JPH08123951A - Picture memory state management device - Google Patents

Abstract

PURPOSE: To reduce the frequency in access to a picture memory by storing the recorded or unrecorded state of picture element data in a high-speed and small-capacity state holding memory at the time of accessing the low-speed and large-capacity picture memory. CONSTITUTION: A picture element generator 11 which generates coordinates and picture element data and a picture memory 14 where picture element data is stored are provided. The state that a picture is already recorded is stored in a picture state holding memory 15 with one picture element as the unit. Another picture is generated by the picture element generator 11 and is stored in the picture memory 14. At this time, contents of the picture state holding memory 15 are referred to clear the unrecorded part of coordinates (addresses) of the picture memory 14 by a picture clear device 16. Thus, the clear operation for recording of the next picture is unnecessary, and the picture generation speed is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image memory state management device which has an improved image refresh method in an image memory for displaying computer graphics images.

[0002]

2. Description of the Related Art In recent years, in computer graphics technology, in order to speed up image generation, in addition to speeding up a pixel generation portion, speeding up writing of generated pixels and 2-port for read-out separation. Research has been conducted on such factors as clearing and clearing on a line-by-line basis, and some have been put to practical use.

An example of the above-mentioned conventional image memory management device will be described with reference to FIG. FIG. 11 is a block diagram showing a configuration example of a conventional image memory device management device. In the figure, an image memory 51 is a memory that holds pixel data with two-dimensional coordinates as an address for the generated image. Pixel data means the brightness and translucency of a pixel. Here, the semi-transparency means, for example, in the case of an image in which a semi-transparent image is displayed with respect to the background image, an area contribution rate of the image superposed on the background image in the unit pixel. The pixel generation device 52 is a device that generates an image in frame units such as computer graphics (CG), and generates two-dimensional coordinates of the image memory 51 and pixel data at the coordinates.

The state reading device 53 is a device for detecting the recording state of the image memory 51 and outputting the pixel data generated by the pixel generating device 52 to the writing device 54. The writing device 54 is a pixel generation device when the image read by the state reading device 53 is not completely opaque (for example, when superimposing a character on a background image, zeroing the brightness of the background image of the character portion). This is a device for writing the pixel data generated by 52 to each address of the image memory 51 based on the pixel data read by the state reading device 53. The image clearing device 55 is a device for clearing the state of the image memory 51 to a state in which it has not been written even once.

The operation of the conventional image memory management device thus configured will be described with reference to FIGS. 12 and 13. FIG. 12 is an explanatory diagram showing a storage area of two-dimensional pixel data in the image memory 51. Image memory 51
Has storage areas in the X, Y, and Z directions, and a two-dimensional image is
It is held as pixel data at the two-dimensional coordinate position in the Y direction. In the depth direction (Z direction) of each pixel position, the red luminance R, the green luminance G, the blue luminance B, and the area contribution rate AC indicating the ratio of the area already written in the pixels of the coordinates are stored. There is.

FIG. 13 shows the area contribution ratio A in each pixel.
It is explanatory drawing of C. In CG, the enlarged pixel 61 is often composed of a total of 16 sub-pixels, for example, 4 horizontal and 4 vertical. The generated pixel 62 is pixel data generated by the pixel generator 52, and an image is recorded in a part of the enlarged pixel 61 here.

First, before starting drawing, the image clearing device 55
The data of each pixel in the image memory 51 is initialized to the initial value. Initialization clear is generally performed by setting the values of all pixel data to zero. Next, the image generation device 52 generates an image to be generated for each pixel. The pixel data generated at this time also generates red luminance, green luminance, and blue luminance as luminance data, and an area contribution ratio AC indicating how much the pixel data occupies in each enlarged pixel 61.

