A pattern write control circuit of the invention has a graphic memory consisting of a plurality of memory planes each storing corresponding to color data for color display, an address selector for supplying a common address to the plane memories, a register storing the color data corresponding to each memory plane and simultaneously supplying the color data to a common location of the memory planes accessed by the common address, and a decoder for producing write enable signal for writing the color data into a specified memory plane in accordance with the display color data of the dot supplied from a CPU.

A subset of signals corresponding to a two-dimensional set of signals is stored into an area of computer memory smaller than the two-dimensional set for processing. Additional signals are sequentially stored in the computer memory area and processed until the entire set of signals has been processed. In a preferred embodiment, motion estimation processing is performed by sequentially transmitting video signals corresponding to portions of a search region of a previous frame from off-chip memory and storing the video signals to on-chip memory for comparison with a reference block of a current frame. The invention provides reduced computer memory usage, reduced signal transfer, and more uniform signal transfer in computer-implemented processing, such as motion estimation processing, that involves two-dimensional caching.

A picture output apparatus capable of carrying out picture output at a high speed is provided. In the picture output apparatus adapted for converting picture data of a first form, which is not permitted to undergo picture output, inputted along with a picture output instruction into picture data of a second form which is permitted to undergo picture output, wherein this apparatus comprises a configuration to convert picture data of the first form inputted without the picture output instruction into picture data of the second form to hold it as predictive picture data of the second form with respect to picture data of the first form predicted to be inputted along with the picture output instruction later. In the case where the picture data of the first form inputted along with the picture output instruction and the previously inputted picture data of the first form are the same, since the picture data of the second form already exists, it is possible to carry out picture output without conversion processing. In the case where difference is small even if both picture data are not the same, it is sufficient to convert only where the difference occurs.

A graphic display apparatus for generating a vector comprises registers for storing a value R of a vector discrimination, a positive increment P and a negative increment N, and flip-flops for storing magnitude information of .DELTA.X, .DELTA.Y, and .DELTA.X and .DELTA.Y. An address counter of a refresh memory is counted up or down in accordance with the contents of those flip-flops. A control circuit for updating the value R of the vector discrimination is also provided, so that the vector can be generated at a high speed. The registers and the flip-flops are constructed in two stages so that data for generating the next vector can be prepared while the current vector is generated.

A graphics processing system has an image memory for storing data of an image, a data memory for storing data of a vector graphic, a display unit for displaying the data of the image and the data of the vector graphic, an input device for providing an instruction to edit the vector graphic and the image, and a library in which a command having a function for processing including an operation of the vector graphic and a command having a function for processing including an operation of the image are registered; in which the data of the image and the data of the vector graphic are displayed in a superimposed way, operated, and edited, and wherein a series of the processing for operating and editing the data of the vector graphic and the data of the image is performed through the command of the library.