Abstract: A method for drawing a composite figure by combining a plurality of figures. The contours of the plurality of figures are first drawn, and thereafter the insides of the contours are successively filled with in accordance with plane filling attributes of the corresponding figures. Thus, a composite figure with unnecessary contours made to disappear at superposed portions of the figures can be obtained.

Abstract: An advanced user interface operates in an integrated operating environment which supports realtime handwriting, graphical and image data. The integrated operating environment is capable of running several application programs on a standard stand-alone processor, such as a personal computer, each in its own display window. A communication window is established in a first window. Image data is imported into it from a second window. And freehand drawing data is added to the first window. The contents of the first window can then be sent to a second processor. In this manner, hand drawn images can be combined with other image data and communicated over a network.

Abstract: A method and apparatus for simultaneously rendering multiple scanlines. Using a scanline approach to rendering, multiple scanlines may be rendered simultaneously through the use of parallel rendering means. The rendering of multiple scanlines in parallel is enabled by creating scanline independence. Scanline independence is achieved by interpolation through direct evaluation of object information. During the rendering process each of the rendering means vertically interpolates to identify a span corresponding to the scanline being rendered. A span is identified by it's X, Y coordinates on a scanline. The scanline being rendered provides the Y-coordinate.

Abstract: Graphical data are generated and manipulated for display on computer display devices. In the method of the present invention, all graphical images are maintained as a set of base geometries to which all geometrical operations will be applied. The encapsulation of the geometry is referred as a shape and shapes may be aggregated into objects called pictures. Geometrical operations will be performed at all times on the geometries in a local space, while further in the hierarchy the results of these operations will be rendered for whatever display device is being used in a hierarchical output method. Caches are maintained for geometry calculations such that regardless of the resolution of the output display, calculations need only be done once and geometric information is not lost as a result of bitmap processing.

Abstract: An image processing apparatus extracts a local image from an original image which is supplied by an image input unit, the local image corresponding to a local area, designated by a coordinate data input unit, and being supplied to an image output unit. The apparatus extracts local image data by using coordinate data associated with boundary pixels positioned in boundary lines between the local image and other parts of the original image. The extracted local image data are then provided to the image output unit in accordance with horizontal and vertical synchronizing signals applied from a generator.

Abstract: A system and method for interfacing a video subsystem capable of driving a video display monitor to a personal computer (PC) architecture. The system and method involves connecting the video subsystem to a host bus via a host bus video interface. The host bus communicates directly to a central processing unit (CPU) and to a slower system bus through buffers. The central processing unit as well as a system bus master connected to the system bus can communicate at high speeds to the video subsystem. The host bus video interface includes a fast temporary storage buffer so that the CPU or the system bus master, during a write cycle to the video subsystem, can write data at high speed to the video subsystem. The video subsystem may further include SRAM in its video memory to increase performance.

Abstract: A line segment depicting system includes an error discrimination condition memory for designating for each octant an error discrimination condition applied when a DDA (Digital Differential Analyzer) error item is 0.5. First and second different error discrimination conditions are set in the condition memory for first to fourth octants, and for fifth to eighth octants, respectively. A data processing unit receives information of a given line segment and determines in which octant the given line segment is included, and the result of determination is stored in an octant memory, which controls a selector for selecting one of outputs of the error discrimination condition memory. The data processing unit also supplies a DDA parameter to a DDA unit, which sequentially generates a coordinate value (Xn, Yn) of dot positions of an approximate line segment with reference to the error discrimination condition supplied through the selector from the error discrimination condition memory.

Abstract: Apparatus and method for rendering graphic images as bit maps, including: (1) an input for receiving digital input commands; (2) a command interpreter to interpret the input commands and convert them into commands suitable for use inside the system; (3) a halftone screening section; and (4) a rendering section which outputs data suitable for use by a raster display or marking engine. The method and apparatus render multiple output pixels during each clock cycle and apply halftone screens or gray fills to an image.

Abstract: An integrated hardware generator for generating digital signals representative of vectors, polygons and conics primitives and area fills therefor. The primitive signals are used in the formation of a final digital output signal read into a bit map memory of a graphics display processor. Its operation is based on applying one or more of a set of internal subfunctions to generate mathematical solutions for rendering each geometric shape as a graphics primitive digital signal. The basic building block of the generator is a digital differential analyzer which is adapted to accumulate fractional (subpixel) components of x/y coordinate data and to signal when the accumulation overflows across pixel boundaries. This occurrence enables an increment or decrement of the x/y coordinates that indicate the pixel address to be loaded (drawn). The digital differential analyzer forms an independent vector generator and comprises a pair of input differential multiplexers, an arithmetic logic unit and a register file.

Abstract: An image interpolation apparatus receives an image signal in the frequency domain. The image signal is supplied to a filter circuit. The output of the filter circuit is transformed by a two-dimensional fourier transformation circuit into a filtered image signal in the spatial domain. The filtered image signal is linearly interpolated by an interpolation circuit to enlarge or reduce the image representing the image signal. The filter circuit, the fourier transformation circuit and the interpolation circuit are under the control of a processor. The processor sets the filter circuit a filter function representing the inverse of the modulated transfer function of the interpolation circuit to compensate for the degradation caused by the modulated transfer function of the interpolation circuit.

