JPH06274643A - Plotter - Google Patents

Abstract

PURPOSE:To provide the plotter which enables the logical arithmetic of plural clip areas and processes the logical arithmetic and the clip processing of any arbitrary shape at high speed. CONSTITUTION:Plotting information and clip information received by a plotting data input part 11 is sent to a vector generation part 12 and in the case of font, it is converted to vector data by data in a font data storage part 13. An edge list generation part 14 generates an edge list from the vector data and in the case of the clip information, it is sent to a clip data merge part 15 or in the case of the plotting information, it is sent to a clip processing part 17. The clip data merge part 15 merges the edge list and the clip information stored in a clip information storage part 16. These edge list and clip information are processed by the clip processing part 17 and a rasterize part 18 and outputted to a printer 20 or the like later.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing device for converting input data into a raster image and outputting the image.

[0002]

2. Description of the Related Art In recent years, in the fields of computer graphics (hereinafter referred to as CG) and desktop publishing (hereinafter referred to as DTP), input character data, graphics data, image data, etc. have been edited on a computer. An editing apparatus has been developed that outputs these to an output device such as a display or a printer.

The editing result by such an editing device is usually expressed by a vector expression (page description language, etc.) so as to be independent of the output device such as a display and a printer, for example, without depending on the resolution. It is expressed. In addition, since flexible editing and high-quality output are required, the vector expression becomes complicated, and in order to output to an output device such as a printer, a high-performance vector / raster with high accuracy is required. Conversion is required.

As a particularly important process in such vector / raster conversion, there is a clip process for partially displaying drawing elements. Since the conventional clip processing method targets only the rectangular area as the clip area, all the intersections of the drawing element and the rectangular area that is the clip area are calculated, and the inside / outside is determined to determine the clip area. A method of displaying only a target area is generally used, and techniques based on such processing are disclosed in JP-A-1-103784, JP-A-63-245576, and JP-A-63-198174. There is.

In the case where an arbitrary shape is frequently clipped like CG and DTP, the number of intersections where the drawing element and the rectangular area which is the clip area intersect is very large, so that the inside of the clip area is large. / The calculation required for external judgment became enormous and it took a very long time.

It is also desired that the clip area itself be changed by editing by the operator. This editing is possible by a logical operation between a plurality of clip areas, but since the conventional method does not consider performing such a logical operation between a plurality of clip areas, the editing is impossible. there were.

Further problems are as follows. When the thickness of the vector which is a drawing element is 1, the clip area can be processed only by the number of intersections. But,
When the vector is modified so that it has a thickness, it becomes the same as obtaining a clip region between regions having an area, so compared to the case where the vector has a thickness of 1,
This leads to an increase in the number of intersections, which again results in a huge amount of computation and processing time. As a solution to this, there is an invention described in JP-A-1-103784, but this invention is based on the assumption that the clip area is rectangular, and cannot cope with an arbitrarily shaped clip area. In addition, processing is added to cope with the case where the vector has a thickness.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and enables logical operation of a plurality of clip areas, and the operation, clip processing of arbitrary shape, and thickness can be performed. It is an object of the present invention to provide a drawing device capable of high-speed processing even for clip processing of the vector.

[0009]

According to a first aspect of the present invention, information on a starting point, which is a position to start drawing, and information on an ending point, which is a position to end drawing, are provided for input drawing information. First edge list conversion means for converting to an included edge list, second edge list conversion means for converting clip information displaying a part of the drawing information into an edge list, and the first edge list conversion The edge list of drawing information converted by means and the second
Clip processing means for performing clip processing based on the edge list of the clip information converted by the edge list converting means to generate an edge list, and image generation for generating an image based on the edge list clipped by the clip processing means. And means.

