为什么Windows会绘制自己的min-max-close按钮,即使WM_NCPAINT正确(？)重新实现？

Question

正如我们从这个截图中看到的,我采取了:

http://www.picpaste.com/pics/skinned_window.1386408792.png

出于一些奇怪的原因,Windows在我的蒙皮标题栏(黄色矩形)顶部的标题栏中绘制了自己的(未设置样式)最小化/最大化/关闭按钮,如红色箭头所示.它还在这些按钮的底部绘制了一条令人烦恼的1像素大小的线条,正如您从screeenshot中看到的那样.

您可以注意到我正在为窗口蒙皮:我正在绘制自己的标题栏(黄色矩形),并调整边框(青色,品红色,红色矩形)的大小.它们现在只是矩形,但我无法理解为什么Windows在我的黄色矩形上绘制,我在非客户区绘制,只需在WM_NCPAINT发生时绘制.一切都很好,除了这个奇怪的事情.

这种情况不会一直发生,它会在使用蒙皮窗口一段时间后发生,调整大小并最大化/最小化2-3次.特别是当我在小块程序的执行某一点上单击鼠标按下鼠标栏时,会发生这种情况.事实上,我认为WM_NCHITTEST消息中的问题可能有问题,但似乎并非如此.有一些错误,可能是一些Window Style或Window Extended Style标志错了.

我无法解释这一点,我正确地重新实现WM_NCPAINT消息(我猜),所以Windows不应该理解我正在绘制自己的标题栏吗？为什么要覆盖我的图纸？!这是Windows XP的错误吗？它似乎不会发生在Windows 7中,但我不太确定.

也许我只是错过了为此重新实现WM_*消息.有人可以帮帮我吗？这让我疯了!

注意:我不能使用WinForms,Qt或其他一些有助于为窗口设置外观的库,这是一个旧项目,所有这些都必须直接在winapi中完成,处理正确的WM_*消息.没有图书馆可以链接.

注意2:在WM_NCACTIVATE消息中使用SetWindowPos或RedrawWindow会产生相同的结果.

这是代码:

#include <windows.h>
#include <stdio.h>


LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

char szClassName[ ] = "SkinTest";


int left_off;
int right_off;
int top_off;
int bottom_off;


int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */


    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;
    wincl.style = CS_DBLCLKS;
    wincl.cbSize = sizeof (WNDCLASSEX);

    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                
    wincl.cbClsExtra = 0;                     
    wincl.cbWndExtra = 0;                     
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    if (!RegisterClassEx (&wincl))
        return 0;

    DWORD style =  WS_OVERLAPPEDWINDOW;

    hwnd = CreateWindowEx (
       WS_EX_CLIENTEDGE,
       szClassName,
       "Code::Blocks Template Windows App",
       style,
       CW_USEDEFAULT,
       CW_USEDEFAULT,
       500,
       500,
       HWND_DESKTOP,
       NULL,
       hThisInstance,
       NULL
       );

    //
    // This prevent the round-rect shape of the overlapped window.
    //
    HRGN rgn = CreateRectRgn(0,0,500,500);
    SetWindowRgn(hwnd, rgn, TRUE);

    left_off = 4;
    right_off = 4;
    top_off = 23;
    bottom_off = 4;

    ShowWindow (hwnd, nCmdShow);

    while (GetMessage (&messages, NULL, 0, 0))
    {
        TranslateMessage(&messages);
        DispatchMessage(&messages);
    }

    return messages.wParam;
}



#define COLOR_TITLEBAR        0
#define COLOR_LEFT_BORDER     2
#define COLOR_RIGHT_BORDER    4
#define COLOR_BOTTOM_BORDER   6

int win_x, win_y, win_width, win_height;
int win_is_not_active = 0;


COLORREF borders_colors[] =
{
    RGB(255,255,0), RGB(180,180,0),    // Active titlebar - Not active titlebar
    RGB(0,255,255), RGB(0,180,180),    // Active left border - Not active left border
    RGB(255,0,255), RGB(180,0,180),    // Active right border - Not Active right border
    RGB(255,0,0),   RGB(180,0,0)       // Active bottom border - Not active bottom border
};




void draw_titlebar(HDC hdc)
{
    HBRUSH tmp, br = CreateSolidBrush(borders_colors[COLOR_TITLEBAR + win_is_not_active]);
    tmp = (HBRUSH)SelectObject(hdc, br);
    Rectangle(hdc, 0, 0, win_width, top_off);
    SelectObject(hdc, tmp);
    DeleteObject(br);
}

void draw_left_border(HDC hdc)
{
    HBRUSH tmp, br = CreateSolidBrush(borders_colors[COLOR_LEFT_BORDER + win_is_not_active]);
    tmp = (HBRUSH)SelectObject(hdc, br);
    Rectangle(hdc, 0, top_off, left_off, win_height - bottom_off);
    SelectObject(hdc, tmp);
    DeleteObject(br);
}


