Graphic system with read/write overlap detector

摘要

A graphics system for storing and editing graphic images represented by digital data, includes a frame memory for storing pixel data representing graphic images including first and second graphic objects. The pixel data is stored at addresses, each being associated with one or more graphic fragment forming the first and second graphic objects. First and second addresses are respectively associated with those of the graphic fragments forming the first and second graphic objects. A memory controller controls writing and reading the pixel data to and from the frame memory. A fragment editor is provided to receive the pixel data read from the first address and modify the associated fragment with the received pixel data so as to form modified pixel data. An address detector detects the first address responsive to a request to read the pixel data from the first address and the second address responsive to a subsequent request to read pixel data from the second address. The detector compares the detected first and second addresses to identify an overlap of the first and second graphic objects. If an overlap is identified, the controller controls the writing of the modified pixel data to the first address before the reading of the pixel data from the second address. <IMAGE>