JP2695081B2 - Window system reduced image creation 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 method of creating a reduced image in a server type window system.

[0002]

2. Description of the Related Art A window system has been established as a user interface because it can efficiently use a display screen, can improve operability, can display at high speed, and can display various screens. In addition, for the reason of reducing the load on the application program, increasing its ease, and the like, a window server (software) for exclusive access to the frame buffer is provided separately from the application program. Window systems are being adopted.

First, a server type window system will be described.

When using a server-based window system, a user runs a window server. The window server receives a connection request from one or more clients (the application program that uses the window function is called in this way) and establishes a communication path to the client that has requested the connection. Through this communication path, the window server receives a request from a client (a window creation request, etc.), performs processing according to the request, and returns a response. The window server also sends an event (for example, a notification that the user has operated a mouse button) to the client using this communication path.

Since the communication path can be set up via the network, the client can be installed in either the same machine as the window server or a different machine.

FIG. 2 shows a configuration example of a window system in which a client and a window server are mounted on different machines. The window server 1 is installed in a workstation 4 having a bitmap display 2 and an input device (keyboard or mouse) 3, while the client 5 is installed in another workstation 6. The workstations 4 and 6 are connected by the network 7.

In such a case, the user activates the window server 1 on the workstation 4 and then activates the client 5 on the workstation 6. And
When the communication path between the client 5 and the window server 1 is established, the window server 1 displays the window corresponding to the client 5 on the screen of the display 2. When the user operates the window using the input device 3, such information is transmitted from the window server 1 to the client 5 as an event. The client 5 processes the received event and displays the output on the window.
Send a request to. The request sent from the client 5 to the window server 1 is “copy rectangular area between windows”, “draw line on window”,
Basically, the content is "write a character on the window". The client 5 can combine and send many requests, and the window server 1 performs a corresponding process to provide an appropriate screen display to the user and send back a response to the client 5.

By the way, the image displayed on the window is reduced by the processing of the client 5.

In the server type window system, two methods have been conventionally proposed as a method for reducing an image displayed on a window. Hereinafter, description will be made in order.

FIG. 3 is a flowchart showing the first reduced image creating method. In this first reduced image creating method, first, all the image data is transferred from the window server 1 to the client 5 (step 10).
0). Then, the client 5 performs a process of forming a reduced image (steps 101 to 106). That is, when reducing the area of width W and height H to 1 / N,
A reduced image having a width W / N and a height H / N is created by taking out every N pixels horizontally. After that, the completed reduced image is transferred to the window server 1 and displayed (steps 107 and 108).

FIG. 4 is a flow chart showing the second reduced image creating method. In the second reduced image creation method, first, an area for reduced images is prepared on the window server 1 (step 200). Then, a reduced image is created by extracting every N pixels in the vertical and horizontal directions from the original image data and copying them to the prepared area (steps 201 to 206). The window server 1 cannot operate once, and the client 5 issues a copy request to perform area copy processing (step 202). Finally, display the reduced image on the window (step 2
07).

[0012]

However, each of the conventional reduced image forming methods has a problem.

In the first reduced image creating method,
It is necessary to transfer the image data twice from the window server 1 to the client 5 and from the client 5 to the window server 1. Since the image is composed of a large amount of information, problems such as increase of data transfer time and increase of network traffic occur.

In the second reduced image creating method, the client 5 needs to send one area copy request to the window server 1 in order to copy one pixel, so that a large number of copy requests are issued as a whole. I have to send. For example, in the case of reducing the area of width W and height H to 1 / N, only WH / N ² copy requests must be transmitted. Therefore, it takes a considerable amount of time to transfer the request and its response, and it takes a lot of time for the window server 1 to evaluate and judge the request content. Therefore, the efficiency is low and the processing speed is slow.

The present invention has been made in consideration of the above points, and provides an efficient window system capable of quickly obtaining a reduced image without transferring image data between the window server and the client. It is intended to provide a reduced image creation method.

[0016]

In order to solve such a problem, according to the present invention, in a reduced image creating method of a window system according to a server method capable of copying a rectangular area between window images, areas in the following order By copying, original image data is reduced at a predetermined reduction ratio to obtain reduced image data.

That is, the pixels in one or more rows (or columns) of the original image data on the window server are taken out and copied to another first area on the window server, and the pixels are vertically (or horizontally) reduced. The created image data. Next, the pixels in one or more columns (or rows) of the image data in the first area on the window server are taken out and copied to another second area on the window server to repeat the horizontal (or vertical) direction. ) To create the reduced image data.

