A user-friendly procedure for the generation and display of geometric figures on a graphics screen uses a cursor placement device such as a joy stick to both define the initial position and size of the geometrical figure. Two specific examples are described: the generation of a circle and the generation of a square or rectangle. In the first example, the cursor is first positioned to point to the center of the circle at which point a small circle is drawn. The circle is expanded in response to the pressing of a designated key by the user until the desired size is attained. In the second example, the pointing by the cursor is to the upper left corner of the square or rectangle, and the square or rectangle is then expanded in response to the user deflecting the joy stick down and to the right.

A real time graphic processor is disclosed which processes graphic cell specifications on a scan line-by-line basis to generate pixel data. The pixel data from each cell specification is assembled to form a completed scan line of pixel data which is used to modulate a printing element, such as a laser diode. The invented graphic processor contains a special purpose cell specification processor which, in addition to generating the pixel data, modifies the cell specification by substituting new horizontal location and cell height indicator values. The modified graphic cell specification is then recirculated to the cell specification processor memory for processing the next scan line.

A character generator provides video signals representing desired characters which may be held in a store capable of rapid access. The character information is processed in a manipulator to provide a change in shape, size or orientation for example. Field stores receive this manipulated information via switches as well as reference information from a generator. Read out from the respective field stores is arranged to occur when information is not being received by that store. After read out, the information is replaced by reference information, prior to the receipt of further manipulated character information. The reference information may be configured so as to include a portion of previously derived image data.

A video/graphics memory system includes a memory device (30) having a memory core (14) and first and serial registers (16, 36). The memory device thus has a random-access port (24) for graphics data, a first serial access port (22) for image output to a display, and an auxiliary or second serial port (32) for input and output of video signal data. A single memory thus stores both video and graphics data, while the processor still has access to the random access port of the memory. Two video outputs can be provided simultaneously, or the data withdrawn through the auxiliary port can be subject to processing and then written back into the memory. In alternative arrangements, instead of using triple-ported RAM, the auxiliary port is provided by the use of external multiplexing circuitry.

A method of forming an isolation region in an integrated circuit and an integrated circuit formed thereby. A method preferably includes forming at least one trench in a semiconductor substrate, forming an insulation layer of material in the at least one trench and on peripheral regions of the at least one trench of the semiconductor substrate, forming a sacrificial layer of material on the insulation layer having a different polishing rate than the insulation layer, and polishing the layer having the different polishing rate and portions of the insulation layer so that the sacrificial layer having the different polishing rate and portions of the insulation layer are removed, so that other portions of the insulation layer remain in the at least one trench of the substrate, and so that the upper surface of the at least one trench and the peripheral regions thereof in combination provide a substantially planar surface.