According to the second aspect of the invention, an edge list including information on a starting point which is a position to start drawing with respect to the input drawing information and information on an ending point which is a position to end drawing is formed. First edge list conversion means for converting, second edge list conversion means for converting clip information displaying a part of the drawing information into an edge list, and second edge list conversion means for conversion. Merge processing means for merging a plurality of edge lists of clip information, clip information storage means for storing the edge list merged by the merge processing means, and drawing converted by the first edge list conversion means. Clip processing is performed based on the edge list of information and the edge list stored in the clip information storage means, and the edge list is stored. A clip processing unit for generating bets,
And an image generation unit that generates an image based on the edge list clipped by the clip processing unit.

[0011]

According to the present invention, in the invention described in claim 1,
Since the clip processing by the clip processing means is performed using the edge list, the clip processing can be performed at high speed, the clip processing of an arbitrary shape can be performed, and the clip processing of a vector having a thickness can also be processed at high speed. .

According to the present invention, in the invention described in claim 2, the clip processing is performed by using the edge list, and the logical operation between the plurality of clip areas is performed by using the merge processing means and the clip information storage means. Since it is performed, it is possible to perform logical operations on multiple clip areas, perform clip processing at high speed, enable clip processing of arbitrary shapes, and perform high-speed processing even for clip processing of vectors with thickness. it can.

[0013]

1 is a block diagram showing an embodiment of a drawing apparatus of the present invention. In the drawing, 11 is a drawing data input unit, 12
Is a vector generation unit, 13 is a font data storage unit, 14
Is an edge list generation unit, 15 is a clip data merge unit, 16 is a clip information storage unit, 17 is a clip processing unit, 18 is a rasterization unit, 19 is a page memory, 20
Is a printer. First, the edge list will be described with reference to FIG. FIG. 2A shows an image to be drawn. FIG. 2B shows a configuration of an edge list corresponding to each horizontal scan line of the image of FIG. That is, it is composed of the start point sx, the end point ex, and the pointer np pointing to the next edge list cell of the area to be filled, corresponding to each scan line. As shown in the two scan lines at the top of FIG. 2A, when there are two line segments in one scan line, the edge list consists of two edge list cells, and the edge list cell of the first edge list cell The pointer np points to the second edge list cell.
Further, the pointer np of the last edge list cell is in a state where there is no edge list cell pointed to next. The value of the pointer np in this state is indicated as null. Initial setting will be described with reference to FIGS. An initial setting signal is sent from each unillustrated overall control unit to each component unit shown in FIG.
Memory initialization is performed in each unit. Next, as an initial setting of the clip edge list, a clip edge list which is assumed to clip the entire page is generated.
This clip edge list will be described with reference to FIG. FIG. 3A shows the entire one page. The upper left coordinates are (stx, sty) and the upper right coordinates are (enx, st).
y), the lower left coordinate is (stx, ny), and the lower right coordinate is (enx, ny). Figure 3
In (b), one page as clip data is designated as clip information. In this case, the clip data is created for each scan line of the y coordinate, and the pointer sp that points to the first clip edge list cell in the edge list, the start point sx and the end point e that are the clip information body.
It consists of an edge list cell consisting of x and a pointer np pointing to the next edge list cell. Since it is created for each scan line, all start points sx and end points ex
Consists of the x coordinate only. In this case, the value of the actual start point sx is stx and the value of the end point ex is enx. Since the clip range is the entire page, there are no two edge lists in one scan line. Therefore,
Pointer np pointing to the next clip edge list cell
The actual value of is null. As shown in FIG. 3, the drawing vector input unit 11 sends the clip vector data of the rectangular area of the entire page to the vector generation unit 12.
Then, the vector generation unit 12 sends this information to the edge list generation unit 14, and the edge list generation unit 14 passes through the clip data merge unit 15 to the clip information storage unit 1.
Store in 6. Of course, in this processing, when the initial setting signal is sent, only the clip information storage unit 16 may generate data as shown in FIG. 3B and store the data in the clip information storage unit 16 itself.

