JP2634906B2 - Image processing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method in which a contour of a figure is represented by an outline vector, an outline is created from the outline vector, and the inside of the outline is filled. The present invention relates to an image processing method for easily and rapidly performing vector raster conversion of an outline font in DTP (desktop publishing), LBP (laser printer), and the like.

<Prior Art> Seed fill and scan fill are conventionally known as a method for filling an arbitrary region of a figure. Seed fill is used in many image processing processors, but the processing speed is higher than that of scan fill. It has the disadvantage of being slow.

In the scan fill, as shown in FIG. 3, the outline of the figure to be filled is indicated by an outline vector, and the direction of the outline vector is set so that the figure is filled when the left side is painted. For example, an outline vector shown in FIG. 4B is created from the original data shown in FIG. Then, an outline as shown in FIG. 5A is created from this outline vector, scanning is performed in the x direction, and painting is started at an odd-numbered intersection between the horizontal scanning line and this outline, and an even-numbered intersection is performed. Filling is stopped at the intersection, and a graphic as shown in FIG. 5 (b) is obtained.

As an image processing method for filling a figure with such a scan fill, a conventional method is disclosed in Japanese Patent Publication No. 53-4101.
There is one as shown in Japanese Patent Publication No. This image processing method creates an outline from the outline vector according to the well-known Bresenham algorithm, and obtains an outline as shown in, for example, FIGS. 6 (a), 7 (a) and 8 (a). I have.

Then, scanning is performed in the x direction, filling is started at the odd-numbered intersections between the horizontal scanning lines and these outlines, painting is performed including the intersecting pixels, and painting is stopped at the even-numbered intersections. It fills up to the intersecting pixels.

By the way, in the above image processing method, when an outline is created, when the outline vectors overlap on the same pixel as in the top in FIG. 6 (a) or the center in FIG. 7, the position of the pixel is Be an outline. For this reason, when the horizontal scanning line intersects this outline, all the pixels on the right side including that pixel are filled, and the filling error as shown in FIG. 6 (b) and FIG. 7 (b) occurs. Occurs. FIG. 8 (a)
If an outline parallel to the scan direction is created as shown in the above, if the outline ends with an odd-numbered pixel counting from the first pixel where the scanning line intersects,
The pixel on the right side of the odd-numbered pixel is also filled, so that a filling error as shown in FIG. 8B occurs.

In order to prevent such an error from occurring, conventionally, for example, as shown in FIG. 5A, the position of a pixel shifted by one dot in the x-axis direction from the top outline is also taken as the outline. Was processing. Further, in the outline parallel to the scanning direction, the length is set to an even number of dots, or only the starting point and the ending point are plotted. However, in such a case, the processing speed of the host performing this processing becomes slow and the load on the host increases. When the outline obtained by performing the above processing on the vector font is stored in a memory such as a mask ROM, and the outline is reduced or rotated, for example, the outline shown in FIG. When the image is reduced as shown in (b), the above-described painting error may occur. Also, for example, when the above-described processing is performed on the outline shown in FIG. 10 (a), an outline as shown in FIG. 10 is obtained. When the outline is painted out, the outline becomes as shown in FIG. 10 (c). A graphic having a different shape is generated from the graphic indicated by.

A typical example of an outline in which an error occurs or the shape is different when the painting is performed is shown in FIG. The outlines shown in FIGS. 11 (a) and (b) are the same kind of outlines as those shown in FIGS. 6 (a) and 8 (a), and FIG. 11 (c) shows the same pixel as two outlines. If the boundary is shared, FIG. 11 (d) is the limit of FIG. 11 (c) by 2
This shows a case where the two boundaries exactly match. An outline surrounded by a circle indicates an outline causing an error.

As described above, in the above-described conventional image processing method, since an outline as shown in FIG. 11 is created when the outline is created, it is necessary to perform a process on the outline so as not to cause an error when filling the figure. And the processing speed is reduced. In addition, to perform the above processing, the shape of the figure after filling is greatly different from the shape of the original figure, and it is necessary to make full use of the characteristics of vector fonts that are easier to scale and rotate than dot fonts and have beautiful fonts. There was a problem that can not be.

