Development : Zoom (2)

Zooming is added in. The repositioning, joining of pieces, and rotating multipiece when scaling have been corrected. 

Zoom Out

However, it is not working well with high resolution image or big number of pieces. It...is...too...slow... ~>.<~
This may be caused by the excessive call of repaint function, since it is called every time a piece is moved. Recalculation for every scaling done may be another cause.

Another problem is the scroll bar does not change according to the puzzle size. I have tried setting the maximum and minimum size of the scroll bar, setting model of the scroll bar, set viewport of the scrollpane, override the setpreferredsize of the the scrollpane, but none seems to work.
The scroll bar just shrink once and goes back to the original size. Some articles and forum discussions categorize this as a bug. Some concluded with the solution to this matter, for example : https://forums.oracle.com/forums/thread.jspa?threadID=1361016 or http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4297009. However, it did not work in this application. Is this really a bug? Or is it a bug that I created?
Is it the time to give up on the zoom? I...do...not...know............

HWAITING MM12/2C!