KR100647367B1 - Pass rendering method of two dimensions object in the mobile terminal - Google Patents

Abstract

A pass rendering method of a two-dimensional object in a mobile terminal device is provided to realize a graphic engine for accurately and promptly drawing a pass and effectively perform the rendering of the graphic engine in a mobile environment. A control point and a command about a two-dimensional object are transferred from a user(S101). If a curve of a pass is identified, a line-based curve constitution line is extracted using the control point(S105). If a line of the pass is identified, a line is extracted using the control point(S107). When an outline of the pass is drawn correspondingly to the extracted line, X values mapped to Y values are stored in a buffer(S109). A stroke region is determined using the outline and an inline of the pass, and the stroke region is filled(S113).

Description

Pass rendering method of two dimensions object in the mobile terminal

1 is a flowchart illustrating a path rendering method of a 2D object in a mobile terminal according to an exemplary embodiment of the present invention.

2 is an example of a figure for obtaining a cubic curve in the curve rendering method according to the present invention;

3 is an example of a figure for obtaining a two-dimensional curve in the curve rendering method according to the present invention;

Figure 4 is an exemplary view comparing the Y buffer and the existing buffer according to the present invention.

5 is another exemplary diagram comparing a Y buffer and an existing buffer according to the present invention;

6 is a view for explaining a stroke configuration example according to the present invention.

Figure 7 is a view comparing the control points when the circle or hexagon in accordance with the present invention.

8 shows an example of filling a stroke inner region according to the invention;

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a path rendering method for rendering a path that is the basis for each object effectively in a mobile terminal, particularly when implementing a two-dimensional graphics engine.

In general, the two-dimensional graphics engine is composed of a modeling (modeling), rendering (rendering) pipe structure, by repeating the modeling and rendering to show the object (object) on the screen, and to enable animation and interaction. The modeling is to transform an object using a matrix operation containing position and shape information, and the rendering is to fill an object in a screen buffer.

In general, the performance of a graphics engine is compared by the accuracy of modeling and the speed of rendering. Modeling has a small amount of matrix computation at the points constituting the object, but since the model determines the shape of the object, accurate results are required.

Rendering is to grasp the area of the figure using the object point transformed through the modeling, and then fill the desired area. That is, the screen coordinate value matching the object point is obtained, and then the color value is filled. This requires a large amount of computation since all screen coordinates constituting the object are subject to computation.

A path is a figure consisting of a line-to-line connection, a line-to-curve connection, and a curve-to-line connection. The curve drawing method used in this figure is a cubic curve composed of four control points and a quadratic curve composed of four control points. The line drawing method consists of a vertical line, a horizontal line, and a vertical and non-horizontal line. Because curves and lines can represent any object, the accuracy and speed of path rendering will determine the accuracy and speed of engine rendering.

Techniques for applying such a 2D graphics engine to a portable terminal have been developed, and methods for effectively implementing accuracy and speed in rendering a path of the 2D graphics engine to a portable terminal have been proposed.

A first object of the present invention is to provide a path rendering method of a 2D object in a portable terminal so as to implement a 2D graphics engine in a portable terminal and efficiently perform path rendering.

A second object of the present invention is to provide a path rendering method of a two-dimensional object in a mobile terminal that can be drawn on a line basis when drawing a curve of a figure in a two-dimensional graphics engine.

A third object of the present invention is a method for rendering a path of a two-dimensional object in a mobile terminal using integer arithmetic in a two-dimensional graphics engine, and using a central filter having a mask of a 3 * 1 size for information loss caused by integer arithmetic. In providing.

A fourth object of the present invention is to provide a path rendering method of a 2D object in a mobile terminal which intends to use a Y buffer for pixel region storage and a non-zero method for an inner region of a stroke.

Path rendering method of a two-dimensional object in a mobile terminal according to the present invention for achieving the above object,

Receiving a control point and a command from a user;

Checking a curve or line of a path from the user command, extracting a line-based curve configuration line using the control point in the case of a curve, and extracting a line using the control point in the case of a line;

If an outline of a path corresponding to the extracted line is drawn, searching for an X value mapped to each Y value in a buffer by rotating a loop corresponding to a Y height for an area inside the path;

And determining the stroke area by calculating the inner and outer lines of the path, and filling the inner area of the stroke.

Preferably, the line-based curve construction line extracting step uses an integer operation by multiplying a value controlling the number of points constituting the curve by an integer capable of guaranteeing the number of digits up to the second decimal point.

