Texas Instruments Corporation

Lowell Boggs

Venkat V Easwar

Ralph E Payne

Arunabha Ghose

Suvarna Harish Kumar

Glenn R Fitzgerald

Sadhana Gupta

Eric Gregory Moore

Michael Allen Walsh

Amy Dessert

Don L Simpson

Stephanie Luhring Smith

A printer forms an approximate of a Bezier curve as a sequence of line segments. Two parametric equations, X(t) and Y(t), are employed. Two methods can be used to evaluate the parametric equations. Both use fixed point integer arithmetic to directly calculate points along the curve which are the values of the X(t) and Y(t) equations. The first method sets the number of steps of the parametric variable are equal to an integral power of 2. This gives a predictable execution time and uses line segments to connect the points as a piecewise straight line approximation to the curve. The number of steps is set as the next higher power of 2 than an estimated length of the curve. The second method allows Y(t), the scan line variable, to change only in predetermined integer steps. The value of X(t) is evaluated for each t corresponding to the integer step in Y(t). This second method has a natural advantage, if a closed path is being decomposed as a run array rather than a collection of trapezoids. Both methods create the lines segments in natural scan line order. This is advantageous for polygon fill algorithms because it eliminates the need for edge sorting.

Fast, symmetric, integer bezier curve to polygon conversion

This invention cures many inefficiencies with known scan conversion methods. This invention employs a edge array rather than a set linked list from an array of pointers equal in number to the number of scan lines. This invention thus eliminates storage of linked list pointers which in the prior art included many null pointers resulting in better memory utilization. es on-chip memory when employing a single chip microprocessor. This invention sorts the active edge table only at edge intersections and vertices, thus eliminating much unneeded sorting. This invention permits integrated clipping of a subject polygon by a clip polygon and forming trapezoids filling the clipped area by activating trapezoid formation at every vertex of either polygon and at every edge intersection. This process saves code space and computer processing time. This invention efficiently utilizes the resources of a multiprocessor integrated circuit by spawning of subtasks from a RISC type processor to one or more DSP type processors.

Scan conversion of polygons for printing file in a page description language

A method of using a processor-based integrated circuit (IC) tester (12) to automatically invoke diagnostic testing. A diagnostic schedule (30) is user-defined (FIG. 3), and checked by the tester (12) at various times, such as before and after the tester 12 tests an IC lot (FIGS. 6, 7, 8). The schedule (30) has various scheduling parameters that permit diagnostic testing to be scheduled to occur at certain times, at the expiration of intervals, or upon certain events. The schedule (30) also permits different levels of diagnostic testing, each level with its own schedule. The tester (12) is programmed to run an appropriate level of diagnostic testing if more than one level is due to occur.

Scheduling diagnostic testing of automated equipment for testing

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Lewisville, TX, United States of America

Lowell Boggs