使用Image_NativeModule完成多图对象解码

创建ImageSource实例，解码获取Picture，然后释放ImageSource实例。

开发步骤

添加链接库

在进行应用开发之前，开发者需要打开native工程的src/main/cpp/CMakeLists.txt，在target_link_libraries依赖中添加libimage_source.so 以及日志依赖libhilog_ndk.z.so。

target_link_libraries(entry PUBLIC libhilog_ndk.z.so libimage_source.so)

Native接口调用

具体接口说明请参考Image_NativeModule。

在Deveco Studio新建Native C++应用，默认生成的项目中包含index.ets文件，在entry\src\main\cpp目录下会自动生成一个cpp文件（hello.cpp或napi_init.cpp，本示例以hello.cpp文件名为例）。在hello.cpp中实现C API接口调用逻辑，示例代码如下：

解码接口使用示例

部分接口在API version 20以后才支持，需要开发者在进行开发时选择合适的API版本。

导入相关头文件。

#include <hilog/log.h>
#include <multimedia/image_framework/image/image_native.h>
#include <multimedia/image_framework/image/image_packer_native.h>
#include <multimedia/image_framework/image/image_source_native.h>
#include <multimedia/image_framework/image/picture_native.h>
#include <multimedia/image_framework/image/pixelmap_native.h>

日志宏定义可参考下述代码按实际需求自行修改。

#undef LOG_DOMAIN
#undef LOG_TAG
#define LOG_DOMAIN 0x3200
#define LOG_TAG "IMAGE_SAMPLE"

定义ImagePictureNative类。

class ImagePictureNative {
public:
    Image_ErrorCode errorCode = IMAGE_SUCCESS;
    OH_DecodingOptionsForPicture *options = nullptr;
    OH_ImagePackerNative *imagePacker = nullptr;
    OH_PackingOptions *packerOptions = nullptr;
    OH_PictureNative *picture = nullptr;
    OH_ImageSourceNative *source = nullptr;
    ImagePictureNative() {}
    ~ImagePictureNative() {}
};

创建一个ImagePictureNative实例。

static ImagePictureNative *g_thisPicture = new ImagePictureNative();

定义ImageAuxiliaryPictureNative类。

class ImageAuxiliaryPictureNative {
public:
    Image_ErrorCode errorCode = IMAGE_SUCCESS;
    Image_AuxiliaryPictureType type = AUXILIARY_PICTURE_TYPE_GAINMAP;
    OH_AuxiliaryPictureNative *auxiliaryPicture = nullptr;
    size_t buffSize = 640 * 480 * 4; // 辅助图size：`长 * 宽 * 每个像素占用的字节数`。
    ImageAuxiliaryPictureNative() {}
    ~ImageAuxiliaryPictureNative() {}
};

创建一个ImageAuxiliaryPictureNative实例。

static ImageAuxiliaryPictureNative *g_thisAuxiliaryPicture  = new ImageAuxiliaryPictureNative();

创建GetJsResult函数处理napi返回值。

// 处理napi返回值。
napi_value GetJsResult(napi_env env, int result)
{
    napi_value resultNapi = nullptr;
    napi_create_int32(env, result, &resultNapi);
    return resultNapi;
}

创建解码参数，配置解码参数，调用解码接口进行解码并获取辅助图。

// 释放ImageSource。
napi_value ReleasePictureSource(napi_env env, napi_callback_info info)
{
    if (g_thisPicture->source != nullptr) {
        g_thisPicture->errorCode = OH_ImageSourceNative_Release(g_thisPicture->source);
        g_thisPicture->source = nullptr;
        return GetJsResult(env, g_thisPicture->errorCode);
    }
    
    if (g_thisPicture->picture != nullptr) {
        g_thisPicture->errorCode = OH_PictureNative_Release(g_thisPicture->picture);
        g_thisPicture->picture = nullptr;
        return GetJsResult(env, g_thisPicture->errorCode);
    }
    
    OH_LOG_DEBUG(LOG_APP, "ReleasePictureSource source is null !");
    return GetJsResult(env, g_thisPicture->errorCode);
}

// 创造解码参数。
napi_value CreateDecodingOptions(napi_env env, napi_callback_info info)
{
    g_thisPicture->errorCode = OH_DecodingOptionsForPicture_Create(&g_thisPicture->options);

    if (g_thisPicture->errorCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "OH_DecodingOptionsForPicture_Create failed, errCode: %{public}d.",
                     g_thisPicture->errorCode);
        return GetJsResult(env, g_thisPicture->errorCode);
    } else {
        OH_LOG_DEBUG(LOG_APP, "OH_DecodingOptionsForPicture_Create success !");
    }