Preferably, the step of storing in the buffer, characterized in that for storing the X value corresponding to the value based on the Y value of the screen size in the Y buffer.

Preferably, the method further comprises blending by using a center filter having a mask having a size of 3 * 1 to solve a problem of loss of pixel values in the mask resulting from the conversion to the integer operation.

Preferably, the pass stroke region is characterized by using a non-zero method.

A path rendering method of a 2D object in a mobile terminal according to an exemplary embodiment of the present invention as described above will be described with reference to the accompanying drawings.

First, the path rendering of an object obtains screen coordinate values matching the object point by using the object point converted through modeling, and then fills the color value. Here, the path is a figure composed of lines and curves.

If one or more control points are input from the user (S101), it is determined whether the area of the figure is a curve or a line (S103), and in the case of a curve, equations and curve construction lines to be described later are extracted (S105). If the line is not a curve, the line is extracted using the start point and the end point (S107).

Here, the control point is a value input from the user, and the shape of the curve is determined only by receiving the input value of the control point. Also, in step S103, a command (line = L, curve = C) indicating a curve or a line is input together with the control point to distinguish the curve or the line.

In addition, the curve rendering method for extracting the curve line configuration in step S104 includes a cubic curve and a two-dimensional curve using four control points. The curve will include circles, ellipses, and curves.

The cubic curve method uses four control points P (x, y), as shown in Equation (1). 2 shows four control points (P ₀ , P ₁ , P ₂ , P ₃ ) (P ₀ ′, P ₁ ′, P ₂ ′, P ₃ ′) applied to Equation 1 of the cubic curve. The figure shown.

x = a _3n (1-t) ³ + a _{3n + 1} t (1-t) ² + a _{3n + 2} t2 (1-t) ² + a _{3n + 3} t ³

y = b _3n (1-t) ³ + b _{3n + 1} t (1-t) ² + b _{3n + 2} t2 (1-t) ² + b _{3n + 3} t ³

Where a _3n , a _{3n + 1} , a _{3n + 2} . a _{3n + 3} is the x value of the control point b _3n , b _{3n + 1} , b _{3n + 2} . b _{3n + 3} is the y value of the control point. t is a value for controlling the number of points constituting the cubic curve and has a value from 0 to 1.

In this way, cubic curves are obtained using four control points, and four control points can be obtained by connecting lines to lines. That is, a cubic curve may be obtained based on a line.

The cubic curve configuration line adjusts the section constituting the curve and has coordinates according to the value corresponding to the section, and when connected with the coordinates from the previous section, the line becomes a line. In this way, the cubic curve configuration line is extracted, and the result of applying the t value to 0.1 or 0.01 and then inserting the t value from 0 to 1 is connected to the lines.

The two-dimensional curve is obtained from Equation 2 below, in which four control points P0, P1, P2, and P3 are used. The resultant value obtained by applying the four control points P (x, y) to Equation 2 is the Q value of FIG. 3. That is, P is a control point and Q is on the curve with the result value extracted by Equation 2.

x = a _3n (1-t) ² + 2 (1-t) ta _{3n + 1} + t ² a _{3n + 2}

y = b _3n (1-t) ² + 2 (1-t) tb _{3n + 1} + t ² b _{3n + 2}

Where a _3n , a _{3n + 1} , and a _{3n + 2} are the x values of the control point, b _3n , b _{3n + 1} , and b _{3n + 2} are the y values of the control point. t is a value for controlling the number of points constituting the cubic curve and has a value from 0 to 1.

In the method of extracting a line from the two-dimensional curve, four control points (P0, P1, P2, and P3) are used to obtain a line-to-line connection, thereby extracting a two-dimensional curve on a line basis. The Q value is a result value extracted by Equation 2.

The shape of the cubic curve or the two-dimensional curve is determined according to the number of t values, that is, the sections constituting the curve. The larger the number of t is, the more accurate the curve is drawn. t consists of a value between 0 and 1.

The curve configuration line has coordinates according to the values corresponding to the intervals by adjusting the sections constituting the curve, and when connected with the coordinates from the previous section, the curves become lines. In this way, it is possible to extract a construction line such as a cubic or two-dimensional curve, and input the t value from 0 to 1, and then apply the t value differently according to the object by 0.1 or 0.01. To connect them to the line.

In this way, line-based curve creation is performed on the curve. In addition, to reduce the amount of computation, the amount of computation is reduced by converting the t value to an integer.

