#include <QtGlobal>
#include <QtWidgets>
#include "thumbgen.h"
#include "pdf_page_widget.h"

ThumbGen::ThumbGen(void) {
  
}

double ThumbGen::calcDpi(Poppler::Page* pdfPage, QSize targetSize) {
  double dpi;
  QSizeF oriSize = pdfPage->pageSizeF();
  double oriDpi = 72;

  if(targetSize.width() > targetSize.height()) {
    dpi = targetSize.height() / (float)oriSize.height()*72;
  } else {
    dpi = targetSize.width() / (float)oriSize.width()*72;
  }

  return dpi;
}

void ThumbGen::run(void) {
  while(pWidgets.size() != 0) {
    mutex.lock();
    PDFPageWidget* pw = pWidgets.first();
    pWidgets.pop_front();
    Poppler::Page* pp = pPages.first();
    pPages.pop_front();
    mutex.unlock();

    double dpi = calcDpi(pp, pw->size());
    QImage pageImage = pp->renderToImage(dpi, dpi);
    emit updateThumbnail(pageImage, pw);
  }
}

void ThumbGen::render(PDFPageWidget* pw, Poppler::Page* pp) {
  mutex.lock();
  pWidgets.append(pw);
  pPages.append(pp);
  mutex.unlock();
}