The process after actually receiving the drawing data will be described. The drawing data input unit 11 receives the input drawing data, interprets the drawing data, processes each drawing data, and sends the interpreted result to the vector generating unit 12. The drawing data that is input includes data such as graphic data, character code data, and raster data. As the drawing data received by the drawing data input unit 11, in addition to the above, as information necessary for drawing, the line width and the shape of the line end of the line to be drawn, the connection shape at the connection point when connecting the lines to be drawn, There is a typeface when drawing characters. These data are stored in a storage unit (not shown) and are used by each unit as appropriate. In addition, the clip information also includes the drawing data input unit 11
Will be entered more. The clip information also has data such as graphic data, character code data, raster data, etc., like the drawing data. The handling is the same as the drawing data, except that an identifier indicating that it is clip information is added. Using this identifier, the destination sent from the edge list generating unit 14 which is a later process is the clip data merging unit 15 in the case of clip information and the clip processing unit 17 in the case of drawing data.

The vector generation unit 12 generates vector data according to the data to be drawn sent from the drawing data input unit 11, and sends the vector data to the edge list generation unit 14. If the data to be drawn is graphic data, the graphic data is subjected to processing such as scale conversion and sent to the edge list generation unit 14. If the data to be drawn is character code data, the character code data is used to receive font vector data from the font data storage unit 13,
Scale conversion is performed and the result is sent to the edge list generation unit 14.
If the data to be drawn is raster data, a rectangular vector of the raster area, which is a portion of a color different from the background portion, is generated and sent to the edge list generation unit 14.

The edge list generator 14 generates an edge list from the vector data sent from the vector generator 12 and sends it to the clip processor 17. In addition, the edge list generation unit 14 processes the clip vector data sent from the vector generation unit 12 to generate a clip edge list, and the clip data merge unit 15
Send to.

The clip data merging unit 15 merges the clip edge list sent from the edge list generating unit 14 and the clip edge list stored in the clip information storage unit 16. If the clip edge list is not stored in the clip information storage unit 16, the clip edge list is stored in the clip information storage unit 16 as it is.

Next, the flow of processing performed by the clip data merging unit 15 will be described with reference to FIGS. In this processing, the start point and the end point of the two clip edge lists are referred to, the coordinate values of the start point and the end point of the clip edge list cell stored in the clip information storage unit 16 are corrected, or a new clip edge list cell is added. By doing so, a clip edge list obtained by merging two clip edge lists can be created. The description of this processing is for only one scan line. Let K be the target scan line. When this K is changed so as to target all the scan lines for one page, it means that the clip data for one page has been merged. In this process, the edge list stored in the clip information storage unit 16 is called a clip edge list, and the edge list sent from the edge list generation unit 14 is called a source edge list. One unit in the edge list is an edge list cell. The relationship between the line segments represented by the clip edge list cell and the source edge list cell is shown in FIG. The upper line segment in FIGS. 16A to 16H is the line segment represented by the source edge list cell, and the lower line segment is the line segment represented by the clip edge list cell. Only the overlapping parts of these line segments will be clipped.

First, it is determined whether or not the scan line K has a clip edge list (S601). Without it, the scanline will not be drawn, so
All the source edge lists of the scan line K are made free (S603), and the process for the scan line K is completed.
If there is, the first clip edge list cell is set as the target clip edge list cell (S602).

Next, it is determined whether or not the scan line K has a source edge list (S604). If there is no scan line, drawing is not performed on that scan line, so the clip edge list of scan line K is made free (S
606), and the processing of the scan line K is completed. If there is, the first source edge list cell is set as the target source edge list cell (S605).

The starting point X coordinate value of the target clip edge list cell is set in the variable CSX (S607), and the variable CEX is set.
Is set to the end point X coordinate value of the target clip edge list cell (S608), the start point X coordinate value of the target source edge list cell is set to the variable SX (S609), and the end point of the target source edge list cell is set to the variable EX. Set X coordinate value (S
610).

