JP3879804B2 - Character / graphic processing unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a character / graphic processing apparatus that develops information of contour lines indicating characters / graphics into a bitmap.
[0002]
[Prior art]
An output device based on a bitmap screen such as a page printer or a display requires more bitmap data in order to output a character / graphic pattern of the same size as the resolution improves. Furthermore, in order to cope with output of character / graphic patterns of various sizes, the bitmap data must be held for each size, resulting in poor efficiency. Therefore, especially for a pattern having a fixed outline such as a character, the outline of the basic pattern is held as outline information (outline information) composed of a plurality of straight line segments and curved segments, and a desired pattern is stored. The memory efficiency is improved by using a method of filling the inside of the contour line after scaling to the size.
[0003]
A process for drawing a character / graphic pattern using the method of painting the inside of the outline will be briefly described below. FIG. 7 is an explanatory diagram of an example of a contour line and a bitmap obtained from the contour line. In FIG. 7, the thick lines connecting the control points (indicated by x marks in the circles) are the segments constituting the contour information. The letter “A” shown in FIG. 7 is composed of 11 straight line segments. Based on such contour information, pixels existing inside the contour line are inverted, for example, to obtain a bitmap of the character “A” as shown by hatching in FIG.
[0004]
FIG. 8 is an explanatory diagram of one method for determining whether or not a pixel is inside a contour line. As described above, in order to invert the pixels existing inside the outline, for example, it is necessary to determine whether each pixel is inside the outline. As one of the determination methods, it is determined here whether or not the center position of each pixel is inside the contour line. That is, whether or not the center position of each pixel indicated by a rectangle (◯ in the figure) is present inside the outline (thick line connecting control points indicated by X to ○ in the figure). Just judge. By such a determination method, it is determined that the pixel (rectangle) indicated by hatching in FIG. 8 is inside the contour line. By reversing these pixels, for example, a bitmap of characters and figures can be obtained.
[0005]
Basically, as described above, based on the information on the contour line, for example, the pixels inside the pixel are inverted and the filling process is performed. In fact, a scan conversion method is a typical method for performing such a filling process. FIG. 9 is an explanatory diagram of the painting process by the scan conversion method. Here, an example will be described in which the inside / outside of the contour line is determined under a condition called an EVEN-ODD rule that does not consider the extending direction (stroke direction) of the contour line.
[0006]
Now, it is assumed that contour information as shown by a bold line in FIG. 9A is given. Here, one of the arrangement directions of the pixels of the bitmap is set as the scanning direction. Here, the horizontal direction in the figure is the scanning direction. Of course, the vertical direction in the figure may be the scanning direction.
[0007]
Then, the coordinates of intersections between the plurality of scanning lines parallel to the scanning direction and connecting the center points of the respective pixels and the contour line are obtained. In FIG. 9, the intersection is indicated by ● and the center of each pixel is indicated by ○. Further, here, the pixel having the center at the closest position on the right side of the intersection in the drawing is obtained. This pixel is called an edge and becomes the start point and end point of the filled area. In FIG. 9A, the edge pixels are hatched. In this example, since the scanning line is set in the left-right direction in the figure, no edge appears on the left-right direction contour line because the contour line and the scanning line have no intersection.
[0008]
Next, paint processing is performed according to the rules. In the EVEN-ODD rule, the intersections with the scanning lines are counted from one end, and the range from the odd number to the even number is the filled range. As described above, when the edge is taken to the right of the intersection, the odd-numbered edge counted from the left end is the start point, and the even-numbered edge is the end point. As shown in FIG. 9B, the pixels are examined along the scanning direction according to this rule, and the pixels from the odd edge to the even edge are inverted. Here, since the even edge itself is outside the contour line, it should be noted that the area up to the left of the even edge is the filled range. If an even number of edges overlap, it can be correctly painted by erasing the edges.
[0009]
In the example shown in FIG. 9B, a pixel indicated by a triangle is a start point, and a pixel indicated by an inverted triangle is an end point. Therefore, the hatched pixels are inverted.
[0010]
FIG. 10 is an explanatory diagram of a specific example of the painting process by the scan conversion method. In the case of the letter “A” shown in FIG. 7, an example is shown in which the fill processing is performed by the scan conversion method described in FIG. 9. When information on a contour line as shown by a bold line in FIG. 10A is given, an edge shown by hatching in FIG. 10A is obtained from the intersection of each contour line and each scanning line. Here, an odd-numbered edge (indicated by a triangle) from the left side in the scanning direction is a start point, and an even-numbered edge (indicated by an inverted triangle) is an end point.