This line-based curve creation method is a method of drawing an effective curve with a small curve configuration section. The curve configuration section is constant, and if you draw a curve that requires more than a section, the problem of boiling occurs, and the problem of not accurately grasp the curve area. In order to solve this problem, the present invention uses a line-based curve creation method, and draws a section of the curve as a line, which makes it possible to create a boiling curve even with a small number of sections. In this method, an unnecessary operation occurs that draws the same line several times. Therefore, the coordinates of the points constituting the previous line are memorized, and then, it is determined whether or not to compare and draw them. This method does not provide accurate values at the points that make up the curve, but improves accuracy and speed with little error.

That is, when drawing a curve, the shape of the curve is determined according to the section. Since the path is a shape, the distinction between the inside and the outside must be clear, so determining the correct area is important. In general, when drawing a curve, the section is divided as closely as possible to prevent the shape from boiling, and the shape of the correct shape is obtained, but even if it is a little incorrect for the mobile environment of the present invention, the line-based curve is created to make the distinction between the inside and the outside. We used the method, and when drawing the line, the section is divided into the most suitable sections by giving a tradeoff to the accuracy and speed of the shape through experiments.

In addition, since integer arithmetic saves 6 times the cost of decimal arithmetic, it uses integer arithmetic. To this end, in the present invention, the value of t is converted to an integer. In the 32-bit integer type, a value of -2 ³¹ to 2 ³¹ is an effective range, and when converting to an integer operation, an overflow problem does not occur. The value of t is multiplied by 100 to convert it to an integer operation that guarantees up to two decimal places. This is the same effect as the t value has an accuracy of 0.01, and since the maximum value is 100 ³ , it can be seen that no overflow occurs. In addition, since the integer operation may lose the rounded value of the decimal operation, in the present invention, 100 ³ divided by half is added to restore the value lost during the integer operation.

In other words, minority operations consume a lot of computation speed in a mobile environment. However, since the graphic engine implemented here is an application requiring accuracy, the present invention uses an integer arithmetic method as a method that does not lose accuracy while quickly using a decimal arithmetic operation. For example, if the input value is multiplied by 65536 (= 2 ¹⁶ ) and converted to an integer type and stored, the accuracy of the fractional part corresponding to the power of 16 can be obtained. This method has the disadvantage of limiting the numeric value since the available range of the integer part is up to 15 power of 2, and it is easy to cause overflow in operations such as multiplication and addition. Using it will almost always restore the approximation.

In addition, the line extraction may be performed by connecting two control points (starting point and end point) to each other by looking at the command L inputted together with the control point.

The Y buffer input in step S109 is as follows.

By drawing a path outline using the above lines and curves, the path is divided into an inner region and an outer region. The graphics engine fills the internal region with the desired pixel values, which the present invention uses to populate the pixel values using the Y buffer method. This method is to store the X value corresponding to the value of the screen size in the buffer based on the Y value of the screen size.

In order to know the area of the path, the size of the buffer that stores the value needs the frame buffer size equal to the size of the screen size.

However, since the graphics engine to which the present invention is applied is used in a mobile environment, a large memory cannot be used. Accordingly, the method of using the Y buffer may be applied, and the method of using the buffer having the height of the frame buffer vertically and having an arbitrary value horizontally matched thereto may reduce the size of the buffer. During rendering, the engine can determine the inner region of the path by looking for X values mapped to each Y value by looping through the Y height.

If there is a line as shown in FIG. 4A, the area occupied by the line having the start points 50 and 250 and the end points 250 and 10 is X is 300, and Y is to store 200, as shown in (b). Using a regular buffer will use up all 300 * 200 memory sizes. However, using the Y buffer like (c) requires 200 x 2 memory.

Using the Y buffer like this stores the start and end points of the line in the buffer. That is, after providing a buffer of vertical * constant value, the X value corresponding to the Y coordinate corresponding to the start and end points of the line is stored.

When there is a figure as shown in (a) of FIG. 5, when three points (50,150) (250, 10,) (270, 15) are to be stored, a size of 300 * 200 when using a general buffer as shown in (b) Memory is required. However, using the Y buffer like (c) requires 200 * 3 memory.

And, when determining the area of the figure as shown in FIG. 5 (a), it is possible to know the X value for the Y value, which searches for the X value to be used while scanning the Y value, and displays the corresponding X value on the screen. If you take a picture, a line is formed. In other words, by using the Y buffer, it scans the Y value and compares the two points with the X value so that the internal area of the figure can be understood.