The variable CSX and the variable EX are compared (S6).
11). When CSX> EX, that is, when the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. Since the minutes do not overlap, it will not be drawn. In this case, the process moves to the flow of FIG. The target source edge list cell is made free (S623), and the next source edge list cell is made the target source edge list cell (S624). Then, the process proceeds to S619.

When the result in S611 is No, the variables CSX and SX are compared, the variables CEX and EX are compared, and the variables CSX and EX are compared (S612). CSX ≧ SX, CE
When X> EX and CSX ≦ EX, that is, when the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell have the relationship shown in FIG. 16 (b). , The line segments of each other are overlapping. In this case, the process moves to the flow of FIG. Set EX to CEX (that is, the X coordinate of the end point of the target clip edge list) (S
625). Create a new clip edge list cell, set EX + 1 (a value obtained by adding 1 to the end point X coordinate value of the target source edge list cell) to the start point X coordinate, and set CEX (target clip edge list cell to the end point X coordinate). End point X-coordinate value) is set and inserted next to the target clip edge list cell (S626). Then, the newly created next clip edge list cell is set as the target clip edge list cell (S627). The source edge list cell of interest is made free (S628). The next source edge list cell is the target source edge list cell (S
629). Then, the process proceeds to S619.

In the case of No in S612, the variables CSX and SX are compared, the variables CEX and EX are compared, and the variables CSX and EX are compared (S613). CSX ≧ EX, CE
When X = EX and CSX ≦ EX, that is, when the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. 16 (c). , The line segments overlap each other, and the end points are in the same position. In this case, the process moves to the flow of FIG. The next clip edge list cell is set as the target clip edge list cell (S630). The target source edge list cell is made free (S631). The next source edge list cell is set as the target source edge list cell (S63).
2). Then, the process proceeds to S619.

When the result in S613 is No, the variables CSX and SX are compared, and the variables CEX and EX are compared (S).
614). When CSX ≧ SX and CEX <EX, that is, the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (d), the line segments of each other overlap. In this case, the process moves to the flow of FIG.
The next clip edge list cell is set as the target clip edge list cell (S633). SX (that is, the starting point X coordinate of the target source edge list cell) to CEX + 1 (a value obtained by adding 1 to the ending point X coordinate of the target clip edge list cell)
Is set (S634). Then, the process proceeds to S619.

In the case of No in S614, the variables CSX and SX and the variables CEX and EX are compared (S).
615). When CSX ≦ SX and CEX> EX, that is, the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (e), the line segments of each other overlap. In this case, the process moves to the flow of FIG.
CSX (starting point X coordinate of target clip edge list cell)
Is set to SX (starting point X coordinate of the target source edge list cell) (S635). The subsequent processing is S625 and S6.
26, S627, S628, and S629 (S636, S637, S638, S639, S64).
0). Then, the process proceeds to S619.

When the result in S615 is No, the variables CSX and SX are compared, and the variables CEX and EX are compared (S).
616). When CSX ≦ SX and CEX = EX, that is, the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship of (f), the line segments overlap each other, and the end points are in the same position. in this case,
Moving to the flow of FIG. The process of S641 is the same as the process of S635. Subsequent processing is S627 and S62.
8, the same process as S629 (S642, S643,
S644). Then, the process proceeds to S619.

In the case of No in S616, the variables CSX and SX, the variables CEX and EX, and the variables CEX and SX are compared (S617). CSX ≦ SX, CE
In the case of X <EX, CEX ≧ SX, that is, the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. 16 (g). , The line segments of each other are overlapping. In this case, the process moves to the flow of FIG. The process of S645 is S
This is the same as the processing of 635. The process of S646 is S63.
This is the same as the processing of 4. The process of S647 is the same as the process of S627. Then, the process proceeds to S619.

