JP2707142B2 - Hidden line broken line processing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hidden line broken line processing method, and more particularly, to a method of processing a hidden line portion in a graphic processing apparatus in order to appropriately display an overlapping state of graphics. The present invention relates to a hidden line broken line processing method that can be converted and displayed.

[Conventional technology]

2. Description of the Related Art Conventionally, a graphic processing apparatus outputs a generated graphic to a graphic output device such as a graphic display or an XY plotter. When a graphic is output to a graphic output device, a portion where the lower graphic and the upper graphic overlap with each other is subjected to a hidden line erasing process of erasing a display as a hidden line, and the display output is performed. Is done. As a method of displaying hidden lines in a figure, for example, a "method of removing hidden lines in a two-dimensional figure" described in Japanese Patent Application Laid-Open No. 62-221786 is known. The hidden line elimination method described here is to make the data of a symbol figure accompany an area figure having a background color corresponding to the area where the symbol figure exists, and to output a general figure and a symbol of a line figure and a plane figure at the time of output. There is a method of outputting a background color area figure of a figure and a symbol figure in this order, thereby eliminating a hidden figure from a general figure with a symbol figure. There, specifically, as an example of computer management of water supply and sewage piping diagram, a closed area figure of the same background color as the symbol figure of various valves etc. is output on the water pipe of the map, An example of a method of erasing a part of a water pipe which becomes a hidden line and displaying a graphic is shown.

[Problems to be solved by the invention]

By the way, in the drafting drawings, the processing of the hidden line is generally indicated by a broken line rather than erased. However, since the graphic processing apparatus is not provided with a function for processing a broken line into a dashed line, a designer who creates a figure using a CAD (computer aided design) system, for example, manually cuts out the hidden line. , One by one, from the solid line to the broken line. This manual operation is time-consuming and operation errors are likely to occur. In addition, when the shape of the hidden line portion is modified, the broken line portion also changes. Therefore, the portion that becomes a new hidden line due to the correction is further manually made to be a broken line, and the portion that is newly visible becomes a new one again. Must be solid line.

As described above, it takes time to change a part of a solid line to a dashed line, but it takes more time to return the figure that has been cut once due to an error or correction to a dashed figure to the original solid line figure. Easy to make mistakes.

The present invention has been made to solve the above problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hidden line broken line processing method which can easily and reliably perform a broken line forming operation on a hidden line.

The above and other objects and novel features of the present invention are as follows.
It will become apparent from the description of the present specification and the accompanying drawings.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, there is provided an arithmetic unit which performs graphic calculation, generates graphic data of a graphic to be displayed and mask graphic data of a closed area graphic which hides a hidden line portion, and sends the generated data to a display device. In a graphic processing device including a segment buffer device that stores data, a display control device that controls display of graphic data according to a display priority, and a display device that displays graphic data on a screen, for one graphic, The background color is determined by the solid line graphic data, the broken line graphic data having the same shape as the solid line graphic whose display priority is higher than that of the solid line graphic data, and the display priority between the solid line graphic data and the broken line graphic data. It is characterized in that mask figure data of a closed area figure covering the hidden line part is generated, the figure is displayed according to the display priority, and the hidden line part is turned into a broken line.

[Action]

According to the above means, in the graphic processing device, for one graphic, solid graphic data, broken graphic data having the same shape as the solid graphic having a higher display priority than the solid graphic data, and a solid graphic Generate mask figure data of a closed area figure that covers the hidden line part that is the background color with the display priority between the data and the broken line figure data, display the figure according to the display priority, and dash the hidden line part Become

That is, the display control device superimposes and displays the graphic data on the display device according to the display priority of the graphic data. For this reason, the mask figure data of the background color of the closed area covering the hidden line portion is displayed in front of the solid line figure data, and the hidden line erasing process is performed. Further, a dashed figure having the same shape as the solid line figure is further displayed in front of the figure. As a result, in the graphic area where the mask graphic is present, the dashed graphic is displayed in front of the background color and becomes a dashed line, and in the graphic area where the mask graphic is not present, the dashed graphic having the same shape as the solid graphic overlaps the solid graphic. It is displayed in a solid line.

