_ZOOM25: zoom_factor = 0.25; break;
 144                case ID_ZOOM50: zoom_factor = 0.50; break;
 145                case ID_ZOOM75: zoom_factor = 0.75; break;
 146                case ID_ZOOM100: zoom_factor = 1.00; break;
 147                case ID_ZOOM125: zoom_factor = 1.25; break;
 148                case ID_ZOOM150: zoom_factor = 1.50; break;
 149                case ID_ZOOM200: zoom_factor = 2.00; break;
 150                case ID_ZOOM300: zoom_factor = 3.00; break;
 151             }
 152
 153             // calculate the new width and height
 154             const int new_width =
 155                static_cast<int>(zoom_factor * bmp.bmWidth);
 156             const int new_height =
 157                static_cast<int>(zoom_factor * bmp.bmHeight);
 158
 159             // is zooming in?
 160             bool zoom_in = (new_width > RDest.right - RDest.left);
 161
 162             // caculate the area that needs to be updated
 163             RECT RUpdate = {
 164                RDest.left, RDest.top,
 165                RDest.left + max(new_width, RDest.right - RDest.left),
 166                RDest.top + max(new_height, RDest.bottom - RDest.top)
 167                };
 168
 169             // adjust the dimenstions of the
 170             // destination rectangle
 171             RDest.right = RDest.left + new_width;
 172             RDest.bottom = RDest.top + new_height;
 173
 174             // create an update region from the XOR combination
 175             // of the update and destination rectangles
 176             HRGN HUpdateRgn = CreateRectRgnIndirect(&RUpdate);
 177             HRGN HDestRgn = CreateRectRgnIndirect(&RDest);
 178             int result =
 179                CombineRgn(HUpdateRgn, HUpdateRgn, HDestRgn, RGN_XOR);
 180
 181             // incite a repaint
 182             if (result != NULLREGION && result != ERROR)
 183             {
 184                InvalidateRgn(HWnd, HUpdateRgn, true);
 185                RedrawWindow(HWnd, &RDest, NULL, RDW_NOERASE | RDW_INVALIDATE);
 186             }
 187             else if (result == NULLREGION)
 188             {
 189                InvalidateRect(HWnd, &RUpdate, zoom_in ? false : true);
 190             }
 191
 192             // clean up
 193             DeleteObject(HUpdateRgn);
 194             DeleteObject(HDestRgn);
 195          }
 196          break;
 197       }
 198       case WM_PAINT:
 199       {
 200          PAINTSTRUCT ps;
 201          const HDC Hdc = BeginPaint(HWnd, &ps);
 202 #if 0
 203          try
 204 #endif
 205          {
 206             //
 207             // TODO: add palette support (see Chapter 9)...
 208             //
 209
 210             if (RDest.right - RDest.left > 0)
 211             {
 212                // use BitBlt when not zooming
 213                if (zoom_factor == 1.0)
 214                {
 215                   BitBlt(Hdc, RDest.left, RDest.top,
 216                          RDest.right - RDest.left,
 217                          RDest.bottom - RDest.top,
 218                          HMemDC, 0, 0,
 219                          SRCCOPY);
 220                }
 221                else
 222                {
 223                   if (zoom_factor < 1.0)
 224                   {
 225                      SetStretchBltMode(Hdc, COLORONCOLOR);
 226                   }
 227
 228                   // render the zoomed image
 229                   StretchBlt(Hdc, RDest.left, RDest.top,
 230                              RDest.right - RDest.left,
 231                              RDest.bottom - RDest.top,
 232                              HMemDC, 0, 0,
 233                              bmp.bmWidth, bmp.bmHeight,
 234                              SRCCOPY);
 235                }
 236             }
 237          }
 238 #if 0
 239          catch (...)
 240 #endif
 241          {
 242             EndPaint(HWnd, &ps);
 243          }
 244          EndPaint(HWnd, &ps);
 245          break;
 246       }
 247       case WM_DESTROY:
 248       {
 249          // clean up
 250          DeleteObject(SelectObject(HMemDC, HOldBmp));
 251          DeleteDC(HMemDC);
 252
 253          PostQuitMessage(0);
 254          return 0;
 255       }
 256    }
 257    return DefWindowProc(HWnd, Msg, WParam, LParam);
 258 }
 259 //------------------------------------------------------------------
 260
 261
 262