When the result in S617 is No, the variables CEX and SX are compared (S618). If CEX <SX,
That is, the line segment represented by the target source edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (h), the line segments do not overlap each other. In this case, the flow moves to FIG. The process of S648 is the same as the process of S627.
Then, the process proceeds to S619.

After performing a series of comparison processing, it is determined whether or not there is a target clip edge list cell (S61).
9). In the case of Yes in S619, there is no target clip edge list cell, and thus the processing in the scan line K may be terminated. Therefore, all the remaining source edge list cells are made free (S620). S61
In the case of No in 9, it is determined whether or not there is no target source edge list cell (S621). In the case of Yes in S621, there is no target source edge list cell, and thus the processing in the scan line K may be terminated. Therefore, all the remaining clip edge list cells are made free (S622). In the case of No in S621, there is still both the target clip edge list cell and the target source edge list cell, and therefore the processing is performed for each edge list cell, and the process returns to S607.

The above-described processing from FIG. 5 to FIG. 15 is performed for all scan lines for one page. As a result, processing between clip edge lists is performed.

Here, as an example, the process when the clip area is formed into an arbitrary shape will be described. To make the area where the logical product operation between the inside of the polygon C shown in FIG. 4 and the initial clip (clip information of the entire page shown in FIG. 3) performed as a new clip area, use the clip for polygon C. Vector data is sent from the drawing data input unit 11 to the edge list generation unit 14 via the vector generation unit 12. The edge list generation unit 14 processes the received clip vector data to create a source edge list,
It is sent to the clip data merging unit 15. The clip data merging unit 15 compares the source edge list with the clip edge list stored in the clip information storage unit 16 for each scan line, and processes according to the flowcharts shown in FIGS. As one example among them, the scan line K shown in FIG. 4 will be described. The clip edge list shown in FIG.
The source edge list shown in (b) is read, and first, cs
The values of x, cex, x1 and x2 are compared. In this case c
Since sx <x1, cex> x2 (the relationship of FIG. 16 (e) and Yes in S615), the start point X coordinate of the target clip edge list is x1 as shown in FIG.
Is set (S635), x2 is set to the end point X coordinate of the target clip edge list (S636), and a new clip edge list cell (start point X coordinate is set to x2 + 1 and end point X coordinate is set to cex) is created. Then, it is inserted next to the target clip edge list cell (S637), and is set as the target clip edge list cell (S638).
Also, the source edge list cell of the target is freed (S63
9), the next source edge list cell is set as the target source edge list cell (S640). Then, similarly, x2 +
The values of 1, cex, x3 and x4 are compared. In this case, (x2 + 1) <x3, cex> x4 (the relationship of FIG. 16 (e), and the case of Yes in S615).
2, x3 is set to the start point X coordinate of the target clip edge list (S635), x4 is set to the end point X coordinate of the target clip edge list (S636), and a new clip edge list cell (start point X coordinate is set). x4 +
1. Set cex to the end point X coordinate) and insert it next to the target clip edge list cell (S63).
7) and make it the target clip edge list cell (S
638). Also, the source edge list cell of interest is freed (S639), and the next source edge list cell is made the source edge list cell of interest (S640). Then, the target source edge list cell becomes null (Yes in S621).
Therefore, the current target clip edge list cell just created is freed (S622), and the process is terminated. The result is as shown in FIG.

Next, in the clip processing unit 17, after merging all the clip data by the clip data merging unit 15, the result is stored in the clip information storage unit 16, and the clip data and the edge list generation unit 1 are stored.
Clip processing is performed from the edge list of the vector data to be drawn generated in step 4.