[0011]
Based on the edge information obtained in this way, a bit map as shown in FIG. 10B can be obtained by inverting the pixels from the start point pixel to the pixel before the end point pixel. In the letter “A”, the inside of the upper half is missing, but according to this method, such white missing parts can be accurately expressed.
[0012]
When trying to output a small-size pattern using the above-described method of filling the inside of the contour line, there may be a case where dropout occurs in the fill. This is caused when the interval between the contour lines becomes too narrow and there is no pixel having a center point between the contour lines. In other words, this occurs when a plurality of contour lines penetrate between the center points of adjacent pixels.
[0013]
FIG. 11 is an explanatory diagram of an example of a dropout. For example, as shown in FIG. 11A, when a plurality of contour lines pass through the center points of horizontally arranged pixels, the pixels indicated by the broken lines are not filled, and the figure appears to be broken. This is because the edges obtained from the intersection of the two contour lines and the scanning line shown in FIG. 11 become the same pixel. That is, as shown in FIG. 11B, the center pixel is the start point and end point of the filled area. As described above, in order to perform the painting process normally, even-numbered overlapping edges are deleted. Therefore, the edge of the center pixel shown in FIG. 11B is erased and no painting is performed. In this way, dropout occurs.
[0014]
As described above, dropout occurs in the overlapping portion of the edge, so that it is possible to predict that the dropout will occur if it is detected that two edges overlap at the stage of extracting the edge. However, as described above, in order to perform the painting process normally, the overlapping edges must be deleted, so that the dropout correction process is performed separately from the painting process.
[0015]
FIG. 12 is an explanatory diagram of another example of dropout. FIG. 12 shows a dropout that occurs when a plurality of contour lines penetrate between the center points of pixels adjacent in the vertical direction. In this example, the area to be filled according to the edge obtained from the intersection of each scanning line and the contour line is not continuous in the adjacent scanning line. That is, the edge is obtained as shown in FIG. 12B, but the pixels filled in according to the edge are the hatched pixels in FIG. As described above, since the area to be filled is separated between adjacent scanning lines, the figure appears to be interrupted at a portion surrounded by a broken line.
[0016]
In the example shown in FIG. 12, overlapping edges cannot be found even when examined from the scanning direction as in the example shown in FIG. 11, and the occurrence of dropout cannot be predicted by the same method as shown in FIG. In such a case, as shown in FIG. 12C, when the scanning line is set in the vertical direction in the drawing, it is possible to predict the occurrence of dropout in the same manner as in the example shown in FIG. Become.
[0017]
As described above, in order to discover all dropouts, it is necessary to detect edges from both the left and right directions and the vertical direction in the figure. However, since the result of the painting process is the same from both the horizontal and vertical directions, it is only necessary to perform the painting process on the detected edge.
[0018]
FIG. 13 is an explanatory diagram of a specific example of the painting process by the scan conversion method including the correction of dropout. Here, an example in which a small character “0” is expanded into a bitmap is shown. A small character “0” can be output by painting a portion sandwiched between two curved segments.
[0019]
In this example, by performing paint processing using edges obtained with the horizontal direction (or vertical direction) in the drawing as the scanning direction, the pixels shown in FIG. 13A are hatched. It can be seen that a dropout occurs in a portion where the contour interval is narrow.
[0020]
Next, as described with reference to FIG. 11, when the overlap of edges in the scanning direction is examined, it can be found that the pixels shown by hatching in FIG. 13B are dropped out. In addition, as described in FIG. 12, when the overlapping of edges is examined by changing the scanning direction (for example, changing from the horizontal direction in the drawing to the vertical direction), the pixels shown in FIG. You can discover that you are dropping out. By combining the images in FIGS. 13A, 13B, and 13C, a graphic (character “0”) having no dropout can be obtained as shown in FIG. 13D. In FIG. 13, the bitmap images of FIGS. 13A, 13B, and 13C are shown separately. For example, one bitmap is displayed in both directions shown in FIGS. 13B and 13C. Pixels to be dropped out in the scanning direction may be written. Further, each image of FIGS. 13A, 13B, and 13C may be written in one bitmap.
[0021]
By the way, in order to record the edge selected by the intersection of the contour line and the scanning line in the simplest manner, it is only necessary to invert the pixel on the bitmap as shown in the above examples. In this case, the above-described filling can be performed by examining all the pixels in the paint process. However, when the character size is increased or the resolution is high, the number of pixels in the bitmap is very large. As the number of pixels increases in this way, the process of examining all pixels in the paint process becomes very heavy. Also, the amount of memory for the bitmap is increased. For example, in order to create a vertical and horizontal n-fold bitmap, a memory of n square times is required. In addition, there is a disadvantage that another bit map is required for the dropout processing, or that a more complicated paint rule other than the EVEN-ODD rule is difficult to use due to a simple data structure.
