JPH054718B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a figure input method in which a desired figure belonging to a predetermined range on a coordinate plane is input.
In particular, the present invention relates to a graphic input method that allows the input of graphics that exceed the above-mentioned desired range.

[Conventional technology]

Generally, when performing image communication and image display, images are expressed using graphical commands. In this case, the unit screen (or unit screen)
It is common practice to use the concept of

FIGS. 14 to 17 are diagrams for explaining the concept of this unit screen. FIG. 14 shows an example of the relationship between a unit screen, which is a logical concept, and a physical display screen in an actual image device. In the figure, the unit screen indicated by the dashed line is a logical screen whose coordinates in both the X and Y directions are expressed by decimal values from 0 to 1, and the physical display screen is this unit screen. mapped within. for example,
The display screen of 204 pixels vertically x 248 pixels horizontally has an X coordinate of 0 to 0.11111 (i.e. 248/256), as shown in the shaded area in the figure.
2 with Y coordinate from 0 to 0.110011 (i.e. 204/256)
It can be expressed as a decimal value.

FIG. 15 shows an example of the code format of a graphic command that expresses coordinates using decimal values as described above. In the figure, a to d are part of the code, each 1
It has a length of byte (=8 bits). Figure 15a
is the first byte of a graphic command called an opcode, and represents the type of graphic command (line segment, polygon, etc.). 15 b to d are bytes representing the X and Y coordinates of points (for example, end points of line segments, vertices of polygons, etc.) required for graphic commands,
These 3 bytes represent one point, and these 3 bytes are used repeatedly for the required number of points. Of the three bytes, the b side is the MSB, the d side is the LSB, and bits _b5 and _b2 of b are the signs of the coordinate values, respectively.
The coordinate values expressed in this format are binary decimal values as shown in FIG. 15e. The coordinate values may be absolute coordinates indicating the absolute position of a point, or may be relative coordinates indicating a displacement between points, depending on the type of command.

FIG. 16 is a diagram showing the range of coordinates of points that can be directly represented when absolute coordinates are described using the code format shown in FIG. 15. In this case, since there is a code bit, it is possible to represent the position coordinates of an area four times the area of the unit screen as shown in the figure, but it is not possible to represent positions outside that range. Also, when relative coordinates are written in a code format as shown in Figure 15,
As in FIG. 16, only coordinates within an area four times the area of the unit screen can be directly expressed, centering on the current drawing point position which is the reference.

By the way, the reason for using the concept of a unit screen, which has a limited coordinate representation ability as described above, in image devices is that this representation format expresses image content without depending on the physical display ability of the actual device, that is, the resolution. This is because it has the advantage of being able to For example, the example shown in Fig. 14 is a display device that physically has a display capacity of 204 pixels vertically x 248 pixels horizontally, and if the coordinates of the point 140 at the center of the screen are physically expressed as (102, 124), then 408 pixels vertically A display device with a display capacity of 496 pixels x 496 pixels horizontally cannot express the same point 140 at the center of the screen unless it is converted into coordinates (204, 248). In a decimal value expression such as , both have the same value. That is, the 15th
When expressed as shown in Figure e, the coordinate values of the point at the center of the screen are (0.0110011, 0.011111), which does not depend on physical display capabilities. This also applies to the coordinates of other points on the screen. As can be seen from the above example, in the expression format based on the concept of unit screens, decimal value expression allows
Since image content can be described, image databases such as Videotex have a great advantage in that they only need to store one type of image with the same content.

[Problem that the invention seeks to solve]

On the other hand, in the code format of graphical commands based on the concept of unit screen, coordinates must always be expressed as decimal values, and in decimal value expression, as mentioned above, the range of coordinate positions that can be directly expressed (hereinafter this will be referred to as direct expression). Because the range (simply abbreviated as "range") is limited, when creating image content using graphic commands, a problem arises in that coordinate positions cannot be freely specified.