The flow of processing performed by the clip processing unit 17 will be described with reference to FIGS. 18 to 26. The description of this process is almost the same as the process in the clip data merging unit 15 described above. The description of the processing in the clip processing unit 17 is also processing for only one scan line. Let K be the target scan line. When this K is changed so as to target all the scan lines for one page, it means that the clip processing of the drawing information is performed using the clip data for one page. In this process, the edge list stored in the clip information storage unit 16 is called a clip edge list, and the edge list sent from the edge list generation unit 14 is called a drawing edge list.
One unit in the edge list is an edge list cell. FIG. 27 shows the relationship between the line segments represented by the clip edge list cell and the drawing edge list cell. The upper line segment in FIGS. 27A to 27F is the line segment represented by the drawing edge list cell, and the lower line segment is the line segment represented by the clip edge list cell. Only the part where these line segments overlap will be drawn.

First, it is determined whether or not the scan line K has a clip edge list (S701). Without it, the scanline will not be drawn, so
All the drawing edge lists of the scan line K are made free (S703), and the process for the scan line K is completed.
If there is, the first clip edge list cell is set as the target clip edge list cell (S702).

Next, it is determined whether or not the scan line K has a drawing edge list (S704). If it is not present, drawing is not performed on the scan line, so that the clip edge list of the scan line K is made free (S706), and the process on the scan line K ends.
If there is, the first drawing edge list cell is set as the target drawing edge list cell (S705).

The start point X coordinate value of the target clip edge list cell is set in the variable CSX (S707), and the variable CEX is set.
Is set to the end point X coordinate value of the target clip edge list cell (S708), the start point X coordinate value of the target drawing edge list cell is set to the variable SX (S709), and the end point X coordinate of the target drawing edge list cell is set to the variable EX. Set value (S
710).

The variable CSX and the variable EX are compared (S7).
11). In the case of CSX> EX, that is, when the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. Since they do not overlap, they will not be drawn. In this case, the process moves to the flow of FIG. The target drawing edge list cell is made free (S721), and the next drawing edge list cell is made the target drawing edge list cell (S722). Then, the process proceeds to S717.

In the case of No in S711, the variables CSX and SX, the variables CEX and EX, and the variables CSX and EX are compared (S712). CSX ≧ SX, CE
In the case of X> EX and CSX ≦ EX, that is, the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. The line segments of each other overlap. In this case, the flow moves to FIG. Set CSX (starting point X coordinate value of target clip edge list cell) to SX (that is, end point X coordinate of target drawing edge list) (S72)
3) Do. The next drawing edge list cell is set as the target drawing edge list cell (S724). Then, the process proceeds to S717.

In the case of No in S712, the variables CSX and SX are compared, and the variables CEX and EX are compared (S).
713). When CSX ≦ SX and CEX ≧ EX, that is, the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (c), the line segments overlap each other, and the line segment represented by the drawing edge list cell is drawn as it is. In this case, FIG.
Move to the flow. The next drawing edge list cell is set as the target drawing edge list cell (S725). And S71
Move to processing of 7.

When the result in S713 is No, the variables CSX and SX are compared, and the variables CEX and EX are compared (S).
714). When CSX ≧ SX and CEX ≦ EX, that is, the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (d), the line segments of each other overlap. In this case, the process moves to the flow of FIG.
SX (that is, the starting point X coordinate of the target drawing edge list cell) is CSX (the starting point X of the target clip edge list cell)
The coordinate value is set (S726). CEX (end point X coordinate value of target clip edge list cell) is set to EX (that is, end point X coordinate of target drawing edge list cell) (S727). Create a new drawing edge list cell, set CEX + 1 (a value obtained by adding 1 to the end point X coordinate value of the target clip edge list cell) to the start point X coordinate, and set EX (the end point of the target drawing edge list cell) to the end point X coordinate. (X coordinate value) is set and inserted next to the target clip edge list cell (S728). This new drawing edge list cell is made the target drawing edge list cell (S
729). The next clip edge list cell is set as the target clip edge list cell (S730). And S7
The process moves to 17.