    return GetJsResult(env, g_thisPicture->errorCode);
}

// 配置解码参数 从应用层传入。
napi_value SetDesiredAuxiliaryPictures(napi_env env, napi_callback_info info)
{
    size_t argc = 1;
    napi_value args[1] = {nullptr};
    if (napi_get_cb_info(env, info, &argc, args, nullptr, nullptr) != napi_ok || argc < 1 || args[0] == nullptr) {
        OH_LOG_ERROR(LOG_APP, "napi_get_cb_info failed !");
        return GetJsResult(env, IMAGE_BAD_PARAMETER);
    }

    uint32_t length = 0;
    napi_get_array_length(env, args[0], &length);
    if (length <= 0) {
        OH_LOG_ERROR(LOG_APP, "napi_get_array_length failed !");
        return GetJsResult(env, IMAGE_UNKNOWN_ERROR);
    }
    Image_AuxiliaryPictureType typeList[length];
    for (int index = 0; index < length; index++) {
        napi_value element;
        uint32_t ulType = 0;
        napi_get_element(env, args[0], index, &element);
        napi_get_value_uint32(env, element, &ulType);
        typeList[index] = static_cast<Image_AuxiliaryPictureType>(ulType);
        OH_LOG_DEBUG(LOG_APP, "ulType is :%{public}d", ulType);
    }
    
    // 调用OH_DecodingOptionsForPicture_Create接口创建DecodingOptions。
    CreateDecodingOptions(env, info);
    g_thisPicture->errorCode =
        OH_DecodingOptionsForPicture_SetDesiredAuxiliaryPictures(g_thisPicture->options, typeList, length);
    if (g_thisPicture->errorCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "OH_DecodingOptionsForPicture_SetDesiredAuxiliaryPictures failed,errCode: %{public}d.",
                     g_thisPicture->errorCode);
        return GetJsResult(env, g_thisPicture->errorCode);
    } else {
        OH_LOG_DEBUG(LOG_APP, "OH_DecodingOptionsForPicture_SetDesiredAuxiliaryPictures success !");
    }

    return GetJsResult(env, g_thisPicture->errorCode);
}

// 解码。
napi_value CreatePictureByImageSource(napi_env env, napi_callback_info info)
{
    size_t argc = 1;
    napi_value args[1] = {nullptr};

    if (napi_get_cb_info(env, info, &argc, args, nullptr, nullptr) != napi_ok || argc < 1 || args[0] == nullptr) {
        OH_LOG_ERROR(LOG_APP, "CreatePicture_ napi_get_cb_info failed !");
        return GetJsResult(env, IMAGE_BAD_PARAMETER);
    }
    
    char filePath[MAX_SIZE];
    size_t pathSize;
    napi_get_value_string_utf8(env, args[0], filePath, MAX_SIZE, &pathSize);

    g_thisPicture->errorCode = OH_ImageSourceNative_CreateFromUri(filePath, pathSize, &g_thisPicture->source);
    if (g_thisPicture->errorCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "OH_ImageSourceNative_CreateFromUri failed, errCode: %{public}d.",
                     g_thisPicture->errorCode);
        return GetJsResult(env, g_thisPicture->errorCode);
    } else {
        OH_LOG_DEBUG(LOG_APP, "OH_ImageSourceNative_CreateFromUri success !");
    }
    
    // 先创建解码参数，再进行解码，此处创建解码参数的接口在SetDesiredAuxiliaryPictures实现。
    g_thisPicture->errorCode =
        OH_ImageSourceNative_CreatePicture(g_thisPicture->source, g_thisPicture->options, &g_thisPicture->picture);
    
    // 释放options。
    OH_DecodingOptionsForPicture_Release(g_thisPicture->options);
    g_thisPicture->options = nullptr;
    
    g_thisAuxiliaryPicture ->errorCode = OH_PictureNative_GetAuxiliaryPicture(g_thisPicture->picture,
        g_thisAuxiliaryPicture ->type, &g_thisAuxiliaryPicture ->auxiliaryPicture);
    if (g_thisAuxiliaryPicture ->errorCode == IMAGE_SUCCESS) {
        uint8_t* buff = new uint8_t[g_thisAuxiliaryPicture ->buffSize];
        OH_AuxiliaryPictureNative_ReadPixels(g_thisAuxiliaryPicture ->auxiliaryPicture, buff,
            &g_thisAuxiliaryPicture ->buffSize);
        OH_AuxiliaryPictureNative_Release(g_thisAuxiliaryPicture ->auxiliaryPicture);
        g_thisAuxiliaryPicture ->auxiliaryPicture = nullptr;
        delete []buff;
    }
    
    if (g_thisPicture->errorCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageSourceNative_CreatePicture failed, errCode: %{public}d.",
                     g_thisPicture->errorCode);
        return GetJsResult(env, g_thisPicture->errorCode);
    } else {
        OH_LOG_DEBUG(LOG_APP, "ImageSourceNative_CreatePicture success !");
    }
    
    return GetJsResult(env, g_thisPicture->errorCode);
}

开发步骤​

添加链接库​

Native接口调用​

开发步骤

添加链接库

Native接口调用