KR100653514B1 - A figure drawing method - Google Patents

Abstract

A method for drawing a figure is provided to display the figure at high speed even without calculation of floating point by displaying the pixels, which satisfy a predetermined inequality condition, on a display. An input value for drawing a desired figure is received, and then a linear or circular equation is calculated(102). One pixel is selected among plural pixels for a display, and then it is tested whether the selected pixel satisfies an inequality condition, which is obtained by the input values and the linear or circular equation(105). If the selected pixel satisfies the inequality condition, a color of the selected pixel is converted into a data value(106).

Description

{Figure Drawing Method}

1 is a flowchart for explaining a straight line drawing method according to the present invention;

2 is a flowchart illustrating a circle drawing method according to the present invention.

The present invention relates to a figure drawing method such as a straight circle and a computer recording medium on which the same is drawn. More particularly, the present invention relates to a method for drawing a figure such as a straight line in a display device having a limited number of pixels, To a figure drawing method capable of easily displaying a figure and a recording medium on which the figure is drawn.

BACKGROUND ART [0002] With the recent development of the computer graphics field, the importance of graphic accelerators, which determine the speed of the graphics processing, is increasing. Among them, the line drawing engine, which determines how fast a line drawing is performed within a limited time, plays an important role in evaluating the performance of a graphics accelerator.

The Bresenham algorithm is a representative technique for implementing a line drawing engine used to draw shapes based on lines.

식에서 x, y 값을 계산한 후 반올림 등을 통해서 적절한 픽셀 위치를 정한 후, 모두 메모리에 저장했다가 디스플레이한다.In the conventional Bregenz algorithm, given a pixel position ending at the starting pixel position, the pixels constituting the straight line are calculated according to an algorithm, and then all the positions of the linearly arranged pixels are stored in the memory and displayed. For example, when a circle is drawn by the conventional Bregenz algorithm, the pixels located at the center pixel position (a, b) by a radius r are searched

After calculating the x and y values in the equation, the appropriate pixel positions are determined through rounding or the like, and then all of them are stored in the memory and displayed.

Therefore, the conventional Bregenz algorithm has a problem in that the processing speed is lowered because the information must be stored in the memory continuously and the floating point must be computed continuously until the figure to be drawn is drawn at present.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display device having a limited number of pixels to display a graphic object such as a straight line or a circle, And displaying the pixels satisfying the inequality on the display, thereby providing a graphic drawing method and a recording medium on which the graphic drawing can be recorded.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a graphic drawing method applied to a graphics accelerator, comprising: a first step of receiving an input value for drawing a desired graphic form and calculating a linear or circular equation; Selecting one of the pixels of the display and checking whether the input value and an inequality condition obtained by the linear or circular equation are satisfied; A third step of changing the color of the selected pixel to a desired data value when the selected pixel satisfies the inequality condition in the second step; And a fourth step of performing the second step and the third step for all the target pixels.

According to another aspect of the present invention, there is provided a computer-readable storage medium storing a program for causing a computer to execute: a first step of receiving an input value for drawing a desired graphic form and calculating a linear or circular equation; Selecting one of the pixels of the display and checking whether the input value and an inequality condition obtained by the linear or circular equation are satisfied; A third step of changing the color of the selected pixel to a desired data value when the selected pixel satisfies the inequality condition in the second step; And a fourth step of performing the second step and the third step with respect to all the target pixels. The computer readable recording medium records the program.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart for explaining a straight line drawing method according to the present invention.

The process of drawing a straight line according to the present invention will be described with reference to FIG. When the starting pixel coordinates (x1, y1) and the end pixel coordinates (x2, y2) for drawing a straight line are input (101), the linear equation is calculated by the following Equation 1 using the input starting pixel coordinate value and the end pixel coordinate value (102).

y - y1 = {(y2 - y1) / (x2 - x1)} x -

0 = {(y2 - y1) / (x2 - x1)} x - x1 - y -

If a pixel color at a position corresponding to the (x, y) value satisfying the above linear equation is changed to a desired data value, a straight line can be drawn. However, since the (x, y) coordinates of a pixel are integers, if a line is drawn with (x, y) pixels satisfying the above expression, the shape of the line is not continuous and it must be sparsely drawn. In order to solve this problem, a floating point has been conventionally calculated. However, in the present invention, an inequality is calculated without calculating a floating point, and a color of pixels satisfying the inequality is changed to a desired data to display a straight line. This will be described in detail as follows.