FIG. 17 is a diagram showing an example of the above problem. In the figure, the area within the dash-dotted line corresponds to the direct expression range using absolute coordinates in Figure 16 (4 times the unit screen), and when creating the image content to be displayed on the corresponding display screen, Consider a case where a graphic command having a format as shown in FIG. 15 is used. However, it is assumed that the position of the point of the figure can be indicated within a larger range than the display screen. (This case is also assumed in the following explanation unless otherwise specified.) As an example of the type of graphic command, a set of graphic commands known as NALPS of Videotex will be taken as an example. NAPLPS is introduced, for example, in Reference 1 "NAPLPS/Theridon - New standard for graphic character communication". 17th
In the figure, a large arc command that fills the bottom of the display screen should be able to be drawn by specifying the coordinate values of three points 171, 172, and 173 in order.
Since both points 171 and 173 are outside the range in terms of absolute coordinates, such a large arc cannot be expressed as a command. To deal with this, point 174,1
It is necessary to fill in a desired portion of the display screen using two graphics commands: a polygon specified by points 75, 176, and 177, and an arc specified by points 174, 171, and 175. Having to divide the figure in this way forces the creator to be extra careful when creating the image. It also involves an increase in the amount of data describing the image. Furthermore, considering a normal graphic input device for creating images,
Precisely specifying coordinate values on range boundaries such as points 174, 175, 176, and 177 using a coordinate input device such as a tablet is a very time-consuming task, and the drawing efficiency is significantly reduced. There was a problem.

The present invention solves the above-mentioned problems, and
It is an object of the present invention to provide a graphic input device capable of inputting graphic commands having coordinate values outside the direct expression range of an image while expressing coordinates using decimal values based on a unit screen.

[Means for solving problems]

The graphic input method according to the present invention detects graphic commands with absolute coordinates or relative coordinates that exceed the range of direct expression using decimal values based on the concept of a unit screen.
It is automatically converted into a graphical command consisting only of coordinates within the direct expression range.

[Effect]

In the present invention, by automatically converting coordinate values, it is possible to freely input graphic commands with coordinate values that apparently exceed the range directly expressed by decimal values, making it easier to create images and improving drawing efficiency. can be improved.

[Embodiments of the invention]

FIG. 1 is an overall configuration diagram showing the configuration of an embodiment of the present invention. In the figure, reference numeral 1 denotes a coordinate input means for inputting the type of graphic command and the coordinate values of the points of the graphic. Reference numeral 2 denotes an out-of-range coordinate detection means, which detects whether the input coordinate value exceeds the direct expression range using decimal values. Then, if it is outside the range, the coordinate dividing means 3 divides and represents the coordinate value outside the range using a plurality of coordinate values within the direct expression range using decimal values. Reference numeral 4 denotes a graphic display means, which displays a graphic created by the coordinate values expressed in divisions and allows the creator to confirm that the desired graphic has been input.

FIG. 2 shows an example of the system configuration of the graphic input method according to the present invention, in which 21 is a central processing unit (CPU) corresponding to a microprocessor, etc.;
2 is a storage device that stores a control program for controlling this system and a processing program for processing data. Reference numeral 1 denotes a coordinate input means for inputting graphic commands and coordinate values of points of a graphic, and in this embodiment, a tablet is used. On the tablet, there is a menu area for specifying the type of graphical command and a locate area for inputting coordinates. input.
Reference numeral 4 denotes a graphic display device which, when a graphic command is input, displays the portion of the graphic that falls within the display screen as image content.

Next, the operation of the above embodiment will be explained. 3 to 13 are flowcharts and examples of processing for graphical commands input through the tablet 1 and associated coordinate values of points.

