JP2768370B2 - Drawing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic drawing method for drawing an image on an image display device such as a computer display or a printer, and more particularly to a graphic drawing method for drawing a plane figure.

[0002]

2. Description of the Related Art There are two types of figures: line figures and plane figures. A line figure is a figure represented by an arrangement of pixels, such as a straight line or a circle. On the other hand, a plane figure is a figure having an “inside”, such as a filled triangle or a circle. In drawing a plane figure, the inside of the figure is filled with a tiling pattern.

Conventionally, the most general-purpose tiling pattern is defined as a figure having a size of m × n pixels, and when drawing a figure, the tiling pattern is laid in an area to be painted in such a manner as to continue vertically, horizontally, and horizontally. At this time, the correspondence between a certain pixel in the figure and the tiling pattern is given by Equation 1 below.

[0004]

(Equation 1)

[0005] Next, basic processing for drawing a plane figure will be described with reference to FIGS. 3 and 5.

FIG. 3 is a diagram showing coordinates and tiling patterns necessary for drawing a plane figure, and moving directions of the tiling patterns on a scan line. FIG.
7A is a drawing showing the drawing drawing shape, tiling pattern setting information, the processing start scan line and the processing end scan line, and the drawing processing start coordinates and the drawing processing end coordinates on the drawing processing target scan line. FIG. 3B is a diagram showing the movement of the tiling pattern coordinates from the drawing process start coordinates to the drawing process end coordinates.

FIG. 5 is a flowchart showing the flow of processing of the conventional plane figure drawing method.

Here, the x coordinate is defined as a value increasing from left to right, and the y coordinate axis is defined as a value increasing from top to bottom. It shall proceed in the direction of the value.

The processing start scan line is (y = Ya)
And the processing end scan line is (y = Yb).

The scan line to be processed is (y = Yc)
It is assumed that the drawing start coordinate on the processing target scan line is (x = Xc1) and the drawing end coordinate on the processing target scan line is (x = Xc2).

First, an input of a command necessary for drawing of setting information of a tiling pattern and a shape of a screen graphic is received (step 201).

From the shape of the figure obtained in step 201, the range of scan lines which are horizontal lines constituting the figure space to be processed is determined, and the processing start scan line and the processing end scan line are set (step 202). .

The processing start scan line is set as the scan line to be processed (step 203). Here, since the processing start scan line is (y = Ya), this (y)
= Ya) is the scan line to be processed.

When a scan line to be processed is set,
The following processing is sequentially performed on scan lines between the processing start scan line and the processing end scan line.

The drawing processing start coordinates (x = Xc1) and the drawing processing end coordinates (x = Xc2) on the processing target scan line (y = Yc) are calculated (step 204).

The coordinates (Pc1) of the tiling pattern corresponding to the drawing processing start coordinates (Xc1, Yc) are obtained by the above formula 1 (step 205).

The tiling pattern is mapped between the drawing processing start coordinate and the drawing processing end coordinate using the tiling pattern coordinate obtained in step 205 as the map start point. That is, a drawing mask is generated (step 206). Since this mapping is performed assuming that the right end and the left end of the tiling pattern are continuous, the pixel on the right side of the pixel on which _PR is mapped has P
_L is mapped.

Draw a plane figure (step 20)
7).

It is checked whether or not the scan line to be processed is a scan line that has been processed (step 208).
If the scan line to be processed is the process end scan line, the step 208 =) plane figure drawing processing is ended. If the processing target scan line is not the processing end scan line (# in step 208), the processing target scan line is updated (step 209), and step 204 is performed.
Return to That is, the scan line to be processed is (y = Y
The processing from step 204 to step 208 described above is repeated until b).

With the above procedure, a plane figure can be drawn using an m × n size tiling pattern.