Therefore, the present inventor has previously proposed the following three image processing methods as image processing methods that do not cause an error in painting a figure or deformation of the figure.

The first image processing method determines whether the change amount of the outline vector in the y-axis direction is negative, zero, or positive when the outline is created from the outline vector, and determines the change amount of the outline vector in the y-axis direction. If negative, an outline is created according to Bresenham's algorithm. If the amount of change of the outline vector in the y-axis direction is zero, no outline is created. If the amount of change of the outline vector in the y-axis direction is positive, Bresenham is An outline is created at a position shifted by one dot in the x-axis direction from the position determined by the above algorithm, and when the odd outline intersects the created outline with a horizontal scanning line, painting is started. Fill and stop filling at the even-numbered intersection, and The crossed pixel fill up the pixel immediately before is obtained as erased.

Further, in the second image processing method, when an outline is created from an outline vector, it is determined whether or not the change amount of the outline vector in the y-axis direction is zero, and the change amount of the outline vector in the y-axis direction is determined. If it is zero, no outline is created.If the change amount of the outline vector in the y-axis direction is not zero, an outline is created according to the Bresenham algorithm, and the created outline and an address corresponding to the position of the outline in the memory. An exclusive OR with the data stored in the memory is taken as a corrected outline, the corrected outline is stored at the address of the memory, the corrected outline stored in the memory is read, and the corrected outline and the horizontal scanning line are read. Start filling on odd-numbered intersections of Containing even fill including, stop filling had during even-numbered crossing, in which as fill up pixels intersected.

In the third image processing method, the outline of the figure is represented by an outline vector that is continuous in the clockwise direction, and the direction of the outline vector is set so that the figure is painted when the left side of the outline vector is painted. When an outline is created from the outline vector, it is determined whether the change amount in the x-axis direction and the change amount in the y-axis direction of the outline vector are negative, zero, or positive, respectively, and the change amount of the y coordinate of the outline vector is determined. Is changed from a positive state to a zero state, then x
If the amount of change in the coordinates is positive, continuous points at the same y-coordinate are not plotted except for the point immediately before the y-coordinate changes.
For the point immediately before the coordinate change, plotting is performed when the y-coordinate change is positive, and is not plotted when the y-coordinate change is negative. If the change amount changes from a positive state to a zero state and the change amount of the x coordinate at that time is negative, a continuous point of the same y coordinate plots a point immediately after the y coordinate changes, For the point immediately before the y coordinate changes, plotting is not performed when the y coordinate change amount is positive, and plotting is performed when the y coordinate change amount is negative. Consecutive points are not plotted. If the change in the y coordinate of the outline vector changes from a negative state to a zero state and the change in the x coordinate at that time is negative, the same y
Points with continuous coordinates are not plotted except for the point immediately before the y-coordinate changes.
If the change in the y coordinate is positive, do not plot
If the amount of change in the coordinates is negative, plot it.If the amount of change in the y coordinate of the outline vector changes from a negative state to zero, and if the amount of change in the x coordinate at that time is positive, , For consecutive points of the same y-coordinate, plot the point immediately after the y-coordinate changes, and plot the point immediately before the y-coordinate changes if the y-coordinate change becomes positive; If the coordinate change amount is negative, plotting is not performed, and other points on the y coordinate other than those described above are not plotted, and an outline is created. Scanning is performed in the x-axis direction. The filling is started at the odd-numbered intersection with, and is stopped at the even-numbered intersection.

<Problem to be Solved by the Invention> However, the above-described conventional image processing method has a problem that the processing of the first pixel (start point) of the outline becomes incomplete.

For example, taking an outline vector as shown in FIG. 12 as an example, suppose that an outline is created when points A, B, C, and D are the starting points. In this case, points A and D need to be plotted, but points B and C must not be plotted. In this way, even if the same outline needs to be plotted depending on how to take the starting point,
You may not have to plot the starting point.

