CONTINUOUS PDF page problem

I am writing a simple PDF reader using poppler-qt4.

1. Here is what I have done:
QScrollArea ---- show the a PDF file
QWidget ---- widget of the scrollArea
QLabel ---- labels in the widget, one label shows a PDF page.

2. Here is the problem:
I load all the pages. It's continuous but it will be a long time to show the pages if the PDF file is very huge.

3. My question:
What should I do to make the PDF reader continuous and fast.

4. Thanks a lot

I think you can initialize your labels with a blank page (I never used poppler but I hope there's a method to get the total page number without loading all the pages) and then load the pages in a QThread.