As described above, in the figure area which is a hidden line portion, the mask figure having the background color is displayed in front of the figure (solid line figure) having a lower display priority, but is not actually visible because it is the background color. Therefore, only the graphic having the lower display priority, that is, the solid graphic is erased. Further, since the broken line graphic has a higher display priority than the mask graphic, it is displayed further on the front side and is not erased. This hidden line erasing operation is performed irrespective of the number of display figures and the shape of the mask figure.

〔Example〕

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a graphic processing apparatus according to an embodiment of the present invention. In FIG. 1, 1
Is an arithmetic unit for performing graphic calculations, 2 is a display control device, 3 is a segment buffer device, and 4 is a display device.

The arithmetic unit 1 performs an operation for generating graphic data of a mask graphic covering a hidden line portion on graphic data of a graphic to be displayed on the display device 4, determines display priority for each graphic, and generates the graphic data. The obtained graphic data is stored in the segment buffer device 3 via the display control device 2. The display control device 2 is a control device that determines the display order of the graphic data stored in the segment buffer device 3 according to the display priority, and controls transmission to the display device. Further, the segment buffer device 3 is a buffer storage device for storing graphic data of each graphic to be displayed on the display device 4. The graphic data read and transmitted are sequentially superimposed and displayed on the screen.

FIG. 2 is a flowchart showing an example of a process for converting a hidden line portion into a dashed line performed by the arithmetic unit. Referring to FIG. 2, in the broken line processing, first, in step 11
In, the value of a variable PRI indicating the display priority (hereinafter simply referred to as priority) is initialized to 0. Next, in step 12, when an instruction to create a figure is input from the operator, the type of the figure is determined in the determination step of step 13, and processing corresponding to the type of each figure is performed.
That is, if the instruction of the figure is a line figure such as a line segment or a circle, the process proceeds to step 14, and the priority is increased by one.
That is, 1 is added to the variable PRI. Then step 15
Then, line graphic data to be displayed as a solid line graphic is generated from the specified graphic using the variable PRI as a priority. Next, in step 16, line graphic data to be displayed as a broken line figure is generated from the figure specified in the same manner with the highest priority.
As a result, for the designated display graphic, solid-line graphic data of the same shape and broken-line graphic data of high display priority are generated. In the display of the line figure, the broken line figure is displayed on the solid line figure so that only the solid line is displayed on the screen. For some of these line shapes,
When an instruction to create a figure of a plane figure (a plane figure superimposed on a line figure) for which the necessity of hidden line elimination occurs is input (step 12), in response to the instruction, a figure type determination step of step 13 is received. Then, the process proceeds to step 17. In step 17, 1 is added to a preset variable PRI indicating the priority in order to display the surface graphic with one more priority than the solid line graphic.
Using the RI as a priority, mask figure data for displaying the designated figure shape as a mask figure is generated. When this mask graphic data is displayed, it is sent to the display control device first, and the display priority is higher than the displayed solid line graphic, and the plane graphic of the mask graphic data is displayed. The solid line of the line figure is deleted at the portion where the plane figure overlaps, and the broken line of the line figure is displayed on the plane figure of the background color of the mask figure. That is, the display priority of the broken line graphic data is higher than that of the mask graphic data of the background color.
Dashed lines are not deleted. As a result, in the line graphic, the portion where the mask graphic overlaps is displayed as a broken line, and the hidden line portion is displayed as a broken line. Next, if necessary, in step 19, processing for generating graphic data for displaying the frame lines in the plane graphic with the same priority as the mask graphic data is performed, and the processing of the plane graphic is completed.

If an end instruction is input in the input of the figure creation instruction in step 12, this is determined in the determination step of step 13, and the process ends.

In this way, the display priority is determined for each of the line figures, and solid line figure data, dashed line figure data having the same shape as the solid line, and mask figure data of the hidden line portion are generated. By displaying, the hidden line portion of the line figure can be changed to a dashed line.

FIG. 3 is a diagram for explaining the operation of a display process for displaying a hidden line portion of a line graphic as a broken line.

