JPH0816834B2 - Curve generation method - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a curve generation method suitable for use in an information processing apparatus having a pattern processing function.

[Technical background of the invention and its problems]

Conventionally, when a curve represented by the following equation is obtained, x ⁱ is calculated every time x changes.

In an information processing apparatus having a pattern processing function, a dot pattern of a curve represented by the above equation is generated, and therefore, x coordinate value (x), y coordinate value (y), y coordinate value of dots forming the curve pattern are generated. (F) for updating the value (f), data (Δ ₁ f, Δ ₂ f, ... Δ _n f) for updating this value (f), etc. The processing device operates the means in a predetermined procedure to draw a curved dot pattern.

That is, a curve is collectively generated by designating the position of the passing point. By the way, splines,
Since the shape of the local portion of the sploop curve greatly changes depending on the passing point, it is necessary to repeat trial and error to position the passing point when generating a curve having a desired shape.

[Object of the Invention]

It is an object of the present invention to provide a method for generating a curve with an improved operability by providing a means for interactively instructing and redrawing the passing point and redrawing.

[Outline of Invention]

Specifically, the curve is made up of 3 consecutive points in the input order.
Approximately occurs with the following curve. Therefore, in order to achieve the above-mentioned object, it is provided with means for storing the ordered coordinate values in order of input, means for displaying the designated points by a marker, and means for drawing a spline curve, and newly designating the designated points. The curve is modified and redrawn by instructing to move to a different position. Then, a means for adding / deleting instruction points is added.

This allows redrawing while talking to the computer to generate a curve of the desired shape, thus improving operability.

Example of Invention

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 1 is a processing device (CPU) that operates various registers to generate a desired curve pattern based on a curve generation algorithm. Reference numeral 2 is a main memory in which various programs for executing the above-mentioned processing are stored.
A curve generation program, a point table, etc. are included.

3 is an output device. The output device 3 is the processing device 1 described above.
The contents of the register group (not shown) prepared for generating the curve according to the instruction from are read and the dots forming the curve pattern are sequentially set. In the embodiment of the present invention, the display memory 31 and the display monitor 32 correspond. Reference numeral 4 is an input device such as a keyboard. The input device 4 is provided for designating points on the display screen, instructing drawing of curves, correcting, inserting, and deleting points, and corresponds to a keyboard unit in the embodiment of the present invention. Although not shown, a printer and an external memory may be added as the output device 3 depending on the application. The main memory 2, the output device 3, and the input device 4 are commonly connected to the bus 5 of the processing device 1.

FIGS. 2, 3, 4, and 5 are views quoted to explain the operation of the embodiment of the present invention.
Each of a point correction example, a point insertion example, and a point deletion example is shown.

FIG. 6 is a flow chart showing a point correction procedure according to the present invention.

Hereinafter, the operation of the embodiment of the present invention will be described in detail. The example shown in FIG. 2 is an example of sploop drawing by specifying seven positions, and the seven points are their sequential numbers and x · y.
The coordinates are stored in the main memory 2. A method and means for drawing a spline / sploop based on the contents stored in the main memory 2 have been filed by the same applicant on September 30, 1983 (Japanese Patent Application No.
No. 182677; curve generation method), so the description is omitted here.

Now, in the sploop drawing example shown in FIG. 2, since there is a deformation (concave portion) at the portion of point 6, a correction example of expanding this portion will be described. First, the cursor (cross
Move the hair cursor (not shown) onto the Marcus at point 6 and press the "move" key. The processor 1 detects this key press, searches the table contents from the cursor position at that time, and finds out which point is designated. At this time, X ± α dots for the cursor position (x, Y) coordinates,
If the points included in the range of Y ± α dots are indexed, the point error of each of the upper, lower, left, and right dots can be allowed, so that the operability is improved. When Poit 6 is indexed here, next by the instruction of new points,
The X and Y coordinates of sequence number 6 are updated. It is necessary to erase the previous curve before re-displaying with this new table, but if only the curve is to be erased, it is necessary to perform erase drawing before updating the table. If you want to erase the entire area,
Either before or after updating the table. Move point,
An example of redisplay is shown in FIG.

