Using Image_NativeModule to Process Image Information

You can use the ImageInfo class to set and read the rectangle size, component information, and pixel information of an image.

How to Develop

Adding Dependencies

Open the src/main/cpp/CMakeLists.txt file of the native project, add libohimage.so, libimage_receiver.so, libnative_image.so, and libhilog_ndk.z.so (on which the log APIs depend) to the target_link_libraries dependency.

target_link_libraries(entry PUBLIC libhilog_ndk.z.so libohimage.so libimage_receiver.so libnative_image.so)

Calling the Native APIs

For details about the APIs, see Image_NativeModule.

Create a native C++ application in DevEco Studio. The project created by default contains the index.ets file, and a hello.cpp or napi_init.cpp file is generated in the entry\src\main\cpp directory. In this example, the generated file is hello.cpp. Implement the C APIs in hello.cpp. Refer to the sample code below.

#include <hilog/log.h>
#include <multimedia/image_framework/image/image_native.h>
#include <multimedia/image_framework/image/image_receiver_native.h>

#undef LOG_DOMAIN
#define LOG_DOMAIN 0x3200

#undef LOG_TAG
#define LOG_TAG "MY_TAG"

#define IMAGE_WIDTH 320
#define IMAGE_HEIGHT 480
#define IMAGE_CAPACITY 2

static void ImageNativeCTest()
{
    // Create an OH_ImageReceiverOptions instance.
    OH_ImageReceiverOptions* options = nullptr;
    Image_ErrorCode errCode = OH_ImageReceiverOptions_Create(&options);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest create image receiver options failed, errCode: %{public}d.", errCode);
        return;
    }

    Image_Size imgSize;
    imgSize.width = IMAGE_WIDTH;
    imgSize.height = IMAGE_HEIGHT;

    // Set the size property in OH_ImageReceiverOptions. This property is a mandatory input parameter and does not actually take effect. Image properties are determined by the producer, for example, the camera.
    errCode = OH_ImageReceiverOptions_SetSize(options, imgSize);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest set image receiver options size failed, errCode: %{public}d.", errCode);
        OH_ImageReceiverOptions_Release(options);
        return;
    }

    // Set the capacity property of OH_ImageReceiverOptions.
    errCode = OH_ImageReceiverOptions_SetCapacity(options, IMAGE_CAPACITY);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest set image receiver options capacity failed, errCode: %{public}d.", errCode);
        OH_ImageReceiverOptions_Release(options);
        return;
    }

    // Create an OH_ImageReceiverNative instance.
    OH_ImageReceiverNative* receiver = nullptr;
    errCode = OH_ImageReceiverNative_Create(options, &receiver);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest create image receiver failed, errCode: %{public}d.", errCode);
        OH_ImageReceiverOptions_Release(options);
        return;
    }

    // Read the next image object of OH_ImageReceiverNative.
    OH_ImageNative* image = nullptr;
    errCode = OH_ImageReceiverNative_ReadNextImage(receiver, &image);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image receiver next image failed, errCode: %{public}d.", errCode);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the size property in OH_ImageNative. This property does not actually take effect. Image properties are determined by the producer, for example, the camera.
    Image_Size imgSizeRead;
    errCode = OH_ImageNative_GetImageSize(image, &imgSizeRead);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image size failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the number of elements in the component list of OH_ImageNative.
    size_t componentTypeSize = 0;
    errCode = OH_ImageNative_GetComponentTypes(image, nullptr, &componentTypeSize);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image component types failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the component list of OH_ImageNative.
    uint32_t* components = new uint32_t[componentTypeSize];
    errCode = OH_ImageNative_GetComponentTypes(image, &components, &componentTypeSize);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image component types failed, errCode: %{public}d.", errCode);
        delete [] components;
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    delete [] components;

    // Read the buffer object corresponding to the first component of OH_ImageNative.
    OH_NativeBuffer* nativeBuffer = nullptr;
    errCode = OH_ImageNative_GetByteBuffer(image, components[0], &nativeBuffer);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image byte buffer failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the size of the buffer corresponding to the first component of OH_ImageNative.
    size_t nativeBufferSize = 0;
    errCode = OH_ImageNative_GetBufferSize(image, components[0], &nativeBufferSize);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image buffer size failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the row stride corresponding to the first component of OH_ImageNative.
    int32_t rowStride = 0;
    errCode = OH_ImageNative_GetRowStride(image, components[0], &rowStride);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image row stride failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the pixel stride corresponding to the first component of OH_ImageNative.
    int32_t pixelStride = 0;
    errCode = OH_ImageNative_GetPixelStride(image, components[0], &pixelStride);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get image pixel stride failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Read the timestamp of the OH_ImageNative instance.
    int64_t timestamp = 0;
    errCode = OH_ImageNative_GetTimestamp(image, &timestamp);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest get timestamp failed, errCode: %{public}d.", errCode);
        OH_ImageNative_Release(image);
        OH_ImageReceiverOptions_Release(options);
        OH_ImageReceiverNative_Release(receiver);
        return;
    }

    // Release the OH_ImageNative instance.
    errCode = OH_ImageNative_Release(image);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest release image native failed, errCode: %{public}d.", errCode);
    }

    // Release the OH_ImageReceiverOptions instance.
    errCode = OH_ImageReceiverOptions_Release(options);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest release image receiver options failed, errCode: %{public}d.", errCode);
    }

    // Release the OH_ImageReceiverOptions instance.
    errCode = OH_ImageReceiverNative_Release(receiver);
    if (errCode != IMAGE_SUCCESS) {
        OH_LOG_ERROR(LOG_APP, "ImageReceiverNativeCTest release image receiver failed, errCode: %{public}d.", errCode);
    }
}