winapi - 创建没有标题栏、可调整大小边框且没有虚假 6px 白色条纹的窗口

Question

我想要一个没有标题栏但有可调整大小的框架和阴影的窗口。
这可以通过删除 WS_CAPTION 并添加 WS_THICKFRAME 轻松实现，但是，从 Windows 10 开始，有一个 6px 的白色非客户区。

使用以下代码，我创建了一个窗口并用黑色绘制所有客户区，窗口获得左、右和底部 6px 的透明边距，但顶部边距为白色。

#ifndef UNICODE
#define UNICODE
#endif 

#include <windows.h>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
    // Register the window class.
    const wchar_t CLASS_NAME[]  = L"Sample Window Class";

    WNDCLASS wc = { };

    wc.lpfnWndProc   = WindowProc;
    wc.hInstance     = hInstance;
    wc.lpszClassName = CLASS_NAME;

    RegisterClass(&wc);

    // Create the window.

    HWND hwnd = CreateWindowEx(
        0,                              // Optional window styles.
        CLASS_NAME,                     // Window class
        L"",    // Window text
                0,
        // Size and position
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
        NULL,       // Parent window    
        NULL,       // Menu
        hInstance,  // Instance handle
        NULL        // Additional application data
        );

    ShowWindow(hwnd, nCmdShow);

    LONG lStyle = GetWindowLong(hwnd, GWL_STYLE);
    lStyle |= WS_THICKFRAME;
    lStyle = lStyle & ~WS_CAPTION;
    SetWindowLong(hwnd, GWL_STYLE, lStyle);
    SetWindowPos(hwnd, NULL, 0,0,0,0, SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);

    // Run the message loop.

    MSG msg = { };
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hwnd, &ps);


            // Paint everything black
            FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOWTEXT));
            EndPaint(hwnd, &ps);
        }
        return 0;

    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

渲染:


我怎样才能去除白色条纹？
我还发现了这个相关的 Qt 错误报告 QTBUG-47543由于不是 Qt 问题而被关闭，因为它可以用 win32 api 重现。

Answer 1

那不是错误。在 Windows 10 中，左/右/底部的边框是透明的。顶部边框不透明。你应该保持原样。可能没有人会提示。

要更改它，您必须修改非客户区。这在 Windows Vista 及更高版本中相当困难。见 Custom Window Frame Using DWM以供引用。

查找边框粗细

使用 DwmExtendFrameIntoClientArea访问非客户区

使用 BeginBufferedPaint在非客户区绘制不透明颜色

Windows 10 示例:



(有关与 Windows Vista、7、8 的兼容性，请参阅下一个示例)

//requires Dwmapi.lib and UxTheme.lib
#include <Windows.h>
#include <Dwmapi.h>

void my_paint(HDC hdc, RECT rc)
{
    HBRUSH brush = CreateSolidBrush(RGB(0, 128, 0));
    FillRect(hdc, &rc, brush);
    DeleteObject(brush);
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    static RECT border_thickness;

    switch (uMsg)
    {
    case WM_CREATE:
    {
        //find border thickness
        SetRectEmpty(&border_thickness);
        if (GetWindowLongPtr(hwnd, GWL_STYLE) & WS_THICKFRAME)
        {
            AdjustWindowRectEx(&border_thickness, GetWindowLongPtr(hwnd, GWL_STYLE) & ~WS_CAPTION, FALSE, NULL);
            border_thickness.left *= -1;
            border_thickness.top *= -1;
        }
        else if (GetWindowLongPtr(hwnd, GWL_STYLE) & WS_BORDER)
        {
            SetRect(&border_thickness, 1, 1, 1, 1);
        }

        MARGINS margins = { 0 };
        DwmExtendFrameIntoClientArea(hwnd, &margins);
        SetWindowPos(hwnd, NULL, 0, 0, 0, 0, SWP_SHOWWINDOW | SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
        break;
    }

    case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        RECT rc = ps.rcPaint;
        BP_PAINTPARAMS params = { sizeof(params), BPPF_NOCLIP | BPPF_ERASE };
        HDC memdc;
        HPAINTBUFFER hbuffer = BeginBufferedPaint(hdc, &rc, BPBF_TOPDOWNDIB, &params, &memdc);

        my_paint(memdc, rc);

        BufferedPaintSetAlpha(hbuffer, &rc, 255);
        EndBufferedPaint(hbuffer, TRUE);

