A screen of a scanning type display is divided both in the horizontal and vertical directions or abscissa and ordinate directions into a relatively large number of dots, so that the screen comprises an arrangement of dots (of the total number of the relatively large number by the relatively large number) arranged in the horizontal and vertical directions. The arrangement of dots of the screen is divided into columns each having a relatively small number of dots in the horizontal or abscissa direction. Each column is identified by a corresponding ordinal number so that the same may be the abscissa information. On the other hand, each row of each column is identified by a corresponding ordinal number so that the same may be the ordinate information. Two line buffer memories are provided for storing display control information of lines which are different by a predetermined number of lines in the vertical direction. These line buffer memories are alternately controlled such that while one is in a write mode the other is in a read mode, whereby the same are alternately changed to the write mode and the read mode for each line of the horizontal scanning lines. Character information is read from a character pattern storing memory responsive to the display control information read from the other line buffer memory. A display position of the character is freely changed in the vertical direction and/or the horizontal direction on a dot-by-dot basis by controlling the read timing of the character information. A deformed character can also be displayed from the same character information by changing for each line the reading of the character information.
A T.V. game system for displaying a desired picture on the screen of a raster scanning type T.V. set includes a motion picture pattern generator, a still picture pattern generator, a central processing unit for controlling the overall operation of the system under the control of the operator, and a picture processing unit for combining motion and still picture patterns to form a video signal to be supplied to the T.V. set, whereby the picture processing unit includes a motion picture attribute table memory which stores information relating to motion picture pattern for the next following frame during the horizontal blanking period and a temporary memory which stores information relating to motion picture pattern to be displayed in the next following line by accessing the motion picture attribute table memory during the scanning of current line.
An on-screen display system using scan line memories. Complex on-screen display, comprising multiple layers of on-screen display, is achieved using a pixel memory having a maximum capacity of two horizontal lines of display data. Compressed display data (e.g. character, icon, etc.) is read from RAM and expanded into pixel registers. Pixel data from the pixel registers is forwarded to pixel memory for on-screen display. The pixel memory is also written back into one of the pixel registers and the pixel registers are overlaid to form complex on-screen display data.
Text is displayed on a VDU (23) using a character generator (26) and a generator (27) for attributes such as underline, enhanced brightness and so on. The codes for the generators are stored in a page store (29). Two auxiliary memories (35 and 36) are used to store address pointers. These memories are used in alternate raster scans to control the display, the unused memory being updated for the next raster scan. Each address pointer comprises an entry for every VDU scanning line and determines which dot video line signal will be used in that scanning line by specifying the data row address in the page memory (29) and the dot matrix row number to be used by the generators (26 and 27). Such address pointers enable complete control over the display for the purpose of defining windows, scrolling the display smoothly and slowly at the rate of one scanning line per frame and smooth expansion of a strip on the display by dulplication of lines. A CPU 10 effects the control by determining the address pointers written into the auxiliary memories. For graphics display, the address pointers store for each scanning line the number of the bit line to be used in creating the image.
An output display system including an output display; apparatus for controlling the writing of information to the output display; and a double buffered memory including a first bank of video random access memory for furnishing information to the output display, a second bank of video random access memory for furnishing information to the output display, and apparatus for addressing alternate banks of memory as each line of the output display in a frame is written.
When the horizontal size of a display character is given by 9 dots, 8-dot font data is stored in a font register, and 1-dot display attribute data is stored in a register. Display attribute data is data for designating the 8th dot of a character pattern to be displayed. A selector converts 9-dot data supplied from the font register and the register to serial data on the basis of a counter value of a counter and supplies the serial data to a CRT when 80 characters are to be displayed in the horizontal direction on the CRT having a horizontal resolution of 720 dots per scanning line. When an FPD having a horizontal resolution of 640 dots per scanning line is to be used, the selector converts only 8-dot font data supplied from the font register to serial data on the basis of a counter value from the counter and supplies the serial data to the FPD. As a result, eighty 8-dot characters are displayed in the horizontal direction of the FPD despite that display of 9-dot characters is designated. However, the numbers of display characters of the CRT and the FPD in the horizontal direction coincide.
