I think I've found the answer: it cannot be stopped *api->ProcessPages*.
I have tried the following code:
api->SetPageSegMode(tesseract::PSM_AUTO);
Pix* image = pixRead(CStringA(sSrcFile));
api->SetImage(image);
ETEXT_DESC monitor;
monitor.cancel = &CMyDocEx::cancel;
api->Recognize(&monitor);
pixDestroy(&image);
With the following cancel method:
static bool cancel(void* cancel_this, int words)
{
return m_bCancelFlag;
}
Of course, I setup *m_bCancelFlag* at my Escape key (or whatever). And it
stops properly *api->SetImage*, on demand. But this is not the case for
*api->ProcessPages*. Is there a missing feature here ?
On Wednesday, June 22, 2022 at 2:57:12 PM UTC+3 [email protected] wrote:
> I also tried this (inside the thread method):
>
> ETEXT_DESC monitor;
> monitor.cancel = &CMyDocEx::cancel;
> monitor.cancel_this = this;
> api->Recognize(&monitor);
>
>
> std::shared_ptr<tesseract::TessPDFRenderer> renderer =
> std::make_shared<tesseract::TessPDFRenderer>(
> CStringA(sSrcFile), api->GetDatapath(), false);
>
>
> if (! api->ProcessPages(CStringA(sSrcFile), nullptr, 0,
> renderer.get()))
> {
> break;
> }
>
> and
>
> // CMyDocEx header:
> class CMyDocEx : public CDocument
> {
> .....
>
> static bool cancel(void* cancel_this, int words)
> {
> return true;
> }
>
> Stopping *api->ProcessPages* it is a mission impossible ?
> On Tuesday, June 21, 2022 at 6:03:04 PM UTC+3 [email protected] wrote:
>
>> Win10, VS2017, MFC C++ application, Tesseract 4.1.1
>>
>> I started *TessBaseAPI::ProcessPage* call, and I realized I couldn't
>> stop it. I noticed the prototype of *TessBaseAPI::ProcessPages*, if the
>> int timeout_millisec parameter is greater than 0, the library uses
>> internally a *ETEXT_DESC* monitor:
>>
>> // *from TessBaseAPI source code:*
>>
>> bool TessBaseAPI::ProcessPage(Pix* pix, int page_index, const char*
>> filename,
>> const char* retry_config, int
>> timeout_millisec,
>> TessResultRenderer* renderer) {
>> ....
>> PageIterator* it = AnalyseLayout();
>>
>> if (it == nullptr) {
>> failed = true;
>> } else {
>> delete it;
>> }
>> } else if (tesseract_->tessedit_pageseg_mode == PSM_OSD_ONLY) {
>> failed = FindLines() != 0;
>> } else if (timeout_millisec > 0) {
>> // Running with a timeout.
>> ETEXT_DESC monitor;
>> monitor.cancel = nullptr;
>> monitor.cancel_this = nullptr;
>> monitor.set_deadline_msecs(timeout_millisec);
>>
>> as you see, if *timeout_millisec* is greater than 0, some monitor is set
>> up, however, not to stopping the process on demand, but for timout.
>>
>> My question is: can be stopped *TessBaseAPI::ProcessPages* in a way,
>> maybe using *ETEXT_DESC* ?
>>
>> I have tried this (*ReadImageThread* is used as multi-thread, not as
>> single thread):
>>
>> void CMyDocEx::ReadImageThread(const CString& sSrcFile)
>> {
>> do
>> {
>> std::shared_ptr<tesseract::TessBaseAPI> api =
>> std::make_shared<tesseract::TessBaseAPI>();
>> if (api->Init(CStringA(GetAppPathTemp()), "eng"))
>> {
>> break;
>> }
>>
>> api->Recognize(&m_monitor);
>>
>> std::shared_ptr<tesseract::TessPDFRenderer> renderer =
>> std::make_shared<tesseract::TessPDFRenderer>(
>> CStringA(GetFileName(sSrcFile)), api->GetDatapath(),
>> false);
>>
>> if (! api->ProcessPages(CStringA(sSrcFile), nullptr, 0,
>> renderer.get()))
>> {
>> break;
>> }
>> api->End();
>> } while (FALSE);
>> }
>>
>> where *m_monitor* is defined in my *CMyDocEx* header:
>>
>> class CMyDocEx : public CDocument
>> {
>> ....
>> protected:
>> static bool cancel(void* cancel_this, int words)
>> {
>> return m_bCancelFlag;
>> }
>> ....
>> protected:
>> ETEXT_DESC m_monitor;
>> static bool m_bCancelFlag;
>> ....
>> }
>>
>> and implementation file (*cpp*):
>>
>> bool CMyDocEx::m_bCancelFlag = false;
>>
>> CMyDocEx::CMyDocEx()
>> {
>> // TODO: add one-time construction code here
>>
>> m_monitor.cancel = &CMyDocEx::cancel;
>> m_monitor.cancel_this =
>> reinterpret_cast<void*>(CMyDocEx::m_bCancelFlag);
>> }
>>
>> and when I put *m_bCancelFlag* to true, seems to happen nothing ...
>>
>>
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