The pixel generator 52 also generates an address on the image memory 51 for storing the pixel data. Next, the generated pixel data is first input to the state reading device 53. Next, the pixel data in the image memory 51 is read out based on the address, and the area contribution rate among them is examined. The state reading device 53 adds the generated pixel data to the read pixel data and sends it together with the address to the writing device 54, unless the area contribution ratio is 1, that is, the area cannot be written any more. The writing device 54 writes the pixel data synthesized by the state reading device 53 in a designated storage area of the image memory 51. In this way, the transparent image as the second image is superimposed on the background image which is the first image. After writing the image of one screen (one frame), the image memory 51 outputs it to the outside or stores the pixel data in the external storage device. After that, the image clearing device 55 clears the data in the image memory 51.

[0009]

However, in the above-mentioned configuration, first, the entire screen must be cleared each time, and the clear data is also written to the pixels which are subsequently drawn and overwritten. Therefore, the drawing performance was reduced accordingly. Further, since the recent image memory has a large amount of information of 1 pixel and the number of pixels is very large, it is unavoidable to use a memory which is slower than the data amount. Reading the area contribution rate of the pixel data whose area contribution rate is already 1 reduces the overall performance. Further, when actually using the pixel data of the image memory, the purpose of reading out the pixel data containing only clear data also lowered the overall performance.

The present invention has been made in view of the above-mentioned conventional problems, and a part of the storage state of the pixel data of the image memory is provided to another image state holding memory having a small memory capacity. It is an object of the present invention to realize an image memory state management device capable of reducing unnecessary access to the image memory and improving the overall drawing performance.

[0011]

According to a first aspect of the present invention, an image memory for storing pixel data of at least one screen and an image state for storing whether or not a pixel at each coordinate has already been recorded in the image memory. A holding memory, a flag clearing device that clears all coordinate flags of the image state holding memory to an unrecorded state before creating a new image, and coordinates of images forming one screen and pixel data of each pixel are generated. A pixel generating device, a writing device for recording pixel data of coordinates generated by the pixel generating device in the image memory, and a flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device are changed to recorded. A state changing device, and an image clearing device that checks flags of all coordinates in the image state holding memory after image creation and clears pixel data of unrecorded coordinates in the image memory. It is characterized in that it comprises a.

According to a second aspect of the present invention, there is provided an image memory for storing pixel data of at least one screen, and an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded or can be recorded in the image memory. , An image flag clearing device that clears the pixel data and flags of all coordinates to a recordable state in the image memory and the image state holding memory before creating a new image, and the coordinates of the image forming one screen and A pixel generation device that generates pixel data of a pixel, a flag that is recorded in the image state holding memory at coordinates generated by the pixel generation device, and if possible, writes pixel data in the image memory, and an image state holding device Check the state change device that changes the coordinates generated by the pixel generator of the memory to the recorded state, and check the flags of all coordinates in the image state holding memory after the image is created. Is characterized in that it comprises an image clearing device for clearing the pixel data of the coordinate is not the recorded image memory.

According to a third aspect of the present invention, an image memory for storing pixel data of at least one screen, and an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded in the image memory in units of a plurality of pixels. And a flag clearing device for clearing all flags of the image state holding memory to an unrecorded state before creating a new image, and a pixel generating device for generating coordinates of an image forming one screen and pixel data of each pixel. When,
If the state change device that changes the flag of the image state holding memory including the coordinates generated by the pixel generation device to the recorded state and the flag of the image state holding memory corresponding to the coordinates generated by the pixel generation device are checked, A partial clearing device that clears the pixel data of the image memory other than the generated pixels included in the flag, a writing device that records the pixel data of the coordinates generated by the pixel generating device in the image memory, and an image after the image is created. An image clearing device for checking all the flags of the state holding memory and clearing the pixel data of the coordinates of the image memory belonging to the flag of the unrecorded state.

According to the invention of claim 4 of the present application, an image memory for storing pixel data of at least one screen, an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded in the image memory, and a new image memory. A flag clearing device that clears all coordinate flags of the image state holding memory to an unrecorded state before creating an image; a pixel generating device that generates the coordinates of the image forming one screen and the pixel data of each pixel; A writing device for recording the pixel data of the coordinates generated by the pixel generating device in the image memory; a state changing device for changing the flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device to the recorded state; When reading the pixel data of the memory, check the flag of each coordinate of the image state holding memory,
In the unrecorded state, the image reading device outputs the same pixel data as the cleared pixel data without reading the pixel data of the image memory.