Figure 3 shows Point Set (Abs) and Point Set (Rel)
FIG. 4 is a flowchart showing processing for both commands, and FIG. 4 is an explanatory diagram showing an example of the processing contents. The Point Set command is a command that moves the drawing reference point (also referred to as the current drawing point or simply the current point), and does not draw the point that will actually be displayed. When using the Point Set (Abs) command to move the current point to a point within the direct expression range using absolute coordinates, step 31 and step 32 are used.
33 and simply run the command. However, as in the example in Figure 4a, if you want to move the current point from the origin 40 to a point 41 outside the range, the code format as shown in Figure 15 cannot represent the binary value 1.11, so the step 33, use the Point Set (Abs) command to temporarily move to point 42 on the range boundary, and express the rest in relative coordinates. In other words, since point 41 (1.11, 0.11) in Figure 4 a cannot be expressed directly by a decimal value, it is detected that it is outside the predetermined range (1.0, 1.0), and it can be expressed directly by a decimal value. The point 41 is specified by a point 42 using absolute coordinates that can be expressed (that is, below the decimal point) and by relative coordinates from the point 42. In this example, in step 35, point 4
1 is within the direct representation range from point 42 using relative coordinates, so if the relative coordinates are added to the Point Set (Rel) command and executed in step 36, the current point is moved to point 41. If step 35 is outside the direct expression range using relative coordinates, step 37
Then, use the Point Set (Rel) command to temporarily move to the range boundary, express the rest in relative coordinates, and return to step 35. Steps from step 35 onwards are the same as when the Point Set (Rel) command was given from the beginning. As in the example in Fig. 4b, when moving from the current point 43 directly to a point 44 outside the expression range using relative coordinates, step 31 and step
35, go to step 37 and go to point 45 on the range boundary.
Move with Point Set (Rel), move the remaining relative coordinates through step 35, and then move with Point Set (Rel) in step 36.
(Rel) By attaching it to the command and executing it,
Point 44 is reached.

The same processing as Point Set is possible for both the Point (Abs) and Point (Rel) commands, but
The Point command requires drawing the point that will actually be displayed, so in step 33 of Figure 3, draw the Point command.
(Abs) command and also in step 36
The only difference is that it executes Point (Rel). That is, step 31 and the area 38 surrounded by a broken line frame in FIG.
is common to both Point Set and Point commands. Furthermore, part 38 is a Set command among the commands described below.
&Line (Abs), Set&Line (Rel), Set&Arc
(Outlined), Set & Arc (Filled), Set & Rec
(Outlined), Set & Rec (Filled), Set & Poly
(Outlined) and Set & Poly (Filled) commands, this process is commonly used to express the starting point in absolute coordinates. Figure 5 shows Line (Abs) and
This is a flowchart showing processing for both Line (Rel) commands, and FIG. 6 is an explanatory diagram showing an example of the processing contents. The Line command is a command that draws a line from the current point to the end point. Line (Abs) represents the end point in absolute coordinates, and Line (Rel) represents the end point in relative coordinates. This distinction is made in step 51.
In the Line (Abs) command, if the end point is within the direct expression range, from step 52 to step 53,
Drawing continues as is. However, if the end point 61 is outside the range as in the example in FIG. (Abs)
Command and Line from midpoint 62 to end point 61
(Rel) command and processes each as a Line command in step 55. Each of these steps means a return to step 51. In the example of Figure 6a, this division results in the midpoint 6
2 is an absolute coordinate and is within the direct expression range, so
Draw a line from the current point 60 to the end point 62 of the division using the Line (Abs) command, and then use the Line (Rel) command.
The command draws a line from the new current point 62 to the end point 61. Also, if the relative coordinates of the end point are within the direct expression range with the Line (Rel) command,
After going through step 56, proceed to step 57.
Execute drawing using the Line (Rel) command. but,
If the relative coordinates are outside the range in step 56 as shown in FIG.
Step 59 as two Line (Rel) commands
Process each command with . This step also means that the process returns to step 51 for each Line command.