[0022]
Therefore, there is a method called an edge list in which edge coordinates are listed for each scanning line, and two adjacent edge coordinates are extracted from the list and used as a fill range. For example, in the character output device described in Japanese Patent Application Laid-Open No. 5-224653, the X coordinate and Y coordinate of the intersection of the segment and the scanning line are registered in a list, and paint processing is performed based on this list. Yes.
[0023]
FIG. 14 is an explanatory diagram of a specific example of the painting process by the scan conversion method using the edge list. FIG. 14A is an enlarged view showing an example of the relationship between the contour line and the pixel. Here, a pixel filling process on the scanning lines S1 and S2 is considered. Also, (1) to (5) indicated by bold lines are contour segments, and are stored in this order.
[0024]
First, each segment is called sequentially to detect the intersection with the scanning line. For example, the segment {circle around (1)} intersects the scanning line S1 and the scanning line S2 at the positions indicated by ●. The coordinates of ● are added to the list of each scanning line. That is, as shown in FIG. 14B, P1 (1) is stored in the list of the scanning line S1 as the coordinates of the intersection of the segment (1) and the scanning line S1. Similarly, P2 (1) is stored in the list of scanning line S2 as the coordinates of the intersection of segment (1) and scanning line S2. Such processing is also performed for each of the segments (2) to (5). As a result, a list as shown in FIG. 14B is obtained. Here, in addition to storing the X and Y coordinates as in the above-mentioned document, only one coordinate value may be stored because one coordinate value is known by the scanning line S1.
[0025]
When the coordinates of the intersections with the scanning lines are registered in the list for all the segments in this way, the coordinates registered for each scanning line are sorted. Here, when sorting is performed from left to right, the list shown in FIG. 14B is sorted as shown in FIG. 14C.
[0026]
After the sorting, as shown in FIG. 14D, the coordinates of the intersection of the segment and the scanning line are taken out from the head as a pair. Of the coordinates of the pair, the edge corresponding to the previous coordinate is the starting point of the painting process, and the edge corresponding to the subsequent coordinate is the ending point of the painting process. The filling process can be performed by inverting the pixels from the start point to the end point. Note that the end pixel is not inverted as described above.
[0027]
By such a paint process, the pixels indicated by hatching in FIG. 14E are inverted, and the fill process in the scanning lines S1 and S2 ends. FIG. 14 shows an example in which the coordinates of the intersection of the segment and the scanning line are registered in the list. However, for example, the coordinates of the edge corresponding to the coordinates of the intersection may be registered.
[0028]
Since the edge list does not have edge information on the bitmap, the pixels to be dropped out may be directly drawn on the bitmap subjected to the paint processing. Further, it is not necessary to read out the entire bitmap in order to fill between the edges, and it is not necessary to manipulate edge information such as erasing even edges on the bitmap. Therefore, it is not necessary to have a bitmap in the memory of the work area, and the paint process may be executed by directly writing to the frame buffer that is the final output destination.
[0029]
Even in the filling process using the edge list as described above, if the edges corresponding to the two coordinates extracted from the edge list are the same, it can be determined that a dropout occurs, so the process for the dropout can be performed. . It is also conceivable to create the edge lists as described above separately for two orthogonal scanning lines and detect dropouts from the respective edge lists.
[0030]
As described above, when the interval between the outlines becomes too narrow and the fill-out occurs (dropout), the occurrence of dropout is detected and corrected in the scan conversion process to avoid this phenomenon. . However, when there is a dropout portion and a portion other than the dropout portion in one segment of the contour line, there is a problem that a concave shape appears in the portion that is not the dropout.
[0031]
FIG. 15 is an explanatory diagram of an example of a defect caused by the dropout process. FIG. 15A shows an example in which the character “1” is drawn. In the serif portion of the character “1”, P1 and P3 are filled by the dropout process, but P2 is not filled and a concave shape appears. Such a phenomenon is significant not only in the serif portion of the character “1” shown in FIG. 15 but also in a portion where the horizontal portion and the vertical portion intersect, such as the upper portion of the character “T”. This concave shape is called a “bird's foot” because the shape looks like a bird's foot.
[0032]
FIG. 15B is an enlarged view of the bird leg generation portion of FIG. Among the segments constituting the contour line, horizontal segments L1, L2, and L3 extending in the left-right direction in the figure have intersections with the vertical scanning lines in the figure. At this time, dropouts are detected for P1 and P3 among the pixels P1, P2, and P3 that are edges, and are filled by the dropout process. However, since P2 is merely a terminal edge, it is not determined to be a dropout. For example, when a scanning line is set in the vertical direction in the figure, the area up to the pixel one pixel above P2 is the filled area, and P2 is not painted. For example, when scanning lines are set in the left-right direction in the figure, none of P1 to P3 is an edge. Therefore, even if the scanning direction is set in both the horizontal direction and the vertical direction in the figure, P2 is not filled. Therefore, a concave “bird leg” as shown in FIG.