As shown in FIG. 3, solid line figure data in which display priorities are respectively set for line figures for converting hidden line portions into broken lines.
21. When the mask figure data 22 of the plane figure and the dashed figure data 23 having the same shape as the solid figure are displayed in accordance with the display priority, the display screen 25 of the display device displays the line figure data 24 in which the hidden line portion is broken. Is displayed. That is, for a single line figure, first, a certain display priority (PRI = 1) is determined, the solid line figure data 21 is displayed, and the display priority (PRI = highest value) is made higher than the solid line figure data. A dashed line figure data 23 having the same shape as the solid line figure data, and a mask figure data 22 of a closed area which covers a hidden line portion which is a background color with a display priority (PRI = 2) between the solid line figure data 22 and the dashed line figure data 23 Is generated, a graphic is displayed according to the display priority, and the line graphic data 24 in which the hidden line portion is changed to a broken line is displayed on the display screen 25.

Next, another embodiment according to the present invention will be described.
When the hidden line portion of the line figure is displayed as a broken line, particularly when the number of line figures overlapping the plane figure increases, the number of the hidden lines increases, and it is necessary to distinguish and display them. In this case, if the type of the dashed line in the hidden line portion can be changed and displayed, each of the line figures can be distinguished and displayed, and the overlapping of the figures can be appropriately displayed. For example, in order to distinguish and display such a plurality of types of broken lines, the display priority of the broken line here is a value larger than the display priority of the solid line graphic data and the mask graphic data, and a plurality of different values. The type of the broken line is set corresponding to each of the plurality of different display priorities. Then, the type of the dashed line is set according to the set display priority value of the dashed line, and the dashed line graphic data is generated and displayed. This makes it possible to display the broken line processing of the hidden line portion as a plurality of types of broken lines.

FIG. 4 is a flowchart showing another example of a process for converting a hidden line portion into a dashed line performed by an arithmetic unit according to another embodiment of the present invention. Referring to FIG. 4, in the plurality of types of broken line processing, first, in step 31, an initial value of a variable PRI indicating a priority is set to 0.
Next, when an instruction to create a figure is input from the operator in step 32, the type of the figure is determined in the determination step of step 33, and processing corresponding to the type of each figure is performed. That is, if the instruction of the figure is a line figure such as a line segment or a circle, the process proceeds to step 34, where 1 is added to the variable PRI, and the priority is first raised by one. Then step 35
In, the type of the broken line, such as a fine broken line, a one-dot chain line, a two-dot chain line, and a dotted line, is determined by the value of the variable PRI. next,
In step 36, the designated graphic is set as graphic data to be displayed as a solid graphic with the variable PRI as the priority. Then, in step 37, the priority is set to the maximum value, and the figure specified by the broken line of the determined type is displayed as a broken line figure. As a result, for the designated display graphic, solid-line graphic data of the same shape and broken-line graphic data of high display priority are generated. When this series of steps is performed on different line figures, broken line figure data having different types of broken lines is generated. In the display of the line figure, the broken line figure is displayed on the solid line figure so that only the solid line is displayed on the screen.

If an instruction to create a face graphic (a face graphic overlapping on the top of the line figure) for which the necessity of hidden line elimination occurs is input for a part of such a line figure (step 32), this is input. Then, the judgment is made in the step of judging the type of the figure in step 33, and then the process proceeds to step 38. In step 38, 1 is added to a preset variable PRI indicating the priority in order to display the surface graphic with one more priority than the solid line graphic. Next, in step 39, the type of the broken line is determined based on the value of the variable PRI. Next, in step 40, the variable
With PRI as priority, mask figure data for displaying the designated figure shape as a mask figure is generated. When this mask graphic data is displayed, it is sent to the display control device first, and the plane graphic of the mask graphic data having a higher display priority than the displayed solid line graphic is displayed. For this reason, the solid line of the line figure is deleted in the portion where the plane figure overlaps, and the broken line of the line figure is displayed on the plane figure of the background color of the mask figure. Next, in step 41, a process of setting the frame line in the plane graphic to graphic data to be displayed with the same priority as the mask graphic data is performed, and in step 42, the priority is set to the maximum value and the determined type of broken line is displayed. The graphic data for displaying the frame line of the designated surface graphic as a broken line graphic is generated. As a result, the mask graphic data of the same shape and
Solid line graphic data of a frame line of the same shape and broken line graphic data of a frame line of the same shape having a high display priority are generated. When this series of steps is performed on different plane figures, line figure data of a solid frame line is generated, and further, line figure data of the same type of a broken line frame line of a different type is generated. In the display of the line figure, the broken line figure is displayed on the solid line figure so that only the solid line is displayed on the screen. Then, some frame lines of the plane graphic which are overlapped with each other and become a hidden line portion are displayed with different broken lines depending on the type of the graphic.

