fix: Refactor X11 screenshot handling for Qt6 compatibility

[dengzhongyuan365-dev]

• Introduced a new function to initialize Qt6 XCB environment checks, enhancing the detection of X11 environments.
• Updated the ScreenGrabber class to utilize the new environment check for enabling XGetImage workaround.
• Removed deprecated preprocessor directives and streamlined high DPI scaling logic based on the environment.
• Improved logging for clarity during screenshot operations in X11 environments.

This update ensures better compatibility and reliability for screenshot functionality in Qt6 on X11.

[deepin-ci-robot]

deepin pr auto review

我来对这段代码进行审查：

1. 语法逻辑方面：

• 代码整体语法正确，逻辑清晰
• 新增的 initQt6XcbEnv() 函数合理地检测了 Qt6 XCB 环境
• 条件编译的使用恰当

2. 代码质量方面：

• 优点：

  • 移除了编译时的 USE_X11_GETIMAGE 宏，改为运行时检测，更加灵活
  • 将平台检测逻辑集中到 initQt6XcbEnv() 函数中，提高了代码可维护性
  • 日志信息清晰，便于调试

• 建议改进：

  • initQt6XcbEnv() 函数可以添加更多错误处理，比如检查平台名称是否为空
  • 建议在 Utils::isQt6XcbEnv 变量声明处添加注释说明其用途

3. 代码性能方面：

• 性能影响较小，主要改动是运行时检测替代编译时宏定义
• 建议在 initQt6XcbEnv() 中缓存检测结果，避免重复检测

4. 代码安全方面：

• 使用 qEnvironmentVariable() 安全地读取环境变量
• 字符串比较使用了 toLower() 进行大小写不敏感比较，提高了健壮性

具体改进建议：

1. 在 initQt6XcbEnv() 中添加空值检查：

static bool initQt6XcbEnv()
{
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    bool result = false;
    if (QGuiApplication::instance()) {
        const QString platformName = QGuiApplication::platformName();
        if (!platformName.isEmpty()) {
            result = platformName.toLower() == QLatin1String("xcb");
        }
    } else {
        const QString platformEnv = qEnvironmentVariable("QT_QPA_PLATFORM");
        if (!platformEnv.isEmpty()) {
            result = platformEnv.toLower().contains(QLatin1String("xcb"));
        }
    }
    return result;
#endif
    return false;
}

2. 在 utils.h 中添加变量注释：

// Indicates if the application is running in Qt6 with XCB platform
static bool isQt6XcbEnv;

3. 考虑添加一个静态变量缓存检测结果：

static bool initQt6XcbEnv()
{
    static bool cached = false;
    static bool result = false;
    
    if (!cached) {
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
        // ... detection logic ...
#endif
        cached = true;
    }
    return result;
}

这些改动可以进一步提高代码的健壮性和可维护性。总体来说，这是一个很好的重构，使代码更加灵活和可维护。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: dengzhongyuan365-dev, lzwind

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[dengzhongyuan365-dev]

/forcemerge

[deepin-bot]

This pr force merged! (status: unstable)