[0033]
In the prior art, the dropout portion correction processing as described above is performed, but the occurrence of “bird's feet” cannot be prevented.
[0034]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described circumstances, and corrects the concave “bird's feet” generated when the contour information indicating the characters / graphics is developed into a bitmap, so that a good character can be obtained. An object of the present invention is to provide a character / graphic processing device capable of reproducing graphics.
[0035]
[Means for Solving the Problems]
In the present invention, when developing contour information into a bitmap using an edge list, an edge where dropout occurs when the coordinates of two edges are the same is detected and corrected. Correction processing for correcting the concave portion generated by the processing along the segment is performed. More specifically, when the edge list is created, it is determined whether or not the scanning line and the segment are orthogonal with the detection of the edge. If it is determined that the scanning line and the segment are orthogonal, the segment and the scanning line are determined. The coordinates of the edge of the intersection with are sequentially linked. When the edge where the dropout occurs is detected during the dropout correction process, if there is an edge coordinate linked from the edge coordinate, the edge coordinate obtained by following the link Perform correction processing.
[0036]
As a result, even if there is a dropout portion and a portion that does not exist in one segment of the contour line, since the correction process is performed along the segment from the dropout portion, a concave shape called “bird leg” is formed. It is corrected and “bird's feet” never appears on the bitmap. Therefore, it is possible to develop a bitmap of characters / graphics from the information on the contour line.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram showing an embodiment of a character / graphics processing apparatus according to the present invention. In the figure, 1 is a scan conversion unit, 2 is an edge list registration unit, 3 is an edge list generation unit, 4 is a shape correction unit, 5 is an edge list development unit, 6 is contour information, 7 is an edge list, and 8 is a bit. It is a map.
[0038]
The scan conversion unit 1 takes out the outline information 6 of the designated character or figure, reads the segments constituting the outline in the recorded order, calculates the intersection of the segment and the scan line, and calculates the edge from the coordinates of the intersection Ask. Then, the edge information is sequentially transferred to the edge list registration unit 2. At this time, if the segment is perpendicular to the scanning line, the edge list registration unit 2 is instructed to create a link. When all edges are registered, the edge list generation unit 3 is called. Various conversion processes such as an enlargement / reduction process for changing the size of characters and figures may be performed in advance. In addition, a curved segment may be divided and approximated by a straight line segment in order to improve processing efficiency.
[0039]
The edge list registration unit 2 sequentially registers the edge information output from the scan conversion unit 1 together with link information in a list prepared for each scanning line as the edge list 7. The elements to be registered as edge information in the list include at least two pieces of information, such as the coordinates of the edge to be registered and the location where the next edge linked to this edge is stored (for example, array number or memory address in the list). The stored structure. When there is an instruction to create a link from the scan conversion unit 1, the location of the edge information to be registered with the next scan line for the same segment is registered as the location where the next edge in the registered edge information is stored. . When there is no instruction, a termination number (a specific value such as -1) is assigned to the link.
[0040]
The edge list generation unit 3 sorts the edge list 7 for each scanning line by edge coordinates, calls the shape correction unit 4 every time the list sorting for one scanning line is completed, and passes the sorted list. .
[0041]
The shape correction unit 4 examines the list of one scanning line passed from the edge list generation unit 3 and determines whether or not the edge may be dropped out. If there is a possibility of dropout, it is registered in the bitmap 8 for dropout, and if it is a normal edge, the edge list development unit 5 is called. If there is a link at an edge that has been determined to be dropout, the link is tracked and the edge is also registered in the dropout bitmap 8.
[0042]
The edge list development unit 5 develops between the edges output by the shape correction unit 4 on the bitmap 8.
[0043]
As already described, dropout detection needs to be performed in two directions in which bitmap pixels are arranged (in the following description, for the sake of convenience, the horizontal direction and the vertical direction). Therefore, the scan conversion unit 1, the edge list registration unit 2, the edge list generation unit 3, and the shape correction unit 4 perform processing for two cases of a horizontal scanning line and a vertical scanning line, respectively. The edge list development unit 5 is called only at the time of the first (or second) execution of the two processes because the scan line in any direction may be processed.
