JPS6240492A - Auxiliary line display system for display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In a device equipped with a raster scan type display device and a graphic data display mechanism, orthogonal X coordinates, Y coordinates,
The coordinates are defined on the screen of the display device, and each time scanning is performed in the X direction, which is the high-speed scanning direction, for a specific auxiliary line,
The X coordinate value is calculated from the Y coordinate value at that time, and when the calculated X coordinate value matches the scanning coordinate in the X direction, the scanning point is displayed, and the auxiliary line is is displayed.

[Industrial application field]

The present invention provides a device equipped with a raster scan type display device and a graphic data display mechanism, in which orthogonal X and Y coordinates are defined on the screen of the display device, and arbitrary auxiliary lines are drawn on the screen. Regarding the display control method.

The storage capacity of recent computer systems has increased.

With the improvement of processing power, in the computer system,
Image data is increasingly being handled.

In image processing of the image data, for example, it is often desired to cut out an arbitrary part of an amorphous image with a straight line, and it is necessary to be able to specify a straight line that touches an arbitrary point of the amorphous image.

Conventionally, in order to display a straight line on the screen, for example, after specifying two points using a cursor, it has often been done to draw a straight line between the two points by instructing a specific command. .

However, specifying two points using the cursor to draw a straight line that is tangent to any point in the image data is a process that is performed without recognizing the image data, so in principle, This will be a difficult process.

Under these circumstances, in a device equipped with a raster scan type display device and a graphic data display mechanism, it is possible to effectively draw an arbitrary straight line corresponding to the graphic data on the screen of the display device through interactive processing. A method for displaying straight lines has been awaited.

[Prior art and problems to be solved by the invention] FIG. 6 is a diagram illustrating a conventional linear display system.

Conventionally, as shown in this figure, a cursor has been used as an auxiliary display used for screen operations.

In this figure, 1 is called a cross cursor, which displays one vertical line and one horizontal line on the screen.

2 is called a pointer, and various shapes have been considered.

The operability feature of such a cursor is that the cross cursor 1 is located at the intersection of the vertical and horizontal lines.

Pointer 2 is located at the point at the center of the shape.

This point-based instruction is effective for indicating a certain position on the screen a of a raster scan type display device, but for example, using the cursor 1, using a point or a collection of lines,
When drawing an arbitrary figure on the screen, it is difficult to predict the finished state of the figure, so there is a drawback that it is easy to deviate from the figure desired by the operator.

In general, graphics are composed of lines, and since straight lines are the easiest for humans to visually grasp and handle, when considering graphic processing using straight line display, the method of displaying the straight lines becomes an issue.

In the conventional method, a graph ink plane on which any figure can be drawn is formed on the screen a of a raster scan type display device, and the figure is displayed by displaying the straight line on the plane using, for example, a cursor. do. That is, a straight line is displayed directly on the graphic brain.

In this case, a straight line is drawn by a processing device such as a processor recognizing and processing the positional information (X, Y coordinates) of the two points specified by the cursors 1 and 2. .

Therefore, since it is processed without recognizing other image data drawn on the graphic brain,
There is a problem that a gap occurs between the image data and the straight line, resulting in poor operability.

In addition, a program executed by a processor intervenes in the process of generating the straight line, which takes time, and in the case of interactive processing, there is a problem that the response is slow.

In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a method for simplifying operations and processing when drawing a straight line on the screen of a raster scan type display device through interactive processing. That is.

[Means for solving problems]

FIG. 1 is a diagram explaining the concept of the auxiliary line display method of the present invention.

In the present invention, in a device including a raster scan type display device and a graphic plane display mechanism,
When orthogonal X and Y coordinates are defined on the screen a of the display device, and when performing high-speed scanning in the X direction at a certain value Y of the Y coordinate, for example, the reference point (X
O, YO), for a specific auxiliary line with slope A, from the above Y coordinate value (Y) at that time, the X coordinate value X''
,X!・XO+A (Y-YO) Calculated using the formula, and the calculated X coordinate value X゛ is
The scanning point is configured to be displayed when it matches the scanning coordinate in the X direction.

At this time, the graphic plane and the displayed straight line are independent, and operations on the straight line (for example, changing the reference point, changing the slope A, etc.) have no effect on the graphic plane.

Further, although a plurality of the above-mentioned straight lines can be drawn by expanding this mechanism, each straight line is also independent and does not affect each other.

That is, the relationship between the graphic plane and the above-mentioned straight line corresponds to the relationship between a drawing paper and a straight line ruler, and the straight line is read by the processor of the device, and the graphic plane and straight line are read.
Writing to memory completes the desired graphics processing.

