Image display device having multi-window system

A method for displaying an image on a display area capable of displaying first and second overlapping windows, wherein said second window overlaps said first window such that said first window includes a non-overlapped area, said method comprising the steps of:

• storing image data having a first size in a page memory;
• dividing said non-overlapped area of said first window into at least one rectangular area if said first window is overlapped by said second window when said image data having its size modified from said first size to a second size is displayed on said first window;
• extracting a portion of said image data corresponding to said non-overlapped area of said first window from said page memory, modifying said portion of said image data extracted from said page memory from said first size to said second size, and storing said portion of said image data modified to said second size in a display memory, if non-overlapped area of said first window includes only one rectangular area;
• modifying said image data stored in said page memory from said first size to said second size and storing said image data having said second size in a work memory, if said non-overlapped area of said first window includes at least two rectangular areas;
• and
• extracting said image data corresponding to said non-overlapped area including at least two rectangular areas of said first window from said work memory, said image data extracted from said work memory having said second size, and storing said image data having said second size extracted from said work memory in said display memory.