Figure 7 shows Set & Line (Abs) and Set & Line (Rel)
2 is a flowchart showing processing for both commands. The Set & Line command specifies the coordinates of the starting point in absolute coordinates, and then, like the Line command,
This command specifies the end point using absolute coordinates (Abs) or relative coordinates (Rel) from the starting point. First, the processing for the starting point (step 71) is the same as step group 38 in FIG.
If the starting point is within the direct expression range in absolute coordinates in the command, step 72 expresses the starting point using the Set&Line command as is, and then performs the same processing as 500 within the broken line in Figure 5 for the ending point. Expressed in group 73. In other words, if the end point of the Set & Line (Abs) command is also in absolute coordinates and is within the direct expression range, the end point coordinates are added to the command and drawing is executed, but if it is outside the range, the midpoint between the start point and end point is calculated. Then, set the midpoint as the new end point of Set & Line (Abs), and create another Line from the midpoint to the end point.
(Rel) Repeats processing as a command.
Also, if the end point of the Set & Line (Rel) command is within the direct expression range using relative coordinates, step group 73
Add the end point coordinates to the command as is and execute drawing, and if it is outside the range, divide the relative coordinates of the end point into two, set the midpoint as the new end point of Set & Line (Rel), and separate from the midpoint to the end point. Repeat processing as a Line (Rel) command. That is, step group 73 is a process similar to Line (Abs) or Line (Rel). Next, in the Set & Line (Abs and Rel) command, if the starting point is within the direct expression range in absolute coordinates, step group 71 and step 74 indicate that the starting point is the Point Set (Abs) command and one or more Point Sets. (Rel) expressed as a command. Therefore, the end point coordinates are determined by the original command Set & Line
(Abs) then Line (Abs), also Set & Line
(Rel), as a Line (Rel) command,
In step group 75, the same process as 500 within the broken line in FIG. 5 is executed while performing necessary division.

As you can see from the comparison between the Line command and the Set&Line command above, the commands with Set&
This is simply a command that does not include Set &, with the specification of a starting point using absolute coordinates added, and this starting point can be processed by step group 38 in Figure 3, directly expressing the range. If it is within the range, use the command with Set& as it is and perform the subsequent processing, and if it is outside the range, use the Point Set command to express the starting point and then use the command without Set& to perform the subsequent processing. Therefore, in the following explanation, of the remaining commands, Set
The processing for only commands without & will be explained.

In addition, the three commands Arc (circular arc), Rec (rectangle), and Poly (polygon) explained below include the command to draw only the outline (Outlined) and the command to fill in the closed area surrounded by the outline (Filled). ), but since the processing of the fill-in command includes the processing of the command for only the outline, only the processing of the fill-in command will be explained.

FIG. 8 is a flowchart showing processing for the Arc (Filled) command, and FIG. 9 is an explanatory diagram showing an example of the processing contents. The Arc command specifies the coordinates of the intermediate point and end point sequentially using relative coordinates, starting from the current drawing point, and fills in a closed area by an arc passing through three points and a chord.

In the example of FIG. 9, 90 is the starting point, 91 is the intermediate point,
Assume that 92 is the end point. If the intermediate point is within the direct expression range in relative coordinates at step 81, step 83
Proceed to append the relative coordinates of the waypoint to the Arc opcode. However, as in the example in Figure 9, if it is outside the direct expression range, the arc up to the midpoint is divided into two in step 82, the dividing point is used as a new midpoint, and the process returns to step 81, so that the midpoint is directly This division is repeated until the expression range is within the range. In Figure 9, first, dividing point 9
3, but since point 93 is outside the range, it is divided again and point 94 is set as the intermediate point. This division point calculation is performed by finding the intersection of a straight line parallel to the X-axis or the Y-axis and a circular arc, which divides the larger displacement amount in the X direction and the Y direction into two in relative coordinates. In the case of FIG. 9, the displacement in the X direction is divided into two by a straight line parallel to the Y axis. In step 83, after specifying the point 94 as an intermediate point using relative coordinates, the end point of the arc is determined. In step 84, among the points 93, 91, and 92 included in the remaining arc from the intermediate point 94 to the original end point 92, the farthest point 93 that is within the direct representation range from the intermediate point in terms of relative coordinates is selected. If this selected point coincides with the original end point in step 85, the entire original arc is now represented by three points, so the relative coordinates to the end point are added to the command in step 86.
Complete the Arc command and draw. However, as shown in FIG. 9, if the selected point does not match the original end point, in step 87 the relative coordinates from the intermediate point 94 to the selected point 93 are added to the command to create one divided point.
Complete the Arc command and draw. Next step 88
Then, among the remaining arcs, the farthest point within the direct expression range in terms of relative coordinates from the end point 93 of the divided arc, which is the current drawing point, is selected. In FIG. 9, point 91 is selected from points 91 and 92. If this selected point does not coincide with the end point of the original arc in step 89, the step
At step 8A, the selected point 91 is set as the intermediate point, the process returns to step 83, the end point is selected at 92, and the Arc command for the second divided arc is completed and executed at step 86. Subsequently, by dividing, polygons that are not filled in are drawn in step 8D, and all processing is completed. The polygon fill command is
As will be described later, in FIG. 9, it is necessary to fill in the triangles having vertices at points 90, 93, and 92.
If the selection point 91 coincides with the end point of the original arc in step 89, an intermediate point is required to complete the Arc command, so the intermediate point is calculated between the current drawing point and the end point in step 8B. Using this point, complete the Arc command in step 8C, execute drawing, and proceed to step 8D to fill in the remaining polygon.