[0015]

According to the first aspect of the invention having such a feature, first, the flag clearing device clears the flags of all the coordinates of the image state holding memory for creating a new image to the unrecorded state. Next, the pixel generation device generates the coordinates of the image forming one screen and the pixel data of each pixel. Then, the writing device records the pixel data of the coordinates generated by the pixel generation device in the image memory. The state changing device changes the flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device to the recorded state. The image clearing device checks the flags of all the coordinates in the image state holding memory after the completion of the image formation, and clears the pixel data of the unrecorded coordinates in the image memory. In this way, the state of each pixel can be checked only by referring to the contents of the image state holding memory instead of referring to the recorded state or unrecorded state of the image memory.

According to the second aspect of the present invention, first, the image flag clearing device can record pixel data of all coordinates in the image state holding memory and the image memory before creating a new image. To clear. Next, the pixel generation device generates the coordinates of the image forming one screen and the pixel data of each pixel. The writing device checks the state of the image state holding memory at the coordinates generated by the pixel generation device, and if possible, records the pixel data in the image memory. Then, the state changing device changes the coordinates generated by the pixel generating device of the image state holding memory to the recorded state. After the image has been created, the image clearing device checks all the coordinates in the image state holding memory and clears the pixel data of the unrecorded coordinates in the image memory.

Further, according to the invention of claim 3 of the present application, the image state holding memory stores whether or not the pixel at each coordinate of the image memory is already recorded in the image memory in units of a plurality of pixels.
Before creating a new image, the flag clearing device clears all flags in the image state holding memory to the unrecorded state. Then, the pixel generation device generates the coordinates of the image forming one screen and the pixel data of each pixel. Next, the state changing device changes the flag of the image state holding memory including the coordinates generated by the pixel generating device to the recorded state. Further, the partial clearing device checks the flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device, and if it is not recorded, clears the pixel data of the image memory other than the generated pixel included in the flag. The writing device records the pixel data of the coordinates generated by the pixel generation device in the image memory. After the image is created, the image clearing device checks all the flags in the image state holding memory and clears the pixel data of the coordinates of the image memory that belong to the unrecorded state flag. This makes it possible to further reduce the memory capacity of the image state holding memory.

Further, according to the invention of claim 4 of the present application, first, the flag clearing device clears the flags of all the coordinates of the image state holding memory to the unrecorded state before creating a new image. The pixel generation device generates coordinates of an image forming one screen and pixel data of each pixel. Then, the writing device records the pixel data of the coordinates generated by the pixel generation device in the image memory. Next, the state changing device changes the flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device to "recorded". When reading the pixel data of the image memory, the image reading device checks the flag of each coordinate of the image state holding memory, and outputs the cleared pixel data without reading the pixel data of the image memory in the unrecorded state. .

[0019]

【Example】

(Embodiment 1) An image memory state management device according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the image memory state management device in the first embodiment. In FIG. 1, a pixel generation device 11 is a device that generates a set of coordinates and pixel data, and the data is given to a writing device 12 and a state changing device 13.
The writing device 12 is a device that writes each coordinate and pixel data generated by the pixel generation device 11 into a low-speed large-capacity image memory (hereinafter referred to as an image memory) 14.

FIG. 2A is a block diagram of the memory area of the image memory 14, and FIG. 2B is a block diagram of the memory area of the image state holding memory 15. Similar to that shown in FIG. 12, the image memory 14 is a memory for storing the generated at least one frame pixel data, and is composed of, for example, a dynamic random access memory (DRAM) which has a low speed but a large capacity. The coordinates of the image of one frame in the image memory 14 are (1, 1) to (m, n), and the bit depth in the depth (Z direction) of each coordinate is 4 × 8.
(8 bits for each of R, G, B, and AC). in this case,
The image memory 14 requires a storage capacity of m × n × 32 bits.

