# 微距能力设置(C/C++)

从API version 19开始，支持设置微距能力。微距能力是指通过光学设计与算法优化，实现近距离对焦并清晰捕捉微小物体细节的相机功能。

#### 开发步骤

详细的API说明请参考OH\_Camera。

1.  导入NDK接口。选择系统提供的NDK接口能力，导入NDK接口的方法如下。
    
    ```
    #include <cstdint>
    #include <native_buffer/buffer_common.h>
    #include <unistd.h>
    #include <string>
    #include <thread>
    #include <cstdio>
    #include <fcntl.h>
    #include <map>
    #include <string>
    #include <vector>
    #include <native_buffer/native_buffer.h>
    #include "iostream"
    #include "mutex"
    
    #include "hilog/log.h"
    #include "ohcamera/camera.h"
    #include "ohcamera/camera_input.h"
    #include "ohcamera/capture_session.h"
    #include "ohcamera/photo_output.h"
    #include "ohcamera/preview_output.h"
    #include "ohcamera/video_output.h"
    #include "napi/native_api.h"
    #include "ohcamera/camera_manager.h"
    #include <window_manager/oh_display_info.h>
    #include <window_manager/oh_display_manager.h>
    
    namespace OHOS_CAMERA_SAMPLE {
    class NDKCamera {
      public:
        struct CameraBuildingConfig {
            char *str;
            uint32_t focusMode;
            uint32_t cameraDeviceIndex;
            bool isVideo;
            bool isHdr;
            char *videoId;
        };
        ~NDKCamera();
        explicit NDKCamera(CameraBuildingConfig config);
        // ...
    };
    } // namespace OHOS_CAMERA_SAMPLE
    ```
    
2.  在CMake脚本中链接相关动态库。
    
    ```
    target_link_libraries(entry PUBLIC
        libace_napi.z.so
        libohcamera.so
        libhilog_ndk.z.so
    )
    ```
    
3.  通过OH\_CaptureSession\_IsMacroSupported()方法，检测当前设备是否支持微距能力。
    
    ```
    bool NDKCamera::IsMacroSupported(Camera_CaptureSession* captureSession)
    {
        // 判断设备是否支持微距能力。
        bool isMacroSupported = false;
        if (captureSession == nullptr) {
            OH_LOG_ERROR(LOG_APP, "IsMacroSupported: session is nullptr.");
            return isMacroSupported;
        }
        Camera_ErrorCode ret = OH_CaptureSession_IsMacroSupported(captureSession, &isMacroSupported);
        if (ret != CAMERA_OK) {
            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_IsMacroSupported failed.");
        }
        if (isMacroSupported) {
            OH_LOG_INFO(LOG_APP, "support macro capability.");
        } else {
            OH_LOG_ERROR(LOG_APP, "No support macro capability.");
        }
        return isMacroSupported;
    }
    ```
    
4.  使用OH\_CaptureSession\_EnableMacro()方法开启或关闭微距能力。
    
    ```
    void NDKCamera::EnableMacro(bool isMacro)
    {
        OH_LOG_INFO(LOG_APP, "EnableMacro: isMacro is %{public}d", isMacro);
        if (IsMacroSupported(captureSession_)) {
            Camera_ErrorCode ret = OH_CaptureSession_EnableMacro(captureSession_, isMacro);
            if (ret != CAMERA_OK) {
                OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_EnableMacro failed.");
            }
        }
    }
    ```
    

#### 状态监听

从API version 20开始，支持监听微距能力是否发生改变。

通过OH\_CaptureSession\_RegisterMacroStatusChangeCallback()函数注册回调，返回监听结果。

```
void MacroStatusCallback(Camera_CaptureSession *captureSession, bool isMacroDetected)
{
    OH_LOG_INFO(LOG_APP, "MacroStatusCallback isMacro: %{public}d", isMacroDetected);
}

// 注册回调函数。
Camera_ErrorCode NDKCamera::RegisterMacroStatusCallback()
{
    Camera_ErrorCode ret = OH_CaptureSession_RegisterMacroStatusChangeCallback(captureSession_, MacroStatusCallback);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_RegisterMacroStatusChangeCallback failed.");
    }
    return ret;
}

// 解注册
Camera_ErrorCode NDKCamera::UnregisterMacroStatusCallback()
{
    Camera_ErrorCode ret = OH_CaptureSession_UnregisterMacroStatusChangeCallback(captureSession_, MacroStatusCallback);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_UnregisterMacroStatusChangeCallback failed.");
    }
    return ret;
}
```