Therefore, a method is conceivable in which the position of the starting point is brought to a point to be plotted, and that point is always plotted. For example, in FIG. 12, point A is selected as a starting point, and this starting point A is always plotted.
However, according to this method, when the point A is selected as the starting point as described above, the point A is a point that must be plotted even when the vector font is inclined or rotated. However, there are problems in the following cases.

That is, even if a point that does not require vertex processing such as point A in FIG. Also, even if a point requiring vertex processing such as point B in FIG. 13 is taken as a starting point, it is not necessary due to the rotation. For this reason, there is a problem that the point selected as the starting point is restricted. There is also a problem that the starting point cannot be set arbitrarily mechanically.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing method that can arbitrarily select a starting point and that does not cause a painting error.

<Means for Solving the Problems> In order to achieve the above object, according to the present invention, a contour of a figure is represented by an outline vector connected in a counterclockwise direction, and the direction of the outline vector is painted on the left side of the outline vector. And the figure is set to be filled, an outline is created from the outline vector, and scanning is performed in the X-axis direction.
In the image processing method in which filling is started at an odd-numbered intersection between the outline and the horizontal scanning line, and pixels intersected at the even-numbered intersection are erased and filling is stopped, when an outline is created from the outline vector, Without plotting the first pixel of the outline to be created, the outline is sequentially created from the next pixel, and the positional relationship between the first pixel and the next pixel is stored. When trying to plot the pixel of the first pixel, while selecting whether to plot the first pixel from the positional relationship between the first pixel and the previous pixel and the stored positional relationship, Is selected, the pixel at the position shifted by one dot in the X-axis direction from the first pixel is plotted. It is characterized in that so as to choose.

<Operation> The outline of a figure is represented by an outline vector that extends in a counterclockwise direction, and the direction of the outline vector is
When the left side of the outline vector is painted, the figure is set to be painted. Then, when creating an outline from the outline vector,
An outline is created sequentially from the next pixel without plotting the first pixel of the outline to be created.
At this time, the positional relationship between the first pixel and the next pixel is stored in the memory. Then, when the pixel to be plotted finally reaches the first pixel, the first pixel is obtained from the positional relationship stored in the memory and the positional relationship between the first pixel and the previous pixel. Choose whether to plot. At this time, if plotting is selected, an outline is created by selecting whether to plot a pixel at a position shifted by one dot in the X-axis direction from the first pixel. Then, scanning is performed in the X-axis direction, filling is started at the odd-numbered intersection of the outline and the horizontal scanning line, and pixels intersected at the even-numbered intersection are erased and the filling is stopped. By doing so, a simple starting point processing eliminates errors in filling.

<Example> Hereinafter, the present invention will be described in detail with reference to an illustrated example.

In the image processing method according to the present embodiment, the outline of a figure is represented by an outline vector connected in a counterclockwise direction, and the direction of the outline vector is set so that the figure is painted when the left side of the outline vector is painted. Then, when an outline is created from the outline vector, the outline is created sequentially without plotting the first pixel of the outline to be created, and the positional relationship between the first pixel and the next pixel is stored in a memory. Keep it. Then, when the pixel to be plotted reaches the first pixel, the first pixel is plotted based on the positional relationship stored in the memory and the positional relationship between the first pixel and the previous pixel. Choose whether or not. Further, when plotting the first pixel is selected, it is selected whether to plot a pixel at a position shifted by one dot in the X-axis direction from the first pixel. Then, an outline is created based on the selection result, scanning is performed in the X-axis direction, and painting is started at an odd-numbered intersection between the outline and the horizontal scanning line, and is stopped at an even-numbered intersection.

1 and 2 are diagrams each showing an example of a criterion for making the above selection.

