i googled text editors, and yes, this was bad idea to load full text at once.
now i'm splitting text to pages, and draw pages only when it's necessary. but still there is a problem with text objects. i'm using 2 text objects for previous and next page. when previous page is gone from screen, next page will appear. but there is always some space between them. because text object's height is fixed. i need to calculate exact number of lines, then calculate height of text object and place other text right under first one... how??)))