void draw_right_border(HDC hdc)
{
    HBRUSH tmp, br = CreateSolidBrush(borders_colors[COLOR_RIGHT_BORDER + win_is_not_active]);
    tmp = (HBRUSH)SelectObject(hdc, br);
    Rectangle(hdc, win_width - right_off, top_off, win_width, win_height - bottom_off);
    SelectObject(hdc, tmp);
    DeleteObject(br);
}


void draw_bottom_border(HDC hdc)
{
    HBRUSH tmp, br = CreateSolidBrush(borders_colors[COLOR_BOTTOM_BORDER + win_is_not_active]);
    tmp = (HBRUSH)SelectObject(hdc, br);
    Rectangle(hdc, 0, win_height - bottom_off, win_width, win_height);
    SelectObject(hdc, tmp);
    DeleteObject(br);
}



LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
{
switch (message)
{
    case WM_DESTROY:
        PostQuitMessage (0);
        break;

    case WM_SIZE:
        {
            RECT rect;
            HRGN rgn;
            GetWindowRect(hwnd, &rect);
            win_x = rect.left;
            win_y = rect.top;
            win_width = rect.right - rect.left;
            win_height = rect.bottom - rect.top;
            //
            // I use this to set a rectangular region for the window, and not a round-rect one.
            //
            rgn = CreateRectRgn(0,0, rect.right, rect.bottom);
            SetWindowRgn(hwnd, rgn, TRUE);
            DeleteObject(rgn);
        }
        break;

    case WM_PAINT:
    {
        printf("WM_PAINT\n");
        PAINTSTRUCT ps;
        HDC hdc;
        HBRUSH hb;
        RECT rect;

        hdc = BeginPaint(hwnd, &ps);
        hb = CreateSolidBrush(RGB(rand()%255,rand()%255,rand()%255));

        GetClientRect(hwnd, &rect);

        FillRect(hdc, &rect, hb);

        DeleteObject(hb);
        EndPaint(hwnd, &ps);
        break;
    }

    case WM_NCPAINT:
    {
        printf("WM_NCPAINT\n");
        HDC hdc;
        HBRUSH br;
        RECT rect;
        HRGN rgn = (HRGN)wparam;

        if ((wparam == 0) || (wparam == 1))
            hdc = GetWindowDC(hwnd);
        else
            hdc = GetDCEx(hwnd, (HRGN)wparam, DCX_WINDOW|DCX_CACHE|DCX_LOCKWINDOWUPDATE|DCX_INTERSECTRGN);

        draw_titlebar(hdc);
        draw_left_border(hdc);
        draw_right_border(hdc);
        draw_bottom_border(hdc);
        ReleaseDC(hwnd, hdc);
        return 0;
    }

    case WM_NCACTIVATE:
            if (wparam)
                win_is_not_active = 0;
            else
                win_is_not_active = 1;
          // Force paint our non-client area otherwise Windows will paint its own.
          SetWindowPos(hwnd, 0, 0, 0, 0, 0, SWP_NOZORDER|SWP_NOSIZE|SWP_NOMOVE|SWP_NOACTIVATE|SWP_FRAMECHANGED);
          //RedrawWindow(hwnd, 0, 0, RDW_FRAME | RDW_UPDATENOW | RDW_NOCHILDREN);
          return 0;

    case WM_NCCALCSIZE:
        {
            if (wparam)
            {
                NCCALCSIZE_PARAMS * ncparams = (NCCALCSIZE_PARAMS *)lparam;
                printf("WM_NCCALCSIZE wparam:True\n");
                ncparams->rgrc[0].left   += left_off;
                ncparams->rgrc[0].top    += top_off;
                ncparams->rgrc[0].right  -= right_off;
                ncparams->rgrc[0].bottom -= bottom_off;
                return 0;
            } else {

                RECT * rect = (RECT *)lparam;
                return 0;
            }
        }


    case WM_NCHITTEST:
        {
            LRESULT result = DefWindowProc(hwnd, message, wparam, lparam);
            switch (result)
            {
                //
                // I have to set this, because i need to draw my own min/max/close buttons
                // in different coordinates where the system draws them, so let's consider
                // all the titlebar just a tilebar for now, ignoring those buttons.
                //
                case HTCLOSE:
                case HTMAXBUTTON:
                case HTMINBUTTON:
                case HTSYSMENU:
                case HTNOWHERE:
                case HTHELP:
                case HTERROR:
                    return HTCAPTION;
                default:
                    return  result;
            };
        }

    case WM_ERASEBKGND:
        return 1;

    default:
        return DefWindowProc (hwnd, message, wparam, lparam);
}

return 0;
}

Answer 1

你想要适当地处理WM_NCHITTEST,因为Windows也喜欢从该消息中绘制非客户端元素(在默认窗口过程中).

在我的一些自定义窗口中处理此消息后,您所遇到的问题就消失了.

编辑:我看到你已经在处理WM_NCHITTEST了,如果你正在处理一个特定的命中,你不会想要调用DefWindowProc,因为它会尝试绘制这些字幕按钮.