However, the above-described method requires two remainder operations for each scan line. Assuming that the height of the figure is h, 2 × h remainder operations are required for the entire figure.
However, the calculation speed of remainder calculation in a general-purpose CPU is extremely slow, and requires about 100 clocks. DSP (Di
Even a processor such as a digital signal processor, which is good at arithmetic processing, requires several tens of clocks. This operation speed is much slower than memory access (2 to 3 clocks) and addition / subtraction multiplication (1 to 2 clocks).

In the conventional drawing of a drawing, the following method is used in order to eliminate a delay in processing speed due to such a remainder calculation.

In the remainder calculation, when the divisor is a power of 2, the calculation is extremely simple and can be performed at high speed. Therefore, the width of a tiling pattern to be a divisor is limited to a power of two. Generally, 16 bits or 32 bits are used according to the bus width of the graphic drawing system to be used.
Restrict to bits.

The value of the y coordinate changes one by one as the scan line changes. In that case, when the remainder calculation is represented by the following equation 2,

[0025]

(Equation 2)

Using the property represented by the following equation 3, the remainder operation can be replaced with a comparison operation and an addition.

[0027]

(Equation 3)

By using such a method, the remainder calculation for one figure can be reduced to one remainder calculation of the y coordinate for the processing start scan line.

That is, the speed of the plane figure can be greatly improved.

The above method is effective in the case where the processing is performed while changing the scan line one by one, regardless of the limitation of the width of the tiling pattern. Therefore, the above method is also applied to the above basic processing procedure. Can be. In that case, since the remainder calculation in the y direction can be reduced to only once for the processing start scan line,
The number of surplus computation required in the figure of the height h is made to (h + 1) times.

[0031]

Generally, in a graphic drawing system, the drawing processing speed is important.
Many systems limit the width of the tiling pattern.

On the other hand, there is an increasing demand to draw at high speed using a tiling pattern of an arbitrary size. For example, when a part of image data already drawn is used as a tiling pattern, there is a request to use the tiling pattern without restriction.

In some cases, it is desired to change the size of the tiling pattern so that the appearance is the same in devices having different resolutions. For example, when the remodeling degree of the printer has increased 1.5 times in both the vertical and horizontal directions,
If an output is obtained with a tiling pattern of 2 × 32 pixels, a tiling pattern of 48 × 48 pixels must be used to obtain the same result.

However, in the conventional plane figure drawing method, a tiling pattern other than a power of 2 cannot be used, or a drawing processing speed when a tiling pattern other than a power of 2 is used is slow, so that it is not practical. Absent.

For this reason, when a plane figure is drawn using a tiling pattern by a conventional method, as described later,
A trade-off has to be made between the degree of freedom of the tiling pattern and the drawing processing speed. That is, when a tiling pattern of an arbitrary size is used, the remainder calculation must be performed for each scan line, and there is a problem that the drawing processing speed is reduced. Further, in the case that requires high-speed processing, either limits the width of the tiling pattern to a power of 2, or, depending of the width of the tiling pattern such as the bus width of the drawing system the prior art is employed There was a problem that it had to be limited to the default value.

Accordingly, it is an object of the present invention to provide a graphic drawing method which increases a drawing processing speed by reducing a remainder calculation when a tiling pattern of an arbitrary size is used.

Another object of the present invention is to limit the width of the tiling pattern to a power of 2 when drawing requires high-speed processing, and to set the width of the tiling pattern to graphic drawing. An object of the present invention is to provide a graphic drawing method which is not limited to a limited value depending on a system bus width or the like.

