When a drawn object displayed on a screen is selected in an image processing system of the present invention, a selection frame and an operation area for performing a particular operation on the drawn object are displayed. When a center of the drawn object is designated with a pointing device and dragged, the center is moved to a dragged position. When a line segment, connecting the center with a predetermined point on the selection frame, is designated with a pointing device and dragged, the selected drawn object is rotated for a dragged amount. Enlargement or reduction in the lateral or longitudinal directions, or skewing are similarly performed. When an operation area corresponding to each operation is designated, editing processing corresponding to the designated operation area is performed on the object of interest.

The present invention provides a data processing system arranged to run a plurality of applications, each application being associated with one or more windows, and each window being under the control of a user interface provided by the system. A method of operating such a system is also provided. The system according to the invention comprises: a display device for displaying the windows to a user; an input means for receiving events entered by a user from a plurality of input devices connectable to the system; a storage device for storing the user events received by the input means in queues for subsequent processing by the applications; and a queue control means for creating the queues in the storage device and for directing the user events received by the input means to selected queues in the storage device. The system is characterized in that each input device connected to the input means is categorized as either a pointing device or a non-pointing device, and the queue control means comprises: generation means for creating first and second sets of queues in said storage device, each queue in the first set being associated with a specific one of said windows, and each queue in the second set being associated with a non-pointing device from said plurality of input devices; routing means for directing each event entered via a pointing device to the queue in said first set which is associated with the window identified by that pointing device, and for directing each event entered via a non-pointing device to an open queue in the second set which is associated with that non-pointing device; and transfer means for transferring control of queues in said second set between the various windows as requested by the applications with which said windows are associated. By employing the above approach, the present invention uses a hybrid queue to handle user events in a GUI system. The problems associated with prior art techniques, for example, system lockup, extra user effort, and the inability to provide a `type ahead` facility, are avoided.

A dot pattern is generated by using scalable font data on the basis of received print data, and then printed. One scalable font set corresponds to two kinds of dot pattern generating modes. One generates a dot pattern with quality being given precedence, and the other generates a dot pattern with speed being given precedence and for printing at high speed, though quality inferior. The two modes are switchable to perform printing to fit user's needs.

An algorithm programmed into a computer permits the computer to automatically generate a two-dimensional profile curve of an electronically represented three-dimensional solid model without creating separate intersecting planes extending through the three-dimensional solid. The computer is configured to query the three-dimensional solid to identify faces on the three-dimensional solid. The query of the solid begins after a face edge is identified as a seed face and continues from the identified face to each adjacent revolved face circumscribing the solid. As each revolved face is located, a representative curve for the face is created in the two-dimensional plane.

A process for producing endoprosthesis has the data block of a three-dimensional actual model (10) of the existing bone structure of a patient acquired using CT scanning. In a computer the actual model (10) thus determined is subtracted from the data block of an existing or CT scan-generated three-dimensional reference model (14). Then from the difference a computer-internal model for the endoprosthesis is formed. With this process, it is possible to reduce the work required for making the corrective adaptation of the endoprosthesis and to avoid faulty adaptations. The data blocks of the actual model (10) and reference model (14) are converted into the data of a CAD free form surface geometry. This is done by describing the limiting surfaces of the models through Spline and Bezier functions oriented to points of support and are imaged, and superimposed, on the computer monitor. This imaging is used to take back segments of the interface (11) of the actual model (10) by displacing points of support toward the volume of the reference model (14).