A high-speed small-capacity image state holding memory (hereinafter referred to as image state holding memory) 15 has an area (X, Y) of the same size as the image memory 14 as shown in FIG. It is a memory that stores two states (flags) of whether the pixels of the respective coordinates have been written or have not been written. But Figure 2
Unlike the image memory 14 of (a), the memory depth of each coordinate is shallow. Although the image state holding memory 15 has such a small capacity, it is configured by a memory characterized by high speed access, for example, a static memory (SRAM). The storage capacity of the image state holding memory 15 may be m × n bits.

The state changing device 13 is the image state holding memory 1 at the coordinates (address) generated by the pixel generating device 11.
It is a device that changes the flag of 5 to the state that it has already been written. The image clearing device 16 is a device that checks all the coordinates of the image state holding memory 15 when the image has been written, and clears the pixel data of the coordinates that have not been written yet. The flag clearing device 17 is a device for clearing the pixel data of all the coordinates of the image state holding memory 15 to the unwritten state before writing a new image.

The operation of the image memory state management device of the first embodiment thus constructed will be described with reference to the flowchart of FIG. First, in step S10, the flag clearing device 17 changes the flags of all the pixels in the image state holding memory 15 to the clear state. Next, in step S11, since drawing is performed, an image to be drawn is generated by the pixel generation device 11 for each pixel, and pixel coordinates and pixel data thereof are output. Then, the coordinate data is output to the writing device 12 and the state changing device 13, and the pixel data is output to the writing device 12.

In step S12, the state changing device 13
Changes the flag of the corresponding coordinate in the image state holding memory 15 from the clear state to the state already written based on the input coordinate. Then, in the next step S13, the writing device 12 writes the pixel data in the image memory 14 based on the input coordinates. In this way, all the pixel data to be drawn are written, and it is checked in step S14 whether the writing of pixels has been completed. If writing has not been completed, the process returns from step S14 to step S11, and the same processing is repeated. When the writing of the image is completed, the process proceeds to step 15, and the image clearing device 16 checks the flags of all the pixels of the image state holding memory 15 and clears the pixels of the image memory 14 corresponding to the coordinates in the clear state.

As described above, according to the present embodiment, it is not necessary to perform the clearing operation for the entire screen, which is necessary at the beginning of drawing, and it is sufficient to perform the clearing operation only for the undrawn portion. Therefore, it is possible to significantly reduce the clearing time with respect to the drawing time.

(Embodiment 2) Next, an image memory status management apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the image memory state management device in the second embodiment. The same parts as those in the first embodiment are given the same names and their detailed description is omitted. In FIG. 4, as in the first embodiment, the pixel generation device 2
1, a writing device 22 and a state changing device 23 connected to this
Are provided respectively. The memory areas of the image memory 24 and the image state holding memory 25 are the same as those in the first embodiment. The writing device 22 is a device that checks the flag state of the image state holding memory 25 corresponding to the coordinates output by the pixel generation device 21 and writes the pixel data of the coordinates to the image memory 24 if not written yet.

The state changing device 23 is a device for changing the flag of the image state holding memory 25 corresponding to the coordinates generated by the pixel generating device 21 to a state in which the flag is already written. The image state holding memory 25 is a memory that holds two states of whether a pixel at a certain coordinate on the image has already been written or whether it can be written. The image flag clearing device 26 uses the image state holding memory 25 and the image memory 2 before writing a new image.
It is a device that clears all the pixels at coordinates 4 in the unwritten state.

The operation of the image memory state management device of the second embodiment having such a configuration will be described with reference to the flowchart of FIG. In step S20, the image flag clearing device 26 clears the flags of all the pixels in the image state holding memory 25, and in the next step S21, the clear data is written in all the pixels in the image memory 24. Next, in step S22, the pixel generation device 21 generates an image to be drawn for each pixel, and the pixel coordinates and the pixel data thereof are output. The coordinate data is given to the writing device 22 and the state changing device 23, and the pixel data is given to the writing device 22.

