如何正确绘制简单的非客户区域(4像素红色边框)? [英] How to correctly draw simple non-client area (4 px red border)?

问题描述

我正在尝试绘制自定义的绘制非客户区域，而不是默认主题边框(Windows 10).

I'm trying to draw a custom painted non-client area, instead of default theme border (Windows 10).

我处理了 WM_NCCALCSIZE 将非客户区域的尺寸调整为每侧4个像素，然后处理了 WM_NCPAINT 绘制红色边框.

I handled WM_NCCALCSIZE to resize the non-client area to 4 pixels on each side and then handled WM_NCPAINT to draw the red border.

我的自定义绘画在首次显示应用程序时成功，但是在重新调整应用程序大小或最小化和还原应用程序时都无法重绘，尽管 WM_NCCALCSIZE 和 WM_NCPAINT 在调整大小或还原窗口时被调用.

My custom painting succeeds when application is first displayed, but fails to redraw either when application is resized, or when minimized and restored, despite the fact that both WM_NCCALCSIZE and WM_NCPAINT are called during resizing or when window is restored.

#pragma comment(lib, "UxTheme")
#include <windows.h>
#include <uxtheme.h>

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) 
{
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = NULL;
    wcex.hCursor = (HICON) LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = CreateSolidBrush(RGB(0,128,0));
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = "window";
    wcex.hIconSm = NULL;

    RegisterClassEx(&wcex);

    HWND hWnd = CreateWindowEx(
        WS_EX_COMPOSITED,
        "window",
        NULL,
        WS_OVERLAPPEDWINDOW,
        100,
        100,
        600,
        400,
        NULL,
        NULL,
        hInstance, 
        NULL); 

    ShowWindow(hWnd, nCmdShow);

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return static_cast<int>(msg.wParam);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg) {
        case WM_CREATE:
            SetWindowTheme(hWnd, L"", L"");
            return 0;
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
        case WM_NCCALCSIZE:
        {
            RECT rect;
            GetWindowRect(hWnd, &rect);
            LPNCCALCSIZE_PARAMS ncParams = (LPNCCALCSIZE_PARAMS) lParam;
            ncParams->rgrc[0].top = rect.top + 4;
            ncParams->rgrc[0].left = rect.left + 4;
            ncParams->rgrc[0].bottom = rect.bottom - 4;
            ncParams->rgrc[0].right = rect.right - 4;
            return 0;
        }
        case WM_NCPAINT:
        {
            RECT rect;
            GetWindowRect(hWnd, &rect);
            HDC dc = GetDCEx(hWnd, (HRGN) wParam, DCX_WINDOW | DCX_CACHE | DCX_INTERSECTRGN | DCX_LOCKWINDOWUPDATE);
            HPEN pen = CreatePen(PS_INSIDEFRAME, 4, RGB(255, 0, 0));
            HGDIOBJ old = SelectObject(dc, pen);
            int width = rect.right - rect.left;
            int height = rect.bottom - rect.top;
            Rectangle(dc, 0, 0, width, height);
            SelectObject(dc, old);
            DeleteObject(pen);
            ReleaseDC(hWnd, dc);
            return 0;
        }
        case WM_NCACTIVATE:
            RedrawWindow(hWnd, NULL, NULL, RDW_UPDATENOW);
            return 0;
        break;
    }
    return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

推荐答案

WM_NCPAINT 消息的 wParam 有时返回1，而不是区域的句柄(HRGN ).在这种情况下，必须使用 CreateRectRgn 函数创建 HRGN .

The wParam of WM_NCPAINT message sometimes returns 1 instead of a handle to a region (HRGN). In that case HRGN must be created using CreateRectRgn function.

#pragma comment(lib, "UxTheme")
#include <windows.h>
#include <uxtheme.h>

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) 
{
    WNDCLASSEX wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = NULL;
    wcex.hCursor = (HICON) LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = CreateSolidBrush(RGB(0,128,0));
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = "window";
    wcex.hIconSm = NULL;

    RegisterClassEx(&wcex);

    HWND hWnd = CreateWindowEx(
        NULL,
        "window",
        NULL,
        WS_OVERLAPPEDWINDOW,
        100,
        100,
        600,
        400,
        NULL,
        NULL,
        hInstance, 
        NULL); 

    ShowWindow(hWnd, nCmdShow);

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return static_cast<int>(msg.wParam);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg) {
        case WM_CREATE:
            SetWindowTheme(hWnd, L"", L"");
            return 0;
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
        case WM_NCCALCSIZE:
        {
            LPNCCALCSIZE_PARAMS ncParams = (LPNCCALCSIZE_PARAMS) lParam;
            ncParams->rgrc[0].top += 4;
            ncParams->rgrc[0].left += 4;
            ncParams->rgrc[0].bottom -= 4;
            ncParams->rgrc[0].right -= 4;
            return 0;
        }
        case WM_NCPAINT:
        {
            RECT rect;
            GetWindowRect(hWnd, &rect);
            HRGN region = NULL;
            if (wParam == NULLREGION) {
                region = CreateRectRgn(rect.left, rect.top, rect.right, rect.bottom);
            } else {
                HRGN copy = CreateRectRgn(0, 0, 0, 0);
                if (CombineRgn(copy, (HRGN) wParam, NULL, RGN_COPY)) {
                    region = copy;
                } else {
                    DeleteObject(copy);
                }
            }
            HDC dc = GetDCEx(hWnd, region, DCX_WINDOW | DCX_CACHE | DCX_INTERSECTRGN | DCX_LOCKWINDOWUPDATE);
            if (!dc && region) {
                DeleteObject(region);
            }
            HPEN pen = CreatePen(PS_INSIDEFRAME, 4, RGB(255, 0, 0));
            HGDIOBJ old = SelectObject(dc, pen);
            int width = rect.right - rect.left;
            int height = rect.bottom - rect.top;
            Rectangle(dc, 0, 0, width, height);
            SelectObject(dc, old);
            ReleaseDC(hWnd, dc);
            DeleteObject(pen);
            return 0;
        }
        case WM_NCACTIVATE:
            RedrawWindow(hWnd, NULL, NULL, RDW_UPDATENOW);
            return 0;
        break;
    }
    return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

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