After calculating the linear equations using the input coordinate values as described above, (102), it is determined whether or not the pixels in the rectangle having the starting pixel coordinates and the end pixel coordinates as diagonal lines are referred to as pixels constituting a straight line (103). The reason for limiting the pixels to be referred to in this way is to reduce the number of clocks according to the inquiry.

Then, one pixel among the set reference pixels is selected (104) and it is checked whether an inequality (105) as shown in the following Equation (2) is satisfied.

-1 <{(y2-y1) / (x2 - x1)} x - x1 - y -

- (x2 - x1) <{(y2 - y1) x (x - x1)

(X2 - x1)} + (x2 - x1)} - {(y - y1)

x2 - x1) < (x2 - x1) - (y2 - x1)

x2-x1) - (x2-x1) < = (y2-y1)

If the selected pixel (x, y) satisfies the inequality condition of Equation (2), the color of the corresponding pixel is changed to a desired data value (106). As a result, a straight line is displayed on the display.

On the other hand, if the selected pixel does not satisfy the inequality condition or the color of the pixel is changed to a desired data value, it is checked whether all the target pixels set in step 103 satisfy the inequality (107) The next pixel is selected (108) sequentially to check if the inequality condition is satisfied. And ends when it has completed for all target pixels.

FIG. 2 is a flowchart illustrating a process of drawing circles according to the present invention.

In the process of drawing a circle, the center coordinates (a, b) and the radius (r) of the circle are input (201), and the circular equation is calculated using Equation 3 using the input values 202).

In order to reduce the number of clocks according to the inquiry, pixels in a rectangle having a straight line spaced by a radius in the center pixel coordinates are set as an object of inquiry (203), and one pixel of the set target pixels is selected (204 ).

Then, it is checked whether the selected pixel satisfies the inequality condition (Equation 4) (205).

If the selected pixel (x, y) satisfies the inequality condition of Equation (4), the color of the corresponding pixel is changed to a desired data value (206). As a result, a circle is displayed on the display.

On the other hand, if the selected pixel does not satisfy the inequality condition or the color of the pixel is changed to a desired data value, it is checked whether all pixels set in the step 203 satisfy the inequality (207) The next pixel is sequentially selected 208 to check if the inequality condition is satisfied. And ends when it has completed for all target pixels.

On the other hand, the following Equation (5) can be rearranged as shown in Equation (6).

r-1 < r < 1 + r

In other words, the pixels farther from r-1 and closer to r + 1 in the center form a circle.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

As described above, in the display device having a limited number of pixels, when displaying a figure such as a straight line or a circle, it is determined whether or not any of the pixels satisfies the condition of inequality, It is possible to display a graphic object at a high speed without calculating a floating point.

Claims (6)

A graphic drawing method applied to a graphics accelerator, A first step of receiving an input value for drawing a desired figure and calculating a linear or circular equation; Selecting one of the pixels of the display and checking whether the input value and an inequality condition obtained by the linear or circular equation are satisfied; A third step of changing the color of the selected pixel to a desired data value when the selected pixel satisfies the inequality condition in the second step; And And a fourth step of performing the second step and the third step on all the target pixels. The method according to claim 1, After the first step, In order to reduce the number of required clocks, in the case of a straight line, Further comprising defining the starting pixel coordinates and the end pixel coordinates as pixels in a rectangle diagonally. The method according to claim 1, After the first step, In order to reduce the number of required clocks, Further comprising the steps of: defining pixels in a rectangle having a straight line spaced by a radius in the center pixel coordinates as one side. 3. The method of claim 2, In the second step, The inequality for checking whether the selected pixel (x, y) is contained in a pixel constituting a straight line when the starting pixel coordinate is (x1, y1) and the end pixel coordinate is (x2, y2) And the like. -1 <{(y2-y1) / (x2 - x1)} x - x1 - y - The method of claim 3, In the second step, The inequality for checking whether the selected pixel (x, y) is contained in the pixels constituting the circle is given by the following equation (8) when the center coordinates of the circle are (a, b) and the radius is r &Lt; / RTI &gt;

On the computer, A first step of receiving an input value for drawing a desired figure and calculating a linear or circular equation; Selecting one of the pixels of the display and checking whether the input value and an inequality condition obtained by the linear or circular equation are satisfied; A third step of changing the color of the selected pixel to a desired data value when the selected pixel satisfies the inequality condition in the second step; And And a fourth step of performing the second step and the third step for all the target pixels.

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