[Effect]

That is, according to the present invention, in a device equipped with a raster scan type display device and a graphic data display mechanism, orthogonal X and Y coordinates are defined on the screen of the display device and are in the high-speed scanning direction. Every time you scan in the X direction,
For a specific auxiliary line, the X coordinate value is calculated from the Y coordinate value at that time, and when the calculated X coordinate value matches the scanning coordinate in the X direction, the scanning point is displayed. Since the above-mentioned auxiliary line is displayed in the same way, the auxiliary line can be easily displayed according to the image data without affecting the image data on the graph ink brain, which is another display element. It has the effect of being able to draw at high speed.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a diagram explaining the concept of the slope of the auxiliary line, and FIG.
The figure is a diagram for explaining an interpolation method for auxiliary lines, and FIG. 5 is a diagram for explaining the present invention in detail. Note that the same reference numerals indicate the same objects throughout the figures.

The embodiment shown in FIG. 2 is a configuration example in which only one auxiliary line is drawn, and the display information of the auxiliary line is stored in four types of registers 31. has the following functions:

XOREG (Reference point X coordinate register) Defines the X coordinate position (XO) of the double point.

YOREG (Reference point Y coordinate register) Defines the Y coordinate position (YO) of the double point.

αREG (slope constant register): Defines the degree of slope of the auxiliary line.

MODE REG (display mode register): Specifies the display mode (consisting of mode pit and sign bit).

By writing information into these registers, an auxiliary line with an arbitrary slope passing through a reference point defined at an arbitrary position is displayed.

The above-mentioned FIG. 1 conceptually shows this situation.

An outline of the operation in this case will be explained below.

1) The arithmetic unit 33 calculates the above-mentioned Perform the calculation XO+A(Y-YO) and calculate the X coordinate (X
' value).

2) When the value of the X coordinate to be scanned (this is also given in the same way as the Y coordinate) and the value of the X coordinate (X') to be displayed on the auxiliary line match, the display signal is sent. Occur.

3) By applying this display signal to a readout mechanism (not shown) of the graphic plane, the auxiliary line is displayed on the screen of the raster scan type display device, independently of the image on the graphic plane. .

The above display operation will be explained in more detail.

In the above equation, A is the amount of change in X on the auxiliary line when the Y coordinate value (Y) of the raster scan changes by 1°, that is, the slope.

FIG. 3 shows the concept of this slope A. (a) shows the difference in slope A depending on the mode (MODE 0.1), and (b) shows the movement of the slope constant α.

The details of the inclination A will be explained below with reference to this figure.

This slope A requires a very wide range of values. For example, if there are 1024 pixels in the X direction and the same 1024 pixels between pixels, the minimum change unit of the slope A is 1/1024
The maximum value is 1024.

This value range requires 24 binary digits, which can represent as many as 1 million different values.

However, the number of types of slope A values that are actually displayed and distinguishable is about 2048.

Therefore, this 100. Select 2048 out of ten thousand,
Instructing the slope A requires a very large number of processing steps, which reduces operability.

Therefore, in this embodiment, the value of the slope A is calculated by the following method.

As shown in FIG. 3, the slope A of the auxiliary line is divided into two types depending on the size.

The case where the slope is smaller than 1 is defined as MODE O', and the case where the slope is greater than or equal to 1 is defined as MODE 1'.

Then, a slope constant α' indicating a certain slope is defined, and the above-mentioned slope A is created from this slope constant α'.

In the case of “MODE O”: A is 0 to 1023/1024, and A-α/1024
Calculate with. At this time, the α shows a value of 0 to 1023.

In the case of "MODE L' - A is 1 to 1024, and the unit of change of this slope is not constant. To calculate this, use the formula A = 1024/(1024 - α). At this time, , the α has a value of 0 to 1023.

The α is the slope constant register (αREG) 31
All 10 digits (bits) of the binary number are effectively used.

The above modes are displayed in the display mode register (MODE REG).
) 31 MODE bit 31a (see FIG. 2).

By using the above calculation method, you can not only simplify the specification of the slope A (when α is updated to +1. or -1, the end of the auxiliary line (intersection with the screen frame) Since the robot moves with a treadle, it has the advantage of being easy to grasp visually and easy to operate.

The above explanation is an operation for the auxiliary line with a slope A in the upper half of FIG.
1 sign bit 31b (see Figure 2), the slope A
Reverse the sign of the value. That is, a negative slope is specified. The calculation method for A in this case is the same as when the slope is positive.

Next, the interpolation display required when generating auxiliary lines according to this embodiment will be explained using FIG. 4.

In the case of MODE Oo mentioned above, it is As2, so 1
For each scan in the X direction, the display of the auxiliary line is 1 pixel (see Figure 4 (al)), so the above mechanism operation 2)
As explained in section 1, the display signal is obtained by matching the X coordinate (Xo) of the auxiliary line with the X coordinate (X) to be scanned, but in the case of 'MODE 1', A>1, so ,1
For each scan in the X direction, the auxiliary line is displayed at multiple pixel intervals, resulting in a discontinuous display as shown in FIG. 4 (a2).

The solution to this problem is a so-called interpolation display mechanism, which includes registers (X'y) and (X'y-1) 34, comparators (C) 35 and 36, and AND circuits 370 and 371 shown in FIG. ．．
and selectors 38 and 39.