FIG. 10 is a flowchart showing processing for the Rec (Filled) command, and FIG. 11 is an explanatory diagram showing an example of the processing contents. The Rec command is a command for specifying a rectangle using the relative coordinates of the end point, ie, the diagonal point 111, relative to the starting point, ie, the current drawing point 110. If the end point is within the direct expression range in relative coordinates at step 101, drawing is executed at step 102. However, if it is outside the range, the amount of displacement on the X-axis and Y-axis is examined individually and divided so that it falls within the direct expression range. If in step 103 the X-axis relative coordinate is outside the range (that is, greater than 1.0), the relative coordinate is divided into two in step 104, and if it is still outside the range, the division is repeated. In the example of FIG. 10, two division points 112 and 113 are obtained by one division. Furthermore, the Y-axis relative coordinate is also divided as many times as necessary in steps 105 and 106. In the example of Figure 10, 114 and 115
Two dividing points are calculated. Steps after division
In step 117, drawing is performed by sequentially specifying division points generated by division as vertices using the Poly command described later. At this time, points 116 and 117, which were the vertices of the original Rec, are also included in the vertices of the polygon.
Considering only the filling of a rectangle, it is possible to express a small rectangle after division using Rec (Filled), but for a rectangle with only an outline, Rec (Outline) cannot be used after division, and Poly( Outlined)
Please note that you have no choice but to use commands.

FIG. 12 is a flowchart showing processing for the Poly (Filled) command, and FIG. 13 is an explanatory diagram showing an example of the processing contents. The Poly command is
This command draws a polygon by giving the relative coordinates from the current drawing point to the next vertex.
Relative coordinates returning to the last starting point (ie, the current drawing point) are omitted. In step 121, it is determined whether the relative coordinates to the next vertex are within the direct expression range. If it is within the range and the next point does not match the starting point in step 222, the Poly command is not completed yet, so in step 123 the relative coordinates to the next point are added to the command as they are, and the process returns to step 121. If the relative coordinates with the next point are out of range in step 121,
The relative coordinates are divided into two, and in step 122, the midpoint between the current point and the next point is set as the new next point, and step 121 is performed.
Go back to , and judge whether it is within the range. If the next point matches the starting point in step 222, the Poly command is completed, so in step 124 the Poly command is executed and drawn. In the example of FIG. 13, the starting point 130
It is a polygon consisting of three vertices 131, 132, 133, and from the starting point 130 to the next point 131 is within the direct expression range, but from the point 131 to the next point 132
is out of range. Therefore, the midpoint 134 is calculated in the first division, and since this is also out of range, steps 121 and 122 are repeated, and the midpoint 134 is calculated in the next division.
35 is obtained, and the points 135 and 134 are set as the vertices of the polygon in that order. Since the relative coordinates from point 134 to point 132 are also outside the range, midpoint 136 is calculated and added as a vertex. Similarly, point 132
A midpoint 137 between and point 133 is also found, and in the end, the original quadrangle can be expressed as an octagon using relative coordinate values within the direct expression range.

As explained above, in the above embodiment, a coordinate value outside the direct expression range is detected using absolute coordinates, and this is divided into an absolute coordinate within the range and one or more relative coordinates, and the relative coordinate value is Detects coordinate values that are outside the direct expression range, divides them into two or more relative coordinates, converts them so that they are all within the direct expression range, and then uses the original graphics command or A process is performed to automatically create a command that draws a figure equivalent to the original figure command using related commands.