In step S23, the writing device 22
The flag of the image state holding memory 25 is checked based on the input coordinates. If not yet written, the process proceeds from the next step S24 to step S25, and the state changing device 23 changes the coordinate flag of the image state holding memory 25 from the clear state to the already written state based on the input coordinates. . Then, in step 26, the writing device 22 writes the pixel data in the image memory 24. In this way, the processing from step 22 to step 27 is continued until all writing is completed. When the input of all pixel data is completed in step S27, one screen is completed.

As described above, according to this embodiment, the image state holding memory 25 is accessed without reading the image memory 24 to determine whether or not the pixel at the coordinate to be drawn is writable. are doing. Therefore, the drawing speed can be increased. In the present embodiment, the image-state holding memory 25 binarizes and stores whether or not it is writable, but the area contribution rate AC in each pixel may be binarized and stored.

(Third Embodiment) An image memory state management device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the image memory state management device in the third embodiment. The same parts as those in the first embodiment are designated by the same names and detailed description thereof will be omitted. 7A is a block diagram of the memory area of the image memory 35, and FIG. 7B is a block diagram of the memory area of the image state holding memory 36. The memory area of the image state holding memory 36 is smaller than that of the first and second embodiments.
This is a memory that holds the flag, which is smaller than the number of coordinates of the image memory 35, by indicating the recorded or unrecorded state of the pixel data of a plurality of adjacent coordinates of 1 by one flag. Image memory 35
Is a memory having the same memory size as in the first embodiment.

In FIG. 6, similarly to the first embodiment, a pixel generating device 31, a writing device 32 connected to the pixel generating device 31, and a state changing device 34 are respectively provided. The writing device 32 is a device that writes the pixel data of the coordinates generated by the pixel generation device 31 into the image memory 35. Partial clearing device 3
Reference numeral 3 is a device for checking the flag of the image state holding memory 36 corresponding to the coordinates generated by the pixel generating device 31 and clearing the pixel data of the image memory 35 included in the flag if not written yet. State change device 34
Is a device for setting the flag of the image state holding memory 36 including the coordinates written by the writing device 32 to the written state.

In the image state holding memory 36, it is determined whether one or more of the pixels at a plurality of coordinates on the image have been written, or whether any one has not been written yet.
Holds one state. The image clearing device 37 is a device that checks all the flags in the image state holding memory 36 when the image has been written, and clears the pixel data of the coordinates of the image memory 35 belonging to the unrecorded state flags. The flag clear device 38 stores the image state holding memory 3 before writing a new image.
It is a device that clears all 6 flags to the unwritten state.

The operation of the image memory state management device of the third embodiment having such a configuration will be described with reference to the flowchart of FIG. In step S30, the flag clearing device 38 changes the flags of all the pixels in the image state holding memory 36 to the clear state. Next, in step S31, the pixel generation device 31 generates coordinates and pixel data for the area of the image to be drawn. The coordinate data is output to the writing device 32, the partial clearing device 33, and the state changing device 34, and the pixel data is output to the writing device 32.

In step S32, the partial clearing device 33 checks the flag of the image state holding memory 36 corresponding to the generated coordinates. Then, in the next step S33, if the pixel managed by the flag has not been written even once, the process proceeds to step S34, and the flag of the corresponding coordinate is changed to the already written state. In the next step S35, all pixels at the coordinates of the image memory 35 managed by the flag are cleared. Then, in step S36, the writing device 32 writes the pixel data at predetermined coordinates in the image memory 35. The processing in steps S31 to S37 is repeated. Then, in step S38, the image clearing device 37
Is the image state holding memory 3 after writing all the images.
All the flags 6 are checked, and the pixel data other than the corresponding coordinates in the image memory 35 are cleared. In this way, writing of one screen is completed.

As described above, according to this embodiment, it is not necessary to assign the flag of the image state holding memory 36 for each pixel, and the state can be managed by a small capacity memory.

