c++ - BitBlt 两个图像在另一个之上

Question

我正在尝试编写一个程序，当勾选一个复选框时，它会在屏幕的大面积区域显示一个网格。我正在尝试使用 BitBlt 在 WM_PAINT 中执行此操作，并且我的显示函数肯定是使用正确的 bool 值调用的。但是，它不会对窗口进行任何更改。我是在做一些愚蠢的事情，还是没有实现这一目标的实用方法？如果这是无法实现的，是否有任何方法可以在不指定包含网格的不同图像集的情况下获得类似的结果？

void DisplayRoom(HWND hwnd, char TileList[][100], POINT pMaxDisplay, POINT pMinDisplay, HBITMAP ahbmTileset[], bool bDisplayBars)
{
HBITMAP hbmSprite, hbmMask;
BITMAP bm;
PAINTSTRUCT ps;
HINSTANCE hinNULL = GetModuleHandle(NULL);
HDC hdc = BeginPaint(hwnd, &ps);
HDC hdcMem = CreateCompatibleDC(hdc);
HBITMAP hbmOld;
POINT Position;
hbmSprite = LoadBitmap(hinNULL, MAKEINTRESOURCE(IDB_CLEAR_GROUND));
hbmOld = (HBITMAP)SelectObject(hdcMem, hbmSprite);
GetObject(hbmSprite, sizeof(bm), &bm);
for (int iii = pMinDisplay.x; iii < pMaxDisplay.x; iii++)
    for (int jjj = pMinDisplay.y; jjj < pMaxDisplay.y; jjj++)
    {
        switch(TileList[iii][jjj])
        {
        case 'g':
            hbmSprite = ahbmTileset[0];
            break;
        case 'd':
            hbmSprite = ahbmTileset[1];
            break;
        case 'i':
            hbmSprite = ahbmTileset[2];
            break;
        case 'l':
            hbmSprite = ahbmTileset[3];
            break;
        }
                    assert(hbmSprite != NULL);
        SelectObject(hdcMem, hbmSprite);
        BitBlt(hdc, (iii - pMinDisplay.x) * 34 + 90, (jjj - pMinDisplay.y) * 34 + 60, 34, 34, hdcMem, 0, 0, SRCCOPY);
    }
DeleteDC(hdcMem);
EndPaint(hwnd, &ps);
if (bDisplayBars)
{
    HDC hdc = BeginPaint(hwnd, &ps);
    HDC hdcMem = CreateCompatibleDC(hdc);
    hbmSprite = LoadBitmap(hinNULL, MAKEINTRESOURCE(IDB_GRID));
            assert(hbmSprite != NULL);
    hbmMask = CreateBitmapMask(hbmSprite, RGB(0,0,0));
    for (int iii = pMinDisplay.x; iii < pMaxDisplay.x; iii++)
        for (int jjj = pMinDisplay.y; jjj < pMaxDisplay.y; jjj++)
        {
            SelectObject(hdcMem, hbmMask);
            BitBlt(hdc, (iii - pMinDisplay.x) * 34 + 90, (jjj - pMinDisplay.y) * 34 + 60, 34, 34, hdcMem, 0, 0, SRCAND);
            SelectObject(hdcMem, hbmSprite);
            BitBlt(hdc, (iii - pMinDisplay.x) * 34 + 90, (jjj - pMinDisplay.y) * 34 + 60, 34, 34, hdcMem, 0, 0, SRCPAINT);
        }
    DeleteDC (hdcMem);
    EndPaint(hwnd, &ps);
}
}

对话过程如下所示。

BOOL CALLBACK CreateRoom(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
static char achTileDetails[100][100];
static POINT pDimensions, pMonsterLocations, pMinDisplay, pMaxDisplay;
static HBITMAP ahbmTileset[4];
static bool bShowBars;
switch(Message)
{
case WM_INITDIALOG:
    SetFocus(hwnd);
    for (int iii = 0; iii < 100; iii++)
        for(int jjj = 0; jjj < 100; jjj++)
            achTileDetails[iii][jjj] = 'g';
    pDimensions.x = 20;
    pDimensions.y = 10;
    pMinDisplay.x = 0;
    pMinDisplay.y = 0;
    pMaxDisplay.x = 20;
    pMaxDisplay.y = 10;
    for (int iii = 0; iii < 4; iii++)
        ahbmTileset[iii] = LoadBitmap(GetModuleHandle(NULL), MAKEINTRESOURCE(IDB_CLEAR_GROUND + iii));
    return TRUE;
case WM_PAINT:
    DisplayRoom(hwnd, achTileDetails, pMaxDisplay, pMinDisplay, ahbmTileset, bShowBars);
    break;
case WM_COMMAND:
    switch(LOWORD(wParam))
    {
    case IDCANCEL:
        EndDialog(hwnd, IDCANCEL);
        break;
    case IDC_DISPLAY_GRID:
        switch(HIWORD(wParam))
        {
        case BN_CLICKED:
            bShowBars = SendMessage(GetDlgItem(hwnd, IDC_DISPLAY_GRID), BM_GETCHECK, 0, 0);
            InvalidateRect(hwnd, NULL, TRUE);
            UpdateWindow(hwnd);
            break;
        }
        break;
    }
    break;
case WM_LBUTTONDOWN:

    break;
default:
    return FALSE;
}
}

Answer 1

我看到的主要问题是您调用了 BeginPaint 和 EndPaint 两次。您应该只在任何绘画完成之前执行一次 BeginPaint，在所有绘画完成之后执行一次 EndPaint。

可能还有其他问题，这些东西很难完全正确。