Abstract: In an initial set up sequence, N pels of an original image are stored in N memory positions of an input buffer. The N pels are converted to M pels, which are stored in M memory positions of an output buffer, where M and N are integers larger than 0. In the case of N<M, an enlargement of the original image is made, and in the case of N>M, a reduction of the original image is made. An address counter pointing to an address of a memory position of the input buffer is initially reset to 0. An address counter pointing to an address of the memory position of the output buffer is also reset to 0. The values -N, M, and an initial sum value S (where S is integer satisfying -N.ltoreq.S<M) are initially stored in three registers, respectively. The initially stored sum value S is repeatedly updated to control the scaling up operations or the scaling down operations. There is a first device which determines or checks whether the sum value is negative, or not.

Abstract: A figure filling device fills a figure in memory defined by X-Y coordinate scan line by scan line with reference to a specified pattern. In the filling of a new scan line, the coordinate data for the ends of the new scan line, for the ends of the previously processed scan line and for the reference point of the previous pattern are subjected to a certain processing so that the coordinate data for the reference point of the new pattern is determined. The filling device determines the address in the memory corresponding to the coordinates for the reference point of the new pattern and the address on the memory corresponding to the coordinates for the ends of the new scan line. A filling pattern is read out of the pattern address in the memory and the scan line data is read out of the scan line address on the memory so that they are subjected to a predetermined operation. The result is written to the scan line address.

Abstract: A method and system for generating an antialiased approximation of a line displayed within a data processing system having a raster-scan device for generating images within a two-dimensional grid comprising rows and columns of pixels. A plurality of parameters are generated according to Bresenham's algorithm for the line, including first error term and a second error term. A pixel intensity for an initial pixel for the pixel approximation of the line is generated. The first error term is compared with a threshold to determine an amount of error. The first error term is adjusted by a first selected amount in response to the comparison of the first error term, and the second error term is adjusted by a second selected amount in response to the comparison of the first error term. A pixel proximate to the initial pixel is selected by comparing the first adjusted error term with a second threshold to locate a pixel closest to a point on the line.

Abstract: A method for displaying statements of a computer program during an animation of the program's execution, the display using multiple colors to identify statements based on their respective frequency of execution, is disclosed. As a program statement becomes the current executed statement during the animation, the statement's frequency of execution is calculated as the number of times the statement has been executed so far during the animation, divided by the total number of statement executions throughout the animation. A display color is assigned based on whether the statement's execution frequency has reached one of two or more thresholds. The multi-hued display of program statements based on thresholds of execution frequency assists the programmer in understanding the operation of the program.

Abstract: A three-dimensional pixel cache for use in a computer graphics system comprises source, pattern, and destination tile caches and a barrel shift register, or rotator, that serves as an interface between the tile caches and a frame buffer. The rotator has the capability of performing three types of rotation of data read/written from/to the tile caches horizontal rotation, vertical rotation, and rotation of nibbles within each pixel.

Abstract: An image rotation method and an image rotation processing apparatus in an image processing apparatus are disclosed. The image rotation method obtains the image coordinates (x',y') of a rotated image which is recorded in a second memory, by sequentially scanning a first memory where the M.times.N original image is recorded and adding the increments of x and y corresponding to a rotation angle .theta. repeatedly, and transmits the image element data of the coordinates (x,y) of the first memory to the coordinates (x',y') of the second memory with one-to-one correspondence, thereby obtaining the rotated image through the rotation angle .theta. from the original image. Thus, the present invention can obtain the rotated image using only addition operations and without any multiplication operations, so that high-speed operation is possible and an image can be rotated through a specified angle .theta. through software in common computer graphic systems having no floating point multiplier.

Abstract: A printer and method of operating same which receives print jobs from a host computer encoded in any one of several printer control languages. The printer has the capability of interpreting print jobs in each printer control language. The printer samples a portion of each print job and, using a resident algorithm and data sets obtained by statistical techniques, analyzes the sampled portion of the print job to identify the printer control language in which the print job is encoded.

Abstract: Display control logic for a terminal controller with support for such features as windows and interlace. A display list processor (DLP) (20) communicates with a program memory (12) containing DLP instructions, a display memory (12) containing character codes and attributes for the display, and a font memory (13). As the DLP program executes, it causes accesses to the display memory and brings in character codes and attributes for ultimate display on the screen. These character codes and attributes, as well as information representative of the scan line are input to a video data queue (95). The queue entries are clocked out of the queue by a character clock (170) and are used to generate addresses to font memory. Bitmaps from font memory are read into a dot shifter (190). The DLP instruction set includes a DISPLAY STRING instruction which allows a portion of a scan line to be built up by specifying the length of the scan line segment and the starting address in memory.

Abstract: The apparatus provides a way of receiving graphic symbols whose sizes are mutually different, and whose positions are irregularly arranged, such as a handwritten flow chart. For example, the apparatus automatically generates a flow chart image in which sizes of the graphic symbols are adjusted to be balanced, and in which the positions of the centers of the graphic symbols are aligned. First, the apparatus transforms the input graphic image into vectors representing the graphic symbols. Then, a set of symbol parameters are recognized for each graphic symbol. Center positions of the groups of graphic symbols which fall within a predetermined range, are aligned. Also, the heights and widths of the group of graphic symbol are adjusted through use of the symbol parameters. Finally, aligned, size-adjusted graphic symbols are output in an output image.

Abstract: A graphics processing system arranged to display on a display screen of a display unit a line image produced on the basis of image data stored in a storage and graphics produced on the basis of vector data stored in the storage in an overlapping manner contains a line image delete processing unit for implementing delete processing of the line image in a segment in which a pixel displaying the graphics is displayed so as to overlap with a pixel displaying the line image, wherein the line image delete processing unit is arranged so as to leave only the pixel displaying the graphics undeleted yet to delete the pixel displaying the line image within a range from a range which is broader than a predetermined line width of a distorted line to a line width of the line image.