[0044]
FIG. 2 is a flowchart showing an example of the operation in the embodiment of the character / graphics processing apparatus of the present invention. For example, outline information 6 is input from the outside, or code information is input, and the outline information 6 is read from, for example, an internal ROM or an external storage device according to the code information, and the outline of characters / graphics to be developed into a bitmap When the information 6 is given, the operation of the character / graphics processing apparatus is started. As described above, two processes are performed in different scanning directions for the correction process.
[0045]
First, the bitmap 8 is initialized and the first process is started. The scan conversion unit 1 performs various conversion processes on the given contour information 6 such as coordinate conversion to a size to be output as necessary. Further, the number of divisions of the curve segment is determined from the pixel size, and is divided into short straight line segments. Further, the edge list 7 is initialized.
[0046]
In S <b> 21, the scan conversion unit 1 sequentially obtains edges corresponding to the intersections with the respective scan lines for all the segments constituting the given outline information 6. The edge list registration unit 2 sequentially registers the edge information obtained by the scan conversion unit 1 in the edge list 7. At this time, the scan conversion unit 1 determines whether the segment is perpendicular to the scan line, and instructs the edge list registration unit 2 to create a link for the segment perpendicular to the scan line. In accordance with this instruction, the edge list registration unit 2 sequentially connects the edges registered for each scanning line with respect to the segments perpendicular to the scanning line.
[0047]
Edges are obtained and stored in the edge list 7 for all segments constituting the contour line information 6, and then the processing of the edge list generation unit 3, shape correction unit 4, and edge list development unit 5 is performed for each scanning line. First, in S22, the first scanning line is set, and in S23, it is determined whether or not the processing has been completed for all scanning lines. In S24, the edge list generation unit 3 sorts the list of edges for one scanning line. . Then, initialization is performed so that edge information can be extracted from the beginning of the sorted edge list. Note that two edges are paired and processed as a start point and an end point.
[0048]
In S25, it is determined whether or not all the edges in the list for one scanning line have been processed. If there are unprocessed edges, the process proceeds to S26.
[0049]
In S26, the shape correction unit 4 determines dropout. That is, when two edges are extracted from the list of one scanning line, it can be determined that a dropout occurs if the coordinates are the same. If dropout does not occur, in S27, the edge list developing unit 5 inverts and paints out the bitmap 8 between the extracted edges. At this time, the end point is not inverted. If a dropout has occurred, the process proceeds to S30, where the shape correction unit 4 performs a dropout correction process and a correction process for preventing the occurrence of “bird's feet” associated with the dropout correction process.
[0050]
After that, the two edges are processed, the next two edges are taken out in S28, and the process returns to S25. In this way, the process is performed for every two edges, and when all the edges stored in the list of one scanning line are finished, this is detected in S25, and the process moves to the next scanning line in S29. And return to S23. Since two edges are processed as a pair, even if only one edge remains, it is treated as having been processed for one scanning line.
[0051]
In this way, the processing for each scanning line is sequentially performed, and when the processing for all the scanning lines is completed, this is detected in S23, and the first processing is terminated. Next, the second process is performed by changing the scanning direction. In the second process, the painting process by the edge list developing unit 5, that is, the process in S27 is not performed. The other processes are the same as the first process. When the two processes are finished, the process of developing the contour line information 6 into the bitmap 8 is finished.
[0052]
FIG. 3 is a flowchart showing an example of an operation when dropout occurs in the embodiment of the character / graphics processing apparatus of the present invention. This process is executed when it is determined that a dropout occurs in S26 of FIG. Information on the edge determined to cause dropout in S30 is acquired, and the edge is registered in the bitmap 8 in S31.
[0053]
Further, when an edge determined to cause dropout is included in a segment perpendicular to the scanning line, correction processing is performed on each pixel on the segment. At this time, a pixel on a segment perpendicular to the scanning line can be acquired by following the link included in the edge.
[0054]
In S32, it is determined whether or not the link is the terminal for both of the two edges used when the dropout determination is performed. If both are terminations, the correction process at the time of dropout is terminated.
[0055]
If at least one of the links is not a termination, in S33, it is confirmed whether or not there is a link at the edge serving as the start point. If the link is not the termination, in S34, an edge in the next scan line of the link destination is acquired, and the link of this edge is changed to the termination. Similarly, in S35, it is confirmed whether or not there is an edge link as an end point. If the link is not the termination, in S36, an edge in the next scan line to be linked is acquired, and the link of this edge is changed to the termination. In S37, the scanning line to be processed in the correction process is advanced, and the process returns to S31 to register the edges acquired in S34 and S36 in the bitmap 8. Thereafter, the processing after S32 is repeated with the edge acquired at S34 and S36 as the processing target.