If an end instruction is input in the graphic creation instruction input in step 32, this is determined in the determination step in step 33, and the process ends.

FIG. 5 is a diagram for explaining an operation of a display process for displaying a hidden line portion of a frame line of a plane graphic as a broken line.

As shown in FIG. 5, a frame 51 is provided around the area in the plane figure 50 for the plane figure, and a hidden line similar to the line figure is provided for the line figure data of the frame. Partial broken line processing is performed. In order to convert the hidden line into a dashed line, the solid line figure data 52, the mask figure data 53 of the plane figure, and the broken line figure having the same shape as the solid line figure of the frame are set for each of the frame line figures. When the data 54 is displayed according to the display priority, the display screen 55 of the display device displays another surface graphic.
The graphic data in which a part 57 of the frame line portion which became the hidden line portion by the 56 is turned into a broken line is displayed.

As mentioned above, although the present invention was explained concretely based on an example, the present invention is not limited to the above-mentioned example.
It goes without saying that various changes can be made without departing from the scope of the invention.

〔The invention's effect〕

As described above, according to the present invention, the graphic processing apparatus can automatically perform the dashing of the hidden line portion in the drawing, and can change the dashed portion without any special operation. Therefore, an operator's mistake can be prevented, and the work load can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a graphic processing apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing an example of a process for converting a hidden line portion into a dashed line performed by an arithmetic unit. FIG. 4 is a diagram for explaining an operation of a display process for displaying a hidden line portion of a line graphic with a broken line, and FIG. 4 is a diagram showing another example of a hidden line portion broken line process performed by an arithmetic unit according to another embodiment of the present invention. FIG. 5 is a diagram for explaining an operation of a display process for displaying a hidden line portion of a frame of a plane graphic as a broken line. In the figure, 1 ... arithmetic unit, 2 ... display control unit, 3 ... segment buffer unit, 4 ... display unit, 21, 52 ... solid line figure data, 22, 53 ... mask figure data, 23, 54 …… Dashed line figure data, 24 …… Line figure data, 25,55 …… Display screen, 50
…… surface figure, 51 …… frame line, 56 …… other plane figure

Claims (3)

(57) [Claims] 1. An arithmetic unit for performing graphic calculation, generating graphic data of a graphic to be displayed and mask graphic data of a closed area graphic for concealing a hidden line portion, and sending the generated data to a display device, and a segment buffer for storing the graphic data. Device, a display control device that performs display control of graphic data according to display priority, and a graphic processing device that includes a display device that displays graphic data on a screen. Closes the dashed line graphic data of the same shape as the solid line graphic whose display priority is higher than that of the solid line graphic data, and covers the hidden line part with the display priority between the solid line graphic data and the broken line graphic data as the background color. A hidden line broken line processing method characterized by generating mask figure data of an area figure, displaying a figure according to the display priority, and converting a hidden line portion into a broken line. 2. The hidden line portion dashing processing method according to claim 1, wherein the display priority of the broken line is a value larger than the display priority of the solid line graphic data and the mask graphic data, and a plurality of different values are displayed. And setting the type of the broken line according to the display priority value of the broken line. 3. Graphic data of a frame is provided for graphic data of a plane graphic, and for the graphic data of a frame, solid line graphic data in the form of a frame and a display priority based on the solid graphic data are set. Generates dashed-line figure data of a dashed line having the same shape as the shape of the raised frame line, and mask figure data of a closed-area figure having the same shape as the plane figure with a display priority between the solid-line figure data and the dashed-line figure data. 2. The hidden line broken line processing method according to claim 1, wherein the graphic display is performed according to the degree, and the hidden line portion is broken.