(Embodiment 4) Next, an image memory state management apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram showing the configuration of the image memory state management device in the fourth embodiment. The same parts as those in the first embodiment are designated by the same names and detailed description thereof will be omitted. In FIG. 9, as in the first embodiment, the pixel generation device 4
1, a writing device 42 and a state changing device 4 connected to the device 1.
3 are provided respectively. The memory sizes of the image memory 44 and the image state holding memory 45 are the same as those in the first embodiment.

The writing device 42 is a device for writing the pixel data of the coordinates generated by the pixel generation device 41 into the image memory 44. The state changing device 43 is a device that changes the flag of the image state holding memory 45 corresponding to the coordinates generated by the pixel generating device 41 to a state in which it has already been written.
The image state holding memory 45 is a memory that holds two states of whether a pixel at a certain coordinate on the image has already been written or has not been written yet. The image reading device 46 finishes writing the image, and first checks the flag of the coordinate to be output of the image state holding memory 45 when reading the pixel data of the image memory 44, and if the state has not been written, the image memory The device outputs the same data as the cleared pixel data without reading the pixel data of 44. The flag clearing device 47 is a device for clearing a state in which pixels of all coordinates of the image state holding memory 45 are not written before writing a new image.

The operation of the image memory state management device of the fourth embodiment thus configured will be described with reference to the flowchart of FIG. First, in step S40, the flag clearing device 47 changes the flags of all the pixels in the image state holding memory 45 to the clear state. Then step S4
In step 1, the pixel generation device 41 generates coordinates and pixel data for each pixel of the image to be drawn. Then, the coordinate data is output to the writing device 42 and the state changing device 43, and the pixel data is output to the writing device 42.

In step S42, the state changing device 43 changes the coordinate flag of the image state holding memory 45 from the clear state to the written state based on the input coordinates.
Then, in the next step S43, the writing device 42 writes the pixel data in the image memory 44 based on the input coordinates. In this way, the processes of steps S41 to S44 are repeated to draw all images.

When reading the pixel data recorded in step S45, the image reading device 46 first checks the flag of the image state holding memory 45 corresponding to the coordinates to be read. If it is in the clear state, the process proceeds from step S46 to step S47 to output the clear data without reading the pixel data of the image memory 44. If it is not in the clear state in step S46, the process proceeds to step S48 to read the pixel data in the image memory 44. In this way, the processes of steps S45 to S49 are repeated until all the pixel data are read out. When the reading of all the pixel data is completed in step S49, the pixel data of one screen is displayed on the display device.

As described above, according to this embodiment, the originally necessary clearing operation of the image memory is not performed at all.
You can get the same effect as clearing the whole area or clearing the unwritten area. Therefore, high-speed drawing can be realized.

[0043]

As described above, according to the first aspect of the present invention, the state change device manages the state of clearing or not clearing each pixel drawing by the flag of the image state holding memory. There is. Therefore, after drawing one screen, it is necessary to clear only the pixels of the image memory corresponding to the coordinates in the clear state by referring to the flag of the image state holding memory. This reduces the number of times the image memory is cleared, and high-speed drawing can be performed.

According to the second aspect of the present invention, the image state holding memory and the image memory are cleared before a new image is created. In this case as well, after drawing one screen, high-speed drawing can be performed by referring to the flag of the image state holding memory.

According to the invention of claim 3 of the present application, the memory capacity can be reduced by managing a plurality of coordinate states by using one flag of the image state holding memory.

Further, according to the invention of claim 4 of the present application, when the image is read, the pixel data is output by referring to the corresponding flag of the image state holding memory. Also in this case, since the necessary pixels can be read from the image memory to generate one screen image, the effect of high-speed reading can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of an image memory state management device according to a first exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing memory areas of an image memory and an image state holding memory according to the first embodiment.

FIG. 3 is a flowchart showing the operation of the first embodiment.

FIG. 4 is a block diagram of an image memory state management device according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the second embodiment.

FIG. 6 is a block diagram of an image memory state management device according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram showing memory areas of an image memory and an image state holding memory according to a third embodiment.