When the result in S714 is No, the variables CSX and SX, the variables CEX and EX, and the variables CEX and SX are compared (S715). CSX ≦ SX, CE
In the case of X ≦ EX and CEX ≧ SX, that is, the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell have the relationship of FIG. 27 (e), The line segments of each other overlap. In this case, the process moves to the flow of FIG. S731, S732,
The processes of S733 and S734 are S727, S728, and S.
729 and S730. And S71
Move to processing of 7.

When the result in S715 is No, the variables CEX and SX are compared (S716). If CEX <SX,
That is, the line segment represented by the target drawing edge list cell and the line segment represented by the target clip edge list cell are shown in FIG.
In the case of the relationship (f), the line segments do not overlap each other. In this case, the process moves to the flow of FIG. The process of S735 is the same as the process of S730.
Then, the process proceeds to S717.

After performing a series of comparison processing, it is determined whether or not there is a target clip edge list cell (S71).
7). In the case of Yes in S717, there is no target clip edge list cell, and thus the processing for the scan line K may be terminated. Therefore, all the remaining drawing edge list cells are made free (S718), and the process ends. In the case of No in S717, it is determined whether or not there is no target drawing edge list cell (S719). Y in S719
In the case of es, since there is no target drawing edge list cell, the processing on the scan line K may be terminated. Therefore, all the remaining clip edge list cells are made free (S720), and the process ends. No in S719
In the case of, since there are still both the target clip edge list cell and the target drawing edge list cell, the processing for each edge list cell is performed.
Returning to the processing of 707.

The processing from FIG. 18 to FIG. 26 described above is performed for all scan lines for one page. As a result, a drawing edge list to be finally drawn is created.

The operation of clipping the drawing element will be described as an example. In order to clip the polygon P shown in FIG. 17 in the clip area previously created, the drawing vector data representing the polygon P is transferred from the drawing data input unit 11 to the edge list generation unit 14 via the vector generation unit 12. Sent. The edge list generation unit 14 processes the received drawing vector data to create a drawing edge list, and sends it to the clip processing unit 17. Clip processing unit 1
7, the drawing edge list and the clip information storage unit 1
While comparing the clip edge lists stored in No. 6, the processing is performed according to the flowcharts shown in FIGS. As an example of them, the scan line K shown in FIG. 17 will be described. The drawing edge list of the polygon P on the scan line K is received and set as the target drawing edge list (FIG. 17A). Clip edge list on scan line K, that is, FIG.
The clip edge list shown in (c) is read from the clip information storage unit 16 and used as the target clip edge list (FIG. 17 (b)). First, csx1, cex1, x
The values of 1 and x2 are compared. In this case, csx1 <= x
Since 1, cex1 <= x2, cex1> = x1 (Yes in S715), cex1 is set to the end point X coordinate of the target drawing edge list cell according to the flow of FIG. 25 (S731), and the new drawing edge list cell is set. (Set cex1 + 1 as the start point X coordinate and x2 as the end point X coordinate), insert it next to the target drawing edge list cell (S732), make it the target drawing edge list cell (S733), and target clip edge The list cell is set as the next clip edge list cell (S734). Next is c
The values of sx2, cex2, cex1 + 1 and x2 are compared. In this case, csx2> = (cex1 + 1), ce
Since x2 <= x2 (Yes in S714),
According to the flow of FIG. 24, csx2 is set to the start point X coordinate of the target drawing edge list cell (S726), cex2 is set to the end point X coordinate of the target drawing edge list cell (S727), and a new drawing edge list cell is created,
Cex2 + 1 is set to the X coordinate of the starting point, and the end point X
The ex is set to the coordinate and is inserted after the target drawing edge list cell (S728). The target drawing edge list cell is set as the next drawing edge list cell (S729), and the next clip edge list cell is set as the target clip edge list cell (S730). Next, since there is no clip edge list cell, the remaining drawing edge list is freed and the process ends.

