创建彩色笔和画笔

尽管你可以在创建笔时指定任何颜色，但系统仅使用设备上可用的颜色。 这意味着系统在实现绘图笔时使用最接近的匹配颜色。 创建画笔时，如果指定设备不支持的颜色，系统将生成抖色。 在任一情况下，都可以在创建笔或画笔时使用 RGB 宏指定颜色。

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;
    RECT clientRect;
    RECT textRect;
    HRGN bgRgn;
    HBRUSH hBrush;
    HPEN hPen;


    switch (message)
    {
    
    case WM_PAINT:
        {
        hdc = BeginPaint(hWnd, &ps);
        
        // Fill the client area with a brush
        GetClientRect(hWnd, &clientRect);
        bgRgn = CreateRectRgnIndirect(&clientRect);
        hBrush = CreateSolidBrush(RGB(200,200,200));
        FillRgn(hdc, bgRgn, hBrush);

        
        hPen = CreatePen(PS_DOT,1,RGB(0,255,0));
        SelectObject(hdc, hPen);
        SetBkColor(hdc, RGB(0,0,0));
        Rectangle(hdc, 10,10,200,200);
        
        // Text caption
        SetBkColor(hdc, RGB(255,255,255));
        SetRect(&textRect, 10, 210, 200,200);
        DrawText(hdc,TEXT("PS_DOT"),-1,&textRect, DT_CENTER | DT_NOCLIP);

        
        hPen = CreatePen(PS_DASHDOTDOT,1,RGB(0,255,255));
        SelectObject(hdc, hPen);
        SetBkColor(hdc, RGB(255,0,0));
        SelectObject(hdc,CreateSolidBrush(RGB(0,0,0)));
        Rectangle(hdc, 210,10,400,200);
        
        // Text caption
        SetBkColor(hdc, RGB(255,200,200));
        SetRect(&textRect, 210, 210, 400,200);
        DrawText(hdc,TEXT("PS_DASHDOTDOT"),-1,&textRect, DT_CENTER | DT_NOCLIP);
        

        hPen = CreatePen(PS_DASHDOT,1,RGB(255,0,0));
        SelectObject(hdc, hPen);
        SetBkColor(hdc, RGB(255,255,0));
        SelectObject(hdc,CreateSolidBrush(RGB(100,200,255)));
        Rectangle(hdc, 410,10,600,200);
        
        // Text caption
        SetBkColor(hdc, RGB(200,255,200));
        SetRect(&textRect, 410, 210, 600,200);
        DrawText(hdc,TEXT("PS_DASHDOT"),-1,&textRect, DT_CENTER | DT_NOCLIP);
        

        // When fnPenStyle is PS_SOLID, nWidth may be more than 1.
        // Also, if you set the width of any pen to be greater than 1, 
        // then it will draw a solid line, even if you try to select another style.
        hPen = CreatePen(PS_SOLID,5,RGB(255,0,0));
        SelectObject(hdc, hPen);
        // Setting the background color doesn't matter 
        // when the style is PS_SOLID
        SetBkColor(hdc, RGB(255,255,255));
        SelectObject(hdc,CreateSolidBrush(RGB(200,100,50)));
        Rectangle(hdc, 10,300,200,500);
        
        // Text caption
        SetBkColor(hdc, RGB(200,200,255));
        SetRect(&textRect, 10, 510, 200,500);
        DrawText(hdc,TEXT("PS_SOLID"),-1,&textRect, DT_CENTER | DT_NOCLIP);
    
        hPen = CreatePen(PS_DASH,1,RGB(0,255,0));
        SelectObject(hdc, hPen);
        SetBkColor(hdc, RGB(0,0,0));
        SelectObject(hdc,CreateSolidBrush(RGB(200,200,255)));
        Rectangle(hdc, 210,300,400,500);
        
        // Text caption
        SetBkColor(hdc, RGB(255,255,200));
        SetRect(&textRect, 210, 510, 400,200);
        DrawText(hdc,TEXT("PS_DASH"),-1,&textRect, DT_CENTER | DT_NOCLIP);

        hPen = CreatePen(PS_NULL,1,RGB(0,255,0));
        SelectObject(hdc, hPen);
        // Setting the background color doesn't matter 
        // when the style is PS_NULL
        SetBkColor(hdc, RGB(0,0,0));
        SelectObject(hdc,CreateSolidBrush(RGB(255,255,255)));
        Rectangle(hdc, 410,300,600,500);
        
        // Text caption
        SetBkColor(hdc, RGB(200,255,255));
        SetRect(&textRect, 410, 510, 600,500);
        DrawText(hdc,TEXT("PS_NULL"),-1,&textRect, DT_CENTER | DT_NOCLIP);
        
        
        // Clean up
        DeleteObject(bgRgn);
        DeleteObject(hBrush);
        DeleteObject(hPen);

        GetStockObject(WHITE_BRUSH);
        GetStockObject(DC_PEN);

        EndPaint(hWnd, &ps);
        break;
        }
    

    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}