tesseract v3.03 render PDF with searchable text example

Question

From the tesseract v3.03 's release note, tesseract is now supporting render PDF output with searchable text, but I don't know how to use this feature in my code.
Currently I use tess-two for my android app, then I just wonder can this feature work for android?

It would be great if you can give me an example that uses tesseract api to render pdf, and then I will try to port missing functions for tess-two library.
Thanks in advance.

P/s: I can see the pdfrenderer file which may handle render pdf output, but I don't know how to apply it with base api.

Update: here is my try:

 tesseract::TessResultRenderer* renderer = new tesseract::TessPDFRenderer(nat->api.GetDatapath());
__android_log_print(ANDROID_LOG_ERROR, "Test_tesseract", "data path = %s", nat->api.GetDatapath());
if (!nat->api.ProcessPages(c_file_name, NULL, 0, renderer)) {
    __android_log_print(ANDROID_LOG_ERROR, "Test_tesseract", "process page failed");
    delete renderer;
    return;
}

FILE* fout = fopen(c_pdf_file_name, "wb");
if (fout == NULL) {
    __android_log_print(ANDROID_LOG_ERROR, "Test_tesseract", "Cannot create output file %s\n", c_pdf_file_name);
    delete renderer;
    return;
}

const char* data;
int dataLength;

bool boolValue = renderer->GetOutput(&data, &dataLength);
if (boolValue) {
    fwrite(data, 1, dataLength, fout);
    if (fout != stdout)
        fclose(fout);
    else
        clearerr(fout);
}else{
    __android_log_print(ANDROID_LOG_ERROR, "Test_tesseract", "Cannot get output file");
}
    
delete renderer;

My code is failed at ProcessPages method. After write log (I have a problem with debugging in ndk), I found pdfrender BeginDocument always return false in TessBaseAPI::ProcessPages method of baseapi.cpp:

if (renderer && !renderer->BeginDocument(kUnknownTitle)) {
    success = false;
 }

Do I miss something?

P/s: I use tess-two, which prefer baseapi to capi

Answer 1

It's as follows:

TessResultRenderer renderer = api.TessPDFRendererCreate(dataPath);
api.TessBaseAPIProcessPages1(handle, image, null, 0, renderer);
PointerByReference data = new PointerByReference();
IntByReference dataLength = new IntByReference();
api.TessResultRendererGetOutput(renderer, data, dataLength);
byte[] bytes = data.getValue().getByteArray(0, dataLength);
// then write bytes array to a file with PDF extension.

If you have problem following the codes, check out the renderer example in this post.