[0038]

In order to achieve the above object, a graphic drawing method according to the present invention provides a graphic drawing method in which the inside of a graphic is filled with a tiling pattern of the graphic input to an image processing apparatus from contour information of the graphic. Setting a circumscribed rectangle containing the figure, scanning the inside of the circumscribed rectangle, obtaining drawing coordinates to be filled in the figure by a remainder operation, and tiling the drawn coordinates to be filled. A step of obtaining a circumscribed rectangle; a step of scanning the inside of the circumscribed rectangle; and a step of scanning the inside of the circumscribed rectangle. Generating, and inside the circumscribed rectangle and outside the figure to be filled, Generating a pixel mask that masks the portion of the pixel that is not the target of the crushing; and performing no drawing on the pixel masked by the pixel mask, and tying the pixel masked by the pixel mask. when it possesses the steps of drawing a ring pattern, and to scan the interior of the bounding rectangle, scanning to
The range in the x direction, which is the direction of the circumscribed rectangle,
And between the right ends of the figures .

The remainder calculation is reduced and the drawing speed is increased by performing only the number of times for obtaining the coordinates of the tiling pattern corresponding to a specific point of the circumscribed rectangle irrespective of the figure to be drawn. It is desirable.

[0040]

[0041]

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

FIG. 1 is a flowchart showing the flow of processing of a graphic drawing method according to one embodiment of the present invention.

The graphic drawing method according to the present invention includes a step 101 for receiving an input of a command necessary for drawing concerning setting information of a tiling pattern, a shape of a screen graphic, and the like; Step 102 for obtaining a bounding box), Step 103 for obtaining the coordinates of a tiling pattern corresponding to the point at the upper left corner of the bounding box, setting the drawing process start scan line to the upper side of the bounding box, and setting the drawing process end scan line Step 10 for setting the lower side of the bounding box
4 and a step 105 of setting a scan line to be initially subjected to the drawing process to the above-described drawing process start scan line
And a step 106 for obtaining the drawing start coordinates and the drawing end coordinates of the drawing processing target scan line, and a step of generating a pixel mask for masking a portion of the pixel which is on the above described drawing processing target scan line and is not to be filled. 107, a step 108 of mapping a tiling pattern on a portion of the scan line to be subjected to the drawing process, which is not covered with the pixel mask, and checking the line to be subjected to the drawing process, If the drawing processing end scan line is the drawing processing end scan line, the drawing processing is ended. If the drawing processing target scan line is not the above-described drawing processing end scan line, step 109 proceeds to step 110 described later, and the processing target scan line is updated. Step 110 and tiling pattern coordinates It consists updating step 111..

FIG. 2 is a block diagram showing the configuration of a graphic drawing system to which the graphic drawing method according to one embodiment of the present invention is applied.

A graphic drawing system to which the present invention is applied is as follows:
A CPU 10, a frame memory 11 for holding each pixel constituting image data to be displayed on the screen, and a tiling pattern coordinate control circuit 12 for controlling the coordinates of the tiling pattern
A tiling pattern storage memory 13 for storing a tiling pattern, a drawing coordinate register 14 for storing drawing coordinates, a contour generator 15 for generating a contour of a figure input to the image processing apparatus, Drawing start / end coordinate register 16 for storing coordinates and drawing end coordinates
A drawing mask generating circuit 17 for generating a pixel mask;
It comprises a tiling pattern storage memory 13, a drawing mask generation circuit 17, and a drawing control circuit 18 for controlling information obtained from the frame memory 11.

FIG. 3 has already been described in the section of the prior art and will not be described here.

FIG. 4 is a diagram showing the result of applying the graphic drawing method according to one embodiment of the present invention.

Next, a specific description will be given with reference to FIGS. 2, 3 and 4.

In the present description, a case in which the inside of a figure defined on the basis of an end point given by coordinates or a vector is drawn will be described with reference to an example of filling a triangle shown in FIG. .

In this embodiment, it is assumed that the generation of a tiling pattern is performed for the entire inside of the bounding box. That is, a tiling pattern is generated by performing a tiling pattern on the entire region [1] shown in FIG.

The tiling pattern is shown in FIG.
× n size.

The value of the pixel at the coordinates processed by the drawing mask is defined as MSK.

The value of the pixel at the drawing coordinates in the frame memory 11 is DST.