FIG. 1 shows a case where the vector font has a trapezoidal shape as shown in (c) and point A is selected as a starting point for creating an outline. First, without plotting the start point A, a direction vector of A indicating the positional relationship between the start point A and the next point B, that is, a vector from the point A to the next point B is obtained. If the direction of the direction vector in the X direction is positive, “1” is set, if zero, “0” is set, and if negative, “−” is set.
1 "is stored at the address FDX of the memory shown in Fig. 1 (a). Similarly, in the Y direction," 1 "," 0 "or" -1 "is stored at the address FDX. Since the direction vector is positive in the X direction and zero in the Y direction, "1" and "0" are stored in FDX and FDY, respectively. Is plotted, the direction of the vector toward the end point A immediately before the end point A is stored in the addresses ADX and ADY in the same manner as described above. In this case, since both the X and Y directions are positive,
“1” and “1” are stored in ADX and ADY, respectively. Then,
The data stored in the memory is “1,0,1,1,”, and the end point A is plotted. If the data is “1,0,
For 1,1 ", plot the starting point.

FIG. 2 shows a case where the vector font is a triangle as shown in (c) and the vertex A is selected as a starting point for creating an outline. In this case, the data stored in the memory is “−1, 1, −1, −1”, and two points of the starting point A and a point obtained by shifting the starting point A in the X-axis direction are plotted. As described above, when the data is “−1, 1, −1, −1”, it is necessary to perform the vertex processing. Therefore, the starting point and a point obtained by shifting the starting point in the X-axis direction are plotted.

As shown in the above example, whether or not the starting point needs to be plotted and whether or not vertex processing needs to be performed are determined based on the positional relationship between the starting point and the next point and the starting point for various cases. The position is determined based on the positional relationship with the preceding point, and when the outline is created, the positional relationship is determined for the starting point, and the processing of the starting point is performed according to the determination criteria.

Therefore, when performing filling without error, the start point can be arbitrarily set without being restricted by the start point, and the set start point can be easily and quickly processed.

<Effects of the Invention> As is apparent from the above, the image processing method of the present invention, when creating an outline from an outline vector, sequentially outlines from the next pixel without plotting the first pixel of the created outline. Create. At this time, the positional relationship between the first pixel and the next pixel is stored in advance, and at the time of plotting the first pixel, the positional relationship between the first pixel and the previous pixel is stored in advance in the memory. From the obtained positional relationship, it is selected whether or not to plot the first pixel. When plotting, the pixel is plotted at a position shifted by one dot in the X-axis direction from the first pixel. You can create an outline that can be filled without color, and there is no restriction on the start point of the outline, so you can set the start point arbitrarily, and for the plot of the set start point, The start point can be accurately and easily processed at high speed as described above by a very simple method such as storing the data in a memory.

[Brief description of the drawings]

FIGS. 1 and 2 are diagrams for explaining a starting point process according to an embodiment of the present invention, FIG. 3 is a diagram for explaining an outlier vector, and FIGS. 4 and 5 are diagrams for explaining filling of a figure by scan fill. FIGS. 6, 7, and 8 are diagrams showing outlines created by the conventional image processing method and figures with erroneous fills, and FIG. 9 is a view showing reduced outlines in the above-described conventional example causing erroneous fills. FIG. 10 is a diagram illustrating a case of an outline, FIG. 10 is a diagram illustrating deformation of a figure in the conventional example, FIG. 11 is a diagram illustrating a typical example of an outline in which a fill error occurs in the conventional example, FIG. 12 and FIG. FIG. 13 is a diagram for explaining the starting point processing in the conventional example.

Claims (1)

(57) [Claims] 1. The outline of a figure is represented by an outline vector connected in a counterclockwise direction, and the direction of the outline vector is set such that the figure is painted when the left side of the outline vector is painted. , An outline is created, scanning is performed in the X-axis direction, filling is started at an odd-numbered intersection of the outline and the horizontal scanning line, and pixels intersected at the even-numbered intersection are erased and the filling is stopped. In the processing method, when creating an outline from the outline vector, an outline is created sequentially from the next pixel without plotting the first pixel of the outline to be created, and the first pixel and the next pixel are created. Is stored, and finally the first pixel is When plotting, the user selects whether or not to plot the first pixel from the positional relationship between the first pixel and the previous pixel and the stored positional relationship, while plotting the first pixel. And selecting whether or not to plot a pixel at a position shifted by one dot in the X-axis direction from the first pixel.