[0056]
By such repeated processing, an edge corresponding to a segment perpendicular to the scanning line is tracked and sequentially registered in the bitmap 8. When two segments reach the end, the corresponding edge link ends. This is detected in S32, the correction process is terminated, the process returns to S28, and the process for the two edges determined to cause dropout is terminated.
[0057]
An example of the above operation will be described using a specific example. FIG. 4 is an explanatory diagram showing an example of the state of the edge list that is transitioned in an example of the operation in the embodiment of the character / graphics processing apparatus of the present invention, and FIG. . Here, consider an example in the serif portion under the character “1” as shown in FIG. An example similar to FIG. 15B is shown in FIG. The symbols are the same as in FIG. As shown in FIG. 5A, the vertical direction in the figure is the scanning direction, and two segments (segments L1 and L2 and segments L3 and L2) perpendicular to the scanning line are vertically adjacent pixels. It is assumed to exist between the centers.
[0058]
FIG. 4A shows an edge list 7 generated by the edge list registration unit 2 in S21 when the contour information 6 indicated by a thick line in FIG. 5A is passed. That is, since the segment L1 intersects with the scanning lines S1, S2, and S3, the edges P1 (L1), P2 (L1), and P3 (L1) corresponding to the respective intersections are registered for each scanning line. The At this time, since the segment L1 is perpendicular to the scanning line, edges are connected by links. That is, the storage position of the edge P2 (L1) is stored in the edge list 7 as the link destination of the edge P1 (L1). Further, the storage position of the edge P3 (L1) is stored in the edge list 7 as the link destination of the edge P2 (L1). In FIG. 4, this link is indicated by an arrow line. For the edge P3 (L1), the link destination is the end.
[0059]
Since the segment L2 intersects with the scanning line S1, the edge P1 (L2) corresponding to the intersection of the scanning line S1 and the segment L2 is registered in the list corresponding to the scanning line S1. Similarly, since the segment L3 intersects with the scanning line S3, the edge P3 (L3) corresponding to the intersection of the scanning line S3 and the segment L3 is registered in the list corresponding to the scanning line S3. Note that the segments L2 and L3 are also tracked with respect to these edges, but since the segments L2 and L3 do not reach the next scanning line and there is no next edge, the link is terminated.
[0060]
In this manner, the edge list 7 created as shown in FIG. 4A is sorted by edge list for each scanning line by the edge list generation unit 3 in S24. First, when the registered edges for the scanning line S1 are sorted, P1 (L1) and P1 (L2) indicating the same edge are arranged as shown in FIG. 4B. The sorted edges are processed two by two from the top, but usually the edges P1 (L1) and P1 (L2) are processed simultaneously.
[0061]
When the dropout is determined in S26, it is determined that there is a possibility of dropout because the edges P1 (L1) and P1 (L2) indicate the same position. Therefore, first, in S31, the edge P1 (L1) (= P1 (L2)) determined to have the possibility of dropout is registered in the bitmap 8. Thereby, the dropout is corrected as shown by hatching in FIG.
[0062]
Furthermore, the link destination is stored in the edge P1 (L1). Therefore, link tracking processing is performed. In either S34 or S36, the link destination edge P2 (L1) is taken out, and the link destination of the edge P1 (L1) is terminated. In S31, the edge P2 (L1) is registered in the bitmap 8. Further, the link destination is also stored in the edge P2 (L1). Therefore, the link destination edge P3 (L1) is taken out, the link destination of the edge P2 (L1) is terminated, and the edge P3 (L1) is registered in the bitmap 8. Since the link destination of the edge P3 (L1) is the end point, no further tracking processing is performed.
[0063]
By tracking the link destination and registering it in the bitmap 8 in this way, the serif portion under the character “1” is corrected as shown by hatching in FIG. In the edge list 7, since the link destination is changed to the end after the tracking process described above, the link (arrow line) by the segment L1 is deleted as shown in FIG.
[0064]
If it is determined that no dropout occurs from the two edges extracted from the sorted list, a process for filling pixels between the edges is performed on the bitmap 8 in S27.
[0065]
In this way, two edges are registered for each edge registered in the list corresponding to the scanning line S1. When the processing on the scanning line S1 is completed, as shown in FIG. 4D, processing on the edge registered in the list corresponding to the next scanning line S2 is performed. For the scanning line S2, an edge P2 (L1) is registered in the list. This edge is extracted together with another edge (the upper edge of the character “1”). Since no dropout occurs, the painting process is performed with the edge P2 (L1) as the end point. In this process, the edge P2 (L1) is not filled. However, the edge P2 (L1) is filled by the correction process by tracking the link from the edge P1 (L1) described above. Since it is determined that no dropout occurs for the edge P2 (L1), the correction processing by the shape correction unit 4 is not performed.