The specific processing contents for this purpose are not limited to the method described in the above embodiment. For example, in the method of dividing coordinates, in Figure 9, the intersection of a straight line parallel to the axis and a circular arc is calculated to divide the axis with the larger amount of displacement between the X axis and the Y axis into two, and the dividing point is determined. Although it has been explained that the center point 95 of the arc is calculated, the point where a straight line perpendicular to the line segment connecting two points on the arc from this center intersects with the arc may be calculated and used as the dividing point. . Further, the dividing point does not need to be an exact bisecting point, and calculations may be made by taking coordinate values with appropriate rounding on at least one axis. In addition, in how to use the figure command after coordinate division, for example, the 7th
In the diagram, if the starting point is within the direct expression range in absolute coordinates using the Set&Line (Abs) command, it will remain as it is.
It was explained that the start point is expressed with the Set & Line (Abs) command, and the end point coordinates are processed in the same way as Line (Abs) in step group 73, but by converting the end point coordinates from absolute coordinates to relative coordinates, the Set & Line (Rel) command It is also possible to express it using only . Also, as explained in the example of Figure 11, Rec
(Filled) If you split the command, Poly
Rec(Filled) after splitting, not the (Filled) command
There is no problem in expressing it by a command. In short, if it is possible to divide absolute or relative coordinates that are outside the range of direct expression using the original graphical commands into coordinate values within the range that can be directly expressed using decimal values, then you can use the coordinate input device to This makes it possible to input arbitrary graphical commands that are not restricted by the coordinate representation ability of decimal value representation.

In the above embodiment, a tablet is used as the coordinate input means 1, but it goes without saying that other coordinate input means such as a trackball, mouse, light pen, etc. may be used. Furthermore, although the image display means 4 uses a graphic display device, if the graphic drawing function can also be realized in software by the programs in the central processing unit 21 and the storage device 22, the display means 4 can be used as a simple image display device. It is also possible to configure it as a memory and a display device such as a TV monitor connected to it. Furthermore, in the explanation of the above embodiment, it is assumed that the type of graphic command is a set of NAPLPS graphic commands, but even if it is a set of other graphic commands, the graphic commands may not be treated as graphic commands at all due to the division of coordinate values. The method of this invention can be used as long as it does not become impossible to express. Furthermore, in the explanation of the above embodiment, the case where the display screen coincides with the direct expression range using absolute coordinates shown in FIG. It goes without saying that this is possible, and that coordinate values outside the direct expression range can be similarly divided and converted.

〔Effect of the invention〕

As explained above, according to the present invention, absolute coordinates or relative coordinates outside a predetermined range that can be directly expressed by decimal values are specified by dividing them into absolute coordinates or relative coordinates within the predetermined range. A desired figure can be input freely without being restricted by a predetermined range, which has the effect of improving drawing efficiency.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a system configuration diagram of a graphic input method in an embodiment of the present invention, and FIGS. 3 to 13 are operation diagrams of an embodiment of the present invention. This is an example of a flowchart and processing contents to explain the process, and Figures 3 and 4 are
Point Set command, Figures 5 and 6 are Line commands, Figure 7 is Set & Line command, Figures 8 and 9 are Arc (Filled) commands, Figures 10 and 11 are
The figure shows the Rec (Filled) command, Figures 12 and 13 are explanatory diagrams showing processing related to the Poly (Filled) command, and Figures 14 to 17 are diagrams to explain the concept of the unit screen. The figure shows an example of the relationship between the unit screen and the display screen, Figure 15 shows an example of the code format of a graphical command that represents coordinates using decimal values, Figure 16 shows an example of a direct expression range, and Figure 17 shows coordinate expression in decimal value representation. Provide examples of problems that arise due to limited ability. In the figure, 1...coordinate input means, 4... graphic display means (display means). Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a figure input method comprising a display means having a coordinate plane and a coordinate input means for specifying coordinates on the coordinate plane, and for inputting a figure of a desired shape, Detect absolute coordinates or relative coordinates outside a predetermined range that can be directly expressed by decimal values in , and specify the coordinates by a combination of absolute coordinates and relative coordinates or a combination of relative coordinates and relative coordinates within the predetermined range. A figure input method characterized in that, by doing so, it is possible to input a desired figure located beyond the predetermined range.