Here, Xo is the auxiliary line X calculated using the above formula.
Regarding the coordinates, Xo for the scan to be currently executed is
y, and Xo for the previous scan is X'y-1, the above registers (X'y), (X'y-1) 34
2 is stored.

The X'y is calculated each time a scan is performed, and when one scan is completed, it is moved to X'y-1.

The display of the auxiliary lines interpolated by the above interpolation display mechanism is shown in Figure 4 (
bl), (b2). Here, (bl) shows the case where the slope A is positive, and (b2) shows the case where the slope A is negative.

If the slope A of the auxiliary line is positive, the comparator (C)
35.36 Nioiite, X coordinate (X) when scanning in the X direction
is in the range of X'y ≧X > By using the scanning coordinate in the direction <X) as a display signal, the interpolated display shown in FIG. 4(bl) is performed.

Similarly, when the slope A of the auxiliary line is negative, in the comparator (C) 35.36, the
When the coordinate (X) is in the range of x'y ≦X < By using the scanning coordinate (X) in the X direction at that time as a display signal, the interpolated display shown in FIG. 4 (b2) is performed.

The selector 39 performs a switching operation between MODE L, which requires interpolation, and MODE O, which does not require interpolation.

Of course, the auxiliary line obtained by this method is based on the reference point (X
O, YO).

An example of how to use the auxiliary line obtained in this way is shown below.

[Example 1] When drawing an arbitrary triangle - As shown in FIG. 5(al), in the conventional method, the aforementioned cursor 1. Since the position is specified using the pointer 2 or the like, it is difficult to grasp the finished image, and errors are likely to occur in specifying the position.

Also, once a figure is drawn on the graphic plane, many operations are required to change it.

The method of directly drawing and correcting lines on the graphic brain also has the problem of requiring complicated software processing.

On the other hand, if the auxiliary line display mechanism of the present invention is used, as shown in (a2), the auxiliary line can be freely moved as a draft regardless of the image data on the graphic plane, so errors may occur. This makes it easy to operate even if changes occur at this draft stage.

The finally determined figure has the intersection of each auxiliary line, for example,
By giving an instruction using a cursor 1 or the like, it is possible to wait for software intervention and copy it on the graphics plane.

Furthermore, by increasing the number of auxiliary lines, it is possible to draft more complex figures.

[Example 2] When checking the perspective dimensions of a certain figure: Figure 5 (
For a machine with three rollers as shown in b),
When looking from the upper right slit part, it was difficult to judge whether there is a gap between the three rollers using the conventional method, but if the auxiliary line generated by implementing the present invention is displayed here, it is difficult to judge whether there is a gap between the three rollers. , it can be seen that it is obvious at a glance whether there is a line of sight or not.

The example in this figure shows a case where it has been confirmed that there is a gap between the rollers using two auxiliary lines generated by implementing the present invention.

In this way, in the present invention, an auxiliary line display mechanism (see Figure 2) is provided independently of the graphic brain display mechanism, so that the display can be displayed on the screen of a raster scan type display device without affecting the graphic data. The reference point (KO, Y
O) and the slope A are changed in various ways to generate arbitrary auxiliary lines as if placing a ruler on the graphic data.

〔Effect of the invention〕

As described above in detail, the auxiliary line display method in the display device of the present invention is provided with a raster scan type display device and a graphic data display mechanism, in which orthogonal X coordinates and Y coordinates are Defined on the screen of the display device, each time scanning is performed in the X direction, which is a high-speed scanning direction, the X coordinate value is calculated from the Y coordinate value at that time for a specific auxiliary line, and the calculated X coordinate is When the value of matches the scanning coordinate in the X direction, the scanning point is displayed and the auxiliary line is displayed.
This has the advantage that auxiliary lines matching the image data can be drawn at high speed with a simple operation without affecting the image data on the graphic plane, which is another display element.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the concept of the auxiliary line display method of the present invention. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is a diagram explaining the concept of the slope of the auxiliary line. FIG. 4 is a diagram illustrating an interpolation method for auxiliary lines. FIG. 5 is a diagram showing an example of use of the present invention. FIG. 6 is a diagram explaining a conventional linear display method. It is. In the drawings, a is the screen of a raster scan type display device. 1 is a cross-shaped cursor, 2 is a pointer. 31 are registers (XOREG, YOREG, a R
EG, MODf! REG). 31a is a MODE bit, and 31b is a sign bit. 32 is a scanning X and Y coordinate, and 33 is an arithmetic unit. 34 is a register (X'y + ) Table 6 figure

Claims (1)

[Claims] In a device equipped with a raster scan type display device and a graphic data display mechanism, orthogonal X and Y coordinates are defined on the screen of the display device, and the X direction is a high-speed scanning direction. Each time scanning is performed, the X-coordinate value of a specific auxiliary line is calculated sequentially from the Y-coordinate value at that time, and when the calculated X-coordinate value matches the above-mentioned X-direction scanning coordinate. An auxiliary line display method in a display device, characterized in that the scanning point is controlled to be displayed.