[0066]
When the process for the scanning line S2 is completed, the process is performed for the next scanning line S3. When sorting is performed for the scanning line S3, the edge list 7 is as shown in FIG. The scanning line S3 has edges P3 (L1) and P3 (L3) at the same position. Therefore, it is determined that dropout occurs, and the edge P3 (L1) (= P3 (L3)) is registered in the bitmap 8. Since this pixel has already been registered when the correction process is performed by following the link from the edge P1 (L1), the pixel does not change at all.
[0067]
In this manner, the pixels indicated by hatching in FIG. As shown in FIG. 15 (A), a “bird's feet” that is a concave portion has conventionally occurred in the serif portion under the character “1”, but according to the character / graphic processing device of the present invention, As shown in FIG. 5D, it is understood that “bird's feet” does not occur and the bitmap is developed into a good character.
[0068]
4 and 5 show an example in which processing is performed with the vertical direction in the figure as the scanning direction. With respect to the vertical outline, by performing processing in the horizontal direction in the drawing as the scanning direction, it is possible to perform the dropout correction and the “bird leg” correction processing in the same manner. The filling process from the start point to the end point need only be performed during one of the processes.
[0069]
FIG. 6 is a block diagram showing a configuration example for realizing one embodiment of the character / graphic processing apparatus of the present invention. In the figure, 11 is a CPU, 12 is a RAM, 13 is a ROM, 14 is an external storage device, 15 is a video interface, 16 is a frame buffer, and 17 is a printer interface. The ROM 13 or RAM 12 stores a program for operating the CPU 11. The CPU 11 operates according to a program stored in the ROM 13 or RAM 12 and executes the functions of the scan conversion unit 1, edge list registration unit 2, edge list generation unit 3, shape correction unit 4, and edge list development unit 5. Note that the program is stored in the external storage device 14 and may be executed by the CPU 11 after being read into the RAM 12.
[0070]
In addition to programs executed by the CPU 11, the RAM 12 stores an edge list 7 generated by executing the functions of the edge list registration unit 2 and the edge list generation unit 3 by the CPU 11. Similarly, a bitmap 8 used when executing the functions of the shape correction unit 4 and the edge list development unit 5 is stored. In addition, it is also used for work when the CPU 11 executes.
[0071]
In addition to the program executed by the CPU 11, the ROM 13 can hold contour information as font information.
[0072]
The external storage device 14 is composed of a storage medium capable of storing digital information, such as a hard disk, CD-ROM, MO, FD, and SRAM and ROM, and stores various data in addition to programs executed by the CPU 11. The As one of the stored data, for example, information on the outlines of characters and figures can be stored as a font file.
[0073]
The video interface 15 is connected to a display device such as a CRT, for example, and can send various display signals to the display device. For example, it is possible to display characters and graphics developed in a bitmap using the function of the character / graphic processing apparatus of the present invention. Similarly, the printer interface 17 is connected to a recording device such as a printer, and can record data on recording paper or the like by sending the recording data to the recording device. For example, it is possible to record characters and graphics developed in a bitmap using the function of the character / graphic processing apparatus of the present invention.
[0074]
The frame buffer 16 has a bitmap of one band or one page or more in, for example, one screen or more of a display device connected to the video interface 15 or a recording device connected to the printer interface 17. For example, when the CPU 11 executes the functions of the shape correction unit 4 and the edge list development unit 5, it may be directly written as the bitmap 8, or once developed in the RAM 12 and transferred to the frame buffer 16.
[0075]
In such a configuration, when contour information is directly input from the outside, the CPU 11 executes the function of each configuration shown in FIG. Further, when input is performed using a character code or the like, information on the contour line corresponding to the character code is read from the ROM 13 or the external storage device 14 and developed into a bitmap. For example, the outline / line information is enlarged / reduced according to the size of the designated character or figure, or other various deformation processes are performed, and then the function of the character / figure processing apparatus of the present invention is applied. It may be executed. Further, the bitmap development process based on the contour line information is performed twice while changing the scanning direction for the correction process as described above, and the painting process is performed once.
[0076]
The bitmap developed in the RAM 12 is transferred to a predetermined position in the frame buffer 16. Then, when a bitmap image of a predetermined unit, such as one screen or one page, is completed, or at regular time intervals, it is transferred to the display device via the video interface 15 to display the image, or The image can be transferred to a recording device via the printer interface 17 and recorded on a recording sheet or the like. The contents of the frame buffer 16 can be stored in the external recording device 14 or output to the outside.