The value of the tiling pattern storage memory indicated by the tiling pattern coordinate circuit 12 is defined as PTN.

The coordinates given to the figures, tiling patterns and the like are the same as those used in the prior art, and the description is omitted here.

First, a figure to be drawn and its tiling pattern information are input (step 101).
Here, since one triangle and its interior are painted with a tiling pattern, a command necessary for it is input.

The following is performed as preparation before drawing.

The bounding box of the given figure is calculated (step 102). The bounding box obtained here is
It is a rectangle whose diagonal is a line connecting the point (Xa, Ya) and the point (Xb, Yb).

Point (Xa, Ya) at the upper left corner of the bounding box
Are obtained on the tiling pattern corresponding to (step 103). Using Equation 1, the coordinates Pa are as shown in Equation 4 below.

[0060]

(Equation 4)

The calculated coordinates Pa are stored in the tiling pattern coordinate control circuit 12.

The drawing process start scan line is set on the upper side (y = Ya) of the bounding box, and the drawing process end scan line is set on the lower side (y = Yb) of the bounding box (step 104).

The first scan line to be subjected to the drawing process is set as the scan line for starting the drawing process (step 10).
5).

Next, the following processing is sequentially performed on each scanning target scan line between the rendering processing start scan line and the rendering processing end scan line.

The coordinates of the intersection between the drawing figure and the scan line to be subjected to the drawing process are obtained by using the contour generator 15. Among the intersections between the drawing figure obtained by the contour generator 15 and the scan line to be subjected to the drawing processing, the coordinates of the intersection at the left (Xc
(1, Yc) is set as drawing start coordinates, and the right intersection coordinates (Xc2, Yc) are set as drawing end coordinates (step 106). These drawing start coordinates and drawing end coordinates are stored in the drawing start / end coordinate register 16.

A drawing mask is generated by the drawing mask generation circuit 17 (step 107). The drawing mask includes the value (X) of the drawing coordinate register 14 scanned from the left end to the right end of the bounding box, and the drawing start / end coordinate register 1
6 is compared with the drawing start coordinates (Xc1) and the drawing end coordinates (Xc2), and the drawing is performed only on the portion where Xc1 ≦ X ≦ Xc2, and on the other portions. Is generated in a pattern that is not affected by drawing.

A tiling pattern is mapped using Pc as a mapping start point between the processing start point (Xa, Xc) and the processing end point (Xb, Yc) (step 1).
08).

When the above-mentioned DST, PTN, and MSK are used, drawing is performed by the calculation of the following equation (5).

[0069]

(Equation 5)

The drawing result is as shown in FIG. That is, the portion A holds the value of DST before drawing, and the portion B writes the value of PTN.

After the execution of the drawing, if the scan line to be subjected to the drawing process is the scan line at which the drawing process has been completed, the drawing process is terminated. Do that.

The scan line to be subjected to the drawing process is updated (step 110).
The scan line to be processed is moved to a portion below the pixel. The updated scan line can be expressed as Equation 6 below.

[0073]

(Equation 6)

The coordinates Pc + 1 on the tiling pattern corresponding to the point (Xa, Yc + 1) can be obtained by applying Equation 3 to the value of Pc. (Step 1
11) After updating the tiling pattern, the process returns to step 106 again.

The above processing is repeated until the scan line to be subjected to the drawing process and the scan line at the end of the drawing process match, that is, Yc = Yb.

The drawing processing that has been extended can be considered as follows when the viewpoint is changed. The generation of the tiling pattern is performed for the entire inside of the bounding box. By using the drawing mask, the pixel where the drawing is actually performed is limited to the inside of the drawing target graphic.

As a result, the remainder operation on the x coordinate can be omitted. That is, x at the left end of the bounding box
The coordinates (Xa) do not change between the drawing processing start scan line and the drawing processing end scan line. Therefore, the remainder calculation on the x coordinate is performed only once (X
a mod m) only needs to be calculated.

Next, another embodiment of the graphic drawing method of the present invention will be described.

If the generation of the tiling pattern is performed on the entire inside of the bounding box, only the area [1] shown in FIG. 3A is actually drawn. For the other regions [2] to [4], a tiling pattern is generated, but is not drawn since it is masked by the drawing mask. It suffices to scan up to the rightmost end of the graphic to be painted on the drawing processing target scan line. Therefore, [3] and [4] are useless areas.

In order to eliminate this waste, the above-described steps 107 and 108, that is, the scanning range in the x direction in generating the pixel mask and executing the drawing may be limited from the left end of the bounding box to the drawing end coordinates. Then, generation of a tiling pattern and generation of a drawing mask for the regions [3] and [4] in FIG. 3A can be omitted.

The other processes are the same as those in the above-described embodiment, and thus will not be described here.

[0082]

As described above, the graphic drawing method according to the present invention can be applied to a specific point of a circumscribed rectangle including a graphic input to the image processing apparatus, regardless of the graphic to be drawn for the number of remainder operations. Need only be performed the number of times to obtain the coordinates of the tiling pattern to be performed, so that the remainder calculation can be reduced,
The drawing speed can be increased.

The graphic drawing method of the present invention does not limit the width of the tiling pattern to a power of two and does not limit the width of the tiling pattern to a limited value depending on the bus width of the graphic drawing system. Regardless of the difference between the image processing systems, the drawing processing speed and the degree of freedom of the tiling pattern can be maintained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing flow of a graphic drawing method according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a graphic drawing system to which a graphic drawing method according to one embodiment of the present invention is applied;

FIG. 3 is a diagram showing coordinates and tiling patterns necessary for drawing a plane figure and moving directions of the tiling patterns on a scan line. FIG. 3A is a diagram showing the shape of the drawing, the setting information of the tiling pattern, the processing start scan line, the processing end scan line, and the drawing start coordinates and the drawing processing end coordinates of the drawing processing target scan line. . FIG. 3B is a diagram showing the movement of the tiling pattern coordinates from the drawing process start coordinates to the drawing process end coordinates.

FIG. 4 is a diagram showing a result of applying a graphic drawing method according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a processing flow of a conventional plane figure drawing method.

[Explanation of symbols]

 Reference Signs List 10 CPU 11 Frame memory 12 Tiling pattern coordinate control circuit 13 Tiling pattern storage memory 14 Drawing coordinate register 15 Contour generator 16 Drawing start / end coordinate register 17 Drawing mask generating circuit 18 Drawing control circuit

Claims (2)

(57) [Claims] 1. A graphic drawing method for generating a graphic filled with a tiling pattern inside a graphic from contour information of the graphic input to an image processing apparatus, comprising: setting a circumscribed rectangle including the graphic; A figure drawing method for scanning the inside of a circumscribed rectangle, obtaining drawing coordinates to be filled in the figure by a remainder operation, and drawing the drawing coordinates to be filled with a tiling pattern, wherein the step of obtaining the circumscribed rectangle; Scanning the inside of the circumscribed rectangle, and generating a tiling pattern for the portion to be painted inside the circumscribed rectangle, and inside the circumscribed rectangle, and Pixels that are outside the figure to be filled and are not to be filled. Generating a pixel mask to be masked, and drawing the tiling pattern for pixels not masked by the pixel mask without drawing the pixels masked by the pixel mask. have a, when scanning the interior of the bounding rectangle, the direction of scanning
From the left end of the circumscribed rectangle to the x direction
A graphic drawing method characterized by being between right ends of the graphic. 2. The method according to claim 1, wherein the number of times of the remainder calculation is performed only by the number of times for obtaining the coordinates of the tiling pattern corresponding to a specific point of the circumscribed rectangle, regardless of a figure to be drawn. 2. The graphic drawing method according to claim 1, wherein the drawing speed is increased.