Read Accessibility Info from Electron based apps on Mac

Chrome 以及众多 Electron 的 app 其实都是支持暴露网页内容给 Mac 的 AX 的，只不过和 Safari 不同，这个模式默认是不开启的，只有检测到 VoiceOver 之类的辅助工具在工作时才启动。如果自己有个 app 想实现类似的功能，就要手动设置 AXManualAccessibility 和 AXEnhancedUserInterface 这两个 attribute，有的 app 读前者，有的读后者。

func setAttributes(_ app: NSRunningApplication) {
    let axApp = AXUIElementCreateApplication(app.processIdentifier)
    let manualAccessabilityAttribute = "AXManualAccessibility"
    let enhancedUserInterfaceAttribute = "AXEnhancedUserInterface"
    var result = AXUIElementSetAttributeValue(axApp, manualAccessabilityAttribute as CFString, true as CFTypeRef)
    if result == .success {
        print("Successfully set \(manualAccessabilityAttribute)")
    } else {
        print("Failed to set \(manualAccessabilityAttribute): \(result.rawValue)")
    }
    result = AXUIElementSetAttributeValue(axApp, enhancedUserInterfaceAttribute as CFString, true as CFTypeRef)
    if result == .success {
        print("Successfully set \(enhancedUserInterfaceAttribute)")
    } else {
        print("Failed to set \(enhancedUserInterfaceAttribute): \(result.rawValue)")
    }
}

开启后，就能愉快地读一众 Electron app 了，例如 Slack 或者 Notion，还可以画些 bounding box：