        EndPaint(hwnd, &ps);
        return 0;
    }

    case WM_NCACTIVATE:
        return 0;

    case WM_NCCALCSIZE:
        if (lParam)
        {
            NCCALCSIZE_PARAMS* sz = (NCCALCSIZE_PARAMS*)lParam;
            sz->rgrc[0].left += border_thickness.left;
            sz->rgrc[0].right -= border_thickness.right;
            sz->rgrc[0].bottom -= border_thickness.bottom;
            return 0;
        }
        break;

    case WM_NCHITTEST:
    {
        //do default processing, but allow resizing from top-border
        LRESULT result = DefWindowProc(hwnd, uMsg, wParam, lParam);
        if (result == HTCLIENT)
        {
            POINT pt = { GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam) };
            ScreenToClient(hwnd, &pt);
            if (pt.y < border_thickness.top) return HTTOP;
        }
        return result;
    }

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR, int)
{
    const wchar_t CLASS_NAME[] = L"Sample Window Class";

    WNDCLASS wc = {};
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.lpszClassName = CLASS_NAME;
    RegisterClass(&wc);

    CreateWindowEx(0, CLASS_NAME,   NULL,
        WS_VISIBLE | WS_THICKFRAME | WS_POPUP,
        10, 10, 600, 400, NULL, NULL, hInstance, NULL);

    MSG msg = {};
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

为了与 Windows Vista/7/8 兼容，请改用此过程。这将绘制左/上/下边框以及上边框。此窗口将显示为一个简单的矩形，并带有调整边框的大小:

//for Windows Vista, 7, 8, 10
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    static RECT border_thickness;

    switch (uMsg)
    {
    case WM_CREATE:
    {
        //find border thickness
        SetRectEmpty(&border_thickness);
        if (GetWindowLongPtr(hwnd, GWL_STYLE) & WS_THICKFRAME)
        {
            AdjustWindowRectEx(&border_thickness, GetWindowLongPtr(hwnd, GWL_STYLE) & ~WS_CAPTION, FALSE, NULL);
            border_thickness.left *= -1;
            border_thickness.top *= -1;
        }
        else if (GetWindowLongPtr(hwnd, GWL_STYLE) & WS_BORDER)
        {
            SetRect(&border_thickness, 1, 1, 1, 1);
        }

        MARGINS margins = { 0 };
        DwmExtendFrameIntoClientArea(hwnd, &margins);
        SetWindowPos(hwnd, NULL, 0, 0, 0, 0, SWP_SHOWWINDOW | SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
        break;
    }

    case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        RECT rc = ps.rcPaint;
        BP_PAINTPARAMS params = { sizeof(params), BPPF_NOCLIP | BPPF_ERASE };
        HDC memdc;
        HPAINTBUFFER hbuffer = BeginBufferedPaint(hdc, &rc, BPBF_TOPDOWNDIB, &params, &memdc);

        my_paint(memdc, rc);

        BufferedPaintSetAlpha(hbuffer, &rc, 255);
        EndBufferedPaint(hbuffer, TRUE);

        EndPaint(hwnd, &ps);
        return 0;
    }

    case WM_NCACTIVATE:
        return 0;

    case WM_NCCALCSIZE:
        if (lParam)
            return 0;

    case WM_NCHITTEST:
    {
        POINT pt = { GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam) };
        ScreenToClient(hwnd, &pt);
        RECT rc;
        GetClientRect(hwnd, &rc);
        enum {left=1, top=2, right=4, bottom=8};
        int hit = 0;
        if (pt.x < border_thickness.left) hit |= left;
        if (pt.x > rc.right - border_thickness.right) hit |= right;
        if (pt.y < border_thickness.top) hit |= top;
        if (pt.y > rc.bottom - border_thickness.bottom) hit |= bottom;

        if (hit & top && hit & left) return HTTOPLEFT;
        if (hit & top && hit & right) return HTTOPRIGHT;
        if (hit & bottom && hit & left) return HTBOTTOMLEFT;
        if (hit & bottom && hit & right) return HTBOTTOMRIGHT;
        if (hit & left) return HTLEFT;
        if (hit & top) return HTTOP;
        if (hit & right) return HTRIGHT;
        if (hit & bottom) return HTBOTTOM;

        return HTCLIENT;
    }

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}