The rasterizing unit 18 receives the drawing edge list processed by the clip processing unit 17 as described above, raster-converts it, and writes it in the page memory 19.
The printer 20 prints the information written in the page memory 19. For example, when the drawing edge list shown in FIG. 17 is printed, the image shown in FIG. 28 is output. Here, the output device is not limited to the printer, and may be a display device such as a CRT, or may be an input to another processing device.

[0048]

Since the clip processing can be performed by repeating simple comparison between the starting point coordinate value and the ending point coordinate value of the clip edge list and the edge list of the drawing element, the clipping of an arbitrary shape is processed at a very high speed. it can. In addition, even for logical operations on multiple clip areas, it is possible to reconstruct the edge list by repeating simple comparison of the start point coordinate value and the end point coordinate value of the same edge list and reconstructing the edge list by a simple operation. To be fast. In addition, since these vectors do not require extra processing even if they have a large thickness, the advantage of speeding up is also obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of this embodiment.

FIG. 2 is an explanatory diagram of an edge list.

FIG. 3 is a diagram showing an example of initial setting of a clip edge list.

FIG. 4 is a diagram showing an example of merging clip edge lists.

FIG. 5 is a flowchart of merge processing between clip edge lists.

FIG. 6 is a flowchart of a merge process between clip edge lists.

FIG. 7 is a flowchart of merge processing between clip edge lists.

FIG. 8 is a flowchart of merge processing between clip edge lists.

FIG. 9 is a flowchart of merge processing between clip edge lists.

FIG. 10 is a flowchart of merge processing between clip edge lists.

FIG. 11 is a flowchart of merge processing between clip edge lists.

FIG. 12 is a flowchart of merge processing between clip edge lists.

FIG. 13 is a flowchart of merge processing between clip edge lists.

FIG. 14 is a flowchart of merge processing between clip edge lists.

FIG. 15 is a flowchart of merge processing between clip edge lists.

FIG. 16 is a diagram showing a relationship between clip edge lists.

FIG. 17 is a diagram showing an example of a clip of an edge list.

FIG. 18 is a flowchart of clip processing.

FIG. 19 is a flowchart of clip processing.

FIG. 20 is a flowchart of clip processing.

FIG. 21 is a flowchart of clip processing.

FIG. 22 is a flowchart of clip processing.

FIG. 23 is a flowchart of clip processing.

FIG. 24 is a flowchart of clip processing.

FIG. 25 is a flowchart of clip processing.

FIG. 26 is a flowchart of clip processing.

FIG. 27 is a diagram showing a relationship between an edge list and a clip edge list.

FIG. 28 is an explanatory diagram of an output image.

[Explanation of symbols]

 11 Drawing Data Input Section 12 Vector Generation Section 13 Font Data Storage Section 14 Edge List Generation Section 15 Clip Data Merge Section 16 Clip Information Storage Section 17 Clip Processing Section 18 Rasterization Section 19 Page Memory 20 Printer

Claims (2)

[Claims] 1. A first edge list conversion means for converting input drawing information into an edge list including information on a start point which is a position to start drawing and information on an end point which is a position to end drawing. Second edge list conversion means for converting clip information displaying a part of the drawing information into an edge list; edge list of the drawing information converted by the first edge list conversion means; 2. Clip processing means that performs clip processing based on the edge list of the clip information converted by the edge list conversion means to generate an edge list, and an image that generates an image based on the edge list clipped by the clip processing means. A drawing device comprising: a generation unit. 2. A first edge list conversion means for converting the input drawing information into an edge list including information on a start point which is a position to start drawing and information on an end point which is a position to end drawing. A second edge list conversion means for converting the clip information displaying a part of the drawing information into an edge list; and a plurality of edge lists of the clip information converted by the second edge list conversion means. Merge processing means for performing merge processing, clip information storage means for storing the edge list merged by the merge processing means, edge list of drawing information converted by the first edge list conversion means, and the clip information storage Clip processing means for performing clip processing based on an edge list stored in the means to generate an edge list; An image generating unit that generates an image based on the edge list clipped by the clip processing unit.