[0018]

In order to avoid transferring a large amount of image data between the window server and the client, the present invention utilizes the copy function of the rectangular area between the window images to reduce the original image data at a predetermined reduction ratio. We decided to obtain the reduced image data.

A rectangular area including pixels in one or more rows and a rectangular area including pixels in one or more columns are used as copy areas so that one copy area is as large as possible. Since two types of rectangular areas in the row direction and the column direction are selected as copy areas in this way,
Since a plurality of copy areas are selected for the image data, it is necessary to determine the copy order. In the present invention,
The pixel data of one or more rows (or columns) of the original image data on the window server is taken out and copied to another first area on the window server to create image data reduced in the vertical direction (or horizontal direction). And then
The pixels in one or more columns (or rows) of the image data of the first area on the window server are taken out and copied to another second area on the window server, and reduced in the horizontal direction (or the vertical direction). I decided to create the image data.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. Also in the configuration of the window system to which the reduced image creating method of this embodiment is applied, it is assumed that the window server 1 and the client 5 as shown in FIG. 2 are installed in separate workstations 4 and 6.

The reduced image creating method of this embodiment also basically uses the area copy request issued by the client 5. However, the method of selecting the copy area is different from the above-described second conventional reduced image creating method. Actually, in the case of the server type window system, various types have been proposed in which the client 5 can issue a copy request instructing copying of a rectangular area.

FIG. 1 is a flow chart showing a reduced image creating method according to this embodiment, and FIGS. 5 and 6 are explanatory views of area copying by the processing. Hereinafter, the process of the embodiment will be described with reference to FIG. 1 and appropriately using FIGS. 5 and 6. It is assumed that the original image data having the width W and the height H (area A: existing in the memory) is reduced to 1 / N (N is an integer of 2 or more).

In FIG. 1, the client 5 first
An area B of vertical H / N and horizontal W pixels is prepared on the window server 1 (step 300). Then, the vertical parameter I is set to an initial value 0 (which indicates the first row) (step 301).

After that, an area copy request for copying the rectangular area pixels in the area A determined by the vertical parameter I to the rectangular area in the area B determined by the vertical parameter I (this request is a one-way request with no response). ) Is given to the window server 1 (step 3)
02). That is, the coordinates of the upper left corner of the area A are (0, N ×
I) with a width W and a height of 1 in a rectangular area (pixels for one row), and the coordinates of the upper left corner of the area B is (0, I) with a width of W and a height. Is copied to the rectangular area of 1. FIG. 5 shows the contents of such a copy. Pixels in the rectangular area A1 in the area A, that is, pixels for one row are copied to the rectangular area B1 in the area B.

When such a region copy for one line is requested, the client 5 increments the vertical parameter I and then determines whether or not the region B is completely filled with pixels. And the line number H / N (H / N represents the line next to the last line because the first line is 0) (steps 303 and 30).
4). As a result, when the area B is not completely filled with pixels, the process returns to step 302 described above, and the area copy request is transmitted.

By repeating such a processing loop, the pixels for one row for every N rows in the area A are copied to the area B at intervals, so that the original image data in the area A is vertically oriented. The image data reduced to 1 / N is stored in the area B. In this way, when the region B is filled with the pixels of the image data reduced to 1 / N in the vertical direction, the process proceeds to the reduction process in the horizontal direction after step 305.

In the horizontal reduction processing, the client 5 first prepares an area C of vertical H / N and horizontal W / N pixels on the window server 1 (step 305). Then, the lateral parameter J is set to the initial value 0 (which indicates the first column) (step 306).

Thereafter, an area copy request for copying the rectangular area pixels (pixels for one column) in the area B determined by the lateral parameter J to the rectangular area in the area C determined by the lateral parameter J is given to the window server 1. (Step 307). That is, a pixel in a rectangular area having an upper left corner of the area B of (N × J, 0), a width of 1 and a height of H / N, and an upper left corner of the area C has a coordinate of (J, 0). )
The width is 1 and the height is H / N. FIG. 6 shows the contents of such a copy.
Pixels in the rectangular area B2 in the area B, that is, pixels for one column are copied to the area C1 in the area C.