[0077]
In the above description, an example is shown in which the bitmap 8 is provided on the RAM 12 and transferred to the frame buffer 16 after the expansion process. However, the character / graphic processing apparatus of the present invention does not read out the bitmap, so the frame buffer 16 It is also possible to configure to write directly. In this case, the required amount of memory can be further reduced.
[0078]
In the above-described embodiment, the concave portion (bird's feet) correction processing that appears due to the dropout correction processing is performed by following the link provided in the edge list. The present invention is not limited to this. For example, it is configured to sequentially search for the edges in the next and subsequent scanning lines based on the coordinates where the dropout processing has been performed, or the segments are associated with the edges and the dropout is performed. It is possible to apply various methods for correcting the concave portion (bird's feet) in the shape correction unit 4 such as reading out a segment corresponding to the processed edge and separately drawing a straight line.
【The invention's effect】
As is clear from the above description, according to the present invention, when the contour information is expanded into a bitmap, the dropout is corrected and the “bird's feet” that has conventionally occurred by the dropout correction processing is It can correct also about the concave-shaped part called. Thus, for example, there is an effect that a bitmap can be output with a good shape even when characters and figures are output in a small size and low resolution.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a character / graphics processing apparatus of the present invention.
FIG. 2 is a flowchart showing an example of operation in the embodiment of the character / graphics processing apparatus of the present invention;
FIG. 3 is a flowchart showing an example of an operation when dropout occurs in the embodiment of the character / graphics processing apparatus of the present invention;
FIG. 4 is an explanatory diagram showing an example of a state of an edge list that is transitioned in an example of an operation in the embodiment of the character / graphics processing apparatus of the present invention;
FIG. 5 is an explanatory diagram showing a state of a bitmap that transitions in an example of an operation in the embodiment of the character / graphics processing apparatus of the present invention;
FIG. 6 is a block diagram showing a configuration example for realizing an embodiment of the character / graphics processing apparatus of the present invention;
FIG. 7 is an explanatory diagram of an example of a contour line and a bitmap obtained from the contour line;
FIG. 8 is an explanatory diagram of a method for determining whether or not a pixel is inside a contour line.
FIG. 9 is an explanatory diagram of a painting process using a scan conversion method.
FIG. 10 is an explanatory diagram of a specific example of a painting process using a scan conversion method.
FIG. 11 is an explanatory diagram of an example of a dropout.
FIG. 12 is an explanatory diagram of another example of dropout.
FIG. 13 is an explanatory diagram of a specific example of a painting process by a scan conversion method including correction of dropout.
FIG. 14 is an explanatory diagram of a specific example of a painting process by a scan conversion method using an edge list.
FIG. 15 is an explanatory diagram of an example of a defect caused by dropout processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Scan conversion part, 2 ... Edge list registration part, 3 ... Edge list production | generation part, 4 ... Shape correction part, 5 ... Edge list expansion | deployment part, 6 ... Contour line information, 7 ... Edge list, 8 ... Bit map, 11 ... CPU, 12 ... RAM, 13 ... ROM, 14 ... external storage device, 15 ... video interface, 16 ... frame buffer, 17 ... printer interface.

Claims (4)

In a character / graphic processing apparatus for developing contour information indicating characters / graphics into a bitmap, an edge is formed from an intersection of a segment constituting the contour information and a scanning line parallel to the pixel arrangement direction of the bitmap Scanning conversion means for detecting the edge, edge list registration means for registering the edge coordinates output by the scanning conversion means as a list for each scanning line, and scanning the edge coordinates registered in the list by the edge list registration means Edge list generation means for sorting line by line, and correction processing is performed by detecting an edge where dropout occurs when the coordinates of two edges are the same based on the list sorted by the edge list generation means a shape correction unit for performing a correction process for correcting along the segment concave portion caused by the correction process with the Ejjirisu Characters and graphics processing apparatus characterized by having an edge list expansion means for expanding the original sorted list into a bitmap by the generation means.   The scan conversion means determines whether or not the scan line and the segment are orthogonal with the detection of the edge, and the edge list registration means determines that the scan conversion means determines that the scan line and the segment are orthogonal. When the coordinates of the edge of the intersection of the segment and the scanning line are sequentially linked, and when the shape correction means detects the edge where the dropout occurs, the edge coordinate linked from the edge coordinate exists. 2. The character / graphic processing apparatus according to claim 1, wherein correction processing is performed on edge coordinates obtained by following the link.   The character / graphics processing apparatus according to claim 1, wherein the shape correction unit writes a pixel to be corrected in a bitmap as the correction processing.   4. The character according to claim 1, wherein the shape correction unit performs a correction process each time the edge list generation unit sorts the coordinates of the edge with respect to one scanning line. 5. -Graphic processing device.

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