Next, an example of newly inserting a point between points 2 and 3 in the state shown in FIG. 2 will be described in detail with reference to FIG. At the time of insertion, as a promise of point instruction, a promise is made to insert a point just before the designated point. In the example shown in FIG. 2, point 3 is designated by the cursor and the "insert" key is pressed. The processing device 1 thereby determines that it is in the insert mode and that the point 3 (FIG. 2) is designated by the table search. Next, enter the additional point designation mode, point the cursor to point 3 (Fig. 4), and click "Execute".
By pressing the key, enter the X and Y coordinate values of the cursor at that time into the position of the sequence number 03 in the table shown in FIG.
The X and Y coordinate values of the following tables are shifted backward one by one, and a new entry of number 08 is created. An example in which the table is updated and displayed again is shown in FIG.

Next, an example of deleting the point 5 in the state shown in FIG. 2 will be described with reference to FIG. When point 5 is indicated with the cursor and the "Delete" key is pressed, the processor 1 is in the delete mode and it is detected by the table search that the point 5 in FIG. 2 has been deleted. In the table, the X and Y coordinates are moved forward in order from the entry of point 5, and the last entry, point 7, is deleted. FIG. 5 shows an example in which the table is updated and displayed again.

It should be noted that, of the table entries shown in FIGS. 2 to 5, the last "99" is the table end mark.

〔The invention's effect〕

According to the present invention as described above, by designating the position of the passing point, It is possible to draw a dot pattern of a curved line represented by, and to redraw while correcting points, improving operability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2 to 5 are views cited for explaining the operation of the embodiment of the present invention. The state before correction, point correction example, point insertion FIG. 6 is a diagram showing each of an example and a point deletion example, and FIG. 6 is a flowchart showing a point correction procedure according to the present invention. 1 ... Processing device, 2 ... Main memory, 3 ... Output device, 4 ... Input device.

Claims (4)

[Claims] 1. A curve generation method for generating a curve by passing at least three position-designated points, and position designating means for designating a position of a desired point with a cursor on a display screen of a display device, and this position. A storage means for ordering and storing the position information of the points designated by the designation means in the order of input, a means for drawing a curve passing over the point designated by the input order, and a means for drawing the curve on the curve. Means for displaying a marker of the position-designated point on the display screen, and edit mode instruction means for designating editing of the curve in a predetermined edit mode are provided, and the edit mode designation means is used for a predetermined edit mode. Is designated, and the vicinity of the marker position is arbitrarily designated by the cursor, the storage means is searched and the arbitrarily designated point is searched. Index position and change the position information of the arbitrarily designated point stored in the storage means according to the position information instruction in a predetermined edit mode, or the input order of the arbitrarily designated point. A new position information is added in accordance with the position information instruction in the predetermined edit mode before or after, the contents stored in the storage means are updated, and the curve is redrawn to generate a curve having a desired shape. A method for generating a curve characterized by the following. 2. When the moving mode is instructed by the edit mode instructing means, the arbitrarily designated point position is instructed by the cursor to move to another new position, whereby the storage means is instructed. The curve generation method according to claim 1, wherein the stored old position information is changed to new position information, the contents stored in the upper storage means are updated, and the curve is redrawn. 3. When the insertion mode is instructed by the edit mode instructing means, and when the point to be inserted is specified by the cursor, before or after the input order of the arbitrarily specified point in the storage means. The curve generation method according to claim 1, wherein the position information of the insertion point is added, the content stored in the storage means is updated, and the curve is redrawn. 4. When the delete mode is instructed by the edit mode instructing means, the position information of the arbitrarily designated point is deleted, the contents stored in the storing means are updated, and the curve is redrawn. The method for generating a curve according to claim 1, wherein