When the area copy for one column is requested, the client 5 increments the horizontal parameter J and then determines whether the area C is completely filled with pixels. Column number W / N (where the first column is 0, so W / N represents the column next to the last column).
9). As a result, if the area C is not completely filled with pixels, the process returns to step 307 and the area copy request is transmitted.

By repeating such a processing loop, the pixels for one column for every N columns of the region B are copied to the region C at intervals, and finally, the image data of the region B is 1 in the horizontal direction. The image data reduced to / N is stored in the area C. The image data stored in the area C is reduced by 1 / N vertically and horizontally as viewed from the original image data stored in the area A.

In this manner, when the image data obtained by vertically / horizontally reducing the original image data by 1 / N is stored in the area C (negative result at step 309), the reduced image data is displayed on the window and a series of data is displayed. The process of creating the reduced image is finished (step 310).

Therefore, according to the above-described embodiment, since a large amount of image data is not transferred between the window server 1 and the client 5, the process of creating a reduced image can be speeded up in this respect.

Also, since the region copy request requires a row or column copy rather than a single pixel copy,
The number of area copy requests transmitted from the client 5 to the window server 1 can be significantly reduced as compared with the conventional case. Therefore, it is possible to reduce the total transmission / reception time of the request and the total time for interpreting the request, and from this point, it is possible to efficiently create the reduced image. Incidentally, when the original image data of width W and height H is reduced to 1 / N both vertically and horizontally, the total number of copy requests is W · H / N ² according to the second conventional reduced image creating method. On the other hand, according to the method of this embodiment, W / N + H / N.

In the above embodiment, the case where the window server and the client are mounted on different machines has been described, but the present invention can be applied even when they are mounted on the same machine.

Further, in the above-mentioned embodiment, the case where the reduction in the horizontal direction is performed after the reduction in the vertical direction is shown.
On the contrary, the reduction in the horizontal direction may be performed first.

Further, in the above embodiment, one row or one column of pixels is used as a copy unit.
Pixels of two rows or more or two columns or more may be used as a copy unit. For example, when the reduction ratio is 2/3, it is preferable from the total number of copy requests to set pixels in two rows or two columns as a copy unit. Further, for example, when the reduction ratio is 3/5, a copy in which pixels of two rows (or two columns) are used as a copy unit is set to 1
From the total number of copy requests, it is preferable to alternately repeat the copy in which the pixels of the row (or one column) are set as the copy unit.

Further, in the above-mentioned embodiment, the case where the reduction ratios in the vertical direction and the horizontal direction are the same is shown, but the present invention can be applied to the case where the reduction ratios in the vertical direction and the horizontal direction are different. .

[0038]

As described above, according to the present invention, the pixels in one or more rows (or columns) of the original image data on the window server are repeatedly copied to another first area on the window server. The image data reduced in the vertical direction (or the horizontal direction) is created, and then the pixels in one or more columns (or rows) of the image data in the first area on the window server are transferred to other second pixels on the window server. By repeating copying to the area to create the image data that is reduced in the horizontal direction (or the vertical direction) and obtaining the reduced image data in which the original image data is reduced at a specified reduction ratio, it is efficient and fast. You can create a reduced image.

[Brief description of the drawings]

FIG. 1 is a flowchart showing processing of an embodiment system.

FIG. 2 is a block diagram showing a configuration of a window system.

FIG. 3 is a flowchart showing processing of a conventional first method.

FIG. 4 is a flowchart showing processing of a second conventional method.

FIG. 5 is an explanatory diagram of area copying in the vertical direction according to the embodiment.

FIG. 6 is an explanatory diagram of area copying in the horizontal direction according to the embodiment.

[Explanation of symbols]

1 ... Window server, 4, 6 ... Workstation,
5 ... client, A1, B2 ... copy source rectangular area,
B1, C1 ... Rectangular area of copy destination.

Claims (1)

(57) [Claims] 1. In a reduced image creating method of a window system according to a server method capable of copying a rectangular area between window images, pixels of one or more rows (or columns) of original image data on the window server are extracted to obtain the window server. By repeating copying to the other first area above, image data reduced in the vertical direction (or horizontal direction) is created, and one or more columns (or rows) of the image data of the first area on the window server are created. Image data that is reduced in the horizontal direction (or vertical direction) is created by repeatedly extracting pixels and copying it to another second area on the window server, and reducing the original image data by a prescribed reduction ratio. A window system reduced image creation method characterized by obtaining image data.