FIG. 8 is a flowchart showing the operation of the third embodiment.

FIG. 9 is a block diagram of an image memory state management device according to a fourth exemplary embodiment of the present invention.

FIG. 10 is a flowchart showing the operation of the fourth embodiment.

FIG. 11 is a block diagram of an image memory management device in a conventional example.

FIG. 12 is a memory area X in the conventional image memory,
It is explanatory drawing which shows Y and Z.

FIG. 13 is an explanatory diagram of generated pixels in enlarged pixels.

[Explanation of symbols]

11,21,31,41 Pixel generating device 12,24,32,42 Writing device 13,23,34,43 State changing device 14,24,35,44 Low speed large capacity image memory 15,25,26,45 High speed small Capacity image state holding memory 16,37 Image clearing device 17,38,47 Flag clearing device 21 Two-dimensional image image 22 Pixel data 26 Image flag clearing device 31 Enlarged pixel 32 Generated pixel 33 Partial clearing device 46 Image reading device

Claims (5)

[Claims] 1. An image memory for storing pixel data of at least one screen, an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded in the image memory, and before creating a new image. A flag clearing device for clearing flags of all coordinates of the image state holding memory to an unrecorded state; a pixel generating device for generating coordinates of an image forming one screen and pixel data of each pixel; A writing device for recording pixel data of the generated coordinates in the image memory; a state changing device for changing a flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device to a recorded state; An image clearing device that checks flags of all coordinates of the image state holding memory after completion of creation and clears pixel data of coordinates that have not been recorded in the image memory. An image memory state management device comprising. 2. An image memory for storing pixel data of at least one screen, an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded or can be recorded in the image memory, and a new image is created. Image flag clearing device for clearing the pixel data and flags of all coordinates to a recordable state in the image memory and the image state holding memory, and the coordinate of the image forming one screen and the pixel data of each pixel A pixel generating device that generates a pixel, a writing device that checks a flag of the image state holding memory at the coordinates generated by the pixel generating device, and records pixel data in the image memory if the pixel state can be recorded, A state changing device for changing the coordinates generated by the pixel generating device of the memory to a recorded state; An image memory state management device, comprising: an image clearing device for checking a flag of a mark and clearing pixel data of a coordinate which has not been recorded in the image memory. 3. An image memory for storing pixel data of at least one screen, an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded in the image memory in units of a plurality of pixels, and a new image A flag clearing device for clearing all flags of the image state holding memory to an unrecorded state before creating; a pixel generating device for generating coordinates of images forming one screen and pixel data of each pixel; A state changing device that changes the flag of the image state holding memory including the coordinates generated by the device to a recorded state, and a flag of the image state holding memory corresponding to the coordinates generated by the pixel generation device is checked and must be recorded. For example, a partial clearing device that clears the pixel data of the image memory other than the generated pixels included in the flag, and the coordinates of the coordinates generated by the pixel generating device. A writing device that records pixel data in the image memory, and an image that clears the pixel data of the coordinates of the image memory belonging to the unrecorded state flag by checking all flags of the image state holding memory after the image creation is completed. With a clearing device,
An image memory state management device comprising: 4. An image memory for storing pixel data of at least one screen, an image state holding memory for storing whether or not a pixel at each coordinate has already been recorded in the image memory, and before creating a new image. A flag clearing device for clearing flags of all coordinates of the image state holding memory to an unrecorded state; a pixel generating device for generating coordinates of an image forming one screen and pixel data of each pixel; A writing device for recording pixel data of the generated coordinates in the image memory; a state changing device for changing a flag of the image state holding memory corresponding to the coordinates generated by the pixel generating device to a recorded state; When reading the pixel data of the memory, the flag of each coordinate of the image state holding memory is checked, and if the pixel state is not recorded, the pixel data of the image memory is not read. And an image reading device that outputs the same pixel data as the cleared pixel data, the image memory state management device. 5. The image memory state management device according to claim 1, wherein the image state holding memory is a memory that can be accessed at a higher speed than the image memory.