Method and system for displaying image data

A multi-window image displaying system comprising:

• an image memory for storing an original whole image representative of the whole of a page of document including at least characters, said characters being stored in the form of character font patterns in said image memory;
• image reduction means for reducing said original whole image from said image memory in accordance with a selected reduction factor to produce a reduced whole image;
• partial image producing means for producing a partial image representative of a partial area of said document page;
• a bit map memory for storing said reduced whole image;
• means for storing positioned data indicating correspondence of position between said partial image and said whole image;
• means for supplying mark data representative of a position of said partial area in said document page to said bit map memory to overwrite in said reduced whole image a mark positional in said reduced whole image at the location therein to which said partial image corresponds as indicated by said storing means;
• and
• display means including a display screen, and connected to receive said reduced whole image with said mark and said partial image, for displaying in a first window on said display screen said reduced whole image with said mark and for displaying in a second window on said display screen said partial image with a higher resolution than said reduced whole image.

A multi-window image displaying method comprising:

• a first step of writing in an image memory image data forming an original whole image representative of the whole of a page of a document including at least characters, said characters being stored in said image memory as data in the form of character font patterns;
• a second step of reducing the scale of said original whole image by processing the image data from said image memory in accordance with a selected reduction factor to provide data forming a reduced whole image;
• a third step of storing data representing a postional correspondence between said whole image and a partial image representative of a partial area of said document page in table means which also stores position data defining a position of a first window of a display screen to display said reduced whole image and position data defining a position of a second window of said display screen to display said partial image;
• a fourth step of producing image data forming said partial image by extracting a part of said image data in said image memory on the basis of said positional correspondence data in said table means;
• a fifth step of simultaneously displaying said reduced whole image together with a mark in said first window of said display screen and said partial image in said second window of said display screen on the basis of position data in said table means, said mark being positioned in said reduced whole image at the location to which said partial image being displayed in said second window corresponds in accordance with said stored positional correspondence data, said partial image being displayed with a higher resolution than said reduced whole image.