JPS59188761A - Write system of picture memory - Google Patents

Abstract

PURPOSE:To apply smearing-out at high speed by obtaining in advance an address of a start point group and an end point group of plural straight lines so as to provide the corresponding address of the start point and the end point sequentially to a straight line drawing circuit in smearing out an area by plural straight lines. CONSTITUTION:A CPU1 calculates the address of both end points A and B of the start point group of a smear-out area from a data read out of a memory 2 and outputs the result to a register 6. A straight line drawing circuit (DDA)3 calculates an address of each dot on a straight line AB based on the data in the register 6 and stores the result in a memory 5. This is performed similarly as to the end point group, and an address of each dot on a straight line CD is stored also in the memory 5. Then, the CPU1 extracts the address of the start point and the end point corresponding thereto from the memory 5 and gives the address to the register 6, and a data is written on a picture memory 4 via the DDA3. The CPU1 sets the address of the next start point and end point to the register 6 during the operation of the DDA3.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical Field of the Invention The present invention relates to a writing method for an image memory, and more particularly to a writing method for an image memory that can fill out image data at high speed.

(B) Prior Art and Problems FIG. 1 is a block diagram for explaining a conventional image memory writing method. In the drawing, 1 is a CPU, 2 is a memory, and 4 is a linear drawing circuit. (hereinafter referred to as DDA), 4
is the image memory.

Further, FIG. 2 is a diagram for explaining a filled area in the image memory 4. As shown in FIG. 4 is an image memory, 5 is a starting point, 6 is an end point, and 7, which is indicated by diagonal lines, is a filled area. Conventionally, in order to fill in the inside of the 2-image memory 4, the CPU calculates the starting point 5 and end point 6 of one line (raster) of the filling area using the data read out from the memory 2, and notifies the DDA 3 of this calculation result. Data was written in the shaded area 7 in the image memory 4 shown in FIG. In this case, since writing to the image memory by the DDA 3 is extremely fast, the processing time depends on the calculation time of the starting point 5 and ending point 6 in the CPUI. However, in order to perform high-speed calculations, expensive microprocessors are required.

Even with such an expensive microprocessor, it was difficult to obtain sufficient speed.

(C) Object of the Invention In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a writing method for an image memory that can fill the image memory at high speed and at low cost.

(D) Structure of the Invention The purpose of the invention is to provide an image memory that stores image data in the form of a hint map, and a straight line drawing circuit that generates the address of a dot representing a straight line between the two points by giving the address of two points. An image memory writing method for writing data representing a filled-in figure into the image memory, the method further comprising address generation means for obtaining addresses of a starting point group and an ending point group constituting the filled-in figure in advance. , A corresponding set of addresses of the starting point and the ending point among the addresses of the starting point group and the ending point group obtained by the address generating means are sequentially sent to the straight line drawing circuit, and the filled image is stored in the image memory. This is achieved by providing an image memory writing method characterized by writing data representing a figure.

(E) Embodiments of the Invention One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 3 is a block diagram for explaining one embodiment of the present invention, and FIG. 4 is a diagram for explaining the operating procedure of CPtJ at that time. In the drawings, parts that are the same as those in FIG. 1 are designated by the same numbers. Further, in FIG. 3, 5 is a memory and 6 is a register. 7 is an address generation means, DD
It consists of A3, memory 5, and register 6.

Next, the configuration and operation of the block diagram in FIG. 3 will be explained with reference to FIG. 4. The CPU calculates the starting points (points A and B shown in FIG. 4) based on the data read from the memory 2, stores them in the register 6, and drives the DDA. D.D.A.
The starting point sequence (addresses of each dot on the straight line from point A to point B) is calculated and output to the memory 5 and stored. Similarly, the CPU 1 calculates the 0 point and the D point, stores them in the register 6, and drives the DDA 3. Then, using DDA3, the end point string (
The address of each dot on the straight line from point 0 to point D is calculated and outputted to the memory 5 as well.

Remember. Next, the CPU reads out the addresses of the start and end points of one line (points connected by broken lines in FIG. 4) from the memory 5, sets them in the register 6, and drives the DDA3. The DDA 3 calculates the address of each dot on the broken line shown in FIG. 4 and writes it into the two-image memory 4. While the DDA 3 is writing data to the image memory 4, the CPIJI is the starting point of the next set.

The end point is read from memory 5 and placed in register 6. Thereafter, the same operation is repeated, and when points B and D are read out, the CPUI ends the operation.

Next, another embodiment will be described. The output of the DDA is the address of the image memory 4, which requires several bytes of memory. Therefore, if this is written directly to the memory 5, the capacity of the memory 5 will become large. However, since the address output by the DDA displays a straight line, the addresses of adjacent bits are output sequentially, so the address The amount of change changes by at most ±1 in both the X and Y directions.Therefore, if only the amount of change in the address is stored in the memory 5 instead of the address, the memory capacity can be significantly reduced.

As another embodiment, the object of the present invention can be achieved by adding two DDAs similar to DDA 3 in place of the memory 5 and register 6 shown in FIG. That is, the address generating means 7 is composed of three DDAs. , and in FIG. 4, there are provided a first DDA that calculates a starting point sequence by giving addresses A and B, and a second DDA that calculates an ending point sequence by giving an address C7D. and the first D to the third DDA
Two points of address (starting point and ending point of the broken line shown in FIG. 4) are given from DA and second DDA, and an address of a straight line between these two points is generated.

(F) Effects of the Invention As explained in detail above, according to the present invention, the CPU does not calculate the starting point and ending point of a straight line one by one, and the DDA
Since the addresses of the start point string and end point string are determined by and stored in the memory, the image memory can be filled in quickly.

Furthermore, by storing only the changes in the address in the memory, the memory capacity can be significantly reduced and costs can be reduced.

[Brief explanation of the drawing]

Figure 1 is a block diagram for explaining the conventional image memory writing method, Figure 2 is a diagram for explaining a filled area in the image memory, and Figure 3 is for explaining the image memory writing method according to the present invention. FIG. 4 is a diagram for explaining the filled area in the image memory of the present invention. In the drawing, 1 is a CPU, and 2.5 is a memory. 3 is a straight line drawing circuit (DDA), and 4 is an image memory. 6 is a register, and 7 is an address generating means.

Claims (1)

[Claims] 1) An image memory that stores image data in the form of a hint map, and a straight line drawing circuit that generates a do-no-do address that represents a straight line between the two points by giving addresses of two points. , an image memory writing method for writing data representing a filled-in figure into the image memory,
an address generating means for obtaining addresses of a starting point group and an ending point group constituting the filled-in figure in advance, and addresses of corresponding starting points and ending points among the addresses of the starting point group and the ending point group obtained by the address generating means; 5. A writing method for an image memory, characterized in that data representing the filled figure is written into the image memory by sequentially writing data representing the filled figure into the image memory. 2) A patent claim characterized in that the address generating means is constituted by the straight line drawing circuit that obtains the addresses of the starting point group and the ending point group, and a memory that stores the addresses obtained by the straight line drawing circuit. The writing method of the image memory according to item 1. 3) The address generation means is characterized by comprising the linear drawing circuit that obtains the addresses of the starting point group and the ending point group, and a memory that stores the displacement amount of the address obtained by the linear drawing circuit. An image memory writing method according to claim 1. 4) The address generating means includes a first linear drawing circuit and a second linear drawing circuit.
Claim 1: The linear drawing circuit comprises a straight line drawing circuit, wherein the address of the starting point group is obtained by the first straight line drawing circuit, and the address of the ending point group is obtained by the second straight line drawing circuit. Image memory writing method described in section.