Using these Y-buffers, you can't apply a 3 * 3 mask that examines each adjacent direction of the pixel (e.g. 8 directions) because you know only the information in the corresponding X coordinates, rather than using a complete image buffer.

Thereafter, the blending process of step S111 is as follows.

In the present invention, if a decimal arithmetic expression is converted to an integer arithmetic expression, a loss of value occurs and a neat outline is drawn. In order to solve this problem in other graphics engines, various methods of blending are used. In the present invention, a method of converting a mean-filter is used. Here, the center filter is a filter having a 3 * 1 size mask to fit the Y buffer. In other words, if a 3 * 3 mask is used, when applied to the Y buffer, the Y value is scanned from top to bottom.

The mask of the 3 * 1 sized center filter checks the left and right values of the starting point or the ending point pixel and fills the starting point or the end point with the average value thereof. In other words, it can be called anti-aliasing.

Subsequently, the filling method into the screen buffer of step S113 uses a stroke.

A typical stroke is a basic attribute of a path. This is a method of making a path having a unique area by giving an outline L2 and an inner line L1 to the path as shown in FIG. 6. In the present invention, after connecting the water line to the start and end points of the path configuration line and curve, it can find the outline (L2) and the inner line (L1) of the path by finding a point corresponding to the stroke thickness. The outline and the outline are obtained by Equations 1 and 2, and the control points used are obtained by using the equation of stroke thickness and intersection point. This reflects the stroke thickness in the control point (P) of the figure to obtain a new control point (P, P ') for the outline and the inner line.

In other words, a stroke may be referred to as an outline of a figure, and the figure in the drawing is a path, and in order to obtain an outline of the figure, an inner outline and an outer outline of the figure are required. The outline of the figure can be obtained using the outline and the outline, and as shown in FIG. 6, one figure can be obtained by using only the border without filling the inner region 110, and the figure is referred to as a stroke region.

Specifically, in the method of filling the stroke inner region, when the outline and the outline of the path are obtained, the region of the stroke is determined, and in the present invention, to fill the stroke, the inner region of the stroke is filled using a non-zero method. do. This is a method of determining the area by the value of the slope of the line.

The zero-zero method of the present invention defines a weight buffer, and then loops corresponding to the same height as the Y buffer and fills the buffer with +1 if the slope value of each Y value is positive and -1 if the slope is negative. Next, if the sum of the inclination values is 0, the two points become points on the outline and the inner line of the stroke, and it is determined that the two points are the inner region of the stroke. If the even-odd method without the weight buffer is used, the determination of the inner and outer regions of the stroke becomes unclear when the stroke intersection occurs.

As shown in Fig. 7 (a) and (b), when it is a circle, it becomes a path which consists of a curve which has a control point P, and when it is a hexagon, it consists of a line. After calculating the outlines and outlines of these curves and lines, the area inside the stroke is filled.

When the outline L2 and the inner line L1 of the circle are obtained as shown in FIG. 8, one figure 100 is completed by filling the inner region 110.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

According to the path rendering method of a two-dimensional object in the portable terminal according to the present invention, while providing a graphics engine for quickly and accurately drawing a path, it can be effectively used for rendering the two-dimensional graphics engine in a mobile environment.

Claims (5)

In the path rendering method of a two-dimensional object in a mobile terminal, Receiving a control point and a command for a 2D object from a user; Checking a curve or line of a path from the user command, extracting a line-based curve configuration line using the control point in the case of a curve, and extracting a line using the control point in the case of a line; If an outline of a path corresponding to the extracted line is drawn, searching for an X value mapped to each Y value in a buffer by rotating a loop corresponding to a Y height for an area inside the path; And determining a stroke area by using outlines and outlines of the path, and filling a stroke inside area. The method of claim 1, The method for controlling the number of points constituting the curve by the line-based curve construction line extraction is multiplied by an integer that can guarantee the number of digits up to the second decimal point, and converted into an integer type and then stored. Path rendering method of a two-dimensional object in a mobile terminal. The method of claim 1, The storing in the buffer may include storing an X value corresponding to the value in the Y buffer based on the Y value of the screen size. The method of claim 2, In order to solve the problem of the loss of pixel values in the mask resulting from the conversion to the integer operation, blending by using a center filter having a mask of the size 3 * 1 further comprises Path rendering method